2.3l Eec Iv Tests W/codes Ford Tempo I

DIAGNOSTIC PROCEDURE

There are 2 diagnostic procedure formats used to test and service the EEC-IV system: QUICK TEST and CIRCUIT TESTS. A DIAGNOSIS BY SYMPTOM test chart is available to identify specific CIRCUIT TESTS.

Always start with the QUICK TEST procedures before attempting any CIRCUIT TESTS. If a vehicle passes the QUICK TEST procedures the EEC-IV system is okay and the problem exists somewhere else besides the EEC-IV system. If an intermittent driveability problem exists, use the KEY ON ENGINE RUNNING (KOER) CONTINUOUS SELF-TEST or WIGGLE TEST to set a code and identify the problem.

Note. Procedures in the TESTING section of this article are not in absolute numerical order. Procedures not related to this engine have been removed to eliminate confusion.

TEST EQUIPMENT

The following equipment is recommended to diagnose and test EEC-IV system. Some equipment is REQUIRED to perform tests. DO NOT attempt to test this system without proper equipment. Damage to vehicle components will result if improper equipment is used.

1. The Self-Test Automatic Read-Out (STAR) Diagnostic Tester (Rotunda 007 00004) is recommended but not required. It is specially built for the EEC-IV system and is used to display the 2-digit (numeral) service codes that are programmed into the control module. There are also a number of aftermarket testers available.
2. Analog Volt/Ohmmeter (VOM) with 0-20V DC range. This can be used as an alternate to diagnostic tester.
3. Digital Volt/Ohmmeter (DVOM) with minimum 10-megohm input impedance.
4. Breakout Box (Rotunda 014-00322). This is a jumper wire assembly which connects between the vehicle harness and the ECA. The breakout box is REQUIRED to perform certain tests on the system. Ford Motor Co. specifically states that using the probe from a DVOM will cause PERMANENT DAMAGE to the ECA 60-pin connector. The "Test Pin No." called out in CIRCUIT TESTS refers to Test Pin numbers on breakout box. Once the breakout box has been installed during a test sequence, it may remain connected for the remainder of that test unless otherwise specified.
5. Vacuum gauge with 0-30 in. Hg range and resolution (units on scale) of 1 in. Hg.
6. Tachometer with 0-6000 RPM range, accuracy +/- 40 RPM, and a resolution of 20 RPM.
7. Vacuum pump with 0-30 in. Hg range.
8. Timing light.
9. Spark tester. A modified side electrode spark plug with the electrode removed and an alligator clip attached may be used.
10. Fuel Injection Pressure Gauge (T80L-9974-A).
11. 12-volt test light (non-powered type).
12. Jumper wire, about 15" long.
13. MAP/BP Tester. This unit plugs into MAP/BP sensor circuit and DVOM to check input and output signals. The MAP sensor produces a frequency signal which may be checked using a scope with a millivolt scale.

SELF-TEST CONNECTOR LOCATIONS

The SELF-TEST connector is found in different locations depending upon model. On most Front Wheel Drive (FWD) models, the SELF-TEST connector is located in the right rear of engine compartment, near firewall.

On Thunderbird models, the SELF-TEST connector is on left front shock tower, above voltage regulator.

All Mustang models have SELF-TEST connector on left rear corner of engine compartment.

DESCRIPTION OF TESTS

The QUICK TEST diagnostic procedure is a functional test of the EEC-IV system. It consists of 4 basic test steps. These basic steps must be carefully followed in sequence, otherwise misdiagnosis, or replacement of non-faulty components may result.

1. «PREPARATION»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__preparation) and «EQUIPMENT HOOK-UP»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
2. «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
3. «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
4. «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) .

After all tests, servicing, or repairs have been completed, repeat

QUICK TEST

to ensure all EEC-IV systems work properly.

The KOEO and KOER SELF-TESTS are intended to detect faults present at the time of testing, not intermittent faults. Intermittent faults are detected by CONTINUOUS SELF-TEST and stored in the ECA memory.

Note. Correct test results for system are dependent on the correct operation of several related non-EEC components and systems. All non-EEC problems should be corrected before attempting to diagnose the EEC system.

PREPARATION

Before hooking up any equipment to diagnose the EEC system, make the following checks

1. Verify condition of air cleaner and air ducting.
2. Check all vacuum hoses for leaks, restrictions, and proper routing.
3. Check the EEC-IV system wiring harness electrical connections for corrosion, bent or broken pins, loose wires or terminals, and proper routing.
4. Check the ECA, sensors and actuators for physical damage.
5. Perform all necessary safety precautions to prevent personal injury or vehicle damage.
6. Set parking brake and place shift lever in "P" for automatic transmissions, and Neutral for manual transmissions. DO NOT move shift lever during testing unless specifically directed to do so.
7. Turn off all lights and accessories. Ensure vehicle doors are closed when making voltage or resistance readings.
8. Check engine coolant level.
9. Start engine and idle until upper radiator hose is hot and pressurized, and throttle is off fast idle. Check for leaks around exhaust manifold, exhaust gas oxygen sensor, and vacuum hose connections.
10. Turn ignition key off. Service items as required, then go to «EQUIPMENT HOOK-UP»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .

Analog Volt/Ohmmeter (VOM)

1. Turn ignition key to "OFF" position. Connect jumper wire from Self-Test Input (STI) pigtail to pin No. 2 (Signal Return) on SELF-TEST connector. Set VOM at 0-15V DC range and connect positive lead of VOM to positive battery terminal.
2. Connect negative VOM lead to pin No. 4 (STO) on SELF-TEST connector. Connect timing light, and go to «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .

STAR Tester

Turn ignition key to "OFF" position. Connect color coded adapter cable leads to diagnostic tester. Connect adapter cable's 2 service connectors to vehicle's SELF-TEST connectors. Connect timing light, then go to KEY ON/ENGINE OFF (KOEO) SELF-TEST .

Note. Diagnostic tester hookup instructions apply to STAR tester only. If other than STAR tester is being used, follow diagnostic tester manufacturer's instructions.

Equipment Hookup. Scheme 2

READING SELF-TEST CODES

Service codes are transmitted to Pin No. 4 (Self-Test Output) of SELF-TEST connector in the form of timed pulses. All service codes are 2 digit numbers which are generated one digit at a time. Codes are shown as voltage pulses (needle sweeps) on an analog Volt/Ohmmeter (VOM).

If a VOM is being used, pay careful attention to the length of the pauses in order to read the codes correctly. There will be a 2 second pause between each DIGIT in a code. There will be a 4 second pause between each CODE. The continuous memory codes are separated from the functional test service codes by a 6 second delay, a single 1/2 second sweep, and another 6 second delay. Always record the codes in the order received.

If a diagnostic tester is used, it will count the pulses and display them as a digital code. The STAR tester will add a zero (0) to single digit (Separator and Dynamic Response) codes. See CODE FORMAT DIAGRAMS in (Scheme 3).

If the "CHECK ENGINE" light is used, numeric service codes will be displayed at the light.

Separator Pulse

A single 1/2 second separator pulse is issued 6-9 seconds after last functional KOEO SELF-TEST code. Then 6-9 seconds after the single 1/2 second separator pulse, the continuous memory codes will be displayed.

Continuous Memory Codes

These codes are issued as a result of information stored during CONTINUOUS SELF-TEST. These codes are displayed during a KOEO SELF-TEST after the separator pulse code. These codes should be used for diagnosis, ONLY when KOEO and ENGINE RUNNING SELF-TESTS result in code 11 and all QUICK TEST steps have been successfully completed.

Note. If engine will not start, starts but stalls, idles rough or runs rough, go through KEY ON/ENGINE OFF (KOEO) SELF-TEST . If any of the above conditions are still present after a code 11 in the KOEO SELF-TEST, go to CIRCUIT TEST A1 for a no start condition. If engine stalls or runs rough, go to DIAGNOSIS BY SYMPTOM table.

Code Format Diagrams. Scheme 3

Note. Correct test results for system are dependent on the correct operation of several related non-EEC components and systems. It may be necessary to correct faults in these areas before EEC-IV will pass QUICK TEST. Verify that vehicle has been properly prepared. See PREPARATION and also EQUIPMENT HOOK-UP . Turn ignition on to start SELF-TEST. DO NOT depress throttle during test. Observe and record all service codes.

Test Procedure

1. Turn ignition switch to "OFF" position. Ensure all procedures of «PREPARATION»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__preparation) and «EQUIPMENT HOOK-UP»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) have been followed. Engine should be at normal operating temperature.
2. Ensure VOM or tester is connected properly. Turn ignition on. If Star Tester is being used latch center button in down position at this time.
3. The ECA will run through a test cycle, opening and closing various solenoids and switches. After the completion of the test cycle the codes will appear. Record all codes.
4. The first set of codes to appear are the KOEO SELF-TEST codes; they will be repeated twice, followed by the Separator Pulse signal and then the CONTINUOUS MEMORY codes. These codes will also be repeated twice.
5. A KOEO code 11 indicates the system has passed the self test. A code 11 must be present before continuing. Disregard any CONTINUOUS MEMORY codes at this time. Service KOEO codes (in the order they appear) and rerun KOEO test until a code 11 is displayed. See «KEY ON ENGINE OFF (KOEO) CODE-TO-CIRCUIT TEST MENU»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
6. Whenever a repair is made, repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no codes are displayed, repeat SELF-TEST to verify that other service codes are still present.

No Starts

If engine does not start, go to CIRCUIT TEST A1 step 1). Proceed through this test procedure until engine is running and then repeat KEY ON/ENGINE OFF (KOEO) SELF-TEST . If engine stalls or is unable to complete KOEO SELF-TEST, DIAGNOSIS BY SYMPTOM table may be used until engine is able to complete KOEO SELF-TEST.

KOEO Test Results

If KOEO code 11 is displayed and CONTINUOUS MEMORY CODE is 15, go to CIRCUIT TEST D15 . If no codes are displayed, repeat SELF-TEST to verify that no service codes are present. If codes are not displayed, go to CIRCUIT TEST D14 , step 1).

TIMING CHECK

1. Turn key off, wait 10 seconds. Start engine. Activate «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . After the last service code has been displayed, the timing will remain fixed for 2 minutes, unless SELF-TEST is deactivated.
2. Correct SELF-TEST timing equals base ignition timing (10 degrees BTDC on all engines) plus 17-23 degrees BTDC. If timing is not 27-33 degrees BTDC, go to «CIRCUIT TEST D13»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-d13-spark-timing) . If timing is 27-33 degrees BTDC, proceed with «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .

1. Deactivate SELF-TEST (disconnect jumper wire). Start engine and run it at 2000 RPM for 2 minutes to warm up HEGO sensor. Turn engine off and wait 10 seconds.
2. Start engine. Insert jumper to activate SELF-TEST. The engine ID code will be displayed. On vehicles equipped with Brake On/Off switch (BOO) the brake pedal MUST be depressed and released AFTER the ID code (within 1-2 seconds). On vehicles equipped with Power Steering Pressure Switch, the steering wheel MUST be turned one half turn and released AFTER the ID code.
3. If a Dynamic Response code occurs, briefly depress accelerator pedal to wide open throttle (WOT). A Dynamic Response code is a code 1 or 10 displayed after the Engine ID code and before the Engine Running codes. DO NOT depress throttle during test unless a Dynamic Response code occurs. The ENGINE RUNNING SELF-TEST service codes will then be displayed. Observe and record all codes.

Engine ID Codes

An engine ID code of 2 (20), 3 (30) or 4 (40) indicates 4, 6 or 8 cylinder engines, respectively.

KOER Test Results

1. If no codes are displayed, repeat SELF-TEST to verify that no service codes are present, and then go to «CIRCUIT TEST D14»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-d14-no-codescodes) step 1). If a code 98 appears in the Engine ID segment, with any other code, go back and perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and obtain a code 11 for KOEO portion of QUICK TEST. The code 98 indicates the vehicle DID NOT pass the KOEO test.
2. If Engine ID code is 2, 3 or 4 (20, 30 or 40 with STAR tester), and code 11 is displayed, KOER SELF-TEST portion is okay. If symptom was of an intermittent nature, go to «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) . If symptom is present, go to «DIAGNOSIS BY SYMPTOM»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) table.
3. If Engine ID code is 2, 3 or 4 (20, 30 or 40 with STAR tester), and any code other than 11 appears, KOER SELF-TEST indicates a fault. Perform the test indicated in the «KEY ON ENGINE RUNNING (KOER) CODE-TO-CIRCUIT TEST MENU»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) for that specific engine.
4. Start with the first code displayed. If the tests refer you to other checks, perform them as instructed. When more than one code is displayed, repair problems in the order that codes are displayed. Whenever a repair is made, repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .

CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)

The CONTINUOUS MONITOR SELF-TEST allows a technician to attempt to recreate an intermittent fault while monitoring the system. The CONTINUOUS MONITOR SELF-TEST may be used in both KOEO and KOER modes.

The test is divided into 4 areas: Establishing Continuous Memory Codes, Clearing Continuous Memory Codes, Continuous Memory Codes To Be Tested, and Continuous Monitor (Wiggle) Test. Perform steps in sequence.

Establishing Continuous Memory Codes

1. To ensure proper diagnosis of continuous memory codes, «PREPARATION»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__preparation) , «EQUIPMENT HOOK-UP»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) , «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) , «TIMING CHECK»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__timing-check) , and «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) must be successfully completed. If both KOEO and KOER SELF-TEST display code 11 (Pass), go to «Clearing Continuous Memory Codes»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__clearing-continuous-memory-codes) .
2. If not, return to «PREPARATION»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__preparation) step and make the necessary repairs indicated in «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) before going to «Clearing Continuous Memory Codes»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__clearing-continuous-memory-codes) .

Clearing Continuous Memory Codes

Perform KEY ON/ENGINE OFF (KOEO) SELF-TEST . When the first service code appears, exit SELF-TEST by disconnecting diagnostic tester or by removing jumper wire from Self-Test Input (STI) pigtail. Exiting QUICK TEST in this manner will clear all codes stored in continuous memory.

Continuous Memory Codes To Be Tested

Check the list of Continuous Memory codes that were recorded in KOEO and KOER SELF-TESTS. Disregard any codes that have already been repaired. To confirm remaining codes, go to Continuous Monitor (Wiggle) Test .

Continuous Monitor (Wiggle) Test

The Self-Test Output (STO) will be activated each time a fault is detected. If the STO is activated long enough during the wiggle tests a service code will be stored. A fault is indicated by needle sweep deflection on analog Volt/Ohm Meter (VOM). The STAR tester LED will flash and/or sound an alarm signal when fault is recreated. The CONTINUOUS MONITOR (WIGGLE) TEST is used to attempt to recreate an intermittent fault.

1. KEY ON/ENGINE OFF (KOEO) Test: Connect STAR tester or VOM. Turn ignition key to "ON" position. Activate, deactivate and reactivate SELF-TEST (3 steps) by connecting, disconnecting and reconnecting STI pigtail jumper. This procedure will place the system in Continuous Monitor Mode. Tap, move, and wiggle the suspected sensor and/or harness area. If a fault is detected, a service code will be stored in memory and will be indicated by VOM or diagnostic tester. Retrieve code and perform test indicated in «CONTINUOUS SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) table.
2. ENGINE RUNNING Test: Start engine. Activate SELF-TEST, wait 10 seconds, deactivate, and then reactivate SELF-TEST. DO NOT turn engine off. You are now in engine running Continuous Monitor Mode test mode. Tap, move, and wiggle the suspected sensor and/or harness area. If a fault is detected, a service code will be stored in memory and will be indicated by VOM or diagnostic tester. Retrieve code and perform test indicated in «CONTINUOUS SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) table. NOTE: An alternate method of entering CONTINUOUS MONITOR (WIGGLE) TEST with engine running is to start KOER SELF-TEST, exit, and re-enter KOER SELF-TEST without turning off engine. If alternate method is being used, perform the following steps. Observe VOM while moving, wiggling, and tapping system harness (in short sections), connectors, and sensors. If an intermittent condition is created, the monitor will indicate this by storing a service code. Carefully inspect harness and associated connectors of affected circuits. If an intermittent condition is not created, carefully disconnect sensor from harness. Remove terminals from connector and visually inspect terminals at both ends for corrosion, bad crimps, improperly seated terminals, etc. Reconnect harness after inspection. Disconnect ECA from harness as carefully as possible. Remove and inspect terminals associated with sensor being checked. If an intermittent condition cannot be created, plug-in connector and erase the CONTINUOUS SELF-TEST service codes. To erase service codes, activate «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . Remove jumper wire from Self-Test Input (STI) terminal as soon as first code appears. Repeat SELF-TEST with jumper to verify that service codes have been erased. QUICK TEST is complete.

Dynamic Response Check

The dynamic response check verifies movement of the TPS, VAF, and MAP sensor during the Wide Open Throttle (WOT) part of the ENGINE RUNNING SELF-TEST. The signal to perform WOT is a single pulse when using VOM or code 10 on STAR tester.

Output State Check

The Output State Check is used as an aid in servicing output actuators associated with the EEC-IV system. It allows you to energize and de-energize most of the system output actuators on and off on command.

This mode is entered after all codes have been received from KOEO and CONTINUOUS SELF-TEST. At this time, leave SELF-TEST activated and depress throttle. Each time throttle is depressed and released, the output actuators will change state (go from on to off, or off to on).

Failure Mode Effects Management (FMEM) (Code 98)

The FMEM mode allows system operation when one or more sensors fail or transmit signals which are out of their normal operating range. The ECA will substitute a mid-range signal for the defective sensor and continue to monitor the sensor. If the faulty sensor signals return to within the normal operating range the ECA will use those signals. A code 98 will be displayed when the FMEM mode is in effect.

1. 11 - System "Passes" test procedure.
2. 12 - Idle RPM not within specifications.
3. 13 - Idle Speed Control (ISC) RPM too high.
4. 14 - Erratic ignition signal from PIP.
5. 15 - Power interruption to Keep Alive Memory (KAM), Pin No. 1.
6. 16 - Idle Speed Control (ISC) RPM too high or throttle pedal touched during KOER SELF-TEST.
7. 17 - Idle Speed Control (ISC) RPM too low.
8. 18 - Spark timing incorrect.
9. 19 - Idle Speed Control (ISC) RPM too low
10. 21 - Engine Coolant Temperature (ECT) sensor/signal out of range.
11. 22 - Manifold Absolute Pressure (MAP) sensor/signal out of range.
12. 23 - Throttle Position Sensor (TPS) signal/out of range.
13. 24 - Air Charge Temperature (ACT) sensor/signal out of range.
14. 25 - Knock sensor signal not received by ECA.
15. 27 - Vehicle Speed Sensor (VSS) signal not received (2.3L Turbo MPFI).
16. 28 - Ambient temperature less than 50°F (10°C).
17. 29 - Vehicle Speed Sensor (VSS) not functioning.
18. 31 - Pressure Feedback EGR (PFE) circuit open.
19. 32 - EGR Control solenoid (EGRC) or EGR Vent solenoid (EGRV) signal failure.
20. 33 - EGR valve not operating or sticking.
21. 34 - EGR Control solenoid (EGRC) or EGR Vent solenoid (EGRV) signal failure.
22. 35 - RPM too low for EGR testing or Pressure Feedback EGR (PFE) circuit short.
23. 39 - Converter by-pass clutch not operating correctly.
24. 41 - Heated Exhaust Gas Oxygen (HEGO) sensor, lean signal in closed loop.
25. 42 - Heated Exhaust Gas Oxygen (HEGO) sensor signal rich in closed loop. Excessive fuel pressure or volume.
26. 43 - Heated Exhaust Gas Oxygen (HEGO) sensor signal lean during WOT test.
27. 47 - Idle speed control (by-pass Air), low flow of unmetered air.
28. 48 - Idle speed control (by-pass Air), high flow of unmetered air.
29. 51 - Engine Coolant Temperature (ECT) sensor, signal circuit open.
30. 52 - Power Steering Pressure Switch (PSPS) signal open or shorted, steering wheel not turned during KOER SELF-TEST.
31. 53 - Throttle Position Sensor (TPS) signal circuit short.
32. 54 - Air Charge Temperature (ACT) sensor circuit open.
33. 55 - Key power check circuit open (CFI engines).
34. 56 - Vane Airflow (VAF) sensor, shorted VREF to SIG circuit.
35. 57 - Neutral Pressure Switch (NPS) failed in neutral.
36. 58 - Vane Air Temperature (VAT) sensor circuit open.
37. 59 - Transmission Hydraulic Switch (THS), 4/3 pressure switch, failed in open position.
38. 61 - Engine Coolant Temperature (ECT) sensor, signal circuit short.
39. 62 - Transmission Hydraulic Switch (THS) 4/3 pressure switch failed in closed position.
40. 63 - Throttle Position Sensor (TPS) signal circuit open.
41. 64 - Air Charge Temperature (ACT) sensor circuit short.
42. 65 - Did not go to closed loop fuel control on HEGO switching. Faulty HEGO signal.
43. 66 - Vane Airflow (VAF) sensor, shorted SIG to SIG RTN circuit.
44. 67 - Neutral Drive Switch (NDS), A/C input, Neutral Pressure Switch (NPS) signal interrupted.
45. 68 - Vane Air Temperature (VAT) sensor circuit short.
46. 69 - Transmission Hydraulic Switch (THS) 3/2 pressure switch failed in closed position.
47. 72 - Fault in VPWR circuit to EEC power relay.
48. 73 - Throttle Position Sensor (TPS) did not rotate more than 25% during dynamic response test.
49. 74 - Brake On/Off (BOO) switch always open, or not applied during KOER SELF-TEST.
50. 75 - Brake On/Off (BOO) switch always closed, or signal circuit shorted.
51. 76 - Vane Airflow (VAF) sensor, no voltage signal increase during Dynamic Response Test.
52. 77 - ECA request for Dynamic Response Test.
53. 78 - Power supply circuit to EEC power relay interrupted.
54. 79 - Neutral Drive Switch (NDS), A/C input, Neutral Position Switch (NPS) signal interrupted.
55. 81 - Open or shorted signal from turbo boost solenoid.
56. 82 - Integrated Controller Relay Module (ICRM), electric fan processor signal shorted to ground or open.
57. 83 - Integrated Controller Relay Module (ICRM), high speed electric fan processor signal shorted to ground or open.
58. 84 - EGR Valve Regulator (EVR) resistance signal out of range.
59. 85 - Fuel mixture made leaner (Adaptive Fuel) to accommodate canister purge function or excessive fuel pressure or volume.
60. 86 - Fuel mixture made richer (Adaptive Fuel) due to low fuel pressure or low volume.
61. 87 - Open in fuel pump circuit or VPWR circuit between EEC power relay and fuel pump relay.
62. 88 - Integrated Controller Relay Module (ICRM), electric fan processor signal shorted to ground or open.
63. 89 - Converter by-pass clutch solenoid always open or closed.
64. 91 - Heated Exhaust Gas Oxygen (HEGO) sensor, lean signal in closed loop.
65. 92 - Heated Exhaust Gas Oxygen (HEGO) sensor signal rich in closed loop. Excessive fuel pressure or volume.
66. 95 - Inertia switch or fuel pump circuit shorted or open.
67. 96 - No power to fuel pump relay.
68. 98 - Vehicle did not pass KOEO SELF-TEST. Code 11 necessary to proceed with KOER test.
69. 99 - ECA has not stored enough information to control idle speed.

DIAGNOSIS BY SYMPTOM (SYMPTOM-TO-DIAGNOSTIC TEST)

KEY ON ENGINE OFF (KOEO) CODE-TO-CIRCUIT TEST MENU

KEY ON ENGINE RUNNING (KOER) CODE-TO-CIRCUIT TEST MENU

CONTINUOUS SELF-TEST - CODE-TO-CIRCUIT TEST MENU

INTERMITTENT NO START, QUITS ON ROAD WITH NO RESTART

1. If engine does not start, perform «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) diagnostic procedure.
2. If engine starts, check for operating fuel pump when ignition is on, spark at coil, ignition system (wires, cap and rotor), Thick Film Integrated (TFI) ignition module and baseline key voltages with breakout box.

INTERMITTENT SURGING AT STEADY SPEED

1. Check plug firing voltages, cylinder balance, base ignition timing, spark plug type and MAP and BP sensor (depending on vehicle). See «MAP/BP SPECIFICATIONS»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) table.
2. On Vane Airflow Meter (VAF) equipped vehicles, check for unmetered air leaks. On all vehicles, check flow of fuel injectors and fuel pressure.

MAP/BP SPECIFICATIONS

INTERMITTENT STALLS WHILE DRIVING & ON RESTARTS

Check baseline readings of key voltages while engine is operating. Compare voltages with readings obtained when intermittent problem occurs and perform QUICK TEST .

INTERMITTENT BUCKING & JERKING

1. Check ignition system secondary wires, distributor cap and rotor, Thick Film Integrated (TFI) ignition module, engine spark, plug firing voltages, cylinder balance, and base ignition timing. Check spark plugs for fouling and proper gap.
2. Perform «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . Connect Manifold Absolute Pressure (MAP)/Barometric Pressure (BP) tester to MAP or BP sensor (depending on vehicle). Check readings with engine off and with ignition switch in "ON" position. Compare reading with «MAP/BP SPECIFICATIONS»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) table.
3. On Vane Airflow Meter (VAF) equipped vehicles, check for unmetered air leaks. Check for loose air tubes, missing hoses, or vacuum plugs.

INTERMITTENT ERRATIC RUNNING OR ROUGH IDLE

1. Check color at top of fuel injectors to ensure correct application. Check distributor cap, plug firing voltages, cylinder balance, and base ignition timing.
2. Check spark plugs for fouling and proper gap, cylinder compression, and engine/valve train operation. Check Thick Film Integrated (TFI) ignition module, Profile Ignition Pick-Up (PIP), and coil.
3. Check Spark Output (SPOUT) connector. Connect Manifold Absolute Pressure (MAP)/Barometric Pressure (BS) tester to MAP or BP sensor (depending on vehicle). Check readings with engine off and with ignition switch in "ON" position. Compare reading with «MAP/BP SPECIFICATIONS»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) table.
4. Repeat MAP test with engine running. Reading should decrease at idle and increase when throttle is opened. On MAP sensor equipped vehicles, if readings with engine off and ignition on do not match values given, go to «CIRCUIT TEST B6»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-b6-manifold-absolute) - MANIFOLD ABSOLUTE PRESSURE (MAP)/BAROMETRIC PRESSURE (BP) SENSOR test.
5. If MAP sensor does not change when throttle is opened (engine running), substitute a known good vacuum hose at sensor and repeat test. On vehicles equipped with either MAP or BP sensors, substitute sensor(s) and retest.
6. On Vane Airflow Meter (VAF) equipped vehicles, check for unmetered air leaks. Using breakout box, monitor VAF signal while manually moving vane door. Voltage must smoothly increase as door is opened.
7. Using Fuel Injector Tester/Cleaner (Rotunda 113-00001), check flow of injectors.

HOW TO USE CIRCUIT TESTS

1. DO NOT perform any CIRCUIT TEST unless directed to do so by «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . Ensure all non-EEC related faults are corrected. FOLLOW EACH TEST STEP IN ORDER UNTIL FAULT IS FOUND. DO NOT replace any part unless directed to do so. When more than one service code is received, start with the first code displayed.
2. DO NOT measure voltage or resistance at ECA or connect any test light, unless specified. All measurements are made by probing REAR of connector. Isolate both ends of a circuit and turn key off whenever checking for shorts or continuity, unless specified. NOTE: When directed in testing procedure to service or repair TFI ignition system, see MOTORCRAFT TFI-IV IGNITION article in the DISTRIBUTORS & IGNITION SYSTEMS section.
3. Disconnect solenoids and switches from harness before measuring continuity, resistance, or applying 12 volts. After each repair, check all component connections and repeat CIRCUIT TEST(S).
4. An "open" is defined as any resistance reading greater than 5 ohms. This specification tolerance may be too high for some items in the EEC-IV system. If a resistance approaches 5 ohms, always clean the suspected connector and coat with protective dielectric silicone grease. A "short" is defined as any resistance reading less than 10K ohms to ground, unless specified in CIRCUIT TEST.
5. On FUEL CONTROL CIRCUIT TESTS C1 and C2, to prevent replacement of good components, be aware that the following non-EEC related areas may also be at fault. These areas include ignition coil, distributor cap and rotor, spark plug wires, fouled spark plugs, CANP problems, EGR valve and gasket, air filter, poor power and ground circuits, fuel pressure, intake and exhaust manifold leaks, engine not at normal operating temperature, and problems with PCV valves or fuel contaminated engine oil. NOTE: Fuel contaminated engine oil may affect some service codes. If this is suspected, remove PCV valve from valve cover and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If problem is corrected, change engine oil and filter.
6. On FUEL CONTROL CIRCUIT TESTS C1 and C2, vacuum leaks in non-EEC related areas may also cause code 41 or 91 to be displayed. Check for unmetered air leaks between airflow meter and throttle body, leaking vacuum motors, engine seals, EGR system, PCV system, Canister Purge (CANP) problems, or contaminated HEGO sensor. Code 42 or 92 may be caused by fuel contaminated engine oil, ignition misfire, EGR system, or CANP problems. NOTE: In the following diagnostic charts, circuits and illustrations are supplied courtesy of Ford Motor Co. NOTE: CIRCUIT TESTS are grouped in the following categories: A1-A3 Preliminary Tests B1-B15 Input Sensor Tests C1-C2 Fuel Control Systems D1-D23 ECA Output Tests

TFI Module Circuits. Scheme 4

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: fuel quantity and quality, ignition system damage, cracks, moisture, etc., engine mechanical conditions such as bad valves, timing belt, etc. Also included are starter and battery circuit problems.

1. Starting System - Try to start engine. If engine does not crank, check vehicle starting and charging systems. If engine cranks, but does not start or stalls after starting, go to next step.
2. Checking VREF Signal At TPS - Turn key off and wait 10 seconds. Set DVOM on 20-volt scale and disconnect Throttle Position (TP) sensor. Turn key on, leaving engine off (KOEO). Measure voltage at TPS harness connector between Voltage Reference (VREF) and signal return. If reading is less than 4 volts or more than 6 volts, go to «CIRCUIT TEST A3»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a3-reference-voltage) , step 1). If reading is between 4 and 6 volts, reconnect TPS and go to next step.
3. Checking For Spark - Disconnect any spark plug wire and connect spark tester between plug wire and engine ground. Crank engine and check for spark. If spark exists, connect spark plug wire and go to step 13 . If there is no spark, connect spark plug wire and go to next step.
4. Checking For Spark At Coil - Remove high tension coil wire from distributor and install spark tester. Check for spark while cranking engine. If spark exists, connect coil wire and service or repair TFI ignition system. If there is no spark, connect coil wire and go to next step.
5. Ignition Ground Continuity - Turn key off and wait 10 seconds. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale and disconnect TFI. Measure resistance between Test Pin No. 16 and TFI harness connector ignition ground. If reading is more than 5 ohms, repair harness and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 5 ohms, go to next step.
6. SPOUT Circuit Isolation - With breakout box installed and box timing switch on "DISTRIBUTOR" position, connect TFI and ECA. Try to start vehicle. If vehicle starts, go to step 10 . If vehicle does not start, go to next step.
7. Checking SPOUT Signal - Move breakout box timing switch to "COMPUTED" position. Set DVOM on 20-volt scale and measure voltage between Test Pin No. 36 and chassis ground while cranking engine. If voltage is between 3 and 6 volts, EEC system is NOT at fault. TFI ignition system should be diagnosed. If voltage is less than 3 volts or more than 6 volts, go to next step.
8. Checking SPOUT For Shorts - Turn key off and wait 10 seconds. With breakout box installed, disconnect ECA and TFI. Set DVOM on 200K-ohm scale and measure resistance between Test Pin No. 36 and Test Pins No. 16, 20, 26, 40, and 60 for short to ground. Measure resistance between Test Pin No. 36 and Test Pins No. 37 and 57 for short to power. Measure resistance between Test Pins No. 36 and 56 for short to PIP. If any reading is less than 10K ohms, repair short in harness and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If engine still does not start, go to next step. If all readings are 10K ohms or more, go to next step.
9. Isolating Shorts In Processor - Turn key off and wait 10 seconds. With breakout box installed, connect ECA, but leave TFI disconnected. Set DVOM on 200-ohm scale. Measure resistance between Test Pin No. 36 and Test Pins No. 37 and 57 for short to power. Measure resistance between Test Pin No. 36 and Test Pins No. 40 and 60 for short to ground. If any reading is less than 5 ohms, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If all readings are 5 ohms or more, connect TFI and go to next step.
10. Checking PIP Signal - With breakout box installed and DVOM on 20-volt scale, measure voltage between Test Pins No. 56 and 16, while cranking engine. If reading is between 3 and 6 volts, remove breakout box. Replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 3 volts or more than 6 volts, go to next step.
11. Continuity of PIP Circuit - Install breakout box, turn key off and wait 10 seconds. Set DVOM on 200-ohm scale. Disconnect TFI and ECA. Measure resistance between Test Pin No. 56 and TFI connector PIP circuit. If reading is 5 ohms or more, repair open PIP circuit and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If readings is less than 5 ohms, go to next step.
12. Checking PIP Circuit For Shorts - With breakout box installed and ECA disconnected, turn key off. Disconnect TFI connector and set DVOM on 200K-ohm scale. Measure resistance between Test Pin No. 56 and Test Pins No. 16, 20, 26, 40, and 60 for short to ground. Measure resistance between Test Pin No. 56 and Test Pins No. 37 and 57 for short to power. Measure resistance between Test Pin No. 56 and Test Pin No. 36 for short to Spark Output (SPOUT). If any reading is less than 10K ohms, repair PIP circuit and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If all readings are more than 10K ohms, repair TFI ignition system.
13. Verifying SPOUT Signal - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector and inspect for damaged pins, corrosion, or loose wires. Repair as necessary. Install breakout box and connect ECA. Ensure breakout box timing switch is in "COMPUTED" position. Set DVOM on 20-volt scale and measure voltage between Test Pin No. 36 and chassis ground while cranking engine. If reading is between 3 and 6 volts, go to next step; except vehicles with Mass Air (MA) system, which go to step 16). If reading is less than 3 volts or more than 6 volts, go to step 10 .
14. Fuel Pump Check - Connect pressure gauge to vehicle. Note initial pressure reading, then pressurize fuel system by turning key on for one second, turning key off, and then waiting 10 seconds. Repeat on, off, and wait sequence 5 times. Turn key off and wait 10 seconds. If pressure increased, go to «CIRCUIT TEST D20»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-d20-system-check) , step 1) for MPFI fuel injected engines. If pressure increased, go to «CIRCUIT TEST D20»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-d20-system-check) , step 2) for CFI fuel injected engines. If pressure did not increase, go to next step.
15. Inertia Switch Check - Turn key off and install fuel pressure gauge. Locate fuel pump inertia switch and push button on switch to reset it to on. If switch will not reset to on, replace inertia switch and repeat step 14 . If switch button was already on, go to «CIRCUIT TEST D22»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-d22-integral-relay) , step 11) for 2.3L MPFI engines. If switch button was already on, go to «CIRCUIT TEST D23»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-d23-erratic-ignition) , step 1) for all other engines.

CIRCUIT TEST A2 - VEHICLE BATTERY

Note. Perform this test when code 72 or 78 is displayed during QUICK TEST or when directed here by A3, C2, or D13 test procedures.

Vehicle Battery Circuits. Scheme 5

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: battery cables and ground straps, voltage regulator, alternator, or ignition switch. This test should normally be conducted only when directed by CIRCUIT TEST A3, D23, D13, or by a Continuous Memory Code 72 or 78 in QUICK TEST .

1. Battery Voltage Check - Turn key on, leaving engine off. Set DVOM on 20-volt scale and measure voltage across battery terminals. If reading is less than 10.5 volts, service or replace discharged battery. If reading is 10.5 volts or more, go to next step.
2. Checking EEC Ground Circuit - Turn key off and wait 10 seconds. Inspect ECA connector and pins. Install breakout box, leave ECA connected. Set DVOM on 200-ohm scale and measure resistance between Test Pin No. 40 and negative post on battery. Also measure resistance between Test Pin No. 60 and negative post on battery. If readings are greater than 5 ohms, repair cause of resistance in circuit(s). Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If both readings are less than 5 ohms, go to next step.
3. Checking ECA Ground Insolation - With breakout box installed and ECA connected, turn key off and wait 10 seconds. Set DVOM on 200-ohm scale. Measure resistance between Test Pins No. 40 and 46 and between Test Pins No. 46 and 60 at breakout box. If both readings are less than 5 ohms, go to next step. If readings are greater than 5 ohms, disconnect ECA connector and inspect for corrosion or damaged pins. Repair if necessary. If fault is still present, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
4. Continuity of Signal Return Circuit - With breakout box installed and ECA connected, turn key off and wait 10 seconds. Set DVOM on 200-ohm scale. Measure resistance between Test Pin No. 46 at breakout box and signal return circuit in SELF-TEST connector. If reading is greater than 5 ohms, repair cause of resistance in signal return circuit. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If readings is less than 5 ohms, go to next step.
5. Checking KAPWR Circuit - Turn key on, leaving engine off. With ECA connected, set DVOM on 20-volt scale. Measure voltage between battery negative post and Keep Alive Power (KAPWR) circuit at EEC power relay. If reading is less than 10.5 volts, check KAPWR and Vehicle Power (VPWR) circuits for shorts to ground. Also check KAPWR circuit from EEC power relay to battery positive post for open circuit. If reading is 10.5 volts or more, go to next step.
6. Ignition Circuit Voltage - Turn key on, leaving engine off. With ECA connected, set DVOM on 20-volt scale. Measure voltage between battery negative post and ignition circuit at EEC power relay. If reading is less than 10.5 volts, check for open ignition switch circuits. Repair wiring and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is 10.5 volts or more, go to next step.
7. Checking Power Relay Ground Circuit Continuity - Turn key off and wait 10 seconds. With ECA connected and DVOM on 200-ohm scale, measure voltage between battery negative post and EEC relay ground. If reading is greater than 5 ohms, repair wiring in ground circuit. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 5 ohms, go to next step.
8. Checking Power Circuit (VPWR) at Relay - Turn key on, leaving engine off. With ECA connected and DVOM on 20-volt scale, measure voltage between battery negative post and VPWR circuit at EEC power relay. If reading is 10.5 volts or greater, repair open in VPKR circuit. If okay, repair short to ground in VPWR circuit. If reading is less than 10.5 volts, replace EEC power relay. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
9. WIGGLE Testing VPWR Circuits - Turn key on, leaving engine off (KOEO). Connect VOM or diagnostic tester to SELF-TEST connector. With SELF-TEST deactivated, enter «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) . Observe VOM or diagnostic tester for indication of fault while bending and twisting harness from EEC power relay to ECA.

CIRCUIT TEST A3 - REFERENCE VOLTAGE

Note. Perform this test when a check of a VREF circuit has failed, or directed here by a sensor test or when directed here by other test procedures.

Reference Voltage Circuits. Scheme 6

1. Checking Battery Power Circuit - Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Install breakout box, leaving ECA connected. Turn key on, leaving engine off. Set DVOM on 20-volt scale and measure voltage between Test Pin No. 37 and signal return in SELF-TEST connector. If reading is less than 10.5 volts, go to «CIRCUIT TEST D23»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-d23-erratic-ignition) , step 1) for 2.3L TC/MPFI engines. If reading is less than 10.5 volts, go to «CIRCUIT TEST A2»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a2-vehicle-battery) , step 1) for all other engines. If reading is 10.5 volts or more, go to next step.
2. Checking VREF Voltage - With breakout box installed and ECA connected, turn key on, leaving engine off. Set DVOM on 20-volt scale and measure voltage between Test Pins No. 26 and 46. If reading is 6 volts or more, go to step 4 . If reading is 4 volts or less, go to step 5 . If reading is between 4 and 6 volts, go to next step.
3. VREF and Signal Return Continuity - With breakout box installed and ECA disconnected, turn key off. Disconnect applicable sensor. Set DVOM on 200-ohm scale. Measure resistance from Test Pins No. 26 and 46 to suspect VREF sensor harness connector. If both readings are less than 5 ohms, VREF voltage is okay. Connect all sensors and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If any reading is 5 ohms or more, repair open circuit in VREF or signal return and then repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
4. Checking For Excess VREF Circuit Voltage - Turn key off and wait 10 seconds. With breakout box installed and ECA disconnected, turn key on, leaving engine off. Set DVOM on 20-volt scale and measure voltage between Test Pin No. 26 and battery ground. If reading is less than 0.5 volt, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is .5 volt or more, repair short to battery power in EEC harness. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . Replace ECA if fault still occurs.
5. Shorted TPS Sensor - Turn key off and wait for 10 seconds. With breakout box installed and ECA connected, disconnect Throttle Position Sensor (TPS) from vehicle harness. Turn key on, leaving engine off. Set DVOM on 20-volt scale and measure voltage between Test Pins No. 26 and 46. If reading is 4 volts or more, replace TPS and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If less than 4 volts on models with EVP/PFE sensor, go to step 7 . If reading is less than 4 volts on all other models, go to next step.
6. Shorted EVP/PFE Sensor - Turn key off and wait 10 seconds. With breakout box installed and ECA connected, disconnect EVP/PFE sensor. Turn key on, leaving engine off. Set DVOM on 20-volt scale. Measure voltage between Test Pins No. 26 and 46. If reading is 4 volts or more, replace EVP/PFE sensor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 4 volts, go to next step.
7. Shorted MAP/BP Sensor - Turn key off and wait 10 seconds. With breakout box installed and ECA connected, disconnect MAP/BP sensor. Turn key on, leaving engine off. Set DVOM on 20-volt scale. Measure voltage between Test Pins No. 26 and 46. If reading is 4 volts or more, replace MAP/BP sensor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 4 volts on models without Vane Airflow (VAF) sensor, go to step 9 . If reading is less than 4 volts on models with VAF sensor, go to next step.
8. Shorted VAF Sensor - Turn key off and wait 10 seconds. With breakout box installed and ECA connected, disconnect VAF sensor. Turn key on, leaving engine off. Set DVOM on 20-volt scale. Measure voltage between Test Pins No. 26 and 46. If reading is 4 volts or more, replace VAF sensor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 4 volts, go to next step.
9. VREF Shorted to Ground - With breakout box installed and ECA disconnected, turn key off and wait 10 seconds. Disconnect TPS, MAP/BP, EVP/PFE, and VAF sensor (if equipped). Set DVOM on 200-ohm scale. Measure resistance between Test Pin No. 26 and Test Pins No. 20, 40, 46, and 60. If reading is less than 5 ohms, repair short to ground, connect all sensors and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If original problem still occurs, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is 5 ohms or more, connect sensors, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .

CIRCUIT TEST B1 - VANE AIR TEMPERATURE (VAT) SENSOR

Note. Perform this test only when service code 28, 58, or 68 is received in QUICK TEST.

VAT Sensor Circuit. Scheme 7

Ambient air temperature must be at least 50°F (10°C) for test results to be valid. Avoid performing test in unusually hot or cold conditions.

TYPICAL VANE AIR TEMPERATURE (VAT) SENSOR RESISTANCE

1. Code 28: Check Ambient Temperature - Ensure ambient air temperature is at least 50°F (10°C). If not, repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If temperature is hot enough, go to next step.
2. Voltage Reference at TPS - Turn key off and wait 10 seconds. Set DVOM on 20-volt scale. Disconnect Throttle Position Sensor (TPS). Turn key on, leaving engine off. Measure voltage at TPS connector between voltage reference (VREF) and signal return. If reading is less than 4 volts or more than 6 volts, go to «CIRCUIT TEST A3»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a3-reference-voltage) , step 1). If reading is between 4 and 6 volts, connect TPS and go to next step.
3. Checking VAT Sensor - Turn key off and wait 10 seconds. Disconnect harness from airflow meter. Set DVOM on 200K-ohm scale. Measure resistance at VAT sensor between VAT signal and signal return. If reading is from 125 ohms at 240°F (116°C) to 3700 ohms at 50°F (10°C), replace ECA. Connect airflow meter and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is out of range, replace airflow meter and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
4. Code 58: Testing Airflow Meter - Turn key off and wait 10 seconds. Disconnect harness from airflow meter. Inspect for and repair any damaged wiring. Install a jumper wire between VAT signal and signal return at airflow meter connector. Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 68 is displayed, replace airflow meter. Remove jumper wire, connect airflow meter, and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 68 is not displayed, remove jumper wire and go to next step.
5. Checking VAT Signal and Return - Turn key off and wait 10 seconds. With jumper wire removed, leave airflow meter disconnected. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between Test Pin No. 25 (No. 43 on 2.3L Turbo MPFI), at the breakout box and VAT signal at connector. Also measure resistance between Test Pin No. 46 and signal return at connector. If both readings are less than 5 ohms, replace ECA. Remove breakout box and connect wiring to ECA and airflow meter. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If either reading is 5 ohms or more, repair open circuit. Remove breakout box, connect wiring to ECA and airflow meter. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
6. Code 68: Opposite Code Test - Turn key off and wait 10 seconds. Disconnect harness from airflow meter. Inspect for and repair any damaged wiring. Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 58 is displayed, replace airflow meter and connect harness. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 58 is not displayed, go to next step.
7. Checking VREF at TPS - Turn key off and wait 10 seconds. Set DVOM on 20-volt scale. Disconnect TPS. Turn key on, leaving engine off. Measure voltage between VREF and signal return at connector. If reading is less than 4 volts or more than 6 volts, go to «CIRCUIT TEST A3»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a3-reference-voltage) , step 1). If reading is between 4 and 6 volts, connect TPS and go to next step.
8. Checking For Shorts at VAT Signal - Turn key off and wait 10 seconds. Leave airflow meter disconnected. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200K-ohm scale. Measure resistance between Test Pin No. 25 (No. 43 on 2.3L Turbo MPFI engine) and Test Pins No. 40, 46, and 60. If any reading is less than 10K ohms, repair shorts. Remove breakout box, connect ECA and airflow meter. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If all readings are 10K ohms or more, replace ECA. Remove breakout box and connect ECA. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
9. Continuous Code 58 or 68 Displayed - Using «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) , observe VOM or diagnostic tester for indication of fault while tapping VAT sensor lightly and wiggling connector. If fault is indicated, inspect connector and terminals. If connector and terminals are good, replace VAT sensor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no fault is indicated, go to next step.
10. Wiggle Testing Harness - While in CONTINUOUS MONITOR (WIGGLE) TEST, wiggle and bend EEC-IV harness from VAT sensor to firewall, a small section at a time. Also check harness from firewall to ECA. If fault is indicated, isolate fault and repair as necessary. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no fault is found, go to next step.
11. Inspecting Connectors and Terminals - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect both connector and connector terminals for obvious damage. If connectors and terminals are damaged, repair as necessary and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If connectors and terminals are okay, and you are unable to duplicate fault at this time, continuous code 58 or 68 testing is complete.

CIRCUIT TEST B2 - AIR CHARGE TEMPERATURE (ACT) SENSOR

Note. Perform this test when Service Code 24, 54, or 64 is displayed during QUICK TEST or when directed here by other test procedures.

Air Charge Temperature (ACT) Sensor Circuit. Scheme 8

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: cooling system, improper engine oil level, or air cleaner duct problems. Ambient air temperature must be at least 50°F (10°C) for test results to be valid. Avoid performing test in unusually hot or cold conditions.

TYPICAL AIR CHARGE TEMPERATURE (ACT) SENSOR RESISTANCE

1. Code 24: Checking ACT Sensor - For vehicles with ACT sensor mounted in intake manifold, go to next step. If sensor is properly mounted in air cleaner on all other models, go to next step. If sensor is not properly mounted, install ACT sensor properly and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
2. Checking VREF at TPS - Turn key off and wait 10 seconds. Set DVOM on 20-volt scale and disconnect Throttle Position Sensor (TPS). With key on, engine off (KOEO), measure voltage between VREF and signal return at TPS connector. If reading is less than 4 volts or more than 6 volts, go to «CIRCUIT TEST A3»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a3-reference-voltage) , step 1). If reading is between 4 and 6 volts, connect TPS and go to next step.
3. Checking ACT With Engine Off - Start engine and ensure engine reaches normal operating temperature. Turn key off and wait 10 seconds. Disconnect ACT sensor, set DVOM on 200K-ohm scale, and measure ACT sensor resistance. If reading is less than 1100 ohms or more than 58K ohms, check function of heat stove duct valve. If valve is operating correctly, replace ACT sensor. Connect ACT sensor, and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is between 1100 and 58K ohms, go to next step.
4. Checking ACT With Engine Running - Turn key off. Disconnect ACT sensor harness. Set DVOM on 200K-ohm scale and run engine for 2 minutes. While engine is running, measure ACT sensor resistance. If reading is between 2400 and 29K ohms, replace ECA. Connect ACT harness, and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 2400 ohms or more than 29K ohms, check function of heat stove duct valve. If valve works properly, replace ACT sensor. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
5. Code 54: Generate Code 64 - Turn key off and wait 10 seconds. Disconnect ACT sensor harness. Inspect for and repair any damaged wiring. Install a jumper wire between ACT signal and signal return at connector. Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 64 is displayed, replace ACT sensor. Remove jumper wire, connect ACT sensor, and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 64 is not displayed, remove jumper wire and go to next step.
6. Continuity Check of ACT Signal - Turn key off and wait 10 seconds. Leave ACT sensor harness disconnected. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between Test Pin No. 25 and ACT signal at ACT connector, and between Test Pin No. 46 and signal return at ACT connector. If both readings are less than 5 ohms, replace ECA and remove breakout box. Connect ECA and ACT sensor, and then repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If either reading is 5 ohms or more, repair opens in circuit. Remove breakout box, and connect ECA and ACT sensor. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
7. Code 64: Generate Code 54 - Turn key off and wait 10 seconds. Disconnect ACT sensor. Inspect for and repair any damaged wiring. Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 54 is displayed, replace ACT sensor. Connect harness, and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 54 is not displayed, go to next step.
8. Checking VREF at TPS - Turn key off and wait 10 seconds. Set DVOM on 20-volt scale and disconnect TPS. Turn key on, leaving engine off. Measure voltage between VREF and signal return at TPS connector. If reading is less than 4 volts or more than 6 volts, go to «CIRCUIT TEST A3»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a3-reference-voltage) , step 1). If reading is between 4 and 6 volts, connect TPS and go to next step.
9. Checking ACT Signal for Ground Short - Turn key off and wait 10 seconds. Disconnect harness at ACT sensor. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box and set DVOM on 200K-ohm scale. Measure resistance between Test Pin No. 25 and Test Pins No. 40, 46, and 60. If any reading is less than 10K ohms, repair shorts. Remove breakout box, and connect ECA and ACT sensor. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If all readings are 10K ohms or more, replace ECA. Remove breakout box, and connect ECA and ACT sensor. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
10. Continuous Code 54 or 64 Displayed - Using «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) , observe VOM or diagnostic tester for indication of fault while tapping ACT sensor lightly and wiggling connector. If fault is indicated, inspect connector and terminals. If connector and terminals are good, replace ACT sensor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no fault is indicated, go to next step.
11. Wiggle Testing ACT Harness - While in CONTINUOUS MONITOR (WIGGLE) TEST, wiggle and bend small sections of harness from ACT sensor to firewall. Repeat action from firewall to ECA. If fault is indicated, isolate fault and repair as necessary. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no fault is indicated, go to next step.
12. Inspecting Connectors and Terminals - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect both connector and connector terminals for obvious damage. If connectors and terminals are not okay, repair as necessary and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If connectors and terminals are okay, and you are unable to duplicate fault at this time, continuous code 54 or 64 testing is complete.

CIRCUIT TEST B4 - EGR VALVE POSITION (EVP) SENS EGR CTRL (EGRC) SOLENOID & EGR VENT (EGRV) SOLENOID

Note. Perform this test when Service code 32, 33, 34, 35, or 76 is displayed during QUICK TEST or when directed here by other test procedures.

EVP, EGRC & EGRV Solenoid Circuits. Scheme 9

To prevent replacement of good components, be aware that the following non-EEC related area may be at fault: damaged EGR valve.

1. Code 31 Displayed - Turn key off and wait 10 seconds. Disconnect and plug vacuum line at EGR valve. Perform «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 31 is not displayed, reconnect vacuum and go to step 8 . If code 31 is displayed, go to next step.
2. Checking EVP Resistance With Vacuum Applied - Turn key off and wait 10 seconds. Leave EGR vacuum line disconnected and plugged. Disconnect EVP sensor harness. Set DVOM on 200K-ohm scale and connect vacuum pump to EGR valve. Measure resistance between EVP signal and VREF at EVP connector while vacuum is slowly increased to 10 in. Hg. If reading is less than 100 ohms or more than 5500 ohms, replace EVP sensor. Connect vacuum signal line and harness. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading does not decrease or valve does not hold vacuum, go to step 13 . If reading gradually decreases from a maximum of 5500 ohms to a minimum of 100 ohms, go to next step.
3. Checking VREF at EVP Sensor - Turn key on, leaving engine off. Disconnect and plug vacuum signal line and disconnect EVP sensor harness. Set DVOM on 20-volt scale. Measure voltage between VREF and signal return at EVP connector. If reading is less than 4 volts or more than 6 volts, go to «CIRCUIT TEST A3»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a3-reference-voltage) , step 1). If reading is between 4 and 6 volts, go to next step.
4. Checking EVP Signal Continuity - Turn key off and wait 10 seconds. Disconnect harness at EVP sensor and ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between Test Pin No. 27 and EVP signal at EVP connector. If reading is 5 ohms or more, repair open in circuit. Remove breakout box, connect ECA and EVP sensor, and then repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 5 ohms, go to next step.
5. Checking EVP Signal Circuit for Shorts - Turn key off and disconnect harness at EVP sensor. Install breakout box, leaving ECA disconnected. Set DVOM on 200K-ohm scale. Measure resistance between Test Pin No. 27 and Test Pins No. 26, 40, 46, and 60. If any reading is less than 10K ohms, repair short circuit. Remove breakout box, connect ECA and EVP sensor, then repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If all readings are 10K ohms or more, go to next step.
6. EVP Sensor and EGR Valve Substitution Test - Turn key off and wait 10 seconds. Connect known good EVP sensor and EGR valve assembly to harness and vacuum lines. Remove breakout box and connect ECA. Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 31 is displayed, replace ECA. Connect original EVP sensor and EGR valve assembly. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 31 is not displayed, go to next step.
7. Testing EVP Sensor - Turn key off and wait 10 seconds. Install original EVP sensor to known good EGR valve. Connect EVP sensor and perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 31 is displayed, replace EVP sensor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 31 is not displayed, service EGR system.
8. Codes 32, 33, or 34 Displayed - Use DVOM for this step. DO NOT use diagnostic tester. Turn key off and wait 10 seconds. Set DVOM on 20-volt scale. Connect DVOM negative test lead to STO and positive lead to battery positive post. Connect jumper wire between STI and signal return. Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) until end of CONTINUOUS SELF-TEST codes (DVOM reads 0 volts). Depress and release throttle. If reading does not change to high voltage, depress throttle to WOT and release. If STO voltage does not go high, go to «CIRCUIT TEST D16»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-d16-output-state) , step 1). If DVOM reading does go high, stay in «OUTPUT STATE CHECK»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__output-state-check) and go to next step.
9. Checking EGRC/EGRV Solenoids - Turn key on, leaving engine off. Stay in «OUTPUT STATE CHECK»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__output-state-check) . Set DVOM to 20-volt scale. Connect DVOM between EGRV solenoid, VPWR and EGRV signal. Depress and release throttle several times to cycle output on and off while observing DVOM. Repeat check for EGRC solenoid, VPWR and EGRC signal. If either solenoid does not cycle on and off, exit «OUTPUT STATE CHECK»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__output-state-check) and go to step 14 . If both solenoids cycle on and off, stay in «OUTPUT STATE CHECK»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__output-state-check) and go to next step.
10. Checking EGRC/EGRV Vacuum Cycling - Turn key on, leaving engine off. Stay in «OUTPUT STATE CHECK»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__output-state-check) . Disconnect and plug vacuum line from bottom port of EGRC solenoid. Connect vacuum pump to open port. Connect vacuum gauge in common output (upper) vacuum line to EGR valve. Disconnect, but DO NOT plug vacuum vent line from EGRV solenoid. Maintain source vacuum and cycle output on and off by depressing and releasing throttle. If vacuum does not cycle on and off in less than 2 seconds, check solenoid filter for obstructions, and replace if necessary. If filter is okay, replace solenoid assembly. After repairs, connect all vacuum lines and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If vacuum output cycles on and off in less than 2 seconds, connect all vacuum lines and go to next step.
11. Checking Vacuum Lines - Turn key off and wait 10 seconds. Connect all vacuum lines, and check vacuum lines for proper routing, kinks, cracks, obstructions, leaks, etc. Use vehicle emissions decal as a guide. If vacuum lines are not okay, repair as necessary and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If vacuum lines are okay, go to next step.
12. Checking EVP Resistance - With key off, disconnect EVP sensor harness. Inspect for and repair any damaged wiring. Set DVOM on 200K-ohm scale. Disconnect vacuum line at EGR valve and connect vacuum pump to valve. Measure resistance of EVP sensor between EVP signal and VREF terminals while increasing vacuum to 10 in. Hg. If reading slowly decreases from maximum of 5500 ohms to minimum of 100 ohms, replace ECA. Connect EVP sensor and EGR vacuum line. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading does not slowly decrease, go to next step.
13. Manual Test of EVP Sensor - With key off, disconnect EVP sensor harness. Remove EVP sensor and vacuum line from EGR valve. Measure resistance of EVP sensor between EVP signal and VREF terminals. Observe resistance changes as EVP sensor shaft is slowly pushed in and slowly released. If both readings increase and decrease smoothly in range of 100-5500 ohms, replace EGR valve assembly. Connect EVP sensor and EGR vacuum line. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If either reading changes abruptly during range of 100-5500 ohms, replace EVP sensor. Reconnect harness and EGR vacuum line. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . NOTE: It is normal for EVP sensor total resistance to drop to less than 100 ohms when disconnected from EGR valve. A defective sensor will change resistance suddenly between 5500 and 100 ohms.
14. Checking EGRV/EGRC Solenoid Resistance - Turn key off and wait 10 seconds. Set DVOM on 200-ohm scale. Disconnect EGRC and EGRV solenoids from harness. Inspect for and repair any damaged wiring. Measure resistance of both solenoids. If either reading is less than 30 ohms or more than 70 ohms, replace EGRC/EGRV solenoid assembly. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If both readings are between 30 and 70 ohms, reconnect solenoids and go to next step.
15. Checking VPWR at EGRC/EGRV Solenoids - Disconnect EGRC and EGRV solenoids from harness. Turn key on, leaving engine off. Set DVOM on 20-volt scale. Measure voltage between battery negative terminal and VPWR circuit for both solenoids. If either reading is less than 10.5 volts, repair open circuit and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If both readings are 10.5 volts or more, go to next step.
16. Continuity Check - Turn key off and wait 10 seconds. Leave EGRC and EGRV solenoids disconnected. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between Test Pin No. 33 and EGRV signal at EGRV solenoid connector. Measure resistance between Test Pin No. 52 and EGRC signal at EGRC solenoid connector. If either reading is 5 ohms or more, repair open circuit. Remove breakout box, connect ECA solenoids, and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If both readings are less than 5 ohms, go to next step.
17. Checking For Shorts To Ground - Turn key off and wait 10 seconds. Set DVOM on 200K-ohm scale. Install breakout box, leaving ECA disconnected. Disconnect EGRC and EGRV solenoids. Measure resistance between Test Pin No. 33 and Test Pins No. 40, 46, and 60. Measure resistance between Test Pin No. 52 and Test Pins No. 40, 46 and 60. If readings are less than 10K ohms, repair short to ground. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If readings are 10K ohms or more, go to next step.
18. Checking For Shorts To Power - With key off, disconnect EGRC and EGRV solenoids from harness. Install breakout box, leaving ECA disconnected. Set DVOM on 200K-ohm scale. Measure resistance between Test Pin No. 33 and Test Pins No. 37 and 57. Measure resistance between Test Pin No. 52 and Test Pins No. 37 and 57. If any reading is less than 10K ohms, repair short in circuit. Remove breakout box and connect ECA. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code is repeated, replace ECA. If all readings are 10K ohms or more, replace ECA. Remove breakout box and connect ECA. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
19. Code 35: RPM Too Low For EGR Test - This code indicates that engine RPM is too low for correct EGR testing. If code 12 is also displayed go to «CIRCUIT TEST D5»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-d5-idle-speed) , step 1). If code 12 is not displayed with code 35, go to next step.
20. Retest at 1500 RPM - Turn key off and wait 10 seconds. Install tachometer. Perform «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) at 1500 RPM. IGNORE ALL OTHER SERVICE CODES AT THIS TIME. Record KOER service codes. If code 35 is displayed, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 35 is not displayed, repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and repair codes as necessary.
21. Continuous Code 31 Displayed - Using «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) , observe VOM or diagnostic tester for indication of fault while doing the following: connect vacuum pump to EGR valve. Very slowly apply 6 in. Hg vacuum to EGR valve. Bleed vacuum slowly and lightly tap on EVP sensor. Wiggle EVP sensor connector. If fault is indicated, go to next step. If no fault is indicated, go to step 23 .
22. EVP Signal Voltage During Operation - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box and connect ECA. Stay in CONTINUOUS MONITOR (WIGGLE) TEST. Connect DVOM between Test Pins No. 27 and 46. Set DVOM on 20-volt scale. Turn key on, leaving engine off. Repeat step 21 while watching voltage. If fault occurs below 4.25 volts, disconnect EVP sensor from harness. Inspect for and repair any damaged wiring. If wiring is good, replace EVP sensor. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If fault does not occur below 4.25 volts, EGR valve overshoot may have caused continuous code 31. Sensor test is complete. Go to next step for harness test.
23. Checking Harness - While in CONTINUOUS MONITOR (WIGGLE) TEST, bend, shake, and wiggle small sections of EEC-IV harness from sensor to firewall and from firewall to ECA. If fault is indicated, isolate fault and repair as necessary. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no fault is indicated, go to next step.
24. ECA and Harness Connectors - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect both connector and terminals for obvious damage. If connector and terminals are damaged, repair as necessary, then repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If connector and terminals are okay, fault cannot be duplicated at this time. Continuous code 31 testing is complete.

CIRCUIT TEST B5 - ENGINE COOLANT TEMPERATURE (ECT) SENSOR

Note. Perform this test when directed to by a Code 21, 51, or 61 during QUICK TEST procedure. For purposes of this test, a "warmed up" engine has a coolant temperature of 50-240°F (10-116°C) for KOEO SELF-TEST and 180-240°F (82-116°C) for ENGINE RUNNING (KOER) SELF-TEST. The test procedure will be invalid outside these ranges.

Engine Coolant Temperature (ECT) Sensor Circuit. Scheme 10

TYPICAL ENGINE COOLANT TEMPERATURE (ECT) SENSOR RESISTANCE

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: coolant or oil level, blocked or obstructed airflow, engine not at normal operating temperature, or cooling fan.

1. Code 21: Check Engine Temperature - Start engine and run at 2000 RPM for 2 minutes. Check that upper radiator hose is hot and pressurized. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) before continuing. If vehicle stalls, DO NOT service code 21 at this time, go directly to «DIAGNOSIS BY SYMPTOM»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) table. If code 21 is not displayed, service other codes as necessary (if displayed). If code 21 appears, go to next step.
2. Checking for VREF at TPS - Turn key off and wait 10 seconds. Disconnect TPS. Set DVOM on 20-volt scale. With KOEO measure voltage at TPS harness connector between VREF and signal return. If voltage is less than 4 volts or more than 6 volts, go to «CIRCUIT TEST A3»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a3-reference-voltage) , step 1). If voltage is between 4 and 6 volts, reconnect TPS and go to next step.
3. ECT Sensor Resistance - Ensure engine is fully warmed up for this step. Turn key off and wait 10 seconds. Disconnect wiring harness at ECT sensor. Set DVOM on 200K-ohm scale and measure resistance of ECT sensor. If reading is 1300-7700 ohms at engine coolant temperature of 140-240°F (60-116°C) with engine off and 1550-4550 ohms at 180-230°F (82-110°C) with engine running, replace ECA, connect ECT sensor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If readings are not correct for coolant temperature, replace ECT sensor, connect harness, and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
4. Code 51: Generate Code 61 - Turn key off and wait 10 seconds. Disconnect ECT sensor at wiring harness and inspect wiring for damage or corrosion. Connect a jumper wire between ECT signal and signal return terminals in sensor harness connector. Repeat «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 61 is displayed, replace ECT sensor and remove jumper wire. Reconnect harness to ECT sensor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 61 is not displayed, go to next step.
5. ECT Signal and Return Continuity Check - Turn key off and wait 10 seconds. With harness disconnected at ECT sensor and jumper removed from harness connector, disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between ECT signal at ECT connector and Test Pin No. 7. Measure resistance between signal return at ECT connector and Test Pin No. 46. If both readings are less than 5 ohms, replace ECA. Remove breakout box and connect ECA and ECT sensor. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If either reading is 5 ohms or more, repair open circuits. Remove breakout box, and connect ECA and ECT sensor. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
6. Code 61: Generate Code 51 - Turn key off and wait 10 seconds. Disconnect ECT sensor and inspect connector for damage or corrosion. Repair wiring and repeat «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 51 is displayed, replace ECT sensor, connect sensor, and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 51 is not displayed, go to next step.
7. Checking VREF at TPS - Turn key off and wait 10 seconds. Set DVOM on 20-volt scale. Disconnect TPS. Turn key on, leaving engine off. Measure voltage between VREF and signal return at TPS connector. If reading is less than 4 volts or more than 6 volts, go to «CIRCUIT TEST A3»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a3-reference-voltage) , step 1). If voltage is between 4 and 6 volts, connect TPS and go to next step.
8. Checking ECT Signal for Ground Short - Turn key off and wait 10 seconds. Disconnect harness from ECT sensor. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200K-ohm scale. Measure resistance between Test Pin No. 7 and Test Pins No. 40, 46 and 60. If any reading is less than 10K ohms, repair short circuits. Remove breakout box, connect ECA and ECT sensor, and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If all readings are 10K ohms or more, replace ECA. Remove breakout box, connect ECA and ECT sensor. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
9. Continuous Code 21: Test Drive - Turn key off and wait 10 seconds. Disconnect all SELF-TEST equipment and prepare vehicle for test drive. While driving vehicle, attempt to copy driving style in which complaint was noticed. If problem occurs, try to maintain condition for one or more minutes. After road test, repeat «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 21 is present in CONTINUOUS SELF-TEST, ensure that thermostat is working properly. If thermostat functions properly, replace ECT sensor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 21 is not displayed, fault cannot be duplicated at this time. Continuous code 21 testing is complete.
10. Continuous Code 51 or 61: Check ECT Sensor - Using «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) , observe VOM or diagnostic tester for indication of fault while tapping ECT sensor and wiggling ECT connector. If fault is indicated, disconnect and inspect ECT connector and terminals. If connector and terminals are okay, replace ECT sensor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no fault is indicated, go to next step.
11. Checking Harness - While in CONTINUOUS MONITOR (WIGGLE) TEST, observe VOM or diagnostic tester for indication of fault as you bend, shake or wiggle EEC-IV harness. Start at sensor connector and work toward firewall. Also test harness from firewall to ECA in same manner. If fault is indicated, isolate fault in wiring and repair as necessary. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If fault is not indicated, go to next step.
12. Checking ECA and Harness Connectors - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect both connectors and terminals for obvious damage. If connectors and terminals are damaged, repair as necessary and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If connectors and terminals are okay, fault cannot be duplicated at this time. Continuous code 51 or 61 testing is complete.

CIRCUIT TEST B6 - MANIFOLD ABSOLUTE PRESSURE (MAP)/BAROMETRIC PRESSURE (BP) SENSOR

Note. This test should be performed when Service Code 22 or 72 is displayed in QUICK TEST procedures, or when directed here by CIRCUIT TEST D20 or other symptom. Barometric pressure sensor output is digital and must be measured with MAP/BP tester.

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: unusually high/low atmospheric barometer reading, kinked or blocked vacuum lines, or engine condition (valves, vacuum leaks, valve timing, EGR valve, etc.).

Scheme 11

1. Code 22: Engine Off - Turn key off. Disconnect MAP/BP sensor from harness. Connect MAP/BP tester between wiring harness and MAP/BP sensor. Connect banana plugs of tester into DVOM and set DVOM on 20-volt scale. See MAP/BP TESTER HOOK-UP in (Scheme 11). Go to next step. (Scheme 11): MAP/BP Tester Hook-Up
2. Checking Power to Tester - With MAP/BP tester connected, turn key on. If only Green light on tester is lit, VREF is correct. Go to step 4. If "LESS THAN 4 VOLTS" Red light or no lights come on, VREF is too low. If "MORE THAN 6 VOLTS" Red light comes on, VREF is too high. If VREF is too high or too low, go to next step.
3. VREF Testing - With MAP/BP tester connected, turn key on. Disconnect MAP/BP sensor and repeat step 2). If only Green light comes on, VREF is correct. Replace MAP/BP sensor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If "LESS THAN 4 VOLTS" Red light or no lights come on, VREF is too low. If "MORE THAN 6 VOLTS" Red light comes on, VREF is too high. If VREF is too high or too low, remove MAP/BP tester, connect sensor, then go to «CIRCUIT TEST A3»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a3-reference-voltage), step 1).
4. Tester Output Reading - With MAP/BP tester connected and key on, measure sensor output voltage. If voltage output is in correct range for altitude of vehicle being tested, remove MAP/BP tester and go to next step. If output reading is outside range, remove MAP/BP tester and go to step 6. NOTE: Measure several known good MAP/BP sensors on available vehicles. Mean voltage reading will be typical for your location on date of testing. MAP VOLTAGE OUTPUT Elevation (Ft.) Voltage Output (Volts) 0 1.55-1.63 1000 1.52-1.60 2000 1.49-1.57 3000 1.46-1.54 4000 1.43-1.51 5000 1.40-1.48 6000 1.37-1.45 7000 1.35-1.43
5. Checking Signal Continuity - Turn key off and wait 10 seconds. Disconnect MAP/BP sensor from harness. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between MAP/BP signal at sensor connector and Test Pin No. 45. If reading is less than 5 ohms, replace ECA. Connect ECA and MAP/BP sensor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If reading is 5 ohms or higher, repair opens in wiring. Remove breakout box, connect ECA and MAP/BP sensor. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
6. Checking MAP/BP Signal For Shorts - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Disconnect harness at MAP/BP sensor. Set DVOM on 200K-ohm scale. Measure resistance between Test Pin No. 45 and Test Pins No. 26, 46, 40 and 60. If any reading is less than 10K ohms, repair shorts in wiring. Remove breakout box and connect ECA and MAP/BP sensor. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If all readings are 10K ohms or more, replace MAP/BP sensor. Remove breakout box and connect all wiring. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
7. Code 22 Displayed: Engine Running - Check to see if service codes 31, 32, 33, 34 or 35 are present. If so, go to «KEY ON ENGINE RUNNING (KOER) CODE-TO-CIRCUIT TEST MENU»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and perform appropriate CIRCUIT TEST. If not, go to next step.
8. Checking MAP Sensor - Turn key off and wait 10 seconds. Disconnect vacuum hose from MAP sensor. Connect vacuum pump to MAP sensor and apply 18 in. Hg. vacuum to sensor. If sensor does not hold vacuum, replace sensor, connect vacuum line and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If MAP sensor does hold vacuum, release vacuum and go to next step.
9. Eliminating Code 22 - Turn key off and wait 10 seconds. Plug vacuum hose going to MAP sensor. Start engine and run at 1400-1600 RPM. Slowly apply 15 in. Hg. vacuum to MAP sensor. With engine under these operating conditions, perform «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). Check for code 22, disregard any other codes at this time. If code 22 is still present, replace MAP sensor. If code 22 is no longer displayed, inspect vacuum hose going to MAP sensor. If okay, service other codes at this time. If there are none, check engine for cause of low vacuum.
10. Checking Vacuum at MAP Sensor - Turn key off and wait 10 seconds. Install vacuum gauge with "T" in manifold vacuum line at MAP sensor. Perform «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and observe vacuum reading before and during DYNAMIC RESPONSE CHECK portion of test. If vacuum decreased 10 in. Hg or more, remove vacuum gauge. Reconnect all components, replace MAP sensor and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If vacuum decreased less than 10 in. Hg, go to next step.
11. Vacuum Line Check - Check vacuum lines for correct routing, using vehicle emissions decal as a guide. Also check MAP sensor vacuum lines for kinks or blockage. If lines are good, EEC-IV system is okay. Check engine for cause of low vacuum. If vacuum lines are bad, repair as necessary and repeat step 10.
12. Connecting MAP/BP Tester - Turn key off. Disconnect MAP/BP sensor from harness. Connect MAP/BP tester between wiring harness and MAP/BP sensor. Connect banana plugs of tester into DVOM and set DVOM on 20-volt scale. See MAP/BP TESTER HOOK-UP in (Scheme 11). Go to next step.
13. Tester Output Reading - Turn key on and measure sensor output. Compare values to MAP VOLTAGE OUTPUT table. If reading is within range, go to «DIAGNOSIS BY SYMPTOM»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) table on the 2.3L Turbo MPFI. If reading is within range on all other engines, go to next step. If reading is out of range, replace MAP/BP sensor. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
14. Vacuum Line Check - Check map sensor vacuum lines for leaks, bad connections, kinks or blockage. If vacuum lines are okay, go to «DIAGNOSIS BY SYMPTOM»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) table. If vacuum lines are bad, repair as necessary and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
15. Code 22 Displayed: Operate MAP Sensor - Using «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test), observe VOM or diagnostic tester for indication of fault while doing the following: connect vacuum pump to MAP sensor and slowly apply 25 in. Hg. Bleed vacuum slowly, tap MAP sensor lightly, and wiggle MAP connector. If fault is indicated, disconnect sensor. Inspect connector and terminals for damage. If connector and terminals are okay, replace MAP sensor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If no fault is indicated, go to next step.
16. Checking Harness - Stay in CONTINUOUS MONITOR (WIGGLE) TEST. Observe VOM or diagnostic tester for indication of fault while shaking, bending or wiggling small sections of harness from sensor connector to firewall. Check harness from firewall to ECA in same manner. If fault is indicated, isolate fault in harness and repair as necessary. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If no fault is indicated, go to next step.
17. Checking ECA Connector and Harness - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect both connectors and terminals for obvious damage. If connectors and terminals are not okay, repair as necessary. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If connectors and terminals are okay, fault cannot be duplicated at this time. Continuous code 22 testing is complete.

CIRCUIT TEST B7 - KNOCK SENSOR

Note. Perform this test when Service Code 25 is received during QUICK TEST procedure or you are directed here by other diagnostic tests. Use DYNAMIC RESPONSE CHECK as specified in steps 1 and 6 . There is no need to perform WOT during this test. For additional information see DYNAMIC RESPONSE CHECK under QUICK TEST DIAGNOSTIC AIDS .

Knock (Detonation) Sensor Circuit. Scheme 12

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: fuel quality, engine condition (valves, vacuum leaks, valve timing, EGR valve, etc.) and spark timing.

1. Code 25 Displayed - Have 4 oz. hammer ready. Ensure engine is at normal operating temperature. Perform «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . When DYNAMIC RESPONSE CHECK signal appears, lightly tap above knock sensor with 4 oz. hammer. DO NOT "goose" throttle. After 15 seconds, check for code 25. Ignore all other codes at this time. If code 25 is displayed, go to next step. If code 25 is not displayed, knock system is okay. Repeat KOER SELF-TEST and service other codes.
2. Circuit Voltage Check - Turn key off and wait 10 seconds. Disconnect knock sensor. Inspect for and repair any damaged wiring. Set DVOM on 20-volt scale. With KOEO measure voltage at knock sensor connector between Knock Sensor (KS) signal and signal return. If reading is greater than 4 volts, go to step 5 . If voltage is 1-4 volts, go to step 6 . If reading is less than one volt, go to next step.
3. Check Continuity of KS Signal Return Circuit - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA and knock sensor disconnected. With DVOM on 200-ohm scale, measure resistance between knock sensor connector signal return and Test Pin No. 46, and between knock sensor connector KS signal and Test Pin No. 23. If either reading is 5 ohms or more, service open circuit and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If both readings are less than 5 ohms, go to next step.
4. Checking Circuit for Short to Ground - Turn key off and wait 10 seconds. With breakout box installed, ECA and knock sensor disconnected, set DVOM on 200K-ohm scale. Measure resistance between knock sensor connector KS signal and Test Pins No. 40, 46 and 60. If all readings are 10K ohms or higher, go to step 6 . If any reading is less than 10K ohms, repair shorts in harness and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
5. Checking Circuit for Short to Power - Turn key off and wait 10 seconds. With breakout box installed, ECA and knock sensor disconnected, set DVOM on 20-volt scale. Turn key on, leaving engine off. Measure voltage between Test Pins No. 23 and 40. If reading is 0.5 volt or more, repair knock sensor harness short to power, and then repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 0.5 volt, go to next step.
6. Test By Substitution - Turn key off and wait 10 seconds. Remove breakout box and connect ECA. Connect substitute knock sensor (same Part No.) into harness but do not install in engine. Perform «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . When DYNAMIC RESPONSE CHECK signal appears, lightly tap knock sensor with 4 oz. hammer. DO NOT "goose" throttle. If code 25 is displayed replace ECA, reconnect original knock sensor and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 25 does not appear, install new knock sensor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .

CIRCUIT TEST B8 - THROTTLE POSITION SENSOR (TPS)

Note. Perform this test when Service Code 23, 53, 63, or 73 is displayed during QUICK TEST .

Throttle Position Sensor (TPS) Circuit. Scheme 13

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: idle speed/throttle stop adjustment, binding throttle shaft/linkage or cruise control linkage, or choke/high cam system (if equipped).

1. Code 23 Displayed - If KOEO SELF-TEST code 68 or KOER SELF-TEST codes 31, 41, or 58 are displayed, service these codes first. Disregard code 23 at this time. If these codes have been serviced or are not displayed, go to next step.
2. Check Throttle Plate - Inspect throttle body and linkage for mechanical binding or sticking. Make sure linkage is set with throttle in closed position. If throttle plate or linkage is binding, check for binding throttle or cruise control linkage, vacuum line or harness interference, etc. Repair problem(s) and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no mechanical problem is found, go to next step.
3. Code 53: Generate Code 63 - Turn key off and wait 10 seconds. Disconnect TPS from harness at throttle body. Inspect for and repair any damaged wiring. Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . Check for code 63. Ignore all other codes at this time. If code 63 is not displayed, go to step 5 . If code 63 is displayed, go to next step.
4. Check VREF to Signal Return - Turn key off and wait 10 seconds. Set DVOM on 20-volt scale and disconnect TPS from harness. Inspect for and repair any damaged wiring. With KOEO, measure voltage at TPS connector between VREF and signal return. If reading is less than 4 volts or more than 6 volts, go to «CIRCUIT TEST A3»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a3-reference-voltage) , step 1). If reading is between 4 and 6 volts, replace TPS and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
5. Checking TP Signal For Shorts - Turn key off and wait 10 seconds. Disconnect TPS from harness. Set DVOM on 200K-ohm scale. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Measure resistance between Test Pin No. 47 and Test Pins No. 26 and 57. If either reading is less than 10K ohms, repair short in harness and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If both readings are 10K ohms or more, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
6. Code 63: Generate Code 53 - Turn key off and wait 10 seconds. Disconnect TPS from harness. Install a jumper wire between VREF and TPS signal at connector. Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . Check for codes 53 or 23. Ignore all other codes at this time. If no codes are displayed, immediately remove jumper wire, and go to step 9 . If either code 53 or 23 are displayed, replace TPS and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If neither code 53 or 23 are displayed, go to next step.
7. Code 63: Check Voltage VREF to Signal Return - Turn key off and wait 10 seconds. Disconnect TPS from harness. Inspect for and repair any damaged wiring. Set DVOM on 20-volt scale. Turn key on, leaving engine off. Measure voltage between VREF and signal return at TPS connector. If reading is less than 4 volts or more than 6 volts, go to «CIRCUIT TEST A3»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a3-reference-voltage) , step 1). If reading is between 4 and 6 volts, go to next step.
8. Checking TPS Circuit Continuity - Turn key off and wait 10 seconds. Leave TPS disconnected. Set DVOM on 200-ohm scale and disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box and connect ECA. Measure resistance between TPS signal at connector and Test Pin No. 47. If reading is 5 ohms or more, repair faulty circuit. Remove breakout box, connect ECA and TPS, and then repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 5 ohms, go to next step.
9. Checking Resistance of Ground/Signal Return - Turn key off and wait 10 seconds. Leave TPS disconnected. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box and set DVOM on 200K-ohm scale. Measure resistance at connector between TPS signal and ground, and between TPS signal and Test Pin No. 46. If either reading is less than 10K ohms, repair short circuit and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If both readings are 10K ohms or more, replace ECA. Remove breakout box, connect TPS, and then repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . NOTE: Code 73 in step 10 indicates that TPS did not exceed 25% of its rotation during DYNAMIC RESPONSE CHECK. For additional information, see DYNAMIC RESPONSE CHECK under «QUICK TEST DIAGNOSTIC AIDS»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
10. Code 73: TPS Movement - Turn key off. Install breakout box and set DVOM on 20-volt scale. Connect DVOM to Test Pins No. 46 and 47. Perform «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . Verify that DVOM reading exceeds 3.5 volts during WOT of DYNAMIC RESPONSE CHECK. If reading exceeds 3.5 volts, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading does not exceed 3.5 volts, ensure TPS is correctly installed and adjusted. If okay, replace TPS and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
11. Code 53: TPS Movement - Using «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) , observe VOM or diagnostic tester for indication of fault while slowly opening throttle to WOT. Slowly bring throttle to closed position, lightly tap TPS and wiggle connector. If no fault is indicated, go to step 13 . If fault is indicated, go to next step.
12. TPS Voltage Measurement - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA connected. Stay in «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) and connect DVOM between Test Pins No. 47 and 46. Set DVOM on 20-volt scale. Turn key on, leaving engine off. Observe DVOM and repeat step 11 . If fault occurs at less than 4.25 volts, inspect TPS connectors and terminals. If okay, replace TPS and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If fault does not occur at less than 4.25 volts, TPS over-travel may have caused continuous code 53. TPS is good, go to next step to check harness.
13. Checking Harness - While in CONTINUOUS MONITOR (WIGGLE) TEST, shake, bend and wiggle small sections of EEC-IV harness from TPS sensor to firewall, and from firewall to ECA. If fault is indicated, isolate fault in wiring and repair as necessary. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no fault is indicated, go to next step.
14. Checking Harness Connectors - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect both connectors and terminals for obvious damage. If connectors and terminals are damaged, repair as necessary. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If connectors and terminals are okay, fault cannot be duplicated at this time. Continuous code 53 testing is complete.
15. Continuous Code 63 Displayed - Using «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) , observe VOM or diagnostic tester for indication of fault while slowly opening throttle to WOT. Slowly bring throttle to closed position and lightly tap TPS and wiggle connector. If fault is indicated, disconnect TPS. Inspect connectors and terminals. If connectors and terminals are okay, replace TPS and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no fault is indicated, go to next step.
16. Harness Test - While in CONTINUOUS MONITOR (WIGGLE) TEST, shake, bend and wiggle small sections of EEC-IV harness from TPS sensor to firewall, and from firewall to ECA. If fault is indicated, isolate fault in wiring and repair as necessary. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no fault is indicated, go to next step.
17. ECA Connector Test - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect both connectors and terminals for obvious damage. If connectors and terminals are damaged, repair as necessary. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If connectors and terminals are okay, fault cannot be duplicated at this time. Continuous code 63 testing is complete.

CIRCUIT TEST B9 - VANE AIRFLOW (VAF) SENSOR

Note. Perform this test when Service Code 26, 56, 66, or 76 is displayed during QUICK TEST or when directed here by other test procedures.

VAF Sensor Circuits. Scheme 14

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: check for air leaks between vane airflow meter and throttle body. Check for vacuum leaks. Check engine sealing at PCV, CANP, valve cover(s), and at dipstick seal.

Scheme 15

1. Code 26: VAF Movement Obstructed - Code 26 indicates VAF sensor input to ECA is out of closed (engine not running) or idle limits (engine off 0.15 to 0.50 volts; engine idling 1.5 to 2.7 volts). There have been no shorts or opens in VAF circuit; either code 56 (signal always high) or code 66 (signal always low) would have been displayed. Turn key off and wait 10 seconds. Remove air filter and check for contamination (oil or foreign matter). If code 26 appears in KOEO SELF-TEST, replace airflow meter. Install air cleaner and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If code 26 is not displayed, go to next step.
2. Checking VAF Sensor - With key off and air filter installed, check for air leaks allowing unmetered air into system between airflow meter and throttle body. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box and connect ECA to box. Set DVOM on 20-volt scale. Turn key on, leaving engine off. Place new, unsharpened pencil through air inlet opening of airflow meter. See VAF SENSOR CHECK. (Scheme 15) Measure voltage between Test Pins No. 43 (No. 27 on 2.3L Turbo MPFI) and 46. If reading is between 2.8 and 3.7 volts, airflow meter is okay. Code 26 has been caused by incorrect engine speed or vacuum leak. Repair problem, remove breakout box, then repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If reading is not between 2.8 and 3.7 volts, replace ECA, remove breakout box, repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). (Scheme 15): VAF Sensor Check
3. Code 56: Generate Code 66 - Turn key off and wait 10 seconds. Disconnect harness from airflow meter. Inspect for and repair any damaged wiring. Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If code 66 is not displayed, go to step 5. If code 66 is displayed, go to next step. Disconnecting airflow meter also disconnects VAT sensor. Code 54 should be displayed. Ignore all codes except VAF codes at this time.
4. Checking VAF Signal Return Voltage - Turn key off and wait 10 seconds. Leave harness disconnected from airflow meter. Set DVOM on 20-volt scale. With KOEO measure voltage at harness connector between VREF and signal return. If reading is between 4 and 6 volts, replace airflow meter. Connect harness and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If reading is less than 4 or more than 6 volts, go to «CIRCUIT TEST A3»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a3-reference-voltage), step 1).
5. Checking VAF Signal For Shorts - Turn key off and wait 10 seconds. Leave airflow meter disconnected. Disconnect 60-pin connector from ECA. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200K-ohm scale. Measure resistance between Test Pin No. 43 (27 on 2.3L Turbo MPFI engine) and Test Pins No. 26 and 57. If either reading is less than 10K ohms, repair short in wiring. Remove breakout box. Connect ECA and airflow meter and then repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If both readings are 10K ohms or more, replace ECA. Remove breakout box. Connect ECA and airflow meter. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
6. Code 66: Generate Code 56 - Turn key off and wait 10 seconds. Disconnect harness from airflow meter. Install jumper wire between VREF and VAF signal at connector. Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). Ignore all codes except VAF codes at this time. If no codes are displayed, immediately remove jumper wire and go directly to step 9. If code 56 is displayed, replace airflow meter. Remove jumper wire, connect airflow meter, and then repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If code 56 is not displayed, remove jumper wire and go to next step.
7. Checking VREF at VAF - Turn key off and wait 10 seconds. Leave airflow meter disconnected. Turn key on, leaving engine off. Set DVOM on 20-volt scale. Measure voltage between VREF and signal return at airflow meter harness connector. If reading is less than 4 volts or more than 6 volts, go to «CIRCUIT TEST A3»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a3-reference-voltage), step 1). If reading is between 4 and 6 volts, go to next step.
8. Checking Continuity of VAF Signal - With key off and airflow meter disconnected, disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between VAF signal at airflow connector and Test Pin No. 43 (27 on 2.3L Turbo MPFI engine). If reading is 5 ohms or more, repair open circuit. Remove breakout box, connect ECA and airflow meter. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If reading is less than 5 ohms, go to next step.
9. Checking VAF Signal For Short to Ground - Turn key off and wait 10 seconds. Leave ECA and airflow meter disconnected. Set DVOM on 200K-ohm scale. Measure resistance between VAF signal and signal return at harness connector. Also measure resistance between VAF signal and negative battery terminal. If either reading is less than 10K ohms, repair shorts. Connect airflow meter and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If both readings are 10K ohms or more, replace ECA. Remove breakout box, and connect ECA and airflow meter. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). NOTE: A sharp snap of the throttle may not be sufficient to pass step 10. Be sure to move throttle to WOT. Use DYNAMIC RESPONSE CHECK as specified. For additional information, see DYNAMIC RESPONSE CHECK under «QUICK TEST DIAGNOSTIC AIDS»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
10. Code 76 Displayed - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Install breakout box and connect ECA to box. Set DVOM on 20-volt scale. Connect DVOM to Test Pin No. 43 (27 on 2.3L Turbo MPFI engine) and 46. Perform «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) while observing DVOM. As soon as DYNAMIC RESPONSE CHECK signal is displayed, perform WOT. Reading on DVOM should increase by more than 2 volts from reading before WOT. Observe service codes at end of test. If reading increased by more than 2 volts, go to next step. If not, check air cleaner duct for obstructions. If okay, replace vane airflow meter.
11. Checking Service Codes - Observe KOEO SELF-TEST service codes at end of step 10. If code 76 is still displayed, replace ECA. Remove breakout box and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If code 76 is not displayed, vane airflow meter is okay. Service other codes as necessary.
12. Continuous Code 56 or 66 Displayed - Using «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test), observe VOM or diagnostic tester for indication of fault while lightly tapping VAF sensor and wiggling connector. If a fault is indicated, disconnect connector. Inspect connector and terminals for damage. If connector and terminals are okay, replace VAF sensor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If no fault is indicated, go to next step.
13. Checking Harness - While in CONTINUOUS MONITOR (WIGGLE) TEST, shake, bend and wiggle small sections of EEC-IV harness from VAF sensor connector to firewall and from firewall to ECA. If fault is indicated, isolate and repair damaged wiring. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If no fault is indicated, go to next step.
14. Checking Harness Connectors - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect both connectors and terminals for obvious damage. If connectors and terminals are damaged, repair as necessary and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If connectors and terminals are okay, fault cannot be duplicated at this time. Continuous code 56 or 66 testing is complete.

CIRCUIT TEST B10 - PRESSURE FEEDBACK EGR (PFE) & EGR VALVE REGULATOR (EVR)

Note. Perform this test when Service Code 31, 32, 33, 34, 35 or 84 is displayed during QUICK TEST or when directed here by other test procedures.

Pressure Feedback EGR (PFE) & EGR Valve Regulator (EVR) Circuits. Scheme 16

1. Code 31: Generate Code 35 - Turn key off. Disconnect PFE harness at sensor. Install a jumper wire between VREF and PFE signal at sensor connector. Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . Check for code 35. Ignore all other codes at this time. If no codes are displayed, immediately remove jumper wire and go directly to step 4 . If code 35 is displayed, remove jumper wire and replace PFE sensor. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 35 is not displayed, go to next step.
2. Measuring VREF Signal Return Voltage - With key off and PFE harness disconnected, set DVOM on 20-volt scale. With KOEO, measure voltage at PFE connector between VREF and signal return. If reading is less than 4 volts or more than 6 volts, go to «CIRCUIT TEST A3»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a3-reference-voltage) , step 1). If reading is between 4 and 6 volts, go to next step.
3. PFE Signal Continuity - With key off and PFE harness disconnected, set DVOM on 200-ohm scale. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Measure resistance between PFE signal at connector and Test Pin No. 27. If reading is 5 ohms or more, repair faulty circuit. Connect PFE sensor and remove breakout box. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 5 ohms, go to next step.
4. PFE Signal Circuit Resistance - With key off and PFE harness disconnected, install breakout box leaving ECA disconnected. Set DVOM on 200K-ohm scale. Measure resistance between ground and PFE signal at connector. Measure resistance between PFE signal at connector and Test Pin No. 46. If either reading is less than 10K ohms, repair short circuit. Connect PFE and remove breakout box. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If both readings are 10K ohms or more, replace ECA. Connect PFE and remove breakout box. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
5. Code 35: Generate Code 31 - Turn key off and disconnect PFE harness at sensor. Inspect for and repair any damaged wiring. Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . Check for code 31. Ignore all other codes at this time. If code 31 is not displayed, go to step 7 . If code 31 is displayed, go to next step.
6. Measuring VREF Signal Voltage - With key off and PFE harness disconnected, set DVOM on 20-volt scale. Turn key on, leaving engine off. Measure voltage at PFE connector between VREF and signal return. If reading is between 4 and 6 volts, replace PFE sensor. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 4 volts or more than 6 volts, go to «CIRCUIT TEST A3»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a3-reference-voltage) , step 1).
7. Checking PFE Circuit For Shorts - With key off and PFE harness disconnected, disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200K-ohm scale. Measure resistance between Test Pin No. 27 and Test Pins No. 26 and 57. If either reading is less than 10K ohms, repair short. Connect PFE and remove breakout box. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If both readings are 10K ohms or more, replace ECA. Connect PFE and remove breakout box. Repeat QUICK TEST.
8. Code 34: PFE Sensor Beyond Range - The PFE system can detect lack of pressure in exhaust system. An efficient garage exhaust ventilation system, installed during KOEO SELF-TEST, may cause PFE sensor to generate code 34. Remove exhaust ventilation system and retest. If code 34 is not displayed, service other codes displayed during KOEO SELF-TEST. If none are displayed, continue with «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 34 is displayed, go to next step.
9. Inspecting Supply to PFE Sensor - Remove pressure feed tube from PFE sensor. Inspect complete tube, including PFE inlet for blockage. If blockage is found, repair as necessary. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no blockage is found, go to next step.
10. Measuring VREF Signal Return Voltage - Turn key off and disconnect PFE sensor. Inspect for and repair any damaged wiring. Set DVOM on 20-volt scale. Turn key on, leaving engine off. Measure voltage at PFE connector between VREF and signal return. If reading is between 4 and 6 volts, replace PFE sensor. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 4 volts or more than 6 volts, go to «CIRCUIT TEST A3»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a3-reference-voltage) , step 1).
11. Code 84: Measure EVR Solenoid Resistance - Turn key off. Set DVOM on 200-ohm scale. Disconnect EVR solenoid connector and measure solenoid resistance. If reading is less than 30 ohms or more than 70 ohms, replace EVR solenoid assembly. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is between 30 and 70 ohms, go to next step.
12. Checking VPWR at EVR Solenoid - With key off and EVR solenoid disconnected from harness, set DVOM on 20-volt scale. Turn key on, leaving engine off. Measure voltage between negative battery terminal and VPWR circuit at EVR solenoid connector. If reading is less than 10.5 volts, repair VPWR open circuit. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is 10.5 volts or more, go to next step.
13. Checking Continuity of EVR Circuit - Turn key off and disconnect EVR solenoid from harness. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between Test Pin No. 33 and EVR signal at EVR solenoid connector. If reading is 5 ohms or more, repair open circuit. Connect EVR solenoid and remove breakout box. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 5 ohms, go to next step.
14. Checking EVR Circuit For Ground Shorts - Turn key off. Install breakout box, leaving ECA disconnected. Disconnect EVR solenoid. Set DVOM on 200K-ohm scale. Measure resistance between Test Pin No. 33 and Test Pins No. 37, 57, 40 and 60 at the breakout box. If any reading is less than 10K ohms, repair short circuit. Remove breakout box. Connect ECA and EVR solenoid. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code is repeated, replace ECA. If all readings are 10K ohms or more, replace ECA. Remove breakout box. Connect ECA and EVR solenoid. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
15. Code 32: Verify Engine Running Codes - The PFE system can detect a lack of pressure in exhaust system. An efficient garage exhaust ventilation system, installed during KOER SELF-TEST, may cause PFE sensor to generate code 32. Temporarily remove exhaust ventilation system and retest. If code 32 is not displayed, service other codes displayed during KOER SELF-TEST. If none, continue with «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 32 is displayed, go to next step.
16. Separating EVR From PFE - Turn key off. Disconnect and plug EGR valve vacuum hose. Perform «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If codes 31 or 32 are present, go to next step. If not, go to step 18 .
17. Checking PFE Supply Tube - With key off, check PFE sensor supply tube for blockage and/or leaks. If these faults are found, repair as necessary. Connect all lines and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no faults are found, service exhaust gas recirculation system.
18. EVR Filter Inspection - Turn key off. Remove and inspect EVR filter for contamination. A blocked filter will cause vacuum to be applied to EGR valve prematurely. If filter is contaminated, replace filter. Connect all lines and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If filter is not contaminated, replace EVR solenoid. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
19. Codes 34 or 35: Excessive Backpressure - Service codes 34 and 35 in KOER SELF-TEST indicate excessive exhaust backpressure. There are 2 possible causes: the exhaust system is blocked, or PFE sensor has shifted into high. Turn key off. Substitute known good PFE sensor in place of original. Repeat «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 34 or 35 is not displayed, replace PFE sensor. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 34 or 35 is displayed, check exhaust system for restrictions.
20. Code 33: Verify Vacuum Supply - Turn key off. Using a vacuum "T", connect vacuum gauge at EGR valve. Perform «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) while observing vacuum gauge. Disregard code output. If vacuum reading is greater than one in. Hg, go to step 23 . If vacuum reading is one in. Hg or less, go to next step.
21. Vacuum Hose Inspection - With key off, check vacuum hose from EVR solenoid to EGR valve and from vacuum source to EVR solenoid for loose connections, obstructions, cracks, etc. If vacuum hoses are damaged, repair or replace as necessary. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If hoses are okay, go to next step.
22. Vacuum Supply Verification - Start engine. Attach vacuum gauge to EVR solenoid hose coming from engine manifold (vacuum source). If vacuum is present, replace EVR solenoid. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no vacuum is present, replace vacuum hose to EVR solenoid and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
23. Checking PFE Sensor Tube - Turn key off. If control pressure input tube to PFE sensor is disconnected, blocked or cracked, repair or replace tube as necessary. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If tube is okay, replace PFE sensor. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
24. Continuous Code 31 or 35: Testing PFE Sensor - Using «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) , observe VOM or diagnostic tester for indication of fault while performing the following steps: connect a vacuum pump to PFE sensor, slowly apply 5 in. Hg vacuum to sensor, and then slowly bleed vacuum off PFE sensor. Lightly tap on PFE sensor and wiggle PFE connector. If fault is indicated, disconnect harness and inspect connector. If connector and terminals are okay, replace PFE sensor. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no fault is indicated, go to next step.
25. Checking Harness - Observe VOM or diagnostic tester for fault indication while grasping harness close to sensor connector, then wiggling, shaking or bending small sections of harness while working your way to firewall. Also wiggle, shake or bend harness from firewall to ECA. If fault is indicated, isolate fault and repair as necessary. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If fault is not indicated, go to next step.
26. Checking ECA and Harness Connectors - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect both connector and terminals for damage. If connector and terminals are damaged, repair as necessary. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If connector and terminals are okay, fault cannot be duplicated at this time. Continuous code 31 or 35 testing is complete.
27. Continuous Code 34: PFE Supply Tube - Turn key off. Remove PFE sensor and inspect sensor supply inlet for liquids and/or any type of blockage. Inspect PFE supply tube at EGR valve base for liquids and/or blockage. If supply tube is blocked, clean or service as necessary. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If supply tube is not blocked, fault cannot be duplicated at this time. Continuous code 34 testing is complete.
28. Continuous Code 32: EGR Valve Operation - Turn key off. Connect vacuum pump to EGR valve and apply 10 in. Hg of vacuum. While observing EGR valve, release vacuum, and repeat step if necessary. If EGR valve does not work smoothly, service exhaust gas recirculation system. If EGR valve works smoothly, go to next step.
29. Vacuum Line Inspection - Inspect EGR valve vacuum supply line from EVR solenoid for kinks and/or obstructions. If vacuum supply line is blocked, repair as necessary. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If vacuum supply line is okay, go to next step.
30. EVR Filter Inspection - Carefully check EVR filter for contamination and/or obstructions. If EVR filter is contaminated, replace filter and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If EVR filter is not contaminated, fault cannot be duplicated at this time. Continuous code 32 testing is complete.
31. Continuous Code 33: EGR Valve Operation - Turn key off. Connect a vacuum pump to EGR valve. While observing EGR valve, slowly apply 10 in. Hg of vacuum. EGR valve should begin to open at about one in. Hg and be fully open at 4 in. Hg of vacuum. If EGR valve does not move freely and smoothly, service exhaust gas recirculation system. If EGR valve moves freely and smoothly, go to next step.
32. EVR Harness Test - With key off, disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, then connect ECA to box. Enter «OUTPUT STATE CHECK»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__output-state-check) . Set DVOM on 20-volt scale. Connect DVOM negative test lead to pin No. 40 and DVOM positive test lead on pin No. 33. Move throttle valve to indicate 10.5 volts or more and maintain position. While observing DVOM, grasp harness closest to EVR connector. Wiggle, shake or bend a small sections of harness while working your way to firewall. Lightly tap EVR solenoid to simulate road vibration. If DVOM reads 10.5 volts or less, isolate fault and repair as necessary. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If DVOM reads 10.5 volts or more, fault cannot be duplicated at this time. Continuous code 33 testing is complete.

CIRCUIT TEST B11 - EGR VALVE POSITION (EVP) & EGR VALVE REGULATOR (EVR)

Note. Perform this test when Service Code 31, 32, 33, 34, 35, 38 or 84 is displayed during QUICK TEST or when directed here by other test procedures.

EGR Valve Position (EVP) & EGR Valve Regulator (EVR) Circuits. Scheme 17

1. Code 31: Generate Code 35 - Turn key off. Disconnect EVP harness at sensor. Install a jumper wire between VREF and EVP signal at sensor harness connector. Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . Check for code 35. Ignore all other codes at this time. If code 35 is displayed, replace EVP sensor. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 35 is not displayed, remove jumper wire and go to next step.
2. Checking VREF to Signal Return Voltage - With key off and EVP disconnected, set DVOM on 20-volt scale. With KOEO, measure voltage at EVP connector between VREF and signal return. If reading is less than 4 or more than 6 volts, go to «CIRCUIT TEST A3»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a3-reference-voltage) , step 1). If reading is between 4 and 6 volts, go to next step.
3. Checking EVP Signal Continuity - With key off and EVP sensor disconnected, set DVOM on 200-ohm scale. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, then connect ECA to box. Measure resistance between EVP signal at connector and Test Pin No. 27. If reading is 5 ohms or more, repair open circuit. Connect EVP sensor and remove breakout box. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 5 ohms, go to next step.
4. Checking EVP For Shorts To Ground - With key off and EVP harness disconnected, leave breakout box installed and ECA disconnected. Set DVOM on 200K-ohm scale. Measure resistance between EVP signal at EVP connector and ground. Measure resistance between EVP signal at EVP connector and Test Pin No. 46. If either reading is less than 10K ohms, repair short circuit. Connect EVP and remove breakout box. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If both readings are 10K ohms or more, replace ECA. Connect EVP and remove breakout box. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
5. Code 35: Generate Code 31 - Turn key off. Disconnect EVP harness at sensor. Inspect for and repair any damaged wiring. Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . Check for code 31. Ignore all other codes at this time. If code 31 is not displayed, go to step 7 . If code 31 is displayed, go to next step.
6. Checking VREF To Signal Return Voltage - With EVP harness disconnected, set DVOM on 20-volt scale. With KOEO, measure voltage at EVP harness connector between VREF and signal return. If reading is between 4 and 6 volts, replace EVP sensor. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 4 volts or more than 6 volts, go to «CIRCUIT TEST A3»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a3-reference-voltage) , step 1).
7. Checking EVP Signal For Short To Power - Turn key off and disconnect EVP from harness. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200K-ohm scale. Measure resistance between Test Pin No. 27 and Test Pins No. 26 and 57. If either reading is less than 10K ohms, repair short in harness. Connect EVP sensor and remove breakout box. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If both readings are 10K ohms or more, replace ECA. Connect EVP sensor and remove breakout box. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
8. Code 84: EVR Solenoid Resistance - Turn key off. Set DVOM on 200-ohm scale. Disconnect EVR solenoid connector and measure solenoid resistance. If reading is less than 30 ohms or more than 70 ohms, replace EVR solenoid assembly. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is between 30 and 70 ohms, go to next step.
9. Checking VPWR at EVR Solenoid - Leave EVR solenoid disconnected and set DVOM on 20-volt scale. Turn key on, leaving engine off. Measure voltage between negative battery terminal and VPWR circuit at solenoid harness connector. If reading is less than 10.5 volts, repair VPWR open circuit. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is 10.5 volts or more, go to next step.
10. EVR Circuit Continuity - With key off and EVR solenoid disconnected, disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between Test Pin No. 33 and EVR signal at EVR solenoid connector. If reading is 5 ohms or more, repair open circuit. Connect EVR solenoid and remove breakout box. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 5 ohms, go to next step.
11. Checking EVR Circuit Shorts - With key off, breakout box installed, and ECA and EVR solenoid disconnected, set DVOM on 200K-ohm scale. Measure resistance between Test Pin No. 33 and Test Pins No. 37 and 57, 40, 60, and 46 at breakout box. If any reading is less than 10K ohms, repair short circuit. Remove breakout box, and connect ECA and EVR solenoid. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code is repeated, replace ECA. If all readings are 10K ohms or more, replace ECA. Remove breakout box, and connect ECA and EVR solenoid. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
12. Code 34: Check For Code 84 - Turn key off and wait 10 seconds. Check for Code 84 in «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 84 is present, go to step 8 . If code 84 is not displayed, go to next step.
13. Substitute EVP Sensor on EGR Valve - Install a good known EVP sensor on original EGR valve. Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 34 is present, check EGR valve for mechanical malfunction. If code 34 is not present, replace original EVP sensor. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . NOTE: Code 34 indicates that the EGR valve and/or EVP sensor are not fully seated in the closed position. Preload on EVP sensor makes it difficult to determine whether EGR valve is not seated or if the EVP sensor is not in contact with EGR valve stem.
14. KOEO Self-Test Code 32 Displayed - Turn key off and wait 10 seconds. Install a known good EVP sensor on original EGR valve. Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 32 is present, check EGR valve for mechanical malfunction. If code 32 is not present, replace original EVP sensor. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . NOTE: Code 32 indicates that EGR valve and/or EVP sensor is lower than normal in closed position. Preload on EVP sensor makes it difficult to determine whether the EGR valve has malfunctioned or if the EVP sensor has abnormally high resistance.
15. Code 33: Checking Vacuum at EGR - Turn key off. Using vacuum "T", connect vacuum gauge at EGR valve. Perform «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and observe vacuum gauge. If reading is 1.5 in. Hg or greater, go to step 18 . If reading is less than 1.5 in. Hg, go to next step.
16. Checking Vacuum Supply to EVR Solenoid - Turn key off. Disconnect vacuum source to EVR solenoid. Install vacuum gauge at source vacuum hose. Start engine. If reading is 10 in. Hg or more, go to next step. If reading is less than 10 in. Hg, check vacuum hose to EVR solenoid. Replace if necessary. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
17. Checking Vacuum Hoses - Carefully check vacuum line for cracks, loose connections, blockage, kinks, and leaks. If vacuum hose is not okay, replace hose. Connect new vacuum hose and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If vacuum hose is okay, check EVR solenoid filter for obstructions. Replace if necessary. If filter is okay, replace EVR solenoid. Connect all vacuum hoses and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
18. Substituting EVP Sensor - Turn key off and wait 10 seconds. Install a known good EVP sensor on original EGR valve. Perform «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 33 is present, check EGR valve and/or system for mechanical malfunction. If code 33 is not present, replace original EVP sensor. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
19. Code 34: EGR Valve Operation - Turn key off. Disconnect and plug EGR valve vacuum hose. Perform «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 34 is not present, check EVR filter for obstructions. Replace if necessary. If filter is okay, replace EVR solenoid. Connect all vacuum hoses and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 34 is present, go to next step.
20. Testing EVP Resistance - Turn key off. Disconnect harness from EVP sensor. Inspect connectors for damaged pins or corrosion. Repair if necessary. Set DVOM on 200K-ohm scale. Disconnect vacuum hose to EGR valve and connect vacuum pump to valve. Measure resistance at EVP sensor between signal return and VREF while gradually increasing vacuum to 10 in. Hg. If reading decreases from no more than 5500 ohms to no less than 100 ohms, check EGR valve for mechanical malfunction. If reading does not change as indicated, replace EVP sensor. Reconnect vacuum hose.
21. Code 32: EVP Signal Voltage - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box and connect ECA. Connect vacuum pump to EGR valve. Place DVOM on 20-volt scale and connect between Test Pins No. 27 and 46. With KOEO, observe DVOM readings. Slowly apply 6 in. Hg vacuum to EGR valve. Slowly bleed vacuum off EGR valve and lightly tap on EVP sensor to simulate road shock. If any readings are less than .29 volts the EGR valve may have caused code 32. Check EGR valve for mechanical malfunction. If all readings are more than .29 volts code 32 fault cannot be duplicated at this time. Testing is completed.
22. Continuous Code 31 and/or 35: Check Harness - Using «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) , observe VOM or diagnostic tester for fault indication while grasping harness close to sensor and wiggling, shaking, or bending a small section of EEC-IV harness while working toward firewall. Code 31 indicates a short between the EVP Signal and Signal Return circuit. Code 35 indicates a short between the VREF and EVP signal circuit. Wiggle, shake or bend harness from firewall to ECA. If fault is indicated, isolate fault and repair wiring harness as required. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If fault is not found, go to next step.
23. Checking ECA and Harness Connectors - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector and terminals for obvious damage. If connector and terminals are damaged, repair as necessary. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If connector and terminals are okay, fault cannot be duplicated at this time. Test is completed.
24. Code 33: Leak Test - Turn key off. Connect vacuum pump to EGR valve. Apply 20 in. Hg to EGR valve. If EGR valve opens and holds vacuum, go to next step. If not, check EGR valve for mechanical malfunction.
25. EVR Check - Using «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) , observe VOM or diagnostic tester for fault indication. Grasp harness close to EVR solenoid connector and wiggle, shake, or bend a small section of harness while working toward ECA. Inspect connectors and terminals for obvious damage. If fault is indicated, isolate fault and repair as necessary. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no fault is indicated, fault cannot be duplicated at this time. Testing is completed.
26. Continuous Code 34: EVP Resistance Check - Turn key off. Disconnect harness from EVP sensor. Inspect connector for obvious damage. Place DVOM on 200K-ohm scale. Disconnect vacuum hose to EGR valve and connect vacuum pump to valve. Measure resistance at EVP sensor between Test Pins No. 26 and 27 while increasing vacuum to 10 in. Hg. If reading does not decrease gradually, check EGR valve for mechanical malfunction. If reading gradually decreases from no more than 5500 ohms to no less than 100 ohms, go to next step.
27. EVR Check - Turn key off. Disconnect vacuum hose from EGR valve and plug hose. Perform «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 34 is present, check EVR filter for obstructions. Replace if necessary. If filter is okay, replace EVR solenoid. Connect all vacuum hoses and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 34 is not present, fault cannot be duplicated at this time. Testing is completed.

CIRCUIT TEST B12 - VEHICLE SPEED SENSOR (VSS)

Note. Perform this test when Service Code 29 is displayed during QUICK TEST or when directed here by other test procedures.

Vehicle Speed Sensor Circuit. Scheme 18

To prevent replacement of good components, be aware that the following circuit test is to be used only when Continuous Memory Code 29 is displayed. This test checks vehicle speed sensor, wiring harness, and ECA. Before testing the VSS, perform the following drive cycle procedure

Automatic Transmission Equipped Vehicles

Record and clear CONTINUOUS SELF-TEST codes. Warm engine to normal operating temperature. In Low gear, accelerate moderately to 25 MPH and coast down to idle and stop. Shut off engine. Perform KEY ON/ENGINE OFF (KOEO) SELF-TEST . If Code 29 is present, go to step 1 . If not, fault cannot be duplicated at this time. If any other codes are present, return to QUICK TEST . If codes are not present, test is completed.

Manual Transmission Equipped Vehicles

Record and clear CONTINUOUS SELF-TEST codes. Warm engine to normal operating temperature. Start in first gear, shift to second gear, and accelerate moderately to 40 MPH. Coast down to idle and stop. Shut engine off. Perform KEY ON/ENGINE OFF (KOEO) SELF-TEST . If Code 29 is present, go to next step. If not, fault cannot be duplicated at this time. If any other codes are present, return to QUICK TEST . If codes are not present, test is completed.

1. Continuous Memory Code 29 - Code 29 indicates there is insufficient input to the ECA from the VSS. Possible causes for this code are a faulty VSS, open or shorted circuit or a faulty ECA. Perform drive cycle procedure. If Code 29 is displayed, go to next step. If not, fault cannot be duplicated at this time.
2. Checking VSS Sensor - Turn key off and wait 10 seconds. Disconnect vehicle speed sensor. Set DVOM on 200K-ohm scale. Measure resistance across vehicle speed sensor. If reading is between 190-240 ohms, go to next step. If reading is incorrect, replace vehicle speed sensor and repeat drive cycle procedure.
3. VSS Harness Continuity - Turn key off and wait 10 seconds. Remove ECA 60-pin connector and inspect for damaged pins, corrosion, or loose wires. Repair as necessary. Install breakout box. With ECA and VSS disconnected, set DVOM on 200-ohm scale. Measure resistance between test pin No. 3 at breakout box and VSS harness connector. Also measure resistance between test pin No. 6 at breakout box and VSS harness connector. If both readings are 5 ohms or less, go to next step. If readings are 5 ohms or more, service open circuit in VSS wiring harness. After repairs, repeat step 1 .
4. Checking VSS Harness For Shorts - Turn key off. With ECA and VSS disconnected, set DVOM on 200K-ohm scale. Measure resistance between test pin No. 3 and test pins No. 37, 40 and 6 at breakout box. Also measure resistance between test pin No. 6 and test pin No. 37. If all readings are greater than 10K ohms, go to next step. If any reading is less than 10K ohms, repair short(s) in VSS wiring harness. After repairs, repeat step 1 .
5. Test By Substitution - Substitute VSS with known good sensor and repeat drive cycle procedure. Connect ECA and VSS. Repeat step 1 , and return to this step. If Code 29 is present, replace ECA and repeat step 1 . If no code is present, replace original vehicle speed sensor.

CIRCUIT TEST B13 - NEUTRAL DRIVE SWITCH (NDS) A/C INPUT

Note. Perform this test when Service Code 67 or 79 is displayed during QUICK TEST or when directed here by other test procedures. This test is designed to diagnose the following: A/C input to ECA. Clutch engagement switch. Neutral clutch switch. Neutral drive switch. ECA. Harness connector and electrical circuits.

Scheme 19

Scheme 20

Scheme 21

Scheme 22

Scheme 23

1. Code 67 System Identification - Code 67 indicates that during engine cranking or KOEO SELF-TEST, signal voltage was greater than specification at test pin No. 10 (A/C input) or test pin No. 30 (NDS). Possible causes for this fault are: A/C circuit shorted to power, Neutral clutch/drive circuits open, Neutral clutch/drive switch open, or a faulty ECA. See «TEST STEP APPLICATION REFERENCE»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) table to enter this test at the correct step. TEST STEP APPLICATION REFERENCE Engine/Transmission Application Go To Step Number 2.3L 7) (Scheme 19): Neutral Gear/Clutch Circuit Diagram
2. Checking Neutral Gear/Clutch Input - Turn key off and wait 10 seconds. Ensure A/C control is in "OFF" position. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leave ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pins No. 30 and 46 with transmission in Neutral and clutch pedal in the up position. Measure resistance with transmission in gear and clutch pedal depressed. If both resistances are less than 5 ohms. On vehicles with A/C go to step 9. If vehicle is not equipped with A/C, replace ECA. If reading is more than 5 ohms, go to next step.
3. Checking Neutral Gear/Clutch Switch - Turn key off and wait 10 seconds. Leave breakout box installed and ECA disconnected. Locate Neutral Gear Switch (NGS) on transmission and clutch switch at clutch pedal linkage. Disconnect harness at both switches and inspect connector pins. Set DVOM on 200-ohm scale and measure resistance across NGS with transmission in Neutral, and across clutch switch terminals with clutch pedal depressed. If both resistances are less than 5 ohms, go to next step. If all resistances are more than 5 ohms, replace open switches, remove test equipment, reconnect components and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
4. Checking Neutral Gear/Clutch Switch Harness - Turn key off and wait 10 seconds. Install breakout box, leave ECA disconnected and set DVOM to 200-ohm scale. Disconnect harness at NGS and clutch switch. Measure resistance between test pin No. 30 and NGS harness connector and, between test pin No. 30 and clutch switch harness connector. Measure resistance between test pin No. 46 and NGS harness connector, and between test pin No. 46 and clutch switch harness connector. If all resistances are less than 5 ohms, on vehicles equipped with A/C, go to step 9. If not equipped with A/C, replace ECA. If any reading is greater than 5 ohms, repair open in harness or connector. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). (Scheme 20): Clutch Engage Switch Circuit Diagram NOTE: If clutch pedal is not depressed during KOEO test, a Code 67 will be displayed.
5. Checking Clutch Engage Switch - Turn key off. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box and leave ECA disconnected. Set DVOM on 200-ohm scale. Depress clutch pedal. Measure resistance between test pin No. 30 and test pin No. 46. If both readings are less than 5 ohms, on vehicles equipped with A/C, go to step 9. If not equipped with A/C, replace ECA. If any reading is 5 ohms or more, repair open circuit.
6. Checking Neutral Input Circuit: 2.3L Turbo MPFI With M/T - Turn key off, wait 10 seconds. Ensure A/C is turned off. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box. Leave ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pins No. 30 and 46. If resistance is less than 5 ohms, on vehicles equipped with A/C, go to step 9. If vehicle is not equipped with A/C, replace ECA. If reading is more than 5 ohms, repair open circuit. Rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). (Scheme 21): Neutral Drive Input Circuit Diagram
7. Checking Neutral Drive Input - Turn key off and wait 10 seconds. Ensure heater control is in "OFF" position. Ensure transmission is in Neutral or Park position. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box and leave ECA disconnected. Set DVOM to 20-volt scale. Connect ECA to breakout box. With KOEO, measure voltage between test pin No. 30 at the breakout box and chassis ground. If voltage is less than one volt, on vehicles equipped with A/C, go to step 9. If not equipped with A/C, replace ECA. If reading is more than one volt, go to next step.
8. Checking Neutral Drive Switch - Turn key off and wait 10 seconds. Install breakout box, leave ECA disconnected. Set DVOM on 200-ohm scale. Disconnect vehicle harness from NDS at transmission and measure resistance across switch. If resistance is less than 5 ohms, remove breakout box. Reconnect all components and service open in NDS circuit. If resistance is more than 5 ohms, replace NDS and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). (Scheme 22): A/C Input Circuit Diagram
9. Checking A/C Input Voltage - Ensure A/C is switched "OFF". If A/C was on, rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If Code 67 or 79 is displayed, continue with this test. Install breakout box and leave ECA disconnected. With KOEO, set DVOM on 20-volt scale. Measure voltage at test pin No. 10 at the breakout box and chassis ground. If reading is greater than one volt, remove breakout box and repair short in A/C clutch power circuit. If voltage is less than one volt replace ECA, except on vehicles equipped with E4OD transmissions. Vehicles equipped with E4OD transmissions, go to «CIRCUIT TEST D25»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-d25-axod-transaxle), step 1). Reconnect all components and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
10. Checking A/C Input Circuit - A low idle with A/C switched "ON" could result in the ECA not receiving or recognizing A/C input on pin No. 10. Turn key off and wait 10 seconds. Disconnect ECA, inspect pins, and install breakout box. Leave ECA disconnected. Set DVOM on 20-volt scale. With KOEO, and A/C on, measure voltage between test pins No. 10 and 40. If voltage is greater than 10.5 volts, replace ECA. Reconnect all components and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If voltage is less than 10.5 volts, service open in A/C circuit and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). (Scheme 23): A/C Clutch Circuit Diagram
11. Checking Inoperative A/C With High Idle - A high idle condition with the A/C dash switch in the "ON" position may be the result of a lack of signal reaching the A/C clutch. Turn key off and wait 10 seconds. Disconnect ECA, inspect pins, and install breakout box. Leave ECA disconnected. Disconnect A/C clutch connector. Set DVOM on 20-volt scale. With KOEO, turn on A/C. Measure voltage between input pin on fan connector and test pin No. 40 at the breakout box. If voltage is greater than 10.5 volts, go to next step. If voltage is less than 10.5 volts, repair open circuit and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
12. Check Continuity of A/C Clutch - With KOEO, disconnect A/C clutch harness connector. Measure resistance across both pins of A/C clutch. If resistance is within normal specification of 2.14-3.34 ohms, fault was probably due to faulty connection. If resistance was not within specification repair or replace A/C clutch as necessary.
13. Checking Continuity of A/C Cycle Pressure Switch Circuit - Turn key off and wait 10 seconds. Disconnect ECA, inspect pins, and install breakout box. Leave ECA disconnected. Disconnect A/C cycle pressure switch. Turn on A/C switch. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 43 at the breakout box and battery positive side of the A/C cycle pressure switch. Measure resistance between test pin No. 10 at the breakout box and negative side of the A/C cycle pressure switch connector. If both resistances are less than 5 ohms, EEC-IV system is not at fault. Repair or replace cycle pressure switch. If resistances are greater than 5 ohms, repair open circuit and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
14. Check A/C Demand and A/C Cycle Pressure Switch For Short to Power - Turn key off. Disconnect ECA, inspect pins, and install breakout box. Leave ECA disconnected. Ensure A/C switch is off. Set DVOM on 20-volt scale. With KOEO, measure voltage between test pin No. 43 and chassis ground. If voltage is greater than 1.0 volt, EEC-IV is not at fault. Repair or replace A/C switches or electrical circuit. If voltage is less than 1.0 volt, reconnect components and check switch operation. If switches are okay, repair short in circuit wiring and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
15. Checking NDS Circuit For Short to Ground or Closed NDS - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector, inspect pins, and install breakout box. Place transmission in Drive. Set DVOM on 200K-scale. Measure resistance between test pin No. 30 and test pin No. 40 or 60 at breakout box. If resistance is greater than 10K ohms service high idle condition. If resistance is less than 10K ohms, service circuit short or closed NDS and retest.

CIRCUIT TEST B14 - BRAKE ON/OFF SWITCH (BOO)

Note. Perform this test when Service Code 74 or 75 is displayed during QUICK TEST or when directed here by other test procedures.

Brake ON/OFF (BOO) Circuit (2.5L CFI, 3.0L EFI and 3.8L SEFI AXOD). Scheme 24

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: brake light bulb, brake light switch, or brake light fuse. This test is intended to diagnose a faulty BOO circuit or ECA.

1. Code 74: Verify Brake Pedal Was Depressed - If brake was NOT depressed during KOER SELF-TEST, repeat test and depress brake pedal ONLY once during test. Depress and release brake pedal AFTER dynamic response code but before brief WOT. If pedal was depressed, go to next step.
2. Checking Power Circuit - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, and loose wires. Install breakout box, leaving ECA disconnected. Set DVOM on 20-volt scale. Measure voltage between test pins No. 2 and 40 while applying and releasing brake. If voltage cycles, switch circuit is okay, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If voltage does not cycle, go to next step.
3. Checking For Shorts To Ground - Turn key off. Leave breakout box installed and ECA disconnected. Set DVOM on 200K-ohm scale. Disconnect BOO circuit at 12-pin connector (14290 Harness). Measure resistance between test pins No. 2 and 40 at the breakout box. If resistance is greater than 10K ohms, repair stoplamp circuit as necessary. If resistance is less than 10K ohms remove breakout box repair short, and repeat «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
4. Code 75 Displayed - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Disconnect BOO from Transmission Hydraulic Switch 12-pin connector (14290 Harness). Measure resistance between test pin No. 2 and BOO circuit at the 12-pin connector (14290 Harness). If resistance is greater than 5 ohms, remove breakout box. Reconnect ECA, repair open circuit, and rerun SELF-TEST.
5. Code 75: Cycle BOO Circuit - Turn key off. With breakout box installed and ECA disconnected, set DVOM on 20-volt scale. Measure voltage between test pins No. 2 and 40 at the breakout box while depressing and releasing the brake pedal. If voltage cycles, remove breakout box. Replace ECA, and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If voltage does not cycle, go to next step.
6. Checking BOO Circuit For Short To Power - Turn key off. Install breakout box, leaving ECA disconnected. Set DVOM on 20-volt scale. Disconnect BOO circuit at 12-pin connector. Measure voltage between test pin No. 2 at the breakout box and engine block ground. If voltage is greater than 10.5 volts, BOO circuit is okay. Check and repair brake light circuit as necessary. If voltage is less than 10.5 volts, remove breakout box. Reconnect ECA, repair circuit short and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
7. Code 74: Verify Brake Pedal Was Depressed - Code 74 indicates that brake was NOT depressed during KOER SELF-TEST, the BOO signal did not cycle during test. Repeat test and depress brake pedal ONLY once during test. Depress and release brake pedal AFTER dynamic response code, but before brief WOT. If pedal was depressed, go to next step. If voltage did not cycle, repeat «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and depress brake pedal once during test.
8. Checking BOO Circuit Cycling - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, and loose wires. Install breakout box, leaving ECA disconnected. Set DVOM on 20-volt scale. Measure voltage between test pins No. 2 and 40 while applying and releasing brake. If voltage cycles, switch circuit is okay, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If voltage does not cycle, go to next step.
9. Checking Continuity of BOO Circuit - Turn key off. Leave breakout box installed and ECA disconnected. Set DVOM on 200-ohm scale. Disconnect BOO circuit at 12-pin connector (12A581 to 14290 or 14401 Harness Connector). Measure resistance between test pins No. 2 and 40 at the breakout box. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms remove breakout box repair open circuit, and repeat «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
10. Checking BOO Circuit For Short to Power - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 20-volt scale. Disconnect BOO from Transmission Hydraulic Switch 12-pin connector (12A581 to 14290 or 14401 Harness). Measure voltage between test pin No. 2 at the breakout box and engine block ground. If voltage is greater than 1.0 volt, remove breakout box. Reconnect ECA, repair short circuit, and rerun SELF-TEST. If voltage is less than 1.0 volt, go to next step.
11. Check BOO Circuit For Short to Ground - Turn key off. Leave breakout box installed and ECA disconnected. Set DVOM on 200K-ohm scale. Disconnect BOO circuit at 12-pin connector (12A581 to 14290 or 14401 Harness Connector). Measure resistance between test pin No. 2 and test pin No. 40 at the breakout box. If resistance is greater than 10K ohms, repair stoplamp circuit as necessary. If resistance is less than 10K ohms remove breakout box repair short, and repeat «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .

CIRCUIT TEST B15 - POWER STEERING PRESSURE SWITCH (PSPS)

Note. Perform this test when Service Code 52 is displayed during QUICK TEST or when directed here by other test procedures. Some vehicles' ECAs may be equipped with PSPS software strategy but do not have power steering. If a KOEO Code 52 is displayed, check to see that vehicle is equipped with power steering. If not, disregard Code 52.

Power Steering Pressure Switch (PSPS) Circuit. Scheme 25

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: idle speed/throttle stop adjustment, binding throttle shaft/linkage or cruise control linkage.

1. Code 52 Elimination - Code 52 indicates that PSPS circuit is open. Turn key off and wait 10 seconds. Disconnect PSPS. Install a jumper wire between PSPS circuit and SIG RTN at harness connector. Repeat «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If Code 52 is not displayed, replace PSPS and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If Code 52 is still displayed, go to next step.
2. PSPS Harness Check - Turn key off and wait 10 seconds. Disconnect PSPS and ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale and measure resistance between test pin No. 46 and SIG RTN at the PSPS harness connector. Also measure resistance between PSPS CKT. at the harness connector and test pin No. 24. If both readings are less than 5 ohms, replace ECA. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If readings are greater than 5 ohms, repair open in circuit. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
3. Checking Switch Integrity - Connect tachometer and start engine. Allow engine to idle in Park or Neutral. Disconnect PSPS at switch. If RPM increases, replace PSPS. If RPM does not increase, go to next step.
4. Checking PSPS Harness - Turn key off and wait 10 seconds. Disconnect PSPS and ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200K-ohm scale. Measure resistance between test pin No. 24 and test pin No. 46 at the breakout box. If resistance is 10K ohms or less, repair short in harness. If reading is greater than 10K ohms, replace ECA. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
5. KOER SELF-TEST Code 52 Displayed - If you turned steering wheel 1/2 turn within 1-2 seconds AFTER engine ID code, but BEFORE dynamic response code, go to next step. If steering wheel was not turned, ensure front wheels are centered (no load condition). Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
6. Checking ECA Open Circuit Identifying Capabilities - Turn key off and wait 10 seconds. Disconnect PSPS. Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If Code 52 is present, go to step 8 . If Code 52 is not present, go to next step.
7. PSPS Harness Check - Turn key off and wait 10 seconds. Disconnect PSPS and ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Install breakout box, leaving ECA disconnected, and set DVOM on 200K-ohm scale. Measure resistance between test pins No. 46 and 24 at breakout box. If reading is 10K ohms or less, repair short to SIG RTN in PSPS circuit. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is 10K ohms or more, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
8. PSPS Position Comparison - Turn key off and wait 10 seconds. Install breakout box, leaving ECA connected. With PSPS connected, set DVOM on 200-ohm scale. Turn key on and measure resistance between test pins No. 24 and No. 46. Start engine. If reading remains less than 10 ohms between KOEO and KOER, go to next step. If not, go to step 11 .
9. PSPS Position: Load/No Load - Install breakout box and connect ECA. Connect PSPS and set DVOM on 200-ohm scale. Start engine and allow it to idle. Measure resistance between test pins No. 24 and No. 46 at breakout box. Turn steering wheel 1/2 turn and return. If reading changes from less than 10 ohms to infinity (indicating PSPS opening) and then returns to 10 ohms or less (when steering wheel is centered), PSPS system is okay. Remove breakout box and return to «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading did not change as indicated, go to next step.
10. PSPS Closed or Low Hydraulic Pressure - At this point, there are only 2 possible causes for the original Code 52. They are a PSPS switch that will not open, or low available hydraulic pressure. Turn key off and wait 10 seconds. Substitute original switch with a known good PSPS switch. Perform «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and turn steering wheel at least 1/2 turn after engine ID code. If Code 52 is still present, check for low hydraulic pressure. If Code 52 is not present, replace original PSPS switch. Service other codes if necessary.
11. PSPS Always Open or High Hydraulic Pressure - At this point, there are only 2 possible causes for original Code 52. They are a PSPS switch that is always open, or excessively high hydraulic pressure. Turn key off and wait 10 seconds. Substitute original switch with a known good PSPS switch. Perform «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and turn steering wheel at least 1/2 turn after engine ID code. If Code 52 is still present, check for high hydraulic pressure. If Code 52 is not present, replace original PSPS switch. Service other codes if necessary.

CIRCUIT TEST C1 - FUEL CONTROL-ALL APPLICATIONS

Note. Perform this test when Service Code 41, 91, 42, 92, or 43, 65, 85, 86 is displayed during QUICK TEST or when directed here by other test procedures.

Note. See HOW TO USE CIRCUIT TESTS before performing this test. Fuel contaminated engine oil may affect Service Codes 41, 91 and 42, 92. If this is suspected, remove PCV valve from valve cover and repeat QUICK TEST . If problem is corrected, change engine oil and filter.

INJECTOR BANK RESISTANCE (1)

INDIVIDUAL INJECTOR RESISTANCE

FUEL PRESSURE SPECIFICATIONS: PSI (KG/CM 2 )

MPFI Test Schematic. Scheme 26

Scheme 27

1. Checking Fuel Pressure - Turn ignition key off, wait 10 seconds. Install fuel pressure gauge and verify vacuum supply to fuel pressure regulator (if equipped). Run engine at idle and check fuel pressure. If vehicle will not start; cycle key on and off several times. See «FUEL PRESSURE SPECIFICATIONS»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) table. If fuel pressure is within specification, go to next step. If pressure is not to specification, remove fuel pressure gauge. Repair electric fuel pump or fuel pressure regulator.
2. Checking Fuel Pressure Valve - With KOEO, check that fuel pressure remains to specification for approximately 60 seconds. If system holds pressure go to next step. If system does not hold pressure, go to step 6.
3. Fuel Delivery Test - Ensure fuel quality. With key off, install fuel pressure gauge and pressurize fuel system as in step 1. Disconnect inertia switch. Crank engine for 5 seconds. If fuel pressure drop is greater than 5 psi after 5 seconds of cranking, the EEC-IV system is not the cause of the no start condition. Check additional «DIAGNOSIS BY SYMPTOM»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) tests. Reconnect inertia switch and remove fuel pressure gauge. If problem is rough running, missing, or a fuel service code, go to next step. If fuel pressure drop is less than 5 psi. remove fuel pressure gauge, reconnect inertia switch, and go to next step.
4. Checking Injector and Harness Resistance - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect pins for damage. Install breakout box, leave ECA disconnected, and set DVOM on 200-ohm scale. MPFI Engines: Measure resistance of injector banks No. 1 and 2 between Test Pins No. 37 and 58 (Bank No. 1) or 59 (Bank No. 2) at breakout box. Record resistance. Compare resistance with appropriate specification in «INJECTOR BANK RESISTANCE»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) table. If injector is within specification go to step 6. If injector is not within specifications, go to the next step.
5. Isolating Faulty Injector Circuit - Turn key off. Install breakout box and disconnect ECA. Disconnect all injectors on suspect bank. With DVOM meter set on 200-ohm scale, connect one injector and measure resistance between Test Pins No. 37 and 58 or 59. Disconnect injector and repeat process for all others. See «INDIVIDUAL INJECTOR RESISTANCE»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) table for specifications. If injectors are within specifications, go to step 6. If injectors are not to specification, remove breakout box, reconnect ECA and injectors. Repair open/short in injector harness. If okay, replace injector. Rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
6. Checking Injector Drive Signal - With key off and breakout box installed, connect ECA to breakout box. Use a non-powered 12-volt test light and the following connection procedure: MPFI Engines: Connect test light between Test Pins No. 37 and 58 at the breakout box. Connect light between Test Pins No. 37 and 59 at the breakout box. Crank or start engine. A properly operating system is indicated by a test light that glows dimly. If light glows dim go to next step. If test light does not glow dimly, do the following procedure. No Light: Check for 12 volts at Test Pins No. 37 and 57. Bright Light: Check injector circuit for shorts to ground. If okay, remove breakout box and replace ECA. Rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
7. Fuel Pressure Problems. External Sources - Pressurize fuel system as per step 1. Examine fuel system in the following manner. MPFI Engines: Visually inspect, fuel injector "O" rings, fuel pressure regulator, and fuel rails. If there is a visible leak, remove pressure gauge. Repair leak as necessary. Rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If there is no leak, go to next step for MPFI engines. For CFI engines, remove pressure gauge. Fuel delivery system is okay. Problem is in common area for all cylinders, such as vacuum leak, fuel contamination or EGR leak.
8. Injector Balance Test - Connect tachometer to engine. Start and run engine at idle. Disconnect and reconnect injectors one at a time. Note RPM drop for each injector. Each injector should produce a 100 RPM drop. Note that ISC will attempt to re-establish correct RPM. If each injector does not produce at least 100 RPM drop when disconnected, replace faulty injector(s) and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If RPM drop is correct for all injectors, fuel delivery is okay. Problem is in area common to all cylinders such as a vacuum leak, fuel contamination, EGR, etc. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 8 to step 10. No test procedures have been omitted.
9. 2nd & 3rd Level Balance Tests - Within 2 minutes after the previous test, lightly depress throttle again. This will enter the 2nd/3rd test stages. If code 90 is not present at all levels, go to step 4. If code 90 is present in all levels, go to «DIAGNOSIS BY SYMPTOM»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) table in this article.
10. Code 41 or 91: Fuel Mixture Always Lean - Run engine at 2000 RPM for 2 minutes. Turn key off and wait 10 seconds. Rerun «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). Check for code 41 or 91. If code 41 or 91 is not displayed, go to step 20. If code 41/91 is displayed go to appropriate step number as listed below: Engines equipped with MAP sensors: Go to next step. Engines equipped with VAF meters: Go to step 13. Engines equipped with MA meters: Go to step 14.
11. Checking HEGO Sensor on Engines With MAP Sensors - Turn key off and set DVOM on 20-volt scale. Disconnect appropriate HEGO sensor from vehicle harness. Connect DVOM to HEGO Signal lead at sensor and engine ground. Apply 10-14 in. Hg vacuum to Manifold Absolute Pressure (MAP) sensor and start engine. If reading is less than 0.5 volts, replace HEGO sensor(s) and then repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If reading is more than 0.5 volts, go to step 15. If reading is less than 0.5 volts, replace HEGO sensor, reconnect MAP, and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). NOTE: Vacuum or air leaks in non-EEC-IV related areas may cause codes 41/91. Check the following areas: A/C control motor, engine seals, EGR system, PVC system, Lead contamination of HEGO sensor.
12. Checking HEGO Sensor on Engines With VAF meters - With key off and DVOM set on 20-volt scale, disconnect HEGO sensor from harness. Connect DVOM between HEGO sensor and engine ground. Remove air cleaner in order to reach airflow meter inlet. Use a pencil to prop air meter door in partially open position. Start and run engine at 2000 RPM for 2 minutes. If reading is not greater than 0.5 volts after one minute, replace HEGO sensor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If reading is greater than 0.5 volts after one minute, go to step 15.
13. Checking HEGO Sensor on Engines With MA Sensor - With key off and DVOM set on 20-volt scale, disconnect HEGO sensor from harness. Connect DVOM between HEGO sensor and engine ground. Rerun «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and monitor HEGO sensor voltage. If voltage is greater than.5 volts, at end of test go to next step. If voltage is less than.5 volts, replace HEGO sensor and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). NOTE: Vacuum or air leaks in non-EEC-IV related areas may cause codes 41/91. Check the following areas: A/C control motor, engine seals, EGR system, PVC system, Lead contamination of HEGO sensor, Air leak between VAF meter and Throttle Body. The purpose of this test is to verify that HEGO sensor can generate at least.5 volts.
14. Checking Continuity of HEGO Signal and Ground Circuits - Turn key off. Install breakout box, leaving ECA and HEGO disconnected. Set DVOM on 200-ohm scale and measure resistance between Test Pin No. 49 and engine block ground. Measure resistance between Test Pin No. 29 and HEGO signal at vehicle harness connector. For vehicles with dual HEGO sensors measure resistance between Test Pin No. 43 and HEGO signal at vehicle harness connector. If all readings are greater than 5 ohms, repair open in appropriate circuit and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If all readings are less than 5 ohms, go to next step.
15. Checking HEGO Circuit For Short to Ground - Turn key off. Leave breakout box installed and ECA disconnected. Disconnect HEGO sensor and set DVOM on 200K-ohm scale. Measure resistance between Test Pin No. 29 and Test Pin No. 40 at the breakout box. For vehicles with dual sensors measure resistance between Test Pin No. 43 and Test Pin No. 40. If any reading is less than 10K ohms, repair short to ground. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If reading is 10K ohms or higher, go to next step.
16. Checking HEGO Sensor For Short to Ground - With key off, breakout box installed, and ECA disconnected, set DVOM to 200K-ohm scale. Disconnect HEGO sensor. Measure resistance between HEGO power ground and HEGO signal at the sensor connector. If resistance is less than 10K ohms, replace HEGO sensor and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If resistance is greater than 10K ohms, do the appropriate following procedure: Engines equipped with MAP sensor: Go to next step. Engines equipped with VAF meter: Go to step 19. Engines equipped with MA (Mass Air Sensor): Remove breakout box, reconnect HEGO sensor, replace ECA and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
17. Eliminating Code 41: Engines With MAP Sensor - Turn key off. Install breakout box and connect ECA and HEGO sensor. Ensure MAP sensor vacuum hose is disconnected and plugged. Apply 10-14 in. Hg to MAP sensor. Start and run engine at 2000 RPM for one minute. Allow engine to return to idle. Perform «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If code 41 is still present, check ECA connector for corroded or damaged pins. If connector is okay, replace ECA. Connect MAP sensor vacuum hose and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If code 41 is not present, connect MAP sensor vacuum hose. HEGO input circuit is okay. Go back to step 1.
18. Eliminating Code 41: Engines With VAF Meter - With key off, install breakout box and connect ECA. Reconnect HEGO sensor. Remove air filter and insert a pencil in VAF meter inlet. Start engine and run at 2000 RPM for approximately 2 minutes. Rerun SELF-TEST. If code 41 is not present, the HEGO circuit is okay, Remove breakout box, reconnect ECA and go to step 1 of this test. If code 41 is displayed, remove test set-up, replace ECA, and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
19. Checking HEGO Heater Element - Turn key off, disconnect HEGO sensor, and set DVOM on 200-ohm scale. Measure resistance between ignition run circuit and power ground circuit at HEGO connector. Hot to warm resistance should be 5-20 ohms. Room temperature resistance is 2-5 ohms. If resistance is within specification, go to next step. If resistance is not within specifications, replace HEGO sensor and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
20. Checking Power at HEGO Harness Connector - With KOEO, and HEGO disconnected, set DVOM on 20-volt scale. Measure voltage between ignition run circuit and power ground circuit at HEGO harness connector. If voltage is greater than 10.5 volts, HEGO system is okay, go to step 1 of this test. If voltage is less than 10.5 volts go to next step.
21. Checking Continuity of Power Ground Circuit - Turn key off and wait 10 seconds. Disconnect HEGO sensor and set DVOM on 200-ohm scale. Measure resistance between Power Ground circuit at HEGO vehicle harness connector and battery ground. If resistance is less than 5 ohms, repair open in ignition run circuit and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If resistance is more than 5 ohms, reconnect HEGO sensor and repair open in power ground circuit. Rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
22. Code 42 or 92 Displayed: Fuel Control Rich - Turn key off and wait 10 seconds. Disconnect appropriate HEGO sensor. Set DVOM on 20-volt scale. Turn key on. Measure voltage between HEGO signal and HEGO power ground at HEGO harness connector. If reading is more than.5 volt, repair short to power in HEGO circuit. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If reading is less than.5 volts, go to next step.
23. Checking HEGO Circuit For Short in Key Power Circuit - Turn key off and leave HEGO disconnected. Set DVOM on 200K-ohm scale. Measure resistance from key power input to HEGO signal circuit at HEGO sensor connector. If reading is 10K ohms or less, replace HEGO sensor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If reading is greater than 10K ohms, go to next step.
24. Attempt to Generate Code 41 or 91 - Turn key off and wait 10 seconds. Disconnect appropriate HEGO sensor. Using jumper wire, connect HEGO signal circuit at HEGO harness connector to battery negative. Repeat «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If codes 41 or 91 are present, remove jumper wire and go to next step for engines with MAP. All others, go to step 28. If codes 41 or 91 are not present, remove jumper wire. Disconnect ECA connector and inspect for damage. If connector is okay, replace ECA. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
25. Checking MAP Sensor For Vacuum Leaks - Turn key off and wait 10 seconds. Disconnect vacuum hose from MAP sensor and connect vacuum pump to sensor. Apply 18 in. Hg of vacuum to MAP sensor. If sensor does not hold vacuum, replace MAP sensor. Connect vacuum hose and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If MAP holds vacuum, release vacuum and go to next step.
26. Checking For Loss of Vacuum to MAP Sensor - Using vacuum "T", connect vacuum gauge in intake manifold vacuum hose at MAP sensor. Start engine and note vacuum reading. Turn key off and wait 10 seconds. Remove "T" and vacuum gauge. Reconnect hose to MAP sensor. Connect vacuum gauge at a different intake manifold location. Start engine and note vacuum reading. If readings differ by more than one in. Hg, inspect vacuum hoses for leaks, kinks, or blockage. Repair as required. If readings are within one in. Hg of each other, go to next step.
27. HEGO Sensor Check - Turn key off and wait 10 seconds. Disconnect HEGO sensor. Set DVOM on 20-volt scale and connect to HEGO Signal at HEGO sensor connector. Remove a vacuum hose to create a vacuum leak, which will cause the HEGO sensor to go lean. Start engine and run at 2000 RPM. The DVOM should indicate.4 volts within 30 seconds. If voltage is within specification, HEGO is okay, go to step 1 of this test. If voltage is not within specification, replace HEGO sensor and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). Create a vacuum leak in the following manner: 2.3L Turbo MPFI Engines: Disconnect the manifold vacuum hose as illustrated. All Other Engines: Disconnect the PCV valve hose from the PCV valve. (Scheme 27): 2.3L Turbo MPFI Engines: Induced Vacuum Leaks
28. Continuous Testing: Code 41 or 91 - Indicates that a HEGO circuit has not switched during closed loop fuel control. In this situation a code 41 or 91 may not indicate a lean condition. Diagnose all other driveability complaints in the «DIAGNOSIS BY SYMPTOM»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) table before attempting to service a continuous memory code 41 or 91. Check the following areas. Unmetered Air/Vacuum Leaks. Canister Purge System. PVC System. Engine Sealing. Crimped Fuel Lines. Plugged Fuel Filter. Fouled Injectors. HEGO Fuel Fouled. If an over-rich condition is suspected of fouling the HEGO sensor, run the vehicle at sustained high (legal) speeds followed by a few hard acceleration runs. This will allow the HEGO contamination to be burned off. Ignition System. Check for DEFAULT base timing in «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) procedure. Improper Fuel Used. Lead Fouled HEGO Sensor. Fuel Pressure. Check Pressure Using Steps 1 and 2. TP Sensor. With KOEO, move throttle slowly to WOT. Measure voltage between Test Pins No. 47 and 46 at breakout box. If voltage does not increase with throttle opening replace TP sensor or linkage as necessary. If vehicle still has driveability problems perform test steps 1 through 6.
29. Continuous Testing: Codes 41, 42, 43, 65, 85 or 86 - Diagnose all other driveability complaints before servicing these codes. Code 41: HEGO indication that the fuel system was lean for more than 15 seconds when the fuel system should have been in closed loop fuel control. Code 42: HEGO indication that the fuel system was rich for more than 15 seconds when the fuel system should have been in closed loop fuel control. Code 43: HEGO indicated that the fuel system was lean during WOT for more than 3 seconds. Code 65: Closed loop not activated on HEGO switching. Code 85: Excessive rich mixture condition corrected. Code 86: Excessive lean fuel mixture condition corrected. If an over-rich fuel condition is suspected or experienced, check ignition system. Burn off fuel deposits on HEGO by operating the vehicle at sustained high (legal) speeds followed by a few hard acceleration runs. This will allow the HEGO contamination to be burned off. Check the following areas: Code 41: Intermittent HEGO Signal (Signal or Ground). If Code 65 Also Present, Repair HEGO Circuit (Signal or Ground). If Code 43 Also Present, Service Code 43 First. Check VAF For Leaks or Sticking. Low Fuel Pressure at WOT, Check Fuel Supply. Low Fuel Flow at WOT (Pressure Okay), Check Clogged Injectors or Low Battery. Code 42: Intermittent HEGO Signal (Signal or Ground Circuit). Airflow Meter Indicating Incorrect Airflow, Check Voltage Output. Excessive Fuel Pressure, Pressure Regulator Vacuum Supply Disconnected. Excessive Fuel Flow, Damaged or Stuck Open Injector(s). Codes 41 and 42: Intermittent HEGO Signal (Signal or Ground Circuit). Sticking VAF Vane, Due to Contamination. Contaminated HEGO Sensor, Lead or Silicone Fouled. Code 43: Low Fuel Pressure at WOT, Fuel Pump or Restricted Supply. Low Fuel Flow at WOT, Injectors Plugged or Low Battery Voltage. Code 65: Check For Faulty HEGO Signal. Code 85: If Code 42 Also Displayed, Service it First. Excessive Fuel Pressure, Check Regulator Vacuum Line and Fuel Supply Line. Excessive Fuel Flow, Check Injector(s) Pintles or Injector Stuck Open. Code 86: If Code 41 Also Displayed, Service it First. Low Fuel Pressure, Low Pressure Pump or Restricted Fuel Supply. Low Fuel Flow, Clogged Injectors or Low Battery Voltage.

CIRCUIT TEST C2 - FUEL PUMP CIRCUIT (INERTIA SWITCH)

Note. Perform this test when Service Code 87, 95, or 96 is displayed during QUICK TEST or when directed here by other test procedures.

2.3L MPFI Fuel Pump Schematic. Scheme 28

2.3L OHC MPFI Fuel Pump Schematic. Scheme 29

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: fuel lines, fuel filters, throttle body, fuel pump or contaminated fuel.

1. No Fuel Pressure. Electrical Check - Install fuel pressure gauge. Cycle key from off to on several times to check if fuel pump runs. DO NOT crank engine. Pump should operate each time key is on. If pump runs as indicated, check fuel pump for problems. If pump does not run as indicated, go to next step.
2. Checking For VPWR to ECA - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Install breakout box and reconnect ECA. With KOEO, set DVOM on 20-volt scale and measure voltage between Test Pins No. 37 and 40, and between Test Pins No. 57 and 60. If either reading is less than 10.5 volts, go to «CIRCUIT TEST A2»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a2-vehicle-battery) , step 1). If both readings are 10.5 volts or more, go to next step.
3. Checking Inertia Switch Resistance - Turn key off and wait 10 seconds. Leave breakout box installed and ECA connected. Locate and disconnect fuel pump inertia switch. Set DVOM on 200-ohm scale and measure switch resistance. If reading is 5 ohms or more, reset or replace inertia switch. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 5 ohms, reconnect inertia switch and go to next step.
4. Check Voltage to Pump(s) - With KOEO, breakout box installed and ECA connected. Locate fuel pump relay. Set DVOM on 20-volt scale. Measure voltage between chassis ground and power-to-pump circuit at fuel pump relay while cranking engine. If reading is less than 8 volts, go to next step. If reading is 8 volts or more, check the following: Open in power-to-pump circuit, open in pump and open in ground circuit.
5. Checking Battery Voltage to Fuel Pump Relay - Turn key on, leaving engine off. Leave breakout box installed and ECA connected, locate fuel pump relay. Set DVOM on 20-volt scale. Measure voltage between chassis ground and V BATT circuit at fuel pump relay. If reading is less than 10.5 volts, repair open in BATT+ circuit between fuel pump relay and battery positive post. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is 10.5 volts or greater, go to next step.
6. Checking VPWR to Fuel Pump Relay - Turn key on, leaving engine off. Leave breakout box installed and ECA connected. Locate fuel pump relay. Set DVOM on 20-volt scale. Measure voltage between chassis ground and VPWR circuit at fuel pump relay (ignition start/run circuit on 2.3L HSC engines). If reading is 10.5 volts or more, go to next step. If reading is less than 10.5 volts, ensure inertia switch is on. If inertia switch will not reset, replace switch. If switch is okay, repair open in VPWR circuit between EEC power relay and fuel pump relay (Ignition switch Start/Run circuit and fuel pump relay on 2.3L HSC engines). Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
7. Checking Fuel Pump Circuit Continuity - Turn key off and wait 10 seconds. Leave breakout box installed and ECA connected. With DVOM on 200-ohm scale, measure resistance between fuel pump circuit at pump relay and Test Pin No. 22 at breakout box. If reading is 5 ohms or more, repair open in fuel pump circuit. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 5 ohms, go to next step.
8. Checking For Short to Power - Disconnect ECA and fuel pump relay. With key on, and breakout box installed, set DVOM on 20-volt scale. Measure voltage between Test Pin No. 22 and battery negative terminal. If voltage is less than one volt, go to next step. If voltage is more than one volt, repair short circuit. Reconnect ECA and attempt to start vehicle. If vehicle fails to start, replace ECA. Rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
9. Checking For Shorts to Ground - Turn key off. Leave breakout box installed and disconnect ECA. Disconnect fuel pump relay. With DVOM on 200K-ohm scale, measure resistance between Test Pin No. 22 and Test Pins No. 40 and 60. If reading is less than 10K ohms, repair short in fuel pump circuit. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is 10K ohms or more, go to next step.
10. Checking Voltage at Power-to-Pump Circuit - Leave breakout box installed and ECA disconnected. Install a jumper wire between Test Pin No. 22 and Test Pins No. 40 or 60. Set DVOM on 20-volt scale. With KOEO, measure voltage between chassis ground and power-to-pump circuit at fuel pump relay. If reading is 10.5 volts or more, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 10.5 volts, replace fuel pump relay. Connect ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
11. Code 95: Check Inertia Switch - A KOEO code 95 indicates that one of the following has occurred: Open circuit in or between ECA and fuel pump. Bad ground connection at fuel pump. Circuit shorted to power. Fuel pump relay contacts always closed. Turn key off and wait 10 seconds. Locate and disconnect inertia switch. Set DVOM on 200-ohm scale. Measure resistance of inertia switch. If resistance is less than 5 ohms reconnect inertia switch and go to next step. If resistance is more than 5 ohms, replace or reset inertia switch and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
12. Verifying Fuel Pump is Off - With key off, listen for fuel pump noise. If fuel pump is off, go to step 14 . If fuel pump is on, go to next step.
13. Fuel Pump Relay Check - Turn key off. Remove fuel pump relay. If fuel pump turns off, replace fuel pump relay. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If fuel pump does not turn off, repair short to power-to-pump circuit.
14. Checking Continuity of Fuel Pump Monitor (FPM) Circuit - Turn key off and wait 10 seconds. Inspect connector for damaged pins, corrosion or loose wires. Install breakout box and leave ECA disconnected. Disconnect fuel pump relay. Set DVOM on 200-ohm scale and measure resistance between Test Pin No. 8 at the breakout box and power-to-pump circuit at the fuel pump relay harness. If resistance is less than 5 ohms, go to next step. If resistance is more than 5 ohms, repair circuit and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
15. Checking Continuity Between FPM Circuit and Ground - Turn key off. Install breakout box and disconnect ECA. Disconnect fuel pump relay. Set DVOM on 200-ohm scale and measure resistance between Test Pin No. 8 at the breakout box and battery negative terminal. If rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If resistance is more than 10 ohms, remove test set-up and check the following: Open circuit in fuel pump, poor ground connection at fuel pump, or an open in power-to-pump circuit.
16. Checking Fuel Pump Primary Circuit - Turn key off and wait 10 seconds. Install breakout box and disconnect ECA. Disconnect fuel pump relay and set DVOM on 200K-ohm scale. Measure resistance between Test Pins No. 22 and 40 at the breakout box. If resistance is greater than 10K ohms, remove test set-up. Replace ECA, and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If resistance is less than 10K ohms, remove test set-up. Repair short circuit and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If resistance is greater than 10K ohms, remove test set-up. Replace ECA and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
17. Code 96: Checking VBATT to Fuel Pump Relay - Service code 96 indicates that when the fuel pump relay is activated, no power is supplied to pump. Turn key off and wait 10 seconds. Locate fuel pump relay. With the DVOM on 20-volt scale, measure voltage between VBATT circuit at fuel pump relay and battery negative. If voltage is greater than 10.5 volts, go to next step. If voltage is less than 10.5 volts, repair open circuit and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
18. Verifying Fuel Pump Operation - With key off, set DVOM on 20-volt scale. Connect DVOM between pump power circuit at relay and battery negative. Check voltage while turning key on (one second) and off (5 seconds). Cycle at least 5 times. If meter registers greater than 10.5 volts for approximately one second after key is turned off, replace ECA and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If voltage is not to specification, inspect relay connector and replace fuel pump relay.
19. Checking Continuity of Power-to-Pump Circuit - Turn key off and disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Install breakout box and leave ECA disconnected. With DVOM on 200-ohm scale, measure resistance between Test Pin No. 8 (at breakout box) and Power-to-Pump circuit at relay harness connector. If resistance is less than 5 ohms, remove test set-up, replace ECA, and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If resistance is more than 5 ohms, repair open circuit between FPM connecting splice and relay. Rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
20. Continuous Code 95: Checking EEC-IV Harness - A continuous code 95 indicates that one of the following conditions has occurred intermittently: open circuit between ECA pin No. 8 and pump. Poor ground circuit at pump. Start engine and perform «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) on harness assembly to fuel pump, and to pump ground circuit harness. Lightly tap inertia switch and pump to simulate road shock. Check for engine miss or stumble while performing test. With key off, check harness connectors for corrosion or damage. If no fault is found, go to next step. Isolate and repair any faults that are found, clear memory code 95 and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
21. Checking FPM Circuit - Turn key off. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Install breakout box and leave ECA disconnected. With KOEO, connect a test light between Test Pins No. 8 and 37. With test light lit, perform «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) on FPM circuit between pump and monitor. Light should go out if fault is found during WIGGLE TEST. Isolate and repair any found faults, remove test set-up and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no faults are found, fault cannot be duplicated at this time.
22. Continuous Code 96: Check For Code 87 - If code 87 is also present with code 96, go to step 24 . If code 87 is not displayed, go to next step.
23. Checking EEC-IV Harness - A continuous code 96 without an accompanying code 87 indicates one of the following occurred during vehicle operation: An open in the VBATT circuit between the battery positive and the fuel pump relay, relay contacts opened or open between FPM circuit and pump power circuit. With engine running attempt to cause a miss or stumble while performing «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) on pump harness and connectors. With engine off, inspect all connectors for damage or corrosion. If a fault is found, isolate and repair it. Rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no fault is found, fault may not be duplicated at this time; code 96 testing is complete.
24. Continuous Code 87: Checking EEC-IV Harness - A continuous code 87 indicates one of the following intermittent conditions has occurred: An open in the VPWR circuit between the EEC power relay and the fuel pump relay, open coil in fuel pump relay or open in fuel pump circuit. With engine running, attempt to cause a miss or stumble while performing «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) on VPWR circuit between EEC power relay and fuel pump relay connectors. With engine off, inspect ECA 60-pin connector for damage or corrosion. If a fault is found, isolate and repair it. Rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no fault is found, fault may not be duplicated at this time.

CIRCUIT TEST D1 - EGR ON/OFF CONTROL

Note. Perform this test when Service Code 34 or 84 is displayed during QUICK TEST or when directed here by other test procedures. Code 34 may be result of high volume exhaust vent system reducing backpressure. If this is suspected, perform test in well-ventilated area without exhaust vent connected.

EGR On/Off Circuit. Scheme 30

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: air or vacuum leaks, EGR flow restrictions or EGR valve.

1. Code 34 Displayed - Use only VOM/DVOM, not diagnostic tester, for this step. Turn key off and wait 10 seconds. Set DVOM on 20-volt scale. Connect negative DVOM lead to STO at SELF-TEST connector and positive lead to positive battery terminal. Insert jumper wire between STI and signal return circuit at SELF-TEST connector. Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) until end of CONTINUOUS SELF-TEST code display (DVOM will read zero volts). Depress and release throttle and observe DVOM reading. If DVOM registered high reading, stay in «OUTPUT STATE CHECK»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__output-state-check) and go to next step. If DVOM did not show high voltage, depress throttle to WOT and release. If output voltage does not go high, go to «CIRCUIT TEST D16»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-d16-output-state) , step 1). Leave test equipment hooked up.
2. Checking Solenoid Electrical Operation - Set DVOM on 20-volt scale. Connect DVOM positive lead to VPWR circuit at EGR solenoid and negative lead to EGR output circuit. Depress and release throttle several times to cycle EGR solenoid output on and off. If output does not cycle on and off, remove STI jumper wire and go to step 5 . If output cycles on and off, go to next step.
3. Checking Solenoid For Vacuum Cycling - Connect vacuum pump to solenoid vacuum supply port and vacuum gauge to output port of solenoid. Apply minimum vacuum of 6 in. Hg. Depress and release throttle several times to cycle EGR solenoid output while maintaining vacuum at supply port. Note gauge reading. If vacuum output does not cycle, replace EGR solenoid and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If vacuum output cycles, go to next step.
4. Checking Manifold Vacuum Lines - With vacuum lines disconnected at EGR solenoid, start engine. If vacuum is present, EEC system is not cause of problem. Check exhaust gas recirculation system. If vacuum is not present, correct vacuum source blockage or leak and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
5. Measuring Solenoid Resistance - Turn key off and wait 10 seconds. Disconnect EGR solenoid. Set DVOM on 200-ohm scale and measure solenoid resistance. If reading is less than 65 ohms or more than 110 ohms, replace EGR solenoid and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is between 65 and 110 ohms, go to next step.
6. Checking VPWR Circuit - With KOEO, set DVOM on 20-volt scale. Measure voltage between VPWR circuit at EGR solenoid harness connector and battery ground. If reading is less than 10.5 volts, repair open in harness and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is 10.5 volts or more, go to next step.
7. Checking Continuity of EGR Circuit - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between Test Pin No. 35 (33 on 2.3L Turbo EFI) and EGR circuit at connector. If reading is 5 ohms or more, repair open circuit and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 5 ohms, go to next step.
8. Checking Circuit For Short to Ground - Turn key off and wait 10 seconds. Leave breakout box installed and ECA disconnected. Disconnect EGR solenoid. Set DVOM on 200K-ohm scale. Measure resistance between Test Pin No. 35 (33 on 2.3L Turbo MPFI) and Test Pins No. 40, 46, and 60. If any reading is less than 10K ohms, repair short to ground and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If all readings are 10K ohms or more, go to next step.
9. Checking For Short to Power Circuit - Turn key off and wait 10 seconds. Leave breakout box installed. Disconnect ECA and EGR solenoid. With DVOM on 200K-ohm scale, measure resistance between Test Pin No. 35 (33 on 2.3L Turbo MPFI) and Test Pins No. 37 and 57. If any reading is less than 10K ohms, repair short to power and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code is still repeated, replace ECA. If all readings are 10K ohms or more, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .

CIRCUIT TEST D2 - DC MOTOR/IDLE SWITCH/TPS - IDLE SPEED CONTROL (DC MOTOR/IDLE TRACKING SWITCH ASSEMBLY & TPS)

Perform this test only when codes 12, 13, 16, 17, 23, 38, 53, 58, 63, 68, 71, 73 or 93 are displayed or when directed here by DIAGNOSIS BY SYMPTOM (SYMPTOM-TO-DIAGNOSTIC TEST) table. To prevent replacement of good components be aware that the following non-EEC related areas may be at fault: throttle stop screw out of adjustment, vacuum leaks, sticking throttle, or basic engine (valves, timing, etc.).

Scheme 31

1. Checking DC Motor Operation - Turn key off and wait 10 seconds. Disconnect harness from DC motor. Using jumper wires, connect ISC positive (+) circuit of DC motor to battery positive (+) terminal and ISC negative (-) circuit of DC motor to battery negative (-) terminal for 4 seconds. DC motor shaft should extend more than 2" (50 mm). See DC MOTOR SHAFT MEASUREMENTS in (Scheme 31). Now connect ISC + circuit of DC motor to battery negative terminal and ISC - circuit of DC motor to battery positive terminal for 4 seconds. DC motor shaft should retract to less than 1 3/4" (44 mm). If DC motor shaft moves in and out as indicated, go to next step. If not, replace DC motor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
2. Checking Circuit Continuity - Turn key off and wait 10 seconds. Leave harness disconnected from DC motor. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Connect breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between Test Pin No. 41 and ISC negative (-) circuit at harness connector and between Test Pin No. 21 and ISC positive (+) circuit at harness connector. If both readings are less than 5 ohms, go to next step. If readings are 5 ohms or more, repair circuit(s) and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). (Scheme 31): DC Motor Shaft Measurements
3. Checking For Shorts To Ground - Turn key off and wait 10 seconds. Leave breakout box and ECA disconnected. Set DVOM on 200K-ohm scale. Measure resistance between Test Pin No. 41 and Test Pins No. 40 and 60. Also measure resistance between Test Pin No. 21 and Test Pins No. 40 and 60. If all readings are greater than 10K ohms, go to next step. If any reading is less than 10K ohms, repair faulty circuit(s) and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
4. Checking For Shorts In Power Circuit - Turn key off and wait 10 seconds. Leave breakout box installed and ECA disconnected. Disconnect DC motor from harness. Set DVOM to 20 volt scale. Measure voltage between Test Pin No. 41 and Test Pins No. 40 and 60. Also measure voltage between Test Pin No. 21 and Test Pins No. 40 and 60. If all readings are less than one volt, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If any reading is more than one volt, repair faulty circuit(s) and repeat QUICK TEST.
5. Checking Full Motor Retraction - Turn key off and wait 10 seconds. Disconnect DC motor from harness. Using jumper wires, connect DC motor ISC - circuit to battery positive (+) terminal and ISC positive (+) circuit to battery negative (-) terminal for 4 seconds. If DC motor shaft retracts away from throttle lever, go to step 7. If shaft does not retract, go to next step.
6. Measuring Motor Retraction - Turn key off and wait 10 seconds. Disconnect DC motor from harness. Ensure DC motor is fully retracted. Measure distance from DC motor mounting bracket to tip of motor shaft. See DC MOTOR SHAFT MEASUREMENTS in (Scheme 31). If DC motor shaft is retracted to less than 1 3/4" (44 mm), reconnect DC motor. Check throttle stop adjustment. If DC motor shaft does not retract, replace DC motor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
7. Checking Idle Tracking Switch - Turn key off and wait 10 seconds. Disconnect DC motor from harness. Ensure DC motor is fully retracted and not touching throttle lever. Set DVOM on 200-ohm scale. Measure resistance between ITS circuit and SIG RTN at DC motor connector. If reading is less than 5 ohms, go to next step. If not, replace DC motor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
8. Checking Continuity of ITS & SIG RTN Circuits - Turn key off and wait 10 seconds. Disconnect DC motor from harness. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Connect breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between Test Pin No. 46 and SIG RTN circuit at DC motor harness connector. Also measure resistance between Test Pin No. 28 and ITS circuit at DC motor harness connector. If both readings are less than 5 ohms, reconnect DC motor. Replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If any reading is 5 ohms or more, reconnect DC motor. Repair faulty circuit(s) and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
9. Checking Idle Tracking Switch - Turn key off and wait 10 seconds. Disconnect DC motor from harness. Set DVOM on 200-ohm scale. Measure resistance between ITS circuit and SIG RTN circuit at DC motor connector. If all readings are greater than 5 ohms, go to next step. If any reading is 5 ohms or less, replace DC motor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
10. Checking ITS For Shorts To Ground - Turn key off and wait 10 seconds. Disconnect DC motor from harness. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Connect breakout box, leaving ECA disconnected. Set DVOM on 200K-ohm scale. Measure resistance between Test Pin No. 28 and Test Pins No. 40, 46, and 60. If all readings are greater than 10K ohms, reconnect DC motor. Replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If any reading is 10K ohms or less, reconnect DC motor. Repair faulty circuit(s) and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
11. Checking Throttle Linkage - Turn key off and wait 10 seconds. Inspect throttle for freedom of movement to wide open throttle and for damaged or bent throttle lever. If throttle lever and linkage are okay, replace DC motor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If throttle lever and/or linkage are damaged, repair as necessary and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
12. Checking Throttle Plate - Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). Disconnect DC motor after shaft has fully retracted. Turn key off and wait 10 seconds. Remove air cleaner from throttle body. Inspect throttle for freedom of movement and for proper closing of throttle valves. If throttle moves freely and closes without obstructions, reconnect DC motor and go to next step. If throttle binds or does not close properly, repair as necessary and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
13. Checking Voltage Of VREF/Signal Return - Turn key off and wait 10 seconds. Disconnect TPS harness connector at throttle body. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Set DVOM on 20-volt scale. Turn key on, leaving engine off. Measure voltage between VREF and SIG RTN at harness connector. If reading is between 4-6 volts, reconnect TPS and go to next step. If reading is incorrect, go to «CIRCUIT TEST A3»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a3-reference-voltage), step 1).
14. Checking Throttle Stop RPM - Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). Disconnect DC motor after shaft has fully retracted and exit SELF-TEST. Start engine and verify that throttle stop RPM is less than curb idle speed. If throttle stop RPM is set to less than curb idle speed, replace TPS. Connect DC motor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If throttle stop RPM is not less than curb idle speed, adjust throttle stop RPM. Connect DC motor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
15. Generate Code 63 - Turn key off and wait 10 seconds. Disconnect harness from TPS at throttle body. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and record codes. If code 63 is displayed, go to next step. If code 63 is not displayed, go to step 17. Ignore all other codes.
16. Check Voltage (VREF to SIR RTN) - Turn key off and wait 10 seconds. Disconnect TPS harness at throttle body. Set DVOM on 20-volt scale. Turn key on, leaving engine off. Measure voltage between VREF and SIG RTN at TPS harness connector. If reading is between 4-6 volts, replace TPS and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If not, go to «CIRCUIT TEST A3»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a3-reference-voltage), step 1).
17. Check TP Signal For Short To Power - Turn key off and wait 10 seconds. Disconnect TPS harness at throttle body. Set DVOM on 200K-ohm scale. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Install breakout box, leaving ECA disconnected. Measure resistance between Test Pin No. 47 and Test Pins No. 26 and 57 at breakout box. If both readings are 10K ohms or greater, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If any reading is less than 10K ohms, repair faulty circuit(s) and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
18. Generate Service Code 53 - Turn key off and wait 10 seconds. Disconnect TPS harness at throttle body. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Using jumper wire, connect VREF to TPS signal at harness connector. Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If no codes are displayed, immediately remove jumper wire and go directly to step 21. If code 53 is displayed, replace TPS sensor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If code 53 is not displayed, go to next step. Ignore all other codes.
19. Voltage Check (VREF to SIG RTN) - Turn key off and wait 10 seconds. Disconnect TPS harness at throttle body. Set DVOM on 20-volt scale. Turn key on, leaving engine off. Measure voltage between VREF and SIG RTN at TPS harness connector. If reading is between 4-6 volts, go to next step. If not, go to «CIRCUIT TEST A3»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a3-reference-voltage), step 1).
20. Continuity Check (TP Circuit) - Turn key off and wait 10 seconds. Disconnect TPS harness at throttle body. Set DVOM on 200-ohm scale. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Install breakout box, leaving ECA disconnected. Measure resistance between TPS signal at harness connector and Test Pin No. 47 at breakout box. If reading is less than 5 ohms, go to next step. If not, repair circuit. Reconnect TPS harness and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
21. Checking TP Signal For Short To Ground - Turn key off and wait 10 seconds. Disconnect TPS harness at throttle body. With breakout box installed, set DVOM on 200K-ohm scale. Measure resistance between TPS signal at harness connector and Test Pins No. 40, 46 and 60 at breakout box. If all readings are greater than 10K ohms, replace ECA. Connect TPS and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If any reading is less than 10K ohms, repair faulty circuit(s) and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
22. Code 73 Displayed - Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If code 73 is still displayed, replace TPS and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If code 73 is not displayed, repair other codes.
23. Check For Codes That Could Cause Code 12 - Perform «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If codes 31, 32, 34, 35, 41 or 58 are displayed, repair these codes first. See «KEY ON ENGINE RUNNING (KOER) CODE-TO-CIRCUIT TEST MENU»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) for instructions. If these codes are not displayed, go to next step.
24. Checking Throttle Linkage - Check throttle plates and linkage for binding. Check cruise control linkage for proper adjustment. If throttle opens and closes properly, go to next step. If throttle does not operate properly, repair throttle as required and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
25. Checking DC Motor Operation - Turn key off and wait 10 seconds. Disconnect harness from DC motor. Using jumper wires, connect ISC positive (+) circuit of DC motor to battery positive (+) terminal and ISC negative (-) circuit of DC motor to battery negative terminal for 4 seconds. DC motor shaft should extend more than 2" (50 mm). See DC MOTOR SHAFT MEASUREMENTS in (Scheme 31). Now connect ISC positive (+) circuit of DC motor to battery negative (-) terminal and ISC negative (-) circuit of DC motor to battery positive (+) terminal for 4 seconds. DC motor shaft should retract to less than 1 3/4" (44 mm). If DC motor shaft moves in and out as indicated, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If not, replace DC motor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
26. Erratic Idle Check - Prepare vehicle for normal operation and deactivate SELF-TEST. Ensure A/C is off (if equipped). Start and run engine for 3 minutes, alternating between 30 second idle and 5 second part throttle operation. If idle is not erratic, go to next step. If idle is erratic at end of 3 minute idle/part throttle test, check for vacuum leaks, and codes 22, 31, 32, 34, 35, 41, or 58. Repair these codes before going on to next step.
27. Throttle Plates and Linkage - Inspect throttle plates and/or linkage for binding. If throttle opens and closes properly, replace DC motor and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If throttle binds, repair throttle as required and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
28. Continuous Code 99 Displayed - This code indicates the ECA has not received enough information to control the idle speed motor. Deactivate SELF-TEST and start engine. DO NOT touch the throttle. Allow engine to idle for 2 minutes and shut engine off. When key has been off 10 seconds, run KOEO test. Deactivate SELF-TEST after service codes are displayed. Turn engine off and wait 10 seconds. Run «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If service code 99 is displayed, replace ECA. If code 99 is not displayed, service other service codes.
29. Check For Other "Engine Running" Codes - A service code 12 may indicate a failure of another area. Check for service codes 22, 31, 32, 34, 35 or 41 during KOER SELF-TEST. If any of these codes are present go to «KEY ON ENGINE RUNNING (KOER) CODE-TO-CIRCUIT TEST MENU»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
30. Related Mechanical Problems - A service code 16 may indicate that the accelerator pedal was touched during KOER SELF-TEST. A code 17 indicates an electrical load such as engine cooling fan or A/C compressor was activated during the SELF-TEST. Check engine for vacuum leaks, binding throttle linkage, base ignition timing, and throttle stop screw adjustment.
31. Continuous Code 13 Displayed - This code indicates that in the last 40 engine warm-up cycles, the Throttle Position Sensor (TPS) rotation did not follow the reaction of DC motor when idle speed control was in dashpot mode. This condition may be caused by the following: DC motor sticking at part throttle. An open in ITS circuit which, when coupled with other inputs to ECA, causes EEC system to falsely enter dashpot mode. TPS sticking at part throttle. Each of these areas may generate KOEO SELF-TEST or CONTINUOUS SELF-TEST memory codes. If repairs have been made for KOEO SELF-TEST codes 13 or 58, CONTINUOUS SELF-TEST code 13 can be considered serviced and erased from memory. If CONTINUOUS SELF-TEST codes 13 and 38 are present, service code 13 first. If these codes are not present, make the following checks: Go to step 1) of this test and check for FULL travel of DC motor shaft. Replace DC motor if travel is not obtained. Leave motor in FULL retract position. See DC MOTOR SHAFT MEASUREMENTS in (Scheme 31). With motor in full retract position, and with ITS not touching throttle lever, check for an open in ITS circuit. Turn key off and install breakout box. Make necessary connector/pin inspections. With DVOM on 200-ohm scale, monitor resistance between Test Pins No. 28 and 46 while tapping, wiggling, and bending DC motor connector and harness. DO NOT push in idle tracking switch. If DVOM reading changes from less than 5 ohms to more than 5 ohms, an open circuit exists in wiring. Repair as necessary. Check for binding TPS by monitoring TPS voltage while moving throttle from a wide open position to a closed throttle position. Install breakout box and make all necessary connector/pin inspections. Fully retract DC motor shaft by placing a jumper wire between Test Pins No. 41 and 57. When motor is fully retracted, disconnect it at harness and remove jumper wire from breakout box. Turn key on and set DVOM on 20-volt scale. Slowly move throttle to wide open and closed throttle positions. Readings should move from more than 4 volts to less than 1.5 volts. If voltage readings hang up in mid-range (no voltage indication), replace TPS. If readings are correct, TPS is okay.
32. Continuous Code 38 Displayed - This code indicates that in the last 40 engine warm-up cycles the idle tracking switch was open (ITS touching throttle) when throttle angle was greater than the maximum extension of DC motor shaft. This condition could be caused by the following conditions: An open in ITS circuit. Idle tracking switch stuck in open (pushed in) position. These conditions may cause a code 58 to appear in KOEO SELF-TEST. If repair has been made for code 58, CONTINUOUS SELF-TEST memory code 38 can be considered serviced and erased. If KOEO SELF-TEST code 58 was not displayed, check the following: With DC motor fully retracted and ITS not touching throttle lever, check for an intermittent in ITS circuit. Turn ignition off and install breakout box. Make the necessary connector/pin inspections. With DVOM on 200-ohm scale, measure resistance between Test Pins No. 28 and 46 while tapping, wiggling, or bending DC motor connector and harness. DO NOT push in idle tracking switch. If DVOM reading changes from less than 5 ohms to more than 5 ohms, an open circuit exists in wiring. Repair as necessary.
33. Continuous Code 71 Displayed - This code indicates that in the last 40 engine warm-up cycles the idle tracking switch was closed (ITS not touching throttle lever) when DC motor was in preset position. This condition can be caused by the following: ITS circuit shorted to ground or signal return. ITS stuck in closed position. Either of these conditions may cause KOEO SELF-TEST code 68. If repairs have been made for code 68, CONTINUOUS SELF-TEST memory code 71 can be considered serviced and erased from memory. If code 68 was not displayed, check ITS circuit for an intermittent short to ground or signal return. Turn key off. Enter «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) and systematically tap, wiggle, or bend harness while looking for indication of fault. If fault is created, repair as necessary. Due to nature of this test step, code 71 will NOT reappear in memory if fault is found.
34. Continuous Code 53 Displayed - Using «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test), observe VOM or diagnostic tester for indication of fault, while slowly moving throttle to wide open position. Slowly release throttle to closed position and lightly tap on TPS to simulate road shock and lightly wiggle TPS harness connector. If fault is indicated, go to next step. If not, go to step 33.
35. Throttle Position Signal Voltage - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Connect VOM or diagnostic tester as in step 31. Install breakout box and connect ECA. Set DVOM on 20-volt scale. Connect DVOM from Test Pin No. 47 to Test Pin No. 46. Turn key on, leaving engine off. While observing DVOM, repeat step 31. If fault occurs at less than 4.25 volts, disconnect and inspect connectors. If okay, replace TPS and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If fault occurs at greater than 4.25 volts, TPS overtravel may have caused code 53. Go to next step.
36. Checking EEC-IV Harness - Observe VOM or diagnostic tester for fault indication while grasping harness close to sensor connector. Wiggle, shake, or bend a small section of harness while working toward firewall. Repeat procedure from firewall to ECA. If fault is indicated, isolate fault and repair as necessary. After repairs repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If no fault occurs, go to next step.
37. Checking ECA and Harness Connectors - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect both connector and connector terminals for obvious fault or damage. If connector and terminals are okay, fault cannot be duplicated at this time. Testing is complete. If connector or terminals are damaged, repair as necessary. After repairs, repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes).
38. Checking Continuous Codes 23 or 63 - Using «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test), observe VOM or diagnostic tester for indication of fault while slowly moving throttle to wide open position. Slowly release throttle to closed position, lightly tap on TPS to simulate road shock and lightly wiggle TPS harness connector. If fault is indicated, disconnect and inspect connectors. If connectors and terminals are okay, replace TPS and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes). If no fault is indicated, go to next step.

CIRCUIT TEST D4 - CANISTER PURGE (CANP) CHECK

Note. Perform this test when Service Code 85 is displayed during QUICK TEST or when directed here by other test procedures.

Canister Purge (CANP) Circuit. Scheme 32

1. Checking System Function - Enter «OUTPUT STATE CHECK»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__output-state-check) ; see «OUTPUT STATE CHECK»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__output-state-check) under «QUICK TEST DIAGNOSTIC AIDS»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . Use only DVOM, not diagnostic tester, for this step. Turn key off and wait 10 seconds. Set DVOM on 20-volt scale. Connect DVOM negative test lead to STO and positive test lead to positive battery terminal. Using jumper wire, connect STI circuit to signal return at SELF-TEST connector. Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) until end of CONTINUOUS SELF-TEST codes (DVOM reads zero volts). Depress and release throttle. DVOM should change to a high voltage reading. If reading did not change, depress throttle to WOT and release. If STO voltage does not go high, go to «CIRCUIT TEST D16»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-d16-output-state) , step 1). Leave test equipment hooked up. If reading changed, remain in «OUTPUT STATE CHECK»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__output-state-check) and go to next step.
2. Checking Solenoid Electrical Function - With KOEO, set DVOM on 20-volt scale. Disconnect CANP solenoid. Connect DVOM positive test lead to VPWR circuit and negative test lead to CANP output circuit on harness connector. While observing DVOM, depress and release throttle several times to cycle output on and off. If CANP circuit does not cycle on and off, remove jumper wire and go to step 6 . If CANP circuit cycles, go to next step.
3. Checking Solenoid For Vacuum Leaks - Turn key on. Leave CANP solenoid disconnected. Disconnect vacuum hose from canister purge solenoid on PCV side. Apply 16 in. Hg vacuum to CANP solenoid. If CANP solenoid does not hold vacuum for 20 seconds, replace it and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If fault is still present, service fuel evaporation system. If CANP holds vacuum for 20 seconds, leave vacuum pump attached and go to next step.
4. Checking Solenoid Mechanical Operation - While still in «OUTPUT STATE CHECK»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__output-state-check) , turn CANP circuit off (no voltage). Reconnect CANP solenoid connector. Apply 16 in. Hg vacuum to CANP solenoid as in step 3 . Depress and release throttle. If vacuum is released, remove jumper wire from STI and go to next step. If vacuum is not released, replace CANP solenoid and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
5. Checking Vacuum Supply - Disconnect vacuum hose from canister purge solenoid on PVC side. Start engine. If vacuum is present at vacuum hose, EEC system is okay. Check fuel system. If vacuum is not present at hose, check vacuum hose for proper routing, kinks, or blockage, If okay, check engine for cause of low vacuum.
6. Measuring Solenoid Resistance - Turn key off and wait 10 seconds. Set DVOM on 200-ohm scale. Disconnect CANP solenoid connector and measure solenoid resistance. If reading is between 40-90 ohms, go to next step. If reading is incorrect, replace CANP solenoid and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
7. Checking Voltage of VPWR Circuit - Turn key off and wait 10 seconds. Set DVOM on 20-volt scale. Measure voltage between VPWR circuit at CANP solenoid harness connector and battery negative terminal. If reading is 10.5 volts or greater, go to next step. If reading is less than 10.5 volts, repair open in circuit and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
8. Checking Continuity of CANP Circuit - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Connect breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between Test Pin No. 31 and CANP harness connector. If reading is less than 5 ohms, go to next step. If reading is 5 ohms or more, repair open circuit and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
9. Checking For Short to Ground - Turn key off and wait 10 seconds. Install breakout box, leaving ECA disconnected. Set DVOM on 200K-ohm scale and disconnect CANP solenoid. Measure resistance between Test Pin No. 31 and Test Pins No. 40, 46, and 60. If all readings are 10K ohms or more, go to next step. If any reading is less than 10K ohms, repair short to ground and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
10. Checking For Short to Power - Turn key off and wait 10 seconds. Install breakout box, leaving ECA disconnected. Set DVOM on 200K-ohm scale and disconnect CANP solenoid. Measure resistance between Test Pin No. 31 and Test Pins No. 37 and 57. If all reading are 10K ohms or more, remove breakout box. Replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If any reading is less than 10K ohms, repair short to power and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code is repeated, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .

CIRCUIT TEST D5 - IDLE SPEED CONTROL (AIR BY-PASS)

Note. Perform this test when Service Code 12, 13, 16, 17, 47 or 48 displayed during QUICK TEST or when directed here by other test procedures. If engine is running rough or has rough idle, correct these conditions before performing test. Causes may be in ignition system, fuel system or EGR system.

Idle Speed Control (Air By-Pass) Circuit. Scheme 33

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: engine temperature not up to operating temperature, engine over operating temperature, A/C input (electrical problem), improper idle speed/throttle stop adjustment or cruise control linkage.

1. Check For RPM Drop - Turn key off. Connect engine tachometer and start engine. Disconnect Idle Speed Control (ISC) harness. If RPM drops or if engine stalls, go to next step. If not, go to step 3 .
2. Checking For EGR Codes - If EGR service codes 31, 32, 33 or 34 are displayed, go to «KEY ON ENGINE RUNNING (KOER) CODE-TO-CIRCUIT TEST MENU»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and perform appropriate CIRCUIT TEST. If these codes are not displayed, go to next step.
3. Checking Other Codes - If service codes 22, 41, 42, 33, or 34 are displayed, go to «KEY ON ENGINE RUNNING (KOER) CODE-TO-CIRCUIT TEST MENU»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and perform appropriate CIRCUIT TEST. If these codes are not displayed, go to next step.
4. Measuring ISC Solenoid Resistance - Turn key off. Disconnect ISC solenoid. Set DVOM on 200-ohm scale, and measure resistance of ISC solenoid. If resistance is between 7 and 13 ohms, go to next step. If resistance is less than 7 ohms or more than 13 ohms, replace ISC solenoid and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
5. Checking For Internal Short - With key off and ISC harness disconnected, set DVOM on 200K-ohm scale. Measure resistance from either ISC pin to ISC solenoid housing. If reading is greater than 10K ohms, go to next step. If reading is 10K ohms or less, replace ISC solenoid. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
6. Checking VPWR Circuit - Leave ISC harness disconnected. Turn key on, leaving engine off. Measure voltage between VPWR circuit at ISC harness connector and battery ground terminal. If reading is less than 10.5 volts, repair open in circuit and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is 10.5 volts or more, go to next step.
7. Checking Circuit Continuity - Turn key off and wait 10 seconds. Leave ISC harness disconnected. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Install breakout box, leaving ECA disconnected. With DVOM on 200-ohm scale, measure resistance between Test Pin No. 21 and ISC circuit at ISC harness connector. If reading is greater than 5 ohms, repair open circuit and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 5 ohms, go to next step.
8. Checking For Circuit Short to Ground - Turn key off and wait 10 seconds. Leave ISC harness disconnected. Install breakout box, leaving ECA disconnected. Set DVOM on 200K-ohm scale. Measure resistance between Test Pin No. 21 and Test Pins No. 40, 46, and 60. If any reading is less than 10K ohms, repair short to ground and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If all readings are 10K ohms or more, go to next step.
9. Checking For Short to Power - Turn key off and wait 10 seconds. Leave breakout box installed. Leave ECA and ISC solenoid disconnected. Set DVOM on 200K-ohm scale. Measure resistance by connecting DVOM negative lead to Test Pin No. 21 and positive lead to Test Pin No. 37. If reading is greater than 10K ohms, go to next step. If reading is 10K ohms or less, repair short to power and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code or symptom are still present, replace ECA.
10. Checking Processor Signal - With key off, connect ECA and ISC. Leave breakout box installed and set DVOM on 20-volt scale. Connect DVOM between Test Pins No. 21 and 40. Start engine and observe DVOM while slowly increasing and decreasing engine RPM. If DVOM reading varies, go to next step. If DVOM reading does not vary, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
11. Checking Curb Idle - Verify curb idle speed. If curb idle speed is within specifications, replace ISC and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If curb idle speed is incorrect, check engine vacuum hoses for proper routing. Use emission label as a guide. Ensure throttle plates are fully closed. Check throttle and/or cruise control linkage for binding. Repair if necessary. If these items are okay, replace ISC and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
12. Code 19 Displayed: ISC RPM Low - Turn key off and wait 10 seconds. Deactivate SELF-TEST. Start and run engine at 2000 RPM for 2 minutes or until top radiator hose is hot and pressurized. Turn key off and wait 10 seconds. Perform «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 19 is still displayed, inspect throttle body and air inlet for contamination, service as necessary and adjust curb idle. Rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 19 has been cleared, service other codes as necessary.
13. Code 17 Displayed: ISC RPM Low - Check and correct excessive engine load conditions, cooling fans, lights, etc. Run engine at 2000 RPM for 2 minutes. Turn key off and wait 10 seconds. Rerun «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 17 is displayed, inspect throttle body and air inlet for contamination. Clean if necessary. If okay, adjust curb idle speed and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 17 is not displayed, service other codes as necessary.
14. Code 13 Displayed: High ISC RPM - Turn key off. Connect tachometer to engine. Start engine. With engine running, disconnect ISC harness connector. If engine RPM drops or if engine stalls, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If engine RPM does not drop, check engine vacuum hoses for proper routing. Use emission label as a guide. Ensure curb idle is correct. Make sure throttle plates are fully closed. Check throttle and/or cruise control linkage for binding. Repair if necessary. If these items are okay, replace ISC and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
15. Code 47 Displayed: Check For Low Flow of Unmetered Air - Check for holes, cracks, or disconnections in fuel charging system (manifold gaskets, vacuum lines, vacuum tees etc.). Check purge valve for sticking. Check injector "O" rings for leaks. Service any faults and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no faults are found, EEC-IV system is okay for metered air.
16. Code 48 Displayed: Check For High Flow of Unmetered Air - Check for and repair holes, cracks, and/or bad connections at air cleaner outlet tube (between vane airflow meter and fuel charging assembly). Perform «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 48 is displayed, check for other sources of unmetered air. If code 48 is not displayed, EEC system is okay. Go to «KEY ON ENGINE RUNNING (KOER) CODE-TO-CIRCUIT TEST MENU»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and service other codes as necessary.
17. Code 16: High ISC RPM - If code 48 is also present, reset throttle plate. Refer to emission decal for curb idle set procedure. Rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code 48 is still present, go to step 16 of this test. If code 48 is not present, check for vacuum leaks at injector "O" rings, purge solenoid and vacuum lines, etc. Service as necessary and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .

Shift Indicator Light (SIL) Circuits. Scheme 34

1. Checking SIL Operation - Inspect SIL while driving vehicle. SIL should turn on when optimum shift RPM is reached in each gear. Light should be off in highest gear. If SIL light is always on, check for a short in SIL circuit. If light is always off, check for an open in SIL circuit. If light is always on, go to step 6 . If light is always off, go to next step.
2. Checking SIL Circuit Fuse - Turn key off and wait 10 seconds. Remove and inspect SIL circuit fuse (No. 18). If fuse is okay, go to next step. If fuse is blown, repair ground short between bulb and fuse, verify system operation.
3. Check SIL Bulb - Turn key off. Remove and inspect SIL bulb. If bulb is okay, go to next step. Replace bulb if necessary.
4. Checking SIL Dimmer Relay Continuity - Turn key off. Disconnect SIL dimmer relay. Set DVOM on 200-ohm scale. Measure resistance between dimmer relay pins No. 3 and 5. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, replace dimmer relay, and check operation.
5. Checking Dimmer Relay Function - Turn key off, and disconnect dimmer relay. Connect a 12-volt circuit between Pins No. 1 and 2. Set DVOM on 200-ohm scale. Measure resistance between Pins No. 3 and 5. If resistance is 40-55 ohms, go to next step. If resistance is not to specification, replace dimmer relay, Check operation of SIL.
6. Check Voltage at Dimmer Relay - With KOEO, disconnect SIL Dimmer Relay. Set DVOM on 20-volt scale. Measure voltage between Test Pin No. 5 on relay harness connector, and battery ground. If voltage is less than 5 volts, repair circuit between relay and fuse. Check operation of SIL. If voltage is greater than 5 volts, go to next step.
7. Checking Voltage at High Gear Switch - With KOEO, disconnect high gear switch and set DVOM on 20-volt scale. Measure voltage between SIL dimmer relay of high gear switch and battery negative. If voltage is greater than 5 volts, go to next step. If voltage is less than 5 volts, repair circuit between high gear switch and dimmer relay. Check SIL operation.
8. Checking Operation of High Gear Switch - Turn key off and wait 10 seconds. Disconnect high gear switch. Set DVOM on 200-ohm scale. Measure resistance of High Gear Switch while shifting from highest gear to next lower gear. If circuit opens and closes, go to next step. If circuit does not open and close, replace switch.
9. Checking Continuity of SIL Circuit - Turn key off, and disconnect high gear switch. Install breakout box and leave ECA disconnected. Set DVOM on 200-ohm scale, and measure resistance between Test Pin No. 53 and the ECA side of the high gear switch. If resistance is less than 5 ohms, reconnect high gear switch, shift transmission into high gear and go to next step. If resistance is more than 5 ohms, repair circuit between high gear switch and ECA.
10. Checking Circuit For Short to Ground - Turn key off, and place transmission in highest gear. Set DVOM on 200-ohm scale, and install breakout box, leaving ECA connected. Measure resistance between Test Pins No. 53 and 60. If resistance is less than 100K ohms, repair short between high gear switch and ECA. If resistance is greater than 100K ohms, rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and check ECT and MAP circuits for influence on SIL system. If okay, replace ECA.

2.3L HSC MPFI Engine WOT A/C Cut-Out Circuits. Scheme 35

2.3L OHC MPFI Engine WOT A/C Cut-Out Circuits. Scheme 36

1. No A/C: Check For Voltage at A/C Clutch - Use only DVOM, not diagnostic tester, for this step. With KOEO, set DVOM on 20-volt scale. Measure voltage between A/C clutch harness connector and negative battery terminal. If voltage is greater than 10.5 volts, EEC-IV system is okay, diagnose A/C system. If voltage is less than 10.5 volts, go to next step.
2. Checking Continuity of Power-to-Clutch Circuit - Turn key off and wait 10 seconds. Set DVOM on 200-ohm scale. Disconnect A/C clutch harness and harness from A/C fan controller. Measure resistance between power side of A/C clutch harness connector and power-to-clutch pin at A/C fan controller. If resistance is less than 5 ohms, reconnect A/C clutch and go to next step. If resistance is more than 5 ohms, service open circuit. Re-test system.
3. Checking Power on A/C Demand Circuit - With KOEO and WAC relay or fan controller disconnected, turn on A/C. Set DVOM to 20-volt scale. Measure voltage between A/C demand input pin at WAC relay or fan controller connector and ground. If voltage is greater than 10.5 volts, go to next step. If voltage is less than 10.5 volts, check switch operation, repair open circuit and re-test system.
4. Checking WAC Circuit For Short to Ground - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector and A/C fan controller. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200K-ohm scale. Measure resistance between WAC circuit at relay or fan controller and chassis ground. If resistance is greater than 10K ohms, go to next step. If resistance is less than 10K ohms, repair short and retest system.
5. Checking A/C Fan Controller Ground Circuit - With key off and A/C fan controller disconnected, set DVOM on 200-ohm scale. Disconnect ECA and measure resistance between ground circuit at A/C fan controller connector and chassis ground. If resistance is less than 5 ohms, go to next step. If resistance is more than 5 ohms, repair open circuit and retest system.
6. Checking For Voltage to A/C Fan Controller - With key on, ECA and A/C fan controller disconnected, set DVOM on 20-volt scale. Measure voltage between ignition switch run circuit at the fan controller connector and ground. If voltage is greater than 10.5 volts, go to next step. If voltage is less than 10.5 volts, repair open circuit, reconnect ECA and controller and re-test system.
7. Checking A/C Output at WOT - Enter «OUTPUT STATE CHECK»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__output-state-check) ; see «OUTPUT STATE CHECK»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__output-state-check) under «QUICK TEST DIAGNOSTIC AIDS»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . Use a VOM or DVOM meter for this test. Turn key off and wait 10 seconds. Set meter on 20-volt scale. Connect meter negative (-) lead to STO at Self-Test connector and positive lead to positive (+) battery terminal. Jumper STI to SIG RTN at Self-Test connector. Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) until completion of Continuous Memory Code sequence. Meter will indicate less than one volt when test is complete. Depress and release throttle. If voltage increases to 10.5 volts or more, remain in «OUTPUT STATE CHECK»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__output-state-check) and go to next step. If voltage does not increase to 10.5 volts, leave test equipment connected and go to «CIRCUIT TEST D16»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-d16-output-state) , step 2).
8. System Identification - If vehicle is equipped with A/C fan controller, go to step 14). (A/C Fan Controller vehicles: 2.3L HSC MPFI, 2.3L OHC MPFI).
9. Checking For Short to Power - Turn key off and wait 10 seconds. Install breakout box, ECA and fan controller disconnected. Set DVOM on 200K-ohm scale. Measure resistance between Test Pin No. 54 and Test Pins No. 37 and 57 at the breakout box. If all readings are greater than 10K ohms, replace ECA, reconnect fan controller and re-test system. If any reading is 10K ohms or less, repair short to power and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If symptom is still present, replace ECA.
10. Cycle A/C Demand Switch - Turn key off and wait 10 seconds. Install breakout box, leaving ECA disconnected. Set DVOM on 20-volt scale. With KOEO, connect DVOM positive test lead to Test Pin No. 24 (No. 43 on 2.3L HSC MPFI) and negative test lead to Test Pin No. 40. If voltage goes high and low as switch is cycled, replace ECA and retest system. If voltage does not cycle, go to next step.
11. Checking Continuity of A/C Demand Circuit - Turn key off and wait 10 seconds. Set DVOM on 200-ohm scale. Measure resistance between Test Pin No. 24 (No. 43 on 2.3L HSC MPFI) at the breakout box and A/C demand switch. If resistance is greater than 5 ohms, repair open in A/C demand circuit and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If resistance is less than 5 ohms, EEC-IV system is okay.
12. Checking A/C Demand Circuit For Short to Power - Disconnect A/C fan controller. Disconnect ECA and install breakout box. With A/C demand switch "OFF", set DVOM on 20-volt scale. Turn key on. Measure voltage between Test Pin No. 24 at breakout box and chassis ground. If voltage is less than one volt EEC-IV system is okay. If voltage is more than one volt, check operation of A/C demand switch, repair short circuit and re-test system.

CIRCUIT TEST D8 - TURBO BOOST

Note. Perform this test when Service Code 81 is displayed during QUICK TEST or when directed here by other test procedures.

Turbo Boost Circuit. Scheme 37

1. Output State Test - Enter «OUTPUT STATE CHECK»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__output-state-check) ; see «OUTPUT STATE CHECK»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__output-state-check) under «QUICK TEST DIAGNOSTIC AIDS»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . Use only DVOM, not diagnostic tester, for this step. Turn key off and wait 10 seconds. Set DVOM on 20-volt scale. Connect DVOM negative test lead to STO at SELF-TEST connector and positive test lead to positive battery terminal. Install a jumper wire between STI and signal return at SELF-TEST connector. Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) until end of CONTINUOUS SELF-TEST codes (DVOM reads less than one volt). Depress and release throttle while watching DVOM reading. If reading did not change to a high voltage, depress throttle to WOT position and release. If STO voltage does not go to high reading, go to «CIRCUIT TEST D16»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-d16-output-state) , step 1). Leave test equipment hooked up. If reading changes to high voltage, remain in «OUTPUT STATE CHECK»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__output-state-check) and go to next step.
2. Checking Boost Output Electrical Operation - With KOEO, set DVOM on 20-volt scale. Connect DVOM positive test lead to VPWR circuit at boost solenoid connector and negative test lead to boost output on boost solenoid connector. Depress and release throttle several times while reading DVOM. If boost solenoid does not cycle, remove jumper wire and go to step 4 . If boost solenoid cycles, go to next step.
3. Checking Boost Solenoid Function - Remain in «OUTPUT STATE CHECK»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__output-state-check) . Disconnect turbo boost control solenoid vacuum hose at turbocharger inlet end. Attach vacuum pump to hose. Depress throttle once to cycle solenoid to closed position. Apply vacuum to solenoid, then depress throttle to cycle solenoid to open position and release vacuum. If solenoid does not hold and release vacuum properly, replace solenoid and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If solenoid works correctly, EEC system is okay. Check turbocharger boost system.
4. Check Voltage of VPWR Circuit - Turn key off and wait 10 seconds. Disconnect boost solenoid connector. With DVOM on 20-volt scale, measure voltage between VPWR circuit of boost solenoid at vehicle harness and battery negative terminal. If reading is less than 10.5 volts, repair wiring circuit and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If voltage is more than 10.5 volts, go to next step.
5. Measuring Boost Solenoid Resistance - With KOEO, disconnect boost solenoid and set DVOM on 200-ohm scale. Measure solenoid resistance. If resistance is 65-110 ohms, go to next step. If resistance is not within specification, replace solenoid and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
6. Checking Continuity of Boost Circuit - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion or loose wires. Repair if necessary. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between Test Pin No. 31 and boost circuit at harness connector. If reading is 5 ohms or more, repair open and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 5 ohms, go to next step.
7. Checking For Short to Ground - Turn key off and wait 10 seconds. Leave breakout box installed and ECA disconnected. Disconnect boost solenoid and set DVOM on 200K-ohm scale. Measure resistance between Test Pin No. 31 and Test Pins No. 40, 46, and 60. If any reading is less than 10K ohms, repair short to ground and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If all readings are 10K ohms or more, go to next step.
8. Checking For Short to Power - Turn key off and wait 10 seconds. Leave breakout box installed, ECA disconnected, and DVOM on 200K-ohm scale. With boost solenoid disconnected, measure resistance between Test Pin No. 31 and Test Pins No. 37 and 57. If any reading is less than 10K ohms, repair short to power and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If symptom is still present, replace ECA. If all readings are 10K ohms or more, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
9. Checking For Change in Octane Switch - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion or loose wires. Repair if necessary. Install breakout box. Connect ECA to breakout box. Set DVOM to 20 Volt scale. Connect negative test lead to Pin 46 and positive test lead to Pin 24 at the breakout box. Turn key on, and leave engine off. While observing DVOM, cycle octane switch several times. If voltage readings fluctuate from 1 to 5 volts, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If voltage readings do not fluctuate from 1 to 5 volts, test turbocharger boost system.

CIRCUIT TEST D9 - CONVERTER CLUTCH OVERRIDE (CCO) SHIFT SOLENOID 3/4-4/3 (SS 3/4-4/3)

Note. Perform this test when Service Code 85, 86, 88 or 89 is displayed during QUICK TEST or when directed here by other test procedures.

CCO Circuit. Scheme 38

Codes 88 or 89 Displayed

1. Measuring CCO Solenoid Resistance - Turn key off and wait 10 seconds. Set DVOM on 200-ohm scale. Disconnect CCO solenoid connector and measure solenoid resistance. If resistance is less than 26 ohms or greater than 40 ohms, replace CCO solenoid and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If resistance is between 26 and 40 ohms, connect solenoid and go to next step.
2. Checking Voltage to VPWR Circuit - With KOEO, set DVOM on 20-volt scale and measure voltage at CCO solenoid connector between VPWR circuit and ground. If reading is 10.5 volts or less, repair open circuit in harness and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is 10.5 volts or more, go to next step.
3. Checking Continuity of CCO Circuit - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between Test Pin No. 53 and CCO circuit at solenoid harness connector. If reading is 5 ohms or more, repair open circuit in harness and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 5 ohms, go to next step.
4. Checking CCO Circuit For Short to Ground - Turn key off and wait 10 seconds. Leave breakout box installed and ECA disconnected. Disconnect CCO solenoid. Set DVOM on 200K-ohm scale. Measure resistance between Test Pin No. 53 and Test Pins No. 40, 46, and 60. If any reading is less than 10K ohms, repair short to ground and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If all readings are 10K ohms or more, go to next step.
5. Checking CCO Circuit For Short to Power - Turn key off and wait 10 seconds. Leave breakout box installed, ECA and CCO solenoid disconnected. Set DVOM on 200K-ohm scale. Measure resistance between Test Pin No. 53 and Test Pins No. 37 and 57. If all readings are 10K ohms or more, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If any reading is less than 10K ohms, repair short to power and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code is repeated, replace ECA.

Codes 85 or 86 Displayed

1. 6) Checking SS 3/4-4/3 Resistance - Turn key off and wait 10 seconds. Set DVOM on 200-ohm scale. Disconnect SS 3/4-4/3 connector and measure solenoid resistance between SS and VPWR. If resistance is less than 26 ohms or more than 40 ohms, diagnose A4LD transmission. If resistance is between 26 and 40 ohms, go to next step.
2. 7) Checking Voltage to VPWR Circuit - Disconnect SS 3/4-4/3. With KOEO, set DVOM on 20-volt scale and measure voltage at SS 3/4-4/3 solenoid connector between VPWR circuit and ground. If reading is less than 10.5 volts, repair open circuit in harness and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is 10.5 volts or more, go to next step.
3. 8) Checking Continuity of SS 3/4-4/3 Circuit - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Install breakout box, leaving ECA and shift solenoid disconnected. Set DVOM on 200-ohm scale. Measure resistance between Test Pin No. 42 and shift solenoid circuit at solenoid harness connector. If reading is 5 ohms or more, repair open circuit in harness and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 5 ohms, go to next step.
4. 9) Checking Circuit For Short to Ground - Turn key off and wait 10 seconds. Leave breakout box installed and ECA disconnected. Disconnect shift solenoid. Set DVOM on 200K-ohm scale. Measure resistance between Test Pin No. 42 and Test Pins No. 40, 46, and 60 at breakout box. If any reading is less than 10K ohms, repair short to ground and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If all readings are 10K ohms or more, go to next step.
5. 10) Checking SS 3/4-4/3 Circuit For Short to Power - Turn key off and wait 10 seconds. Leave breakout box installed, ECA and shift solenoid disconnected. Set DVOM on 200K-ohm scale. Measure resistance between Test Pin No. 42 and Test Pins No. 37 and 57 at breakout box. If all readings are 10K ohms or more, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If any reading is less than 10K ohms, repair short to power and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If code is repeated, replace ECA.

CIRCUIT TEST D10 - DYNAMIC RESPONSE TEST

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: person testing EEC system did not perform brief Wide Open Throttle (WOT) after Dynamic Response code, mechanical engine problems, or engine did not go over 2000 RPM.

Note. If throttle is snapped open briefly it may not pass the WOT test. Ensure that the throttle is depressed fully to WOT and that engine exceeds 2000 RPM.

Code 77 Displayed: System Failed to Recognize WOT Test - Rerun KOER SELF TEST as follows

1. Activate KOER test and start engine.
2. Observe ID code 2 (0 with STAR tester)
3. Observe Dynamic Response Code 1 (0 with STAR tester).
4. Perform WOT.
5. Testing complete; service code output begins.

If code 77 is still displayed, replace ECA and rerun QUICK TEST . If code 77 is no longer present, vehicle has passed Dynamic Response Test; service other codes as necessary.

CIRCUIT TEST D11 - "CHECK ENGINE" LIGHT (MALFUNCTION INDICATOR)

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: fuses, bulb, or socket. This circuit test checks STO-MIL circuit and ECA.

"CHECK ENGINE" Light (Malfunction Indicator) Circuit. Scheme 39

Note. All service codes, except a code 11 (pass), must be cleared before continuing.

1. Light Always On, Checking Short to Ground - If vehicle will not start, go to «CIRCUIT TEST A1»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) step 1). Verify presence of KOEO SELF-TEST code 11. If not, repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . Turn key off. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Connect DVOM between Test Pins No. 17 and No. 40 at the breakout box. If reading is greater than 5 ohms, replace ECA. If reading is less than 5 ohms, repair short to ground in harness from Test Pin No. 17 to SELF-TEST connector or to "CHECK ENGINE" light.
2. Light Never On, Check Continuity of STO/MIL Circuit - If vehicle will not start, go to «CIRCUIT TEST A1»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) step 1). Verify presence of KOEO SELF-TEST code 11. If not, repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . Turn key off. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between Test Pin No. 17 and STO at SELF-TEST connector. Also measure resistance between Test Pin No. 17 and "CHECK ENGINE" light. If both readings are less than 5 ohms, go to next step. If not, repair open circuit in wiring harness.
3. Checking For Power to "CHECK ENGINE" Light Bulb - If power exists at bulb, replace bulb or socket and go to next step. If no power exists at socket, check fuse and input circuit, and then go to next step.
4. Confirming Circuit Repair - Remove breakout box and reconnect ECA to harness. Turn key to "RUN" position. See if "CHECK ENGINE" light is on. If light is on, malfunction indicator system is okay. If light does not come on, replace ECA.
5. "CHECK ENGINE"/"CHECK DCL" Message Displayed - If vehicle does not start, go to «CIRCUIT TEST A1»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) step 1). Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If result is 11-10-11 (pass codes), malfunction is in Message Center Unit. If 11-10-11 is not displayed, go to «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .

IDM Circuit. Scheme 40

Note. Perform this test when Service Code 18 is displayed during QUICK TESTS or when directed here by other test procedures. The IDM circuit has a 20K-ohm resistor between Test Pin No. 4 and the ignition coil negative terminal.

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: ignition module, ignition coil, spark plugs and/or high tension cables, distributor and PIP sensor.

1. Checking Continuity of IDM Circuit - Turn key off and wait 10 seconds. Disconnect E-core ignition connector from coil. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Install breakout box, leaving ECA disconnected. Set DVOM on 200K-ohm scale. Measure resistance between Test Pin No. 4 and ignition coil negative terminal. If reading is less than 20K ohms or greater than 24K ohms, repair open circuit and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is between 20K and 24K ohms, go to next step.
2. Checking For Short to Ground - Turn key off and wait 10 seconds. Leave breakout box installed and ECA disconnected. With DVOM on 200K-ohm scale, measure resistance between Test Pin No. 4 and Test Pins No. 40, 46, and 60. If any reading is less than 10K ohms, repair short to ground and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If all readings are 10K ohms or more, go to next step.
3. Checking TFI Module - Turn key off and wait 10 seconds. Deactivate SELF-TEST. Using «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) , observe VOM or diagnostic tester for indication of fault while lightly tapping on TFI module and wiggling TFI harness connector. If fault is indicated, disconnect TFI harness. Inspect connector and terminals for damage. If connector and terminals are okay, check TFI ignition system. If no fault is indicated, go to next step.
4. Checking EEC-IV Harness - While in CONTINUOUS MONITOR (WIGGLE) TEST, observe VOM or diagnostic tester for indication of fault while wiggling, shaking, or bending small sections of harness while working from TFI connector toward firewall. Repeat process from firewall to ECA. Perform this test to check for faults in the following circuits: PIP Open/Shorted to Ground: Check circuit at Test Pin No. 56. SPOUT Shorted to Ground: Check circuit at Test Pin No. 36. Ignition Ground Open: Check circuit at Test Pin No. 16. IDM Open to Ground: Check circuit at Test Pin No. 4. IDM Shorted to Power: Check circuit at Test Pin No. 4. Perform «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) on these circuits one at a time in order to isolate fault. If fault is indicated, isolate fault and repair harness. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no fault is indicated, go to next step.
5. Checking ECA and Harness Connectors - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion or loose wires. If connector is damaged, repair as necessary and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If connector is okay, replace ECA. Start and run engine for one minute. Perform «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and observe codes. Connect ECA when step is completed.

CIRCUIT TEST D13 - SPARK TIMING CHECK

Note. Perform this test when Service Code 18 is displayed during QUICK TEST or when directed here by other test procedures.

Spark Timing Check Circuit. Scheme 41

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: engine condition (valves, vacuum leaks, valve timing, EGR valve, etc.), PIP sensor, and TFI ignition module.

1. Checking Spark Timing - Perform «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and verify that SELF-TEST is activated. Check and record timing while in ENGINE RUNNING SELF-TEST. System locks timing and then returns to normal 2 minutes after last service code is displayed. If timing is equal to base timing plus 20 degrees (+/-3 degrees), spark timing is correct. See VECI decal for base timing specification. Go to «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If timing is not to specification, go to next step.
2. Checking Spark Output (SPOUT) Circuit of TFI Module - Locate Spark Output (SPOUT) connector and open the connection. Start engine and check for 10 degrees BTDC base timing +/- 3 degrees. If base timing is correct, reconnect SPOUT connector and go to next step. If base timing is not correct, adjust base timing. After timing is adjusted, reconnect SPOUT and perform «TIMING CHECK»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__timing-check) under «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
3. Checking For Power to ECA - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Install breakout box. With KOEO, and DVOM set on 20-volt scale, measure voltage between Test Pins No. 37 and 40, and between Test Pins No. 57 and 60. If either reading is less than 10.5 volts, go to «CIRCUIT TEST D22»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-d22-integral-relay) , step 1) on the 2.3L Turbo MPFI engine. If either reading is less than 10.5 volts, go to «CIRCUIT TEST A2»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a2-vehicle-battery) , step 1) for all other engines. If both readings are 10.5 volts or more, go to next step.
4. Checking Continuity of Harness - Turn key off and wait 10 seconds. Disconnect harness connector at TFI module. With DVOM on 200-ohm scale, measure resistance between Test Pin No. 36 at breakout box and pin No. 2 (SPOUT circuit) at TFI harness connector. If reading is greater than 5 ohms, repair open circuit. Connect SPOUT connector and check timing as described in step 1 . If reading is 5 ohms or less, go to next step.
5. Checking Harness For Ignition Ground - Leave breakout box installed and reconnect ECA. Reconnect TFI module. Switch breakout box to "COMPUTED" position. Set DVOM on 20-volt scale. Measure voltage between Test Pin No. 36 at breakout box and battery negative terminal, during KOER SELF-TEST. If voltage is 4-8 volts, EEC-IV system is okay. Diagnose TFI ignition system. If voltage is not to specification, replace ECA and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .

CIRCUIT TEST D14 - NO CODES/CODES NOT LISTED

Note. Perform this CIRCUIT TEST when directed by other test procedures.

No Codes/Codes Not Listed Circuits. Scheme 42

1. Checking For VREF - Turn key off and wait 10 seconds. Set DVOM on 20-volt scale. Install breakout box, leaving ECA connected. With KOEO, measure voltage between Test Pins No. 26 and 46 at breakout box. If reading is less than 4 volts or more than 6 volts, go to «CIRCUIT TEST A3»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a3-reference-voltage) , step 1). If reading is between 4 and 6 volts, go to next step.
2. Checking SELF-TEST Input Continuity - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between Test Pin No. 48 and Self-Test Input (STI) at SELF-TEST connector pigtail. If reading is 5 ohms or more, repair open in circuit. If reading is less than 5 ohms, go to next step.
3. Checking SELF-TEST Output Circuit Continuity - With breakout box installed and DVOM on 200-ohm scale, measure resistance between Test Pin No. 17 and Self-Test Output (STO) at SELF-TEST connector. If reading is 5 ohms or more, repair open in circuit. If reading is less than 5 ohms, go to next step.
4. Checking EGO Sensor Ground Continuity - Turn key off. With breakout box installed and DVOM on 200-ohm scale, measure resistance between Test Pin No. 49 and EGO sensor engine block ground. If reading is 5 ohms or more, repair EGO sensor ground wire or open circuit bad connection. If reading is less than 5 ohms, go to next step.
5. Checking For STO Short to Ground - With breakout box installed and DVOM on 200-ohm scale, measure resistance between STO at SELF-TEST connector and engine block ground. If reading is 5 ohms or less, repair STO circuit for short to ground and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is greater than 5 ohms, go to next step.
6. Intermittent: No Codes Displayed (NDS) - Turn key off. Install breakout box, and connect ECA to breakout box. Set DVOM on 20-volt scale. Connect DVOM between Test Pin No. 30 and Test Pins No. 40 or 60. Perform «KEY ON ENGINE RUNNING (KOER) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is greater than one volt, repair intermittent fault in NDS harness connector or switch. If okay, go to KOER SELF-TEST for appropriate service codes. If reading is not greater than one volt, go to next step.
7. Power Relay Always On - Leave key off and breakout box installed. Set DVOM on 20-volt scale. Connect DVOM between Test Pins No. 37 or 57 and between Test Pins No. 40 or 60. Turn key on and then off. Wait 10 seconds. If reading does not change from 10.5 volts (or more) to zero volts, go to next step. If reading changes from 10.5 volts (or more) to zero volts, go to step 9 only if vehicle is equipped with Malfunction Indicator Light (MIL) or Shift Indicator Light (SIL). If vehicle is NOT equipped with either of these lights, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . NOTE: Malfunction Indicator Light (MIL) is displayed as "CHECK ENGINE" light on instrument cluster.
8. VPWR Harness Short to Power - With key off, breakout box installed and power relay or IRC disconnected, set DVOM on 20-volt scale. Connect DVOM to Test Pin No. 37 or 57 and to Test Pin No. 40 or 46 at the breakout box. If voltage is greater than 10.5 volts, repair short to power circuit and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If voltage is less than 10.5 volts, replace EEC-IV power relay or IRC and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
9. Malfunction Indicator Light (MIL) or Shift Indicator Light (SIL) - If shift indicator light is always on or off, go to «CIRCUIT TEST D6»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) , step 1). If malfunction indicator light is always on, go to «CIRCUIT TEST D11»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-d11-check-engine) , step 1). If malfunction indicator light is always off, go to «CIRCUIT TEST D6»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) , step 1). If MIL or SIL is working normally, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .

CIRCUIT TEST D15 - CODE 15 KOEO CONTINUOUS

Note. Perform this CIRCUIT TEST when directed by other test procedures.

EEC Power Relay Circuit. Scheme 43

1. Continuous Code 15 Displayed - Clear continuous memory codes using procedure outlined in «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) . Repeat «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) through continuous memory code output. If continuous code 15 is not displayed, continuous code 15 testing is complete. If continuous code 15 is displayed, go to next step. NOTE: Continuous code 15 may be displayed when power to Keep Alive Memory (KAM) Test Pin No. 1 at ECA is interrupted. Code 15 may also be displayed the first time SELF-TEST is performed and power is restored to ECA. Repeat SELF-TEST to ensure correct diagnosis.
2. Engine Compartment Wire Routing - Ensure that EEC components and wiring are not close to high tension secondary voltage wires or ignition components. If EEC wiring is close to high tension wires, reroute EEC wiring. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If continuous code 15 is no longer displayed, continuous code 15 testing is complete. If continuous code 15 is still displayed, go to next step.
3. Checking Power Circuit For Keep Alive Memory (KAM) - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector and inspect for damage. Install breakout box, leaving ECA disconnected. Set DVOM on 20-volt scale. Connect DVOM positive test lead to Test Pin No. 1 and negative test lead to pins No. 40 or 60. Turn key on and observe voltage reading. If reading is less than 10.5 volts, repair open to KAM circuit. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is 10.5 volts or more, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .

CIRCUIT TEST D16 - OUTPUT STATE CHECK NOT FUNCTIONING

Note. Perform this CIRCUIT TEST when directed by other test procedures.

Output State Check Circuit. Scheme 44

1. Checking Service Codes - Turn key off and wait 10 seconds. Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and leave key on to enter OUTPUT STATE CHECK. If codes 23, 53, 63 or 68 are displayed, go to «KEY ON ENGINE OFF (KOEO) CODE-TO-CIRCUIT TEST MENU»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and service code(s) as instructed. If no codes are displayed, go to «CIRCUIT TEST D14»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-d14-no-codescodes) , step 1). If code 11 (Pass) is displayed, go to next step.
2. Checking Throttle Linkage - Check throttle and linkage for sticking or binding. If throttle and linkage are okay, replace TPS and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If throttle and linkage are binding, repair as necessary and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .

CIRCUIT TEST D17 - ECA POWER CHECK

Note. Perform this CIRCUIT TEST when directed by other test procedures.

EEC Power Relay Circuit. Scheme 45

1. Power to ECA Check - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Install breakout box and set DVOM on 20-volt scale. With KOEO, measure voltage between Test Pins No. 37 and 40, and between Test Pins No. 57 and 60.
2. If either reading is less than 10.5 volts, go to «CIRCUIT TEST D22»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-d22-integral-relay) , step 1) for the 2.3L MPFI engine. If either reading is less than 10.5 volts, go to «CIRCUIT TEST A2»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-a2-vehicle-battery) , step 1) for all other engines. If both readings are 10.5 volts or more, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .

CIRCUIT TEST D18 - RE-INITIALIZATION CHECK

Note. Perform this CIRCUIT TEST when directed by other test procedures.

Note. The electrical signatures of some aftermarket components may affect driveability of the vehicle.

EEC Power Relay Circuit. Scheme 46

1. Checking For Electrical Noise Sources - Turn key off. Ensure that EEC wiring and components are more than 2" (50 mm) away from secondary ignition wires. Make sure that EEC wiring and components are more than 4" (100 mm) away from distributor, ignition coil, and starter motor and its wiring. If these items are correct, go to next step. If not, correct as necessary and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
2. Checking Harness and Case Ground - Turn key off. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between Test Pin No. 20 and chassis ground. If reading is less than 5 ohms, go to next step. If not, repair wiring harness and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
3. Case Ground Check With Harness Disconnected - Turn key off. Connect ECA to breakout box, but disconnect harness from breakout box. Set DVOM on 200-ohm scale. Measure resistance between Test Pin No. 20 and ECA metal case. If reading is less than 5 ohms, go to next step. On 2.3L Turbo MPFI, go to «CIRCUIT TEST D22»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-d22-integral-relay) , step 10). If reading is more than 5 ohms, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
4. "WIGGLE" Testing VPWR Circuit - With KOEO, connect STAR tester or VOM to SELF TEST connector. Deactivate SELF-TEST. Using «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) , perform "WIGGLE" test on EEC-IV harness from ECA to power relay. If a fault is indicated or a code 72 is displayed, repair intermittent in VPWR circuit. If no fault is indicated, inspect harness connections and pins. Replace power relay and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .

CIRCUIT TEST D19 - KEY POWER CHECK

Note. Perform this test ONLY when a code 55 is displayed in QUICK TEST .

Key Power Circuit. Scheme 47

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: charging system overcharging, battery charger connected with engine running or jump starting vehicle.

1. Checking Continuity of Key Power Circuit - Turn key off and wait 10 seconds. Install breakout box and connect ECA. Disconnect the EEC-IV power relay or IRC. Set DVOM on 200-ohm scale. Measure resistance between Test Pins No. 5 at the breakout box, and KPWR at the EEC-IV power relay, or Test Pin No. 13 at the IRC harness connector. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair open circuit, reconnect system and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
2. Checking KEY POWER (KPWR) Circuit For Shorts - Turn key off, disconnect ECA and install breakout box. Disconnect power relay or IRC. Set DVOM on 200K-ohm scale and measure resistance between Test Pin No. 5 and Test Pins No. 40, 46, and 60, at the breakout box. If resistance is greater than 10K ohms, replace ECA and retest system. If resistance is less than 10K ohms, repair short circuit and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .

CIRCUIT TEST D20 - SYSTEM CHECK

Note. Perform this test ONLY after code 11 is displayed in KOEO SELF-TEST and you have been directed here from CIRCUIT TEST A1 or by DIAGNOSIS BY SYMPTOM (SYMPTOM-TO-DIAGNOSTIC TEST) table.

System Check Flow Chart. Scheme 48

1. ISC-BPA Check - On all engines except 2.3L Turbo MPFI, if you are here for any reason other than engine stall or no start, go to next step. On 2.3L Turbo MPFI engines, go to step 3 . If engine stalls or if it does not start, attempt to start engine at part throttle. If engine runs rough, go to next step. If engine runs smoothly at part throttle, go to «CIRCUIT TEST D5»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-d5-idle-speed) , step 4). If engine does not run (2.3L Turbo MPFI models), go to step 3 . If engine does not run (all other models), go to step 2 .
2. MAP Check - Turn key off and disconnect MAP sensor. Connect MAP tester between harness and MAP sensor. Connect banana plugs of tester into DVOM and set DVOM on 20-volt scale. Turn key on and measure sensor output voltage while cranking engine. If DVOM reading is not to specification, go to «CIRCUIT TEST B6»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-b6-manifold-absolute) , step 14). If DVOM reading decreases from specified range, go to next step. If MAP voltage does not reduce to appropriate voltage while cranking, go to «CIRCUIT TEST B6»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-b6-manifold-absolute) , step 15). MAP VOLTAGE OUTPUT Elevation (Ft.) Voltage Output (Volts) 0 1.55-1.63 1000 1.52-1.60 2000 1.49-1.57 3000 1.46-1.54 4000 1.43-1.51 5000 1.40-1.48 6000 1.37-1.45 7000 1.35-1.43
3. EGR Vacuum Check - Disconnect vacuum hose at EGR valve. DO NOT plug vacuum line. Start or attempt to start engine. If symptom is driveability related, check to see if vacuum is present at vacuum line. If vehicle is a "No Start", does engine start? If results are negative, go to the following tests depending on engine application: 2.3L Turbo MPFI models: Go to «CIRCUIT TEST D1»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-d19-key-power) , step 1). 2.3L OHC MPFI models: Go to «CIRCUIT TEST D5»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-d5-idle-speed) , step 11). 2.3L HSC MPFI models: Go to «CIRCUIT TEST B10»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-b10-pressure-feedback) , step 23)
4. Checking EGR Valve - Inspect EGR valve for leaking. If valve is fully closed, go to «CIRCUIT TEST C1»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-c1-fuel-control-all) , step 1). If EGR valve is leaking or not fully seated, replace or repair valve.

CIRCUIT TEST D22 - INTEGRAL RELAY CONTROL MODULE (IRCM)

Note. Perform this test only when KOEO SELF-TEST Codes 72, 78, 82, 83, 87, 88, 95 or 96 are displayed, or when you are directed here by CIRCUIT TEST A1 , CIRCUIT TEST A3 , or by DIAGNOSIS BY SYMPTOM (SYMPTOM-TO-DIAGNOSTIC TEST) table.

2.5L A/T AXOD MPFI. Scheme 49

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: fuel lines and fuel filters, contaminated fuel, fuel pump, ignition switch, battery cables and ground straps, alternator and voltage regulator, A/C clutch or A/C demand, and cooling fan motor.

1. Checking Battery Supply Voltage - With KOEO, set DVOM on 20-volt scale. Measure voltage across battery terminals. If reading is less than 10.5 volts, service or replace discharged battery. If reading is 10.5 volts or more, go to next step.
2. Checking Battery Ground - With KOEO, and ECA connected, set DVOM on 20-volt scale. Measure voltage between negative battery post and SIGNAL RETURN circuit in SELF-TEST connector. If reading is less than .5 volt, go to step 6). If reading is .5 volt or more, go to next step.
3. Isolating Ground Fault - Turn key off. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box and connect ECA. Turn key on, leaving engine off. Set DVOM on 20-volt scale. Measure voltage between negative battery post and test pins No. 40 and 60. If one or both readings are .5 volt or more, repair open in circuit(s) and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If both readings are less than .5 volt, go to next step.
4. ECA Ground Fault Isolation - Turn key off and wait 10 seconds. With breakout box installed and ECA connected, set DVOM on 200-ohm scale. Measure resistance between test pins No. 46 and 40, and between test pins No. 46 and 60. If one or both readings are 5 ohms or more, disconnect ECA connector. Inspect connector for damage, repair if necessary and repeat this step. If fault is still present, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If both readings are less than 5 ohms, go to next step.
5. Checking Continuity of Signal Return Circuit - Turn key off and wait 10 seconds. With breakout box and ECA connected, set DVOM on 200-ohm scale. Measure resistance between test pin No. 46 and SIGNAL RETURN circuit at SELF-TEST connector. If reading is less than 5 ohms, system is okay. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is 5 ohms or more, correct cause of high resistance in SIGNAL RETURN circuit. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
6. Measure Voltage and Ground to IRCM - Turn key off and disconnect Integral Relay Control Module (IRCM). Set DVOM on 20-volt scale. Measure voltage between IRCM harness connector pin No. 8 (battery positive) and pin No. 15 (ground). If reading is less than 10.5 volts, go to step 9 . If reading is 10.5 volts or more, go to next step.
7. Key Power to IRCM - With key off, disconnect IRCM and set DVOM on 20-volt scale. Turn key on. Measure voltage between pins No. 13 (+) and 15 (-) at IRCM harness connector. If reading is less than 10.5 volts, repair open between pin No. 13 and ignition switch. Connect IRCM and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is 10.5 volts or more, go to next step.
8. Checking Continuity of VPWR Circuit - Turn key off. Disconnect IRCM and ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pins No. 37 and 57 at the breakout box to IRCM harness connector pin No. 24. If reading is 5 ohms or more, repair open in VPWR circuit. Connect IRCM and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 5 ohms, replace IRCM and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
9. Checking Continuity of Power Ground to IRCM - With key off and IRCM disconnected, set DVOM on 200-ohm scale. Measure resistance from negative battery post to IRCM harness connector pin No. 15. If reading is 5 ohms or more, repair open in ground circuit to IRCM harness connector pin No. 15. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 5 ohms, repair open in battery positive to pin No. 8 of IRCM harness connector. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
10. Code 72: Intermittent Open in VPWR Circuit - Code 72 indicates that while key power was present voltage to the IRCM was interrupted, or electrical noise caused the ECA to reset. Driveability problems such as, stalling, high idle, lack of power on acceleration or other drive symptoms could result. Possible causes for this fault are: intermittent open in VPWR circuit between IRCM and ECA, intermittent fault in EEC power relay, intermittent open in VBAT circuit of IRCM, intermittent open in KEY POWER circuit or EEC harness too close to spark plug wires. Using «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) , observe VOM or diagnostic tester for indication of fault while wiggling, bending, or twisting harness from IRCM to ECA and from ignition switch to battery positive terminal. If fault is indicated or if Code 72 reappears, repair intermittent fault in VPWR circuit and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If fault is not found or if codes do not reappear, inspect all component and harness connectors for damaged pins, corrosion, or loose wires. Repair if necessary. If okay, replace IRCM and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
11. Checking Power to Fuel Pump(s) - With KOEO, locate and disconnect fuel pump(s). Set DVOM on 20-volt scale. Measure voltage between CHASSIS GROUND and POWER-to-PUMP circuit at fuel pump while cranking engine. If reading is 8.0 volts or more, service electric fuel pump system. If reading is less than 8.0 volts, go to next step.
12. Checking Power-to-Pump Circuit Continuity - With key off and DVOM on 200-ohm scale, disconnect IRCM and fuel pump(s). Measure resistance between IRCM harness connector pin No. 5 and POWER-to-PUMP circuit at harness connector at fuel pump(s). If reading is less than 5 ohms, replace IRCM. Connect all components and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is 5 ohms or more, repair open in POWER-to-PUMP circuit. Connect IRCM and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
13. Checking Power-to-Pump Circuit For Shorts to Power - With key off and DVOM on 200K-ohm scale, disconnect IRCM and fuel pump(s). Measure resistance between pin No. 5 and pin No. 24 at IRCM harness connector. Measure resistance between pin No. 5 at the IRCM harness connector and battery positive post. If any reading is less than 10K ohms, repair short circuit. Connect all components and attempt to start vehicle. If vehicle runs, repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If vehicle does not run, replace IRCM and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If all readings are 10K ohms or more, replace IRCM and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
14. Code 83 or 87: Checking Continuity of Fuel Pump Circuit - Code 83 or 87 indicates voltage output for the high or low fuel pump circuit did not change when activated during KOEO SELF-TEST. Possible causes for this fault are: open or grounded fuel pump circuit, open or grounded ECA driver or disconnected or open solenoid. Turn key off. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Disconnect IRCM and set DVOM on 200-ohm scale. Code 83: Measure resistance of fuel pump(s) circuit, from breakout box test pin No. 22 to IRCM harness connector pin No. 18. Code 87: Measure resistance between breakout box test pin No. 41 and IRCM harness connector pin No. 11. If reading is 5 ohms or more, repair open in fuel pump circuit. Connect all components and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 5 ohms, go to next step.
15. Checking Fuel Pump Circuit For Shorts to Ground - With key off, breakout box installed, and ECA and IRCM disconnected, set DVOM on 200K-ohm scale. Code 87: Measure resistance between test pin No. 22 and test pins No. 37, 57, and battery positive post. Measure resistance between test pins No. 22, 40, and 60, and battery negative terminal. Code 83: Measure resistance between test pin No. 41 and test pins No. 37, 57, and battery positive post. Measure resistance between test pins No. 41 and test pins No. 40, 60, and battery negative terminal. If any reading is less than 10K ohms, repair fuel pump(s) circuit shorts to power or ground. Connect all components and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If Code 83 or 87 is still present, go to next step. If all readings are 10K ohms or more, go to next step.
16. Checking Fuel Pump Relay Coil Resistance - Turn key off. Disconnect IRCM and set DVOM on 200-ohm scale. Disconnect ECA and install breakout box. Measure resistance of IRCM between pins No. 18 and 24 or pins No. 11 and 24. If resistance is between 65 and 100 ohms, replace ECA. Connect all components and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If resistance is not between 65 and 100 ohms, replace IRCM. Connect all components and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
17. No Fan Operation - Turn key off. Disconnect IRCM and set DVOM on 20-volt scale. Measure voltage between battery negative post and IRCM harness connector pins No. 1, 2, 6, and 7. If any reading is less than 10.5 volts, service open in power circuit. Re-evaluate symptom. If all readings are 10.5 volts or more, go to next step.
18. Checking Fan Motor Operation - Turn key off and disconnect IRCM connector. Install a jumper wire between IRCM harness connector pins No. 3 and 6. If cooling fan does not run, go to step 20 . If cooling fan runs, go to next step.
19. Checking Fan Low Speed - Turn key off. Connect IRCM and disconnect ECA. Turn key on. If fan does not run at low speed, replace IRCM. Connect ECA and re-evaluate symptom. If fan runs at low speed, go to step 22 .
20. Measuring Voltage Supply at Fan - With key off, disconnect cooling fan and IRCM. Install a jumper wire between IRCM harness connector pins No. 3 and 6. Set DVOM on 20-volt scale and measure voltage at cooling fan harness connector. If reading is 8.0 volts or more, replace cooling fan motor and re-evaluate symptom. If reading is less than 8.0 volts, go to next step.
21. Checking Cooling Fan Ground Circuit - Turn key off. Disconnect cooling fan and IRCM. Install a jumper wire between IRCM harness connector pins No. 3 and 6. Set DVOM on 20-volt scale. Measure voltage between positive terminal at cooling fan harness connector and battery negative post. If reading is 8 volts or more, repair open in ground circuit to fan. After repairs, connect IRCM and re-evaluate symptom. If reading is less than 8 volts, repair open in power-to-fan circuit from pins No. 3 and 4 of IRCM harness connector to cooling fan connector. After repairs, connect IRCM and re-evaluate symptom.
22. Connecting High Speed Electric-Drive Fan Signal (HEDF) to Ground - Turn key off. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Turn key on. With IRCM connected, install a jumper wire between test pins No. 52 and 40. If fan does not run at high speed, replace IRCM. Connect ECA and re-evaluate symptom. If fan runs at high speed, go to next step.
23. Checking ECT Sensor - Connect ECA and check engine coolant level. Warm engine to normal operating temperature. Turn key off and wait 10 seconds. Disconnect Engine Coolant Temperature (ECT) sensor harness. Set DVOM on 200K-ohm scale. Measure resistance of ECT sensor. If reading is between 1500 and 2000 ohms, replace ECA. Connect all components and re-evaluate symptom. If reading is not between 1500 and 2000 ohms, replace ECT sensor. Connect all components and re-evaluate symptom.
24. Checking A/C Pressure Switch Harness Continuity - With key off, install breakout box and connect ECA. Disconnect A/C pressure switch. Set DVOM on 200K-ohm scale. Measure resistance between test pin No. 2 at the breakout box and A/C pressure switch circuit at the harness connector. Measure resistance between test pin No. 46 at the breakout box and SIGNAL RETURN at the A/C pressure switch harness connector. If both resistances are less than 5 ohms, go to next step. If resistances are greater than 5 ohms, remove breakout box, repair open circuit and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
25. Checking HEDF Operation - With key off, disconnect A/C pressure switch. Jumper A/C pressure circuit to SIGNAL RETURN at the switch vehicle harness connector. Turn key on. If HEDF is on, replace A/C pressure switch. If HEDF is not on, replace ECA, reconnect components and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
26. Code 83 Displayed: Check HEDF Circuit Resistance - Code 83 indicates a failed HEDF circuit. Turn key off and disconnect IRCM. Set DVOM on 200-ohm scale. Measure resistance of IRCM between pins No. 17 and 24. If reading is not between 50 and 100 ohms, replace IRCM and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is between 50 and 100 ohms, go to next step.
27. Checking HEDF ECA Signal to IRCM For Open - Turn key off. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Disconnect IRCM connector. Set DVOM on 200-ohm scale and measure continuity between test pin No. 52 and IRCM harness connector pin No. 17. If reading is greater than 5 ohms, repair open in HEDF circuit. Connect all components and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is 5 ohms or less, go to next step.
28. Checking HEDF Circuit For Shorts to Ground - With key off, breakout box installed, and ECA and IRCM disconnected, set DVOM on 200K-ohm scale. Measure resistance between test pins No. 52 and 40. If reading is 10K ohms or less, repair short to ground in HEDF circuit. Reconnect components and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is greater than 10K ohms, go to next step.
29. Checking HEDF Circuit For Short to Power - With key off, breakout box installed, and ECA and IRCM disconnected, set DVOM on 200K-ohm scale. Measure resistance between test pins No. 52 and 37. If reading is more than 10K ohms, replace ECA. Connect all components and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is 10K ohms or less, repair short to power. Connect all components and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If Code 83 is still present, replace ECA and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
30. Low Speed Fan Always On - Turn key off. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Disconnect IRCM and set DVOM on 200-ohm scale. Measure resistance between test pin No. 55 and IRCM harness connector pin No. 14. If reading is more than 5 ohms, repair open in EDF circuit. Connect all components and re-evaluate symptom. If reading is 5 ohms or less, go to next step.
31. Checking EDF Circuit For Shorts to Power - With key off, breakout box installed, and ECA and IRCM disconnected, set DVOM on 200K-ohm scale. Measure resistance between test pins No. 55 and 37, and from test pin No. 55 to battery positive post. If reading is 10K ohms or less, repair short to power in EDF circuit, and then go to next step. If reading is more than 10K ohms, go to next step.
32. Checking EDF Circuit For Short to Ground - With key on, breakout box installed and ECA disconnected, connect IRCM. Install a jumper wire between test pin No. 55 and test pins No. 40 or 60 (ground). If cooling fan continues to run, replace IRCM, reconnect components and re-evaluate symptom. If cooling fan stops running, replace ECA. Re-evaluate symptom.
33. Check A/C Pressure Switch Input - With key off, disconnect vehicle harness at A/C pressure switch. Turn key on. If fan still runs, reconnect components and go to next step. If fan does not run, replace A/C pressure switch and re-evaluate symptom.
34. Check A/C Pressure Switch For Short to Ground - With key on, disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Disconnect IRCM and set DVOM on 200K-ohm scale. Measure resistance between test pin No. 2 and test pins No. 40, 46 and 60. If resistance is less than 10K ohms, repair short circuit, remove breakout box and reconnect components. Re-evaluate system. If resistance is greater than 10K ohms, go back to step 30 .
35. Checking Fan Voltage - Turn key off. Disconnect IRCM and set DVOM on 20-volt scale. Measure voltage between battery negative post and pins No. 1 and 2 at IRCM harness connector. If readings are less than 10.5 volts, repair open in power circuit and re-evaluate symptom. If reading is 10.5 volts or more, go to next step.
36. Checking Fan Motor - Turn key off and disconnect IRCM connector. Install a jumper wire between IRCM harness connector pins No. 1 and 3. If cooling fan does not run, go to step 38 . If cooling fan runs, go to next step.
37. Checking Fan Run Mode - With key off and ECA disconnected, connect IRCM. Turn key on. If cooling fan does not run, go to step 39 . If cooling fan runs, go to step 41 .
38. Measure Battery Voltage at Fan: By-Pass IRCM - Turn key off. Disconnect cooling fan harness and IRCM connector. Install a jumper wire between IRCM harness connector pins No. 1 and 3. Set DVOM on 20-volt scale and measure voltage at cooling fan harness connector. If reading is 8.0 volts or more, replace cooling fan and re-evaluate symptom. If reading is less than 8.0 volts, go to step 40 .
39. Checking EDF Circuit For Short to Ground - Turn key off. Disconnect ECA and IRCM. Set DVOM on 200K-ohm scale and measure resistance between IRCM harness connector pins No. 14 and 15. If resistance is 10K ohms or more, replace IRCM. Connect all components and re-evaluate symptom. If reading is less than 10K ohms, repair short to ground in EDF circuit. Connect all components and re-evaluate symptom.
40. Checking Cooling Fan Ground Circuit - Turn key off and disconnect cooling fan. Disconnect IRCM connector. Install a jumper wire between IRCM harness connector pins No. 1 and 3. Set DVOM on 20-volt scale and measure voltage between cooling fan harness connector and battery negative terminal. If reading is 8.0 volts or more, repair open in fan ground circuit. Connect IRCM and re-evaluate symptom. If reading is less than 8.0 volts, repair open in power-to-fan circuit from IRCM harness connector pins No. 3 and 4 to cooling fan connector. Connect IRCM and re-evaluate symptom.
41. Checking ECT Sensor - Connect ECA and check engine coolant level. Warm engine to normal operating temperature. Turn key off and wait 10 seconds. Disconnect ECT sensor. Set DVOM on 200K-ohm scale and measure resistance of ECT sensor. If reading is between 1500 and 2000 ohms, replace ECA. Connect all components and re-evaluate symptom. If reading is not between 1500 and 2000 ohms, replace ECT sensor. Connect all components and re-evaluate symptom.
42. Checking Voltage at A/C Clutch - Turn key on, leaving engine off. Place A/C demand switch to A/C "ON" position. Set DVOM on 20-volt scale and check voltage at A/C clutch harness connector. If voltage reading is 10.5 volts or more, service A/C compressor and/or system. If voltage is less than 10.5 volts, go to next step.
43. Checking Continuity of IRCM to A/C Clutch Circuit - Turn key off and disconnect IRCM connector. Set DVOM on 200-ohm scale. Measure resistance between IRCM harness connector pin No. 23 and power circuit terminal pin at A/C clutch harness connector. Also measure resistance between IRCM harness connector pin No. 16 and ground circuit at A/C clutch harness connector. If readings are more than 5 ohms, repair open in power or ground A/C circuit(s) and re-evaluate symptom. If readings are 5 ohms or less, go to next step. NOTE: DO NOT use diagnostic tester in step 44 , use VOM/DVOM only. Enter «OUTPUT STATE CHECK»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__output-state-check) as specified in test. For additional information see «OUTPUT STATE CHECK»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__output-state-check) under «QUICK TEST DIAGNOSTIC AIDS»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
44. Turn key off and wait 10 seconds - Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. After inspection, reconnect breakout box and ECA. Set DVOM on 20-volt scale. Connect DVOM negative test lead to Self-Test Output (STO) and positive lead to battery positive terminal. Using jumper wire, connect Self-Test Input (STI) to signal return at SELF-TEST connector. Perform «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) until completion of CONTINUOUS SELF-TEST codes (DVOM will read zero volts). DVOM should change to a high voltage reading. If DVOM did not change, depress throttle to WOT and release. If STO voltage still does not go high, go to «CIRCUIT TEST D16»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__circuit-test-d16-output-state) , step 1 . If DVOM changes, remain in «OUTPUT STATE CHECK»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__output-state-check) and go to next step
45. Checking WAC Output Operation - With KOEO, place A/C demand switch to A/C "ON" position. Set DVOM on 20-volt scale. Connect DVOM positive test lead to pin No. 37 and negative test lead to test pin No. 54. While observing DVOM, depress and release throttle several times (to cycle output on and off). If voltage output does change, go to step 47 . If voltage output changes, go to next step.
46. Checking Voltage at A/C Clutch Switch - With key on, engine off and A/C demand switch in A/C "ON" position, verify that breakout box is installed and that ECA and IRCM are connected. Set DVOM on 20-volt scale and measure voltage between test pins No. 10 and 40. If reading is less than 10.5 volts, go to step 48 . If reading is 10.5 volts or more, go to next step.
47. Checking Continuity of ACCS to IRCM Circuit - Turn key off and wait 10 seconds. Disconnect ECA and IRCM connectors. Set DVOM on 200-ohm scale and measure resistance between test pin No. 10 and IRCM harness connector pin No. 21. If reading is more than 5 ohms, service open in ACCS circuit and re-evaluate symptom. If reading is 5 ohms or less, replace IRCM and re-evaluate symptom.
48. Checking ACCS Circuit Continuity - Turn key off and wait 10 seconds. Place A/C demand switch to A/C "ON" position. Set DVOM on 200-ohm scale and measure resistance between test pin No. 10 and A/C demand switch. If reading is 5 ohms or less, EEC system is okay. Service A/C system. If reading is more than 5 ohms, repair open in switch circuit. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
49. Checking Continuity in WAC to IRCM Circuit - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Disconnect IRCM connector. Set DVOM on 200-ohm scale and measure resistance between test pin No. 54 and IRCM harness connector pin No. 22. If reading is more than 50 ohms, repair open in WAC circuit and re-evaluate symptom. If reading is 50 ohms or less, go to next step.
50. Checking WAC Circuit For Shorts to Ground - Turn key off and wait 10 seconds. Leave breakout box installed, and ECA disconnected. Disconnect IRCM connector. Set DVOM on 200-ohm scale. Measure resistance between test pins No. 54 and 40, and between test pins No. 54 and 46, and between test pin No. 54 and battery negative post. If any reading is less than 10K ohms, repair shorts to ground in WAC circuit and re-evaluate symptom. If all readings are 10K ohms or more, go to next step.
51. Checking WAC Circuit For Short to Power - Turn key off and wait 10 seconds. Leave breakout box installed, and ECA disconnected. Disconnect IRCM connector. Set DVOM on 200K-ohm scale. Measure resistance between test pins No. 54 and 37, and between test pin No. 54 and battery positive post. If any reading is less than 10K ohms, repair shorts to power in WAC circuit and then go to next step. If all readings are 10K ohms or more, go to next step.
52. Checking Voltage at A/C Clutch - Turn key off and wait 10 seconds. Leave breakout box installed, and ECA disconnected. Connect IRCM connector and disconnect A/C clutch harness. Place A/C demand switch to A/C "ON" position. With KOEO, set DVOM on 20-volt scale and measure voltage at A/C clutch harness connector. If reading is more than 10.5 volts, replace ECA and re-evaluate symptom. If reading is less than 10.5 volts, replace IRCM and re-evaluate symptom.
53. Code 88: Checking EDF Signal to IRCM For Short to Ground - If fan is always on with Code 88, go to step 55 . With key off, disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Disconnect IRCM connector. Set DVOM on 200K-ohm scale and measure resistance between test pins No. 40 and 55. If reading is 10K ohms or less, repair short to ground in EDF circuit. Connect all components and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is more than 10K ohms, go to next step.
54. Check Fan Running Mode - With key off and breakout box installed, disconnect ECA and connect IRCM connector. Turn key on. On 2.5L CFI manual transmission equipped vehicles, cooling fan should run. On 2.5L CFI A/T vehicles, cooling fan should run at low speed. If fan runs as indicated, replace ECA. Connect all components and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If fan does not run as indicated, replace IRCM. Connect all components and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
55. Code 88: Check EDF Signal to IRCM For Open Circuit - Turn key off. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Install breakout box, leaving ECA disconnected. Disconnect IRCM connector. Set DVOM on 200-ohm scale and measure resistance between breakout box test pin No. 55 and pin No. 14 at IRCM harness connector. If reading is 5 ohms or less, go to next step. If not, repair open in EDF circuit. Connect all components and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
56. Checking EDF Circuit For Short to Power - Turn key off. Install breakout box, leaving ECA disconnected. Disconnect IRCM connector. Set DVOM on 200K-ohm scale. Measure resistance between test pins No. 55 and 37, and from test pin No. 55 to battery positive terminal. If readings are 10K ohms or less, repair short to power in EDF circuit. After repairs, go to next step. If readings are greater than 10K ohms, go to next step.
57. Checking EDF For Shorts to Ground - Turn key off. Install breakout box, leaving ECA disconnected. Ensure IRCM is properly connected. Turn key on. Using jumper wire, connect test pin No. 55 to test pins No. 40 or 60. If fan continues to run, replace IRCM. Connect all components and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If fan does not run, replace ECA. Connect all components and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
58. Code 95: Check Inertia Switch - A KOEO SELF-TEST Code 95 indicates one of the following: Open circuit in fuel pump or between fuel pump and FPM circuit. Poor fuel pump ground connection. Short in fuel pump power circuit. Fuel pump relay contacts always closed. Turn key off and wait 10 seconds. Locate and disconnect fuel pump inertia switch. Set DVOM on 200-ohm scale. Measure resistance of fuel pump inertia switch. If resistance is less than 5 ohms, reconnect inertia switch and go to next step. If resistance is more than 5 ohms, replace or reset inertia switch, rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
59. Checking That Fuel Pump is Off - Turn key off. Listen for fuel pump. If pump is still running go to next step. If pump is off, go to step 61 .
60. Checking For Closed Fuel Pump Relay - With key off, locate and disconnect IRCM. If fuel pump shuts off when controller is disconnected, replace IRCM and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If pump does not shut off, repair short in POWER-to-PUMP (FPM) circuit. Rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
61. Checking Continuity of FPM Circuit - With key off, disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Install breakout box, leaving ECA disconnected. Disconnect IRCM connector. Set DVOM on 200-ohm scale and measure resistance between FPM circuit at the breakout box and IRCM harness pin No. 5. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair open circuit and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
62. Checking FPM Circuit Ground Continuity - With key off, disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Install breakout box, leaving ECA disconnected. Disconnect IRCM connector. Set DVOM on 200-ohm scale and measure resistance between FPM circuit at breakout box and battery negative terminal. If resistance is less than 5 ohms, replace ECA, reconnect and test system. If resistance is greater than 5 ohms, repair fuel pump circuit or replace fuel pump and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
63. Code 59 or 96: Fuel Pump Power Circuit Continuity - A Code 59 or 96 indicates that when fuel pump is activated, no power is supplied to pump. Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Install breakout box, leaving ECA disconnected. Disconnect IRCM connector. Set DVOM on 200-ohm scale and measure resistance between FPM circuit at breakout box and IRCM harness connector pin No. 5. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair open in power to pump circuit between FPM splice and IRCM. Rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
64. Checking Fuel Pump Operation - With key off, disconnect ECA 60-pin connector. Install breakout box, reconnect ECA and IRCM. Set DVOM on 20-volt scale. Connect DVOM between FPM circuit and test pin No. 40, at the breakout box. Observe DVOM and turn key to "ON" position. If voltage is 10.5 or more volts, for approximately one second after key is turned on, replace ECA and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If voltage does not increase to specification, replace IRCM and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
65. Continuous Memory Code 95: Checking EEC-IV Harness - A Code 95 indicates that there is an open circuit in the fuel pump or between the fuel pump and FPM circuit in the ECA. The fuel pump ground circuit is poor. Start engine and test for stalling or stumble while performing «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) on fuel pump and ECA harness. Perform "WIGGLE" test on fuel pump ground circuit. Lightly tap on fuel pump to duplicate road shock. Turn key off and inspect connections for corrosion or damage. If no fault is found, go to next step. If fault is found, repair it, clear memory codes, and retest.
66. Checking FPM Circuit - Turn key off. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Install breakout box, leaving ECA disconnected. With KOEO, connect a test light between FPM circuit and test pin No. 37. Observe test light while performing "WIGGLE" test on the monitor circuit (pin No. 8) between the ECA and the connection at the power to pump circuit. If a fault is found, isolate and repair. Clear memory codes and rerun «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no fault is found, fault cannot be duplicated at this time. Clear memory codes for future testing.
67. Continuous Memory Code 59 or 96: Check For Code 83 or 87 Also Displayed - If Code 83 or 87 is also present, go to step 69 . If Code 83 or 87 is not present, go to next step.
68. Checking EEC-IV Harness - A Continuous Memory Code 59 or 96, without the presence of a Continuous Memory Code 83 or 87, indicates that during vehicle operation the fuel pump relay contacts have opened or that there is an open in the POWER-to-PUMP circuit from the IRCM pin No. 5 to the FPM splice. Start engine and listen for fuel pump stopping, stall or stumble while performing "WIGGLE" test on pump power circuit from IRCM. Inspect harness and connectors with key off. If a fault is found, isolate and repair, clear codes and retest. If no fault is found, problem cannot be duplicated at this time. Clear codes for future testing sequence.
69. Continuous Memory Code 83 or 87: Checking EEC-IV Harness - A Continuous Memory Code 83 or 87 indicates that during vehicle operation there has been an open condition in the VPWR circuit of the IRCM, an open coil in the fuel pump relay, or an open in the fuel pump primary circuit. Start engine and listen for fuel pump stopping, stall or stumble while performing «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) on EEC-IV harness fuel pump circuit (pin No. 22 or 41) between the ECA and IRCM (pin No. 18 or 11). Inspect harness and connectors with key off. If a fault is found, isolate and repair, clear codes and retest. If no fault is found, problem cannot be duplicated at this time. Clear codes for future testing sequence.

CIRCUIT TEST D23 - ERRATIC IGNITION

Note. Perform this test ONLY after code 11 is displayed in KOEO SELF-TEST and you have been directed here from TEST A1 or by DIAGNOSIS BY SYMPTOM TEST.

TFI Ignition Circuit. Scheme 50

1. Code 14 Displayed - This code indicates that 2 successive erratic Profile Ignition Pick-Up (PIP) pulses were sent to ECA, causing possible engine miss or stall. Check EEC and TFI ignition system for loose wires and connections, arcing secondary ignition components (coil, cap, wires, etc.), or an on-board 2-way radio. Ensure radio antenna and power leads are routed properly. If any of the above conditions are present, repair as necessary and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If none are present, go to next step.
2. Distributor Check - Turn key off and wait for 10 seconds. Deactivate SELF-TEST. Using «CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes__continuous-monitor-self-test-wiggle-test) , observe VOM or diagnostic tester for indication of fault while lightly tapping on TFI ignition module and distributor, and while wiggling TFI harness connector. If fault is indicated, disconnect and inspect connectors and terminals. If connectors and terminals are okay, diagnose TFI ignition system. If no fault is indicated, go to next step.
3. Checking EEC-IV Harness - While in CONTINUOUS MONITOR (WIGGLE) TEST, observe VOM or diagnostic tester for indication of fault while wiggling, shaking or bending small sections of harness from TFI module to firewall. Also check harness from firewall to ECA. Isolate PIP circuit, if possible. If fault is indicated, isolate and repair problem and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no fault is indicated, go to next step.
4. Checking ECA and Harness Connectors - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector foe damaged pins, corrosion, or loose wires. If connectors and terminals are okay, fault cannot be duplicated at this time. Diagnose TFI ignition system. If connectors and terminals are damaged, repair as necessary and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .

CIRCUIT TEST D25 - AXOD TRANSAXLE - ELECTRICAL SYSTEM DIAGNOSIS

This test should be performed ONLY if a problem has been detected in transaxle. If any of these service codes appeared during SELF-TESTS, the AXOD Drive Cycle Test should be performed. The following AXOD transaxle related items have malfunctioned or failed as indicated

1. Code 39 Displayed: Transaxle converter by-pass clutch is not operating properly.
2. Code 59 Displayed: THS 4/3 pressure switch circuit has failed open.
3. Code 62 Displayed: THS 4/3 pressure switch circuit failed closed. If code appears in KOEO SELF-TEST, THS 3/2 circuit has failed. If code appears in ENGINE RUNNING SELF-TEST, THS 4/3 circuit has failed. If code appears in both SELF-TESTS, both circuits have failed and must be checked.
4. Code 69 Displayed: THS 3/2 circuit has failed open.
5. Code 89 Displayed: Transaxle converter by-pass clutch solenoid has stayed always open or closed.

The following service codes are not AXOD transaxle related, but can affect converter clutch by-pass operation. Service these components before servicing AXOD transaxle codes

1. Code 21 Displayed: Engine Coolant Temperature (ECT) sensor out of range.
2. Code 22 Displayed: Manifold Absolute Pressure (MAP) sensor out of range.
3. Code 23 Displayed: Throttle Position Sensor (TPS) out of range.
4. Code 24 Displayed: Air Charge Temperature (ACT) sensor out of range.
5. Code 29 Displayed: Vehicle Speed Sensor (VSS) not functioning.
6. Code 74 Displayed: Brake ON/OFF (BOO) switch always open or brake not applied during ENGINE RUNNING SELF-TEST.
7. Code 75 Displayed: Brake ON/OFF (BOO) switch always closed.

The following service code indicates that a transaxle component may have caused faulty engine idle speed control

1. Code 57 Displayed: Neutral Pressure Switch (NPS) failed in Neutral (open). The NPS is normally open and closes with hydraulic pressure. Failure of transaxle to engage in "D" or "R" will cause service code 57 to be displayed. Check for proper hydraulic pressure before testing AXOD transaxle electrical components.

Note. Ensure that all components are connected before performing test. Perform AXOD Drive Cycle Test on a slight upgrade or flat terrain. If any other non-AXOD related codes appear, service those codes first as they could affect electrical operation of transaxle.

AXOD Drive Cycle Test

Record and zero service codes. Warm engine to normal operating temperature. With transaxle in "D" range, lightly accelerate from a stop to 40 MPH to allow transaxle to shift into 3rd gear. Hold speed and throttle opening steady for a minimum of 15 seconds (30 seconds above 4000 feet altitude). Shift transaxle into overdrive and accelerate lightly from 40 to 50 MPH to allow transaxle to shift into 4th gear. Hold speed and throttle opening for a minimum of 15 seconds.

With transaxle in 4th gear, throttle open and a steady speed, lightly apply and release brakes (enough to illuminate brake lights). Hold speed and throttle opening steady for a minimum of 15 seconds.

Brake to a stop and remain stopped for a minimum of 20 seconds with transaxle in overdrive. Perform QUICK TEST and record service codes.

1. Code 39 Displayed - Check that vehicle harness connector is fully attached to transaxle bulkhead connector and that vehicle harness connector terminals are fully seated in connector. If connector or terminals are not okay, repair as required and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If connector and terminals are okay, go to next step.
2. Install service jumper harness to transaxle bulkhead connector. Connect VOM positive test lead to Red wire and negative test lead to Black wire. Check resistance. If reading is between 20 and 40 ohms, go to «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and service codes as required. If reading is not between 20 and 40 ohms, go to next step.
3. Connect service jumper harness Red wire to battery positive post. With engine running and transaxle in 3rd gear, connect service jumper harness Black wire to ground (to energize by-pass clutch solenoid). DO NOT connect with polarity reversed, otherwise solenoid diode will be damaged.
4. If by-pass clutch is applied (engine RPM drops), there is no electrical component failure. By-pass clutch is operating properly. Error code may be indicating a slipping by-pass clutch. Service transaxle for a no converter clutch apply condition and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
5. If by-pass clutch is not applied (engine RPM does not drop), check main control by-pass clutch control valve (in valve body) for sticking. If valve is sticking, service valve as required. If valve is okay, go to next step.
6. Remove by-pass solenoid. Check condition of "O" ring. Also check for contamination in/on solenoid or small hole in valve. Shake solenoid vigorously to check for free armature. If solenoid is not okay, replace by-pass clutch solenoid and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If solenoid is okay, service transaxle for a no converter clutch apply condition and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . NOTE: The THS 4/3 and 3/2 pressure switches are normally open and close with hydraulic pressure. Failure of transaxle to engage in "D" will cause code 59 to be displayed. Failure of transaxle to shift into 3rd gear will cause code 69 to be displayed. Check for proper hydraulic operation before testing electrical components.
7. Code 59 Displayed - Check that vehicle harness connector is fully attached to transaxle bulkhead connector and that vehicle harness connector terminals are fully seated in connector. If connector or terminals are not okay, repair as required and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If connector and terminals are okay, go to next step.
8. Install service jumper harness to transaxle bulkhead connector. Using VOM, check for continuity between engine ground and Blue wire. With engine running and transaxle in Neutral, VOM should indicate no continuity (infinite resistance).
9. Shift transaxle into "D". Switch should close and resistance should be less than 10 ohms. Switch should stay closed in 1st, 2nd and 3rd gears, and then open in 4th gear. If circuit is okay, go to «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and service codes as required. If circuit is not okay, go to next step.
10. Remove transaxle side oil pan. Check that internal connector with Blue wire is firmly attached to THS 4/3 pressure switch. Connector should not pull off easily or fit loosely. If connector is not okay, replace bulkhead connector and wiring assembly. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If connector is okay, go to next step.
11. Remove connector from pressure switch by pushing on end of connector, and while pulling on connector wire. Check for continuity in bulkhead connector by measuring resistance between Blue wire and terminal inside connector just removed. If reading is more than 2 ohms, replace bulkhead connector and wiring assembly. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 2 ohms, go to next step.
12. Remove THS 4/3 pressure switch. Install a 1/8-27 pipe fitting that can be connected to LOW pressure air supply in order to pressure leak and test switch closure. With 50 psi (3.5 kg/cm 2 ) applied, check for ruptured diaphragm by submerging switch in clean transmission fluid. Check for bubbles coming out of small vent hole near switch terminal. If bubbles show, diaphragm has failed. Replace THS 4/3 pressure switch and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no bubbles show, go to next step.
13. With 50 psi (3.5 kg/cm 2 ) applied to switch, check resistance between switch terminal and switch case. If reading is less than 8 ohms, hydraulic pressure circuit to switch may have excessive leaks. Service transaxle as required. If reading is more than 8 ohms, replace switch. Repeat step 8 , and then «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . Codes 39, 59, 62, 69 and 89 should no longer be displayed. NOTE: If code 62 appears in KOEO SELF-TEST, THS 3/2 circuit has failed. If code 62 appears in ENGINE RUNNING SELF-TEST, THS 4/3 circuit has failed. If code 62 appears in both SELF-TESTS, follow entire test procedure to determine which circuit has failed.
14. Code 62 Displayed - Remove vehicle harness connector from transaxle bulkhead connector and install service jumper harness. Using VOM, measure continuity between engine ground and White wire (THS 3/2 circuit). With engine off, VOM should indicate no continuity (infinite resistance).
15. Measure continuity between engine ground and Blue wire (THS 4/3 circuit). With engine running and transaxle in Neutral, VOM should indicate no continuity (infinite resistance). If all readings show no continuity, go to «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and service codes as required. If any reading indicates continuity, go to next step.
16. Remove transaxle side oil pan. Check for pinched, cut, or otherwise grounded wiring. If wiring is damaged, replace bulkhead connector and wiring assembly. After repairs, repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If THS 4/3 pressure switch wiring is okay, go to step 18 . If THS 3/2 pressure switch wiring is okay, go to next step.
17. Remove wiring from THS 3/2 pressure switch. Using VOM, check pressure switch for continuity to engine ground by connecting one lead to switch terminal and other lead to valve body. If there is no continuity (infinite resistance), go to step 19 . If there is continuity to ground, replace THS 3/2 pressure switch and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
18. Remove wiring from THS 4/3 pressure switch. Using VOM, check pressure switch for continuity to engine ground by connecting one lead to switch terminal and other lead to valve body. If there is continuity to ground, replace 4/3 pressure switch and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If there is no continuity (infinite resistance), go to next step.
19. Using VOM and with wiring removed from both pressure switches, check for continuity to ground. Connect one test lead to White wire and other test lead to ground. Then connect one test lead to Blue wire and other test lead to ground. Make sure that internal terminals are not touching any metallic parts. If there is continuity to ground, replace bulkhead connector and wiring assembly. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If there is no continuity (infinite resistance), go to «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and service codes as required. NOTE: The THS 4/3 and 3/2 pressure switches are normally open and close with hydraulic pressure. Failure of transaxle to engage in "D" will cause service code 59 to be displayed. Failure of transaxle to shift into 3rd gear will cause code 69 to be displayed. Check for proper hydraulic operation before testing electrical components.
20. Code 69 Displayed - Check that vehicle harness connector is fully attached to transaxle bulkhead connector and that terminals are fully seated in connector. If connector or terminals are not okay, repair as required and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If connector and terminals are okay, go to next step.
21. Install service jumper harness to transaxle bulkhead connector. Using VOM, check for continuity between engine ground and White wire. With engine running and transaxle in Drive, 1st, or 2nd gear, VOM should indicate no continuity (infinite resistance).
22. When transaxle shifts into 3rd or 4th gear, the switch should close. Resistance should be less than 10 ohms between White wire and engine ground. If circuit is okay, go to «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and service codes as required. If circuit is not okay, go to next step.
23. Remove transaxle side oil pan. Check that internal connector with White wire is firmly attached to THS 3/2 pressure switch. Connector should not pull off easily or fit loosely. If connector is not okay, replace bulkhead connector and wiring assembly. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If connector is okay, go to next step.
24. Check for continuity in bulkhead connector by measuring resistance between White wire and terminal inside connector just removed. If reading is more than 2 ohms, replace bulkhead connector and wiring assembly. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 2 ohms, go to next step.
25. Remove THS 3/2 pressure switch. Install a 1/8-27 pipe fitting that can be connected to LOW pressure air supply in order to pressure leak and test switch closure. With 50 psi (3.5 kg/cm 2 ) applied, check for ruptured diaphragm by submerging switch in clean transmission fluid. Check for bubbles coming out of small vent hole near switch terminal. If bubbles show, diaphragm has failed. Replace THS 3/2 pressure switch and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no bubbles show, go to next step.
26. With 50 psi (3.5 kg/cm 2 ) applied to switch, check resistance between switch terminal and switch case. If reading is less than 8 ohms, hydraulic pressure circuit to switch may have excessive leaks. Service transaxle as required. If reading is more than 8 ohms, replace switch. Repeat steps 21 and 22 , and then repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . Codes 39, 59, 62, 69 and 89 should no longer be displayed.
27. Code 89 Displayed - If code 39 is also displayed, go to step 1 . Check that vehicle harness connector is fully attached to transaxle bulkhead connector and that vehicle harness terminals are fully seated in connector. If connector or terminals are not okay, repair as required and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If connector and terminals are okay, go to next step.
28. Install service jumper harness to transaxle bulkhead connector. Connect VOM positive test lead to Red wire and negative test lead to Black wire. Check resistance. If reading is between 20 and 40 ohms, go to «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and service codes as required. If reading is not between 20 and 40 ohms, go to next step.
29. Remove transaxle side oil pan. Check that internal connector is fully attached to solenoid. If connector is okay, go to next step. If connector is not okay, fully engage connector and check continuity once more. If resistance is still not between 20 and 40 ohms, go to next step. If resistance is now okay, repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) .
30. Remove connector from solenoid by pulling on wires at 2-way connector. Check solenoid continuity by connecting VOM positive test lead to solenoid positive terminal and negative test lead to solenoid negative terminal (polarity symbols are stamped on solenoid frame).
31. If circuit is open (infinite resistance), replace solenoid and then repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If solenoid is okay (20 to 40 ohms resistance), replace bulkhead connector and wiring assembly. Connect all internal connectors and repeat step 28 . If circuit tests okay, install oil pan. Repeat «KEY ON/ENGINE OFF (KOEO) SELF-TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . Code 89 should no longer be displayed. NOTE: The NPS is normally open and closes with hydraulic pressure. Failure of transaxle to engage in "D" or "R" will cause service code 57 to be displayed. Check for proper hydraulic pressure before testing electrical components.
32. Code 57 Displayed - Check that vehicle harness connector is fully attached to transaxle connector and that vehicle harness terminals are fully seated in connector. If connector or terminals are not okay, repair as required and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If connector and terminals are okay, go to next step.
33. Install service jumper harness to transaxle bulkhead connector. Using VOM, check continuity between Green wire and engine ground. With engine running and transaxle in "P" or "N", VOM should indicate no continuity (infinite resistance). Shift transaxle into "R" and "D" ranges, switch should close. Resistance should be less than 10 ohms in both ranges. If circuit is okay, go to «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) and service codes as required. If circuit is not okay, go to next step.
34. Remove transaxle side oil pan. Check that terminal connector with Green wire is firmly attached to NPS. Connector should not pull off easily or fit loosely. If connector is not okay, replace bulkhead connector and wiring assembly. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If connector is okay, go to next step.
35. Remove connector from NPS by pushing on end of connector while pulling on connector wire. Check for continuity in bulkhead connector by measuring resistance between Green wire and terminal inside connector just removed. If reading is more than 2 ohms, replace bulkhead connector and wiring assembly. Repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If reading is less than 2 ohms, go to next step.
36. Remove NPS. Install a 1/8-27 pipe fitting that can be connected to LOW pressure air supply in order to pressure leak and test switch closure. With 50 psi (3.5 kg/cm 2 ) applied, check for ruptured diaphragm by submerging switch in clean transmission fluid. Check for bubbles coming out of small vent hole near switch terminal. If bubbles show, diaphragm has failed. Replace NPS and repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . If no bubbles show, go to next step.
37. With 50 psi (3.5 kg/cm 2 ) applied to switch, check resistance between switch terminal and switch case. If reading is 8 ohms or less, hydraulic pressure circuit to switch may have excessive leaks. Service transaxle as required. If reading is more than 8 ohms, replace switch. Repeat step 33 , and then repeat «QUICK TEST»(/ford/tempo/i-1983-1994/remont/testing-diagnostics/#23l-eec-iv-tests-wcodes) . Codes 39, 59, 62, 69 and 89 should no longer be displayed.

2.3L OHC MPFI EEC-IV Wiring Diagram (Mustang). Scheme 51

2.3L Turbo MPFI EEC-IV Wiring Diagram (Thunderbird). Scheme 52

2.3L HSC MPFI EEC-IV Wiring Diagram (Tempo & Topaz). Scheme 53

See also:
• PREPARATION
• EQUIPMENT HOOK-UP
• CONTINUOUS MONITOR SELF-TEST (WIGGLE TEST)
• CIRCUIT TEST D15
• CIRCUIT TEST D14
• CIRCUIT TEST D13
• TIMING CHECK
• Clearing Continuous Memory Codes
• Continuous Monitor (Wiggle) Test
• D20
• B15
• D22
• B7
• B13
• D11
• C1
• C2
• D4
• D8
• D17
• B5
• B6
• B8
• B2
• B4
• B10
• B9
• D9
• D2
• D5
• D1
• B14
• D10
• D23
• D18
• CIRCUIT TEST A3
• CIRCUIT TEST A2
• CIRCUIT TEST D16
• OUTPUT STATE CHECK
• HOW TO USE CIRCUIT TESTS
• AXOD Drive Cycle Test