3.8l Cfi Tests Ford Thunderbird IX

DIAGNOSTIC PROCEDURE

1. Always use the same sequence when diagnosing driving or running problems on a vehicle equipped with EEC-IV. Make sure all NON-EEC problems are solved first. Loose wires, low compression, fouled plugs, etc. can cause problems that waste valuable servicing time.
2. Connect test equipment (as described later in this article) to the engine. The location of the Self-Test connector varies with model. See Self-Test Connector Location in this article. The location will also be described in each engine testing section.

KEY ON/ENGINE OFF (KOEO) SELF-TEST PROCEDURES

1. This is a static check of processor input and output circuits. Connect STAR tester or VOM to vehicle Self-Test connector. (Scheme 99)for correct VOM connections. Turn ignition switch to ON position to start Self-Test. DO NOT depress throttle during test. Observe and record all On Demand and Continuous/Memory service codes.
2. If any codes appear, refer to the proper test shown in the reference table for that specific engine. Start with the first code displayed. If the tests refer you to other checks, perform them as instructed. When more than 1 code is displayed, repair problems in the order that codes are displayed.

Note. When any repair has been completed, QUICK TEST MUST be repeated BEFORE attempting to repair any other problems identified by service codes. Proceed with repairs as indicated by Key ON/Engine OFF Self-Test Results table and then by On Demand Codes table.

Analog VOM Hook-Up for Reading Codes. Scheme 99

COMPUTED IGNITION TIMING CHECK PROCEDURES

This checks the system's ability to correctly change and maintian spark timing. Ignition timing will be advanced 20° from base timing. Timing will be locked in through Self-Test and during 2 minute period after end of Self-Test outs.

Note. If engine will not start, go to TEST A . If engine stalls while testing, go to Diagnosis By Symptom Test which can be found in specific engine section.

KEY ON/ENGINE RUNNING (KOER) SELF-TEST PROCEDURES

1. This is a dynamic check of system sensors and output devices under actual operating conditions and at normal operating temperature. any faults must be present at time of test to be detected. Connect tester to vehicle Self-Test connector but leave jumper to input disconnected. (Scheme 99)for correct VOM connections.
2. Start engine and run it at 1500 RPM for 2 minutes to warm up EGO sensor. Turn engine OFF and wait 10 seconds. Insert jumper to activate Self-Test. Start engine.
3. Engine ID code will be displayed first, followed by the Dynamic Response code (single digit) after a 6-20 second pause. When Dynamic Response code is displayed, a brief WOT test must be made. If WOT test is not done properly or within 15 seconds, code 77 will be displayed. Next display of codes will be On Demand service codes, which should be recorded. If any codes appear, refer to the proper test shown in the reference table.

Note. When any repair has been completed, QUICK TEST MUST be repeated BEFORE attempting to repair any other problems identified by service codes. Proceed with repairs as indicated by Key On/Engine Running (KOER) Self-Test Results table.

CONTINUOUS SELF-TEST PROCEDURES

1. Codes shown in this test are intermittent service codes. Unless instructed otherwise, DO NOT disconnect any sensor with ignition turned ON as this may cause a service code to be stored.
2. Verify that all previous Self-Test procedures indicated a pass (Code 11). If any On De,and code is displayed during this test, repair it first, as some hard failures will set a code in Continuous Self-Test.
3. Perform key ON/Engine OFF Self-Test. When the first service code is appears, exit Self-Test program by disconnecting STAR tester or by removing jumper wire from Self-Test input. Exiting Self-Test in this manner will clear all codes stored in continuous memory.
4. Repeat Key ON-Engine OFF Self-Test. If code output is not 11-10-11, check Self-Test Input (STI) for short to ground. Repair short and repeat Key ON/Engine OFf Self-Test. If code output is 11-10-11, go to next step.
5. Check list of Continuous/Memory codes that were recorded in Key ON/Engine OFF (KOEO) and Key ON/Engine Running (KOER) Self-Tests. Disregard any codes that have already been repaired. To confirm remaining codes, perform Continuous Monitor (Wiggle) Test.

CONTINUOUS MONITOR (WIGGLE) TEST PROCEDURES

Note. Make sure that Self-Test is deactivated. DO NOT activate Self-Test unless specifically instructed to do so.

1. This test monitors ECA inputs for shorts and opens. Self-Test Output (STO) will be activated each time a fault is detected. If the STO is activated for long enough during key ON/Engine Off portion of test, a service code will be stored. During the Key ON/Engine Running Portion of this test, a service code will be stored for each fault.
2. A detected fault is indicated by a 10.5 volt or greater deflection on VOPM. One or both of the following modes may be used to find the intermittent fault. Key ON/Engine OFF (KOEO): Self-Test deactivated and ignition switch ON. Key On/Engine Running (KOER): Self-Test activated. Perform KOER Self-Test. After service code output has finished, do not turn engine off or deactivate Self-Test. About 2 minutes after code 11 has been displayed. Continuous Monitor (Wiggle) Test mode will start. The system will remain in Continuous Monitor mode until KOER Self-Test is deactivated or engine is turned off. NOTE: An alternate method of entering Continuous Monitor (Wiggle) mode with engine running is to start key ON/Engine Running test, exit, and re-enter Engine Running test without turning engine off.
3. Observe VOM while moving, wiggling, and tapping the system harness, connectors, and sensors. If an intermittent condition is created, the monitor will indicate this by storing a service code.
4. Perform Key ON/Engine OFF Self-Test to retrieve codes. If any codes are indicated, go to proper test as shown in Continuous Test table. If no codes appear, the fault is not in a monitored EEc sensor circuit. EEC testing is complete. Refer to Diagnosis By Symptom Test for additional testing information.

Note. Continuous test can only be run once without turning ignition off. DO NOT miss any of the service codes.

HOW TO USE CIRCUIT TESTS

1. Do no run any test unless codes have been set during QUICK TEST. Make sure all non-EEC related faults are corrected. DO NOT replace any part unless directed to do so. When more than 1 service code is received, start with the first code displayed. 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.
2. DO NOT measure voltage or resistance at ECA or connect any test lamps to it, unless specified. All measurements are made by probing the REAR of the computer. Isolate both ends of a circuit and turn key OFF whenever checking for shorts or continuity, unless specified.
3. Disconnect solenoids and switches from harness before measuring continuity, resistance or applying 12 volts. Follow each test step in order until fault is found. After each repair, check all component connections and repeat Circuit test.

Output State Test

1. These checks are specified in the testing charts. An Output State Test is used to diagnose each actuator. Test is performed in the Key ON/Engine OFF Self-Test mode after Continuous/Memory codes have been sent. With Self-Test activated, momentarily depress throttle to WOT position and release. More auxiliary EEC actuators will be energized at this time.
2. A second full throttle depression will turn them off. Use a digital volt-ohmmeter (DVOM) to check output states. Readings above 10.5 volts indicate actuators, are on readings below 2 volts indicate actuators are off. Each test will tell what action should be taken according to voltage shown on DVOM.

PREPARATION

Note. If vehicle is towed in or is suspected of having intermittent problems, DO NOT turn the ignition key off. Diagnostic codes may be stored in the continuous testing memory. Correct test results for this 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. Before hooking up any equipment to diagnose the EEC system, make the following checks

1. Verify the condition of the air cleaner and air ducting.
2. Check all vacuum hoses for leaks, restrictions and proper routing.
3. Check the EEC system wiring harness electrical connections for corrosion, loose or detached connectors, 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 auto. trans., Neutral for man. trans. DO NOT move shift lever during testing unless specifically directed to do so.
7. Turn off all lights and accessories, and make sure that vehicle doors are closed when making readings.
8. Check and correct 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, oxygen sensor and vacuum connections.
10. Turn ignition key OFF.

READING SELF-TEST CODES

During Self-Test procedures, service codes are transmitted to the Self-Test Output connector by the ECA. All service codes are 2 digit numbers which are generated 1 digit at a time. Codes are shown as voltage pulses (needle sweeps) on an analog volt/ohmmeter (VOM). If a STAR (Self Test Automatic Readout) tester is used, it will count the pulses and display them as a digital code. The STAR tester will add a 0 to single digit (separator and dynamic response) codes.

Codes are shown as sequential groups of three codes. The sequence of groups varies, depending upon which test is being performed. If a VOM is being used, careful attention to the length of the pauses is necessary 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. There is a minimum 6 second pause before and after separator and dynamic response codes.

KEY ON/ENGINE OFF (KOEO) SELF-TEST

There are 4 codes displayed during this test. The first is a Fast code, which is not applicable in field testing. Fast codes are represented by slight needle deflections on analog VOM or flickering LED on STAR tester. These are standard service codes being run at a rate too high for the testers to read. Fast codes are used by automatic equipment during manufacturing processes.

In order of display, the next 3 codes used for this test are the On Demand code, the Separator code, and the Continuous/Memory code. The first service code shown in this test sequence is the On Demand code. The On Demand code indicates a malfunction which is present at time of testing. This type of malfunction is called a "hard fault".

The second code is the Separator code, which indicates that On Demand codes have ended and Continuous/Memory codes are about to start. The third code is the Continuous/Memory code, which indicates a recent problem which is not present at time of test (intermittent fault).

The On Demand first digit is indicated by a pulse or pulses, after which the needle drops to zero for 2 seconds before the second digit of the code is indicated as a pulse or pulses. After a pause of 6-9 seconds, the Separator code (single digit on VOM; 10 on STAR tester) will be displayed for 1/2 second. After 6-9 seconds, the first digit of the Continuous/Memory code will be indicated, the needle then dropping to zero for 2 seconds, and then the second digit of the Continuous/Memory code will be indicated.

Note. If engine will not start, go to Circuit Test A. If engine stalls while testing, go to Diagnosis By Symptom Test which can be found in specific engine section.

KEY ON/ENGINE RUNNING (KOER) SELF-TEST

There are 4 codes displayed during this test. In order of display, these are an Engine ID code, a Dynamic Response code, Fast codes, and On Demand codes.

The first and third codes are not applicable in field tests. The Engine ID codes are displayed as 20, 30, or 40. The first digit is equal to half the number of cylinders in the engine. Fast codes are the same as those run during Key ON/Engine OFF Self-Test. Engine ID codes and Fast codes are used by automatic equipment during manufacturing processes.

The Dynamic Response code appears as the numeral 10. This code instructs the technician to open linkage to WOT position momentarily. This checks inside the TPS and MAPS for proper movement. If WOT does not occur within 15 seconds, the numeral (Code) 77 will be displayed. The On Demand codes are "hard faults" found in system outputs during test.

Analog VOM

1. Turn ignition key OFF. Use 2 jumper leads (4-6" long) with male terminals. Set VOM at 0-15V DC range and connect positive lead of VOM to positive battery terminal. Connect first jumper lead between No. 4 pin (Self-Test Output) pin on Self-Test connector and negative lead of VOM. (Scheme 99)
2. Connect second jumper between No. 2 pin (Self-Test Signal Return) on Self-Test connector and Self-Test input connector. This final connection will activate Self-Test in ECA when ignition key is turned ON.

TEST EQUIPMENT

1. Self-Test Automatic Read-Out (STAR) Tester with Adapter Cable. This tool is recommended, but not required. It is specially built for the EEC-IV system and is used to display, as numerals, the 2-digit service codes that are programmed into the control module. Adapter cable has LED assembly and plugs directly into vehicle self-test connector.
2. Analog Volt/Ohmmeter (VOM) with 0-20V DC range. This can be used as an alternate to the STAR tester.
3. Digital Volt/Ohmmeter (DVOM) with minimum 10 meg-ohm input impedance.
4. Breakout Box. 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 60-pin ECA connector. "Test Pin" as called out in Circuit Tests refers to the pins on the breakout box. Once the breakout box has been installed during a test sequence, it may be left connected for the remainder of the test.
5. Vacuum gauge with 0-30 in. Hg range and resolution (unit on scale) of 1 in. Hg.
6. Tachometer with 0-6000 RPM range, accuracy F 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 spark plug with side electrode removed and alligator clip attached may be used.
10. Fuel injection pressure gauge for all fuel injected models.
11. Non-powered test light.
12. Jumper wire about 15" long.
13. MAP/BP Tester. Unit plugs into MAP/BP sensor circuit and DVOM to check input and output voltages to verify correct sensor operation.

TEST CONNECTOR LOCATIONS

Capri, Cougar, LTD, Marquis, Mustang and Thunderbird models have the Self-Test connector below starter solenoid between the left strut tower and the battery.

KEY ON/ENGINE OFF SELF-TEST

Note. When any repair has been completed, QUICK TEST MUST be repeated BEFORE attempting to repair any other problems identified by service codes. Proceed with repairs as indicated by Key ON/Engine OFF (KOEO) Self-Test Results table and then by On Demand Codes table.

Note. Key On/Engine Off Self-Test procedures are at front of article.

CODE/TEST MENUS (KOEO)

KEY ON/ENGINE OFF (KOEO) SELF-TEST RESULTS

ON DEMAND CODES

CONTINUOUS MONITOR (WIGGLE) TEST

Note. An alternate method of entering Continuous Monitor (Wiggle) mode with engine running is to start Key ON/Engine Running (KOER) test, exit, and re-enter KOER test without turning engine off.

Note. Continuous test can only be run once without turning ignition off. DO NOT miss any of the service codes.

Note. Continuous Monitor Test procedures are at front of article.

CODE/TEST MENU (CONTINUOUS)

CONTINUOUS TEST RESULTS

Note. If engine stalls while testing, go to DIAGNOSIS BY SYMPTOM TEST .

COMPUTED IGNITION TIMING CHECK

Make sure that in-line base timing connector is reconnected if base timing has been checked. Make sure that Self-Test is activated and start engine. Timing is locked for full Self-Test sequence and for 2 minutes after display of last service code. Timing range should be 27-33° BTDC on all models. If timing is correct, go to Key ON/Engine Running (KOER) Self-Test. If timing is not correct, go to TEST MM.

Note. If engine will not start, go to TEST A . If engine stalls while testing, go to Diagnosis By Symptom Test.

KEY ON/ENGINE RUNNING SELF-TEST

Note. When any repair has been completed, QUICK TEST MUST be repeated BEFORE attempting to repair any other problems identified by service codes. Proceed with repairs as indicated by KOER Self-Test Results table.

CODE/TEST MENU (KOER)

KEY ON/ENGINE RUNNING (KOER) SELF-TEST RESULTS

Note. If engine stalls while testing, go to DIAGNOSIS BY SYMPTOM TEST .

DIAGNOSIS BY SYMPTOM TEST

1. ONLY use this test procedure when directed to do so by results of QUICK TESTS or steps in Circuit Tests. Follow test procedure carefully.
2. When engine stalls in operation, runs rough, misfires, or has rough idle, perform the following checks: Check fuel control, using Circuit «TEST T»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-t-cfi-fuel-control) , Steps 1) through 5). Check MAP sensor, using Circuit «TEST H»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-h-manifold-absolute-pressure) , Step 11). Check fuel delivery. Check EGR valve for correct function. Check ignition components (cap, rotor, wires, coil, & plugs). Check basic engine components (valves, cam timing, compression). Check for, and repair, any bad ground or power line connections.
3. On Mustang/Capri models, if detonation (spark knock) occurs, go to Circuit «TEST I»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-i-knock-sensor) .
4. If no fast idle occurs when A/C is on, go to Circuit «TEST AA»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-aa-idle-speed-control) , Step 9).
5. If gasoline fumes accumulates under hood, go to Circuit «TEST Y»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-y-canister-purge-canp) , Step 1).
6. If low idle on cold starts, high idle on hot starts, or dieseling occur, go to Circuit «TEST AA»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-aa-idle-speed-control) , Step 16).
7. If vehicle with automatic transmission idles too high in Drive, check neutral drive switch circuit (test pin 30 on breakout box). If short to ground is found with transmission in Drive, repair wiring.

3.8L CFI EEC-IV Wiring Diagram. Scheme 100

3.8L CFI EEC-IV Inputs/Outputs & Component Locations. Scheme 101

TEST A - NO START

1. Try to start engine. If engine does not crank, check for excess fuel in cylinders (hydraulic lock). Check the starting and charging systems. If engine cranks, but does not start or else stalls after starting, go to next step.
2. With key OFF, wait 10 seconds. Set DVOM to 20 volt scale and disconnect the TPS. Turn key ON, leaving engine OFF, and measure voltage between voltage reference (VREF) and signal return at TPS harness connector. If voltage is less than 4.0 volts or greater than 6.0 volts, go to Circuit «TEST C»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-c-reference-voltage) . If voltage is between 4.0-6.0 volts, reconnect TP sensor and go to next step.
3. Disconnect any spark plug wire and connect spark tester between plug wire and ground. Crank engine and check for spark. If spark exists, go to Step 13). If no spark, reconnect spark plug wire and go to next step.
4. Remove high tension coil wire from distributor and install spark tester. Check for spark while cranking. If spark is produced, service or repair TFI ignition system. If no spark, reconnect coil wire to distributor and go to next step.
5. Turn key OFF and wait 10 seconds. Install breakout box with timing switch in "Computed" position. Leave ECA disconnected. Set DVOM to 200 ohm scale and disconnect TFI. Measure resistance between test pin 16 and TFI harness connector ignition ground. If 5 or more ohms resistance is measured, repair wiring and run QUICK TEST again. If less than 5 ohms is measured, go to next step.
6. Connect TFI and ECA. Move timing switch to "Distributor" position on breakout box. Try to start vehicle. If vehicle starts, go to Step 10). If vehicle does not start, go to next step.
7. Move breakout box timing switch to "Computed" position. Set DVOM to 20 volt scale and measure voltage between test pin 36 and chassis ground while cranking engine. If voltage is between 3.0-6.0 volts, EEC is alright and TFI should be diagnosed. If voltage is more than 6.0 volts or less than 3.0 volts, go to next step.
8. Turn key OFF and wait 10 seconds. Disconnect ECA and TFI. Set DVOM to 200,000 ohm scale. Measure resistance between test pin 36 and test pins 16, 20, 26, 40, and 60 for short to ground. Measure resistance between test pin 36 and test pins 37 and 57 for short to power. Measure resistance between test pins 36 and 56 for short to PIP. If any reading is less than 10,000 ohms, repair short in harness and try to start vehicle. Repeat QUICK TEST if engine will not start. If all readings are 10,000 ohms or greater, go to next step.
9. Turn key OFF and wait 10 seconds. Reconnect ECA and leave TFI disconnected. Set DVOM to 200 ohm scale. Measure resistance between test pin 36 and test pins 37 and 57 for short to power. Measure resistance between test pin 36 and test pins 40 and 60 for short to ground. If any reading is less than 5.0 ohms, replace ECA and repeat QUICK TEST. If all readings are 5.0 ohms or greater, connect TFI and go to next step.
10. Set DVOM to 20 volt scale. Measure voltage between test pin 56 and test pin 16 while cranking engine. If reading is 3.0-6.0 volts, remove breakout box. Replace ECA and repeat QUICK TEST. If below 3.0 volts or above 6.0 volts, go to next step.
11. Install breakout box, turn key OFF and wait 10 seconds. Set DVOM to 200 ohm scale. Disconnect TFI and ECA. Measure resistance between test pin 56 and TFI connector on the PIP circuit. If reading is 5 ohms or more, repair open PIP circuit and repeat QUICK TEST. If less than 5 ohms, go to next step.
12. Disconnect ECA and turn key OFF. Disconnect TFI and set DVOM to 200,000 ohm scale. Measure resistance between test pin 56 and test pins 16, 20, 26, 40, and 60 for short to ground. Measure resistance between test pin 56 and test pins 37 and 57 for short to power. Measure resistance between test pin 56 and test pin 36 for short to spark output (SPOUT). If any reading is lower than 10,000 ohms, repair PIP circuit and repeat QUICK TEST. If all readings are higher than 10,000 ohms, perform TFI diagnosis.
13. Turn key OFF and wait for 10 seconds. Disconnect ECA 60-pin connector and inspect for damaged, loose, or corroded pins or wires. Repair wiring and connect ECA. Set DVOM to 20 volt scale and make sure breakout box timing switch is set in "Computed" position. Measure voltage between test pin 36 and chassis ground while cranking engine. If between 3.0-6.0 volts, go to next step. If less than 3.0 volts or greater than 6.0 volts, go to step 10) of this test. CAUTION: Next 2 steps apply to EFI and CFI models. On all steps involving fuel testing, turn key OFF immediately if any fuel leaks develop. DO NOT allow any smoking or open flame in area of vehicle being tested.
14. Disconnect all electrical connections at injectors. Connect pressure gauge to fuel diagnostic valve (if equipped) on fuel rail. Note any initial pressure reading and then pressurize fuel system. (To pressurize system, turn key ON for 1 second, then turn key OFF. Wait 10 seconds. Repeat "ON, OFF, and wait" sequence 5 times. After final 10 second wait, reconnect all injectors.) If pressure reading did not increase, go to next step. If pressure reading increased, go to «TEST T»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-t-cfi-fuel-control) .
15. With key OFF and fuel pressure gauge hooked up, push button on fuel pump inertia 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 «TEST V»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-v-fuel-pump-circuit) . Observe pressure gauge as system is pressurized as in step 14). If pressure reading increases, repeat QUICK TEST. If pressure reading does not increase, go to «TEST V»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-v-fuel-pump-circuit) .

TFI Module Circuits. Scheme 102

TEST B - VEHICLE BATTERY

1. Turn key ON, leaving engine OFF. Set DVOM to 20 volt scale and measure voltage across battery terminals. If less than 10.5 volts, service discharged battery. If 10.5 volts or higher, go to next step.
2. Turn key ON, leaving engine OFF. With ECA connected, set DVOM to 20 volt scale. Measure voltage between battery negative post and signal return circuit in Self-Test connector. If less than .5 volts, go to step 6). If .5 volts or higher, go to next step.
3. With breakout box installed and ECA connected, turn key ON, leaving engine OFF. Set DVOM to 20 volt scale. Measure voltage between battery negative post and test pins 40 and 60. If either is .5 volts or higher, repair ground circuit and repeat QUICK TEST. If both are less than .5 volts, go to next step.
4. With ECA connected, turn key OFF and wait 10 seconds. Set DVOM to 200 ohm scale. Measure resistance between test pin 46 and test pins 40 and 60. If either is 5 ohms or higher, disconnect ECA connector and inspect for corrosion or damage. Repair wiring and recheck resistance. If reading is still too high, replace ECA and repeat QUICK TEST. If both readings are less than 5 ohms, go to next step.
5. With ECA connected, turn key OFF and wait 10 seconds. Set DVOM to 200 ohm scale. Measure resistance between test pin 46 and signal return circuit at Self-Test connector. If less than 5 ohms, repeat QUICK TEST as system is correct. If 5 ohms or higher, repair cause of excessive resistance in signal return circuit of harness. Repeat QUICK TEST.
6. Turn key ON, leaving engine OFF. With ECA connected, set DVOM to 20 volt scale. Measure voltage between battery negative post and Keep Alive Power (KAPWR) circuit at EEC power relay. If less than 10.5 volts, check KAPWR and vehicle power (V Power) circuits for short to ground. Also check KAPWR circuit from power relay to battery positive post for open circuit. If 10.5 volts or higher, go to next step.
7. Turn key ON, leaving engine OFF. With ECA connected, set DVOM to 20 volt scale. Measure voltage between battery negative post and ignition circuit at EEC power relay. If less than 10.5 volts, check for open ignition switch circuits. Repair wiring and repeat QUICK TEST. If 10.5 volts or higher, go to next step.
8. Turn key ON, leaving engine OFF. With ECA connected, set DVOM to 20 volt scale. Measure voltage between battery negative post and ground circuit at EEC power relay. If .5 volts or higher, repair open circuit or short to ground in ground circuit and repeat QUICK TEST. If less than .5 volts, go to next step.
9. Turn key ON, leaving engine OFF. With ECA connected, set DVOM to 20 volt scale. Measure voltage between battery negative post and vehicle power circuit at EEC power relay. If less than 10.5 volts, replace power relay and repeat QUICK TEST. If 10.5 volts or higher, repair short to ground or open in V Power circuit from EEC power relay to test pins 37 and 57. Repeat QUICK TEST.

Battery Test Circuits. Scheme 103

TEST C - REFERENCE VOLTAGE

1. Install breakout box with ECA connected. Turn key ON, leaving engine OFF, and set DVOM to 20 volt scale. Measure voltage between test pin 37 and signal return in Self-Test connector. If less than 10.5 volts, go to «TEST B»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-b-vehicle-battery) . If 10.5 volts or higher, go to next step.
2. With ECA connected, turn key ON, leaving engine OFF. Set DVOM to 20 volt scale and measure voltage between test pins 26 and 46. If 6.0 volts or higher, go to step 4). If 4.0 volts or lower, go to step 5). If between 4.0 and 6.0 volts, go to next step.
3. With ECA disconnected, turn key OFF. Set DVOM to 200 ohm scale. Measure resistance from test pins 26 and 46 to suspect VREF sensor harness connector. If all readings are less than 5 ohms, reconnect sensors. VREF circuit is alright. Repeat QUICK TEST. If any reading is 5 ohms or more, repair open circuit in VREF or signal return and then repeat QUICK TEST.
4. Turn key OFF and wait for 10 seconds. With ECA disconnected, turn key ON, leaving engine OFF. Set DVOM to 20 volt scale and measure voltage between test pin 26 and battery ground. If less that .5 volts, replace ECA and repeat QUICK TEST. If .5 volts or more, repair short to battery power in EEC harness. Repeat QUICK TEST. Replace ECA if fault still occurs.
5. Shorted TP Sensor. Turn key OFF and wait for 10 seconds. With ECA connected, disconnect TPS from vehicle harness. Turn key ON, leaving engine OFF. Set DVOM to 20 volt scale and measure voltage between test pins 26 and 46. If less than 4.0 volts on models with EGR Valve Position (EVP) sensor, go to next step. If less than 4.o volts on models without EVP, go to step 7). If 4.0 volts or higher, replace TPS and repeat QUICK TEST.
6. Shorted EVP Sensor. Turn key OFF and wait 10 seconds. With breakout box installed and ECA connected, disconnect EVP sensor. Turn key ON, leaving engine OFF. Set DVOM to 20 volt scale. Measure voltage between test pins 26 and 46. If reading is 4.0 volts or more, replace EVP sensor and repeat QUICK TEST. If reading is less than 4.0 volts, go to next step.
7. Shorted MAP/BP Sensor. Turn key OFF and wait for 10 seconds. With ECA connected, disconnect MAP/BP sensor. Turn key ON, leaving engine OFF. Set DVOM to 20 volt scale. Measure voltage between test pins 26 and 46. If 4.0 volts or higher, replace MAP or BP sensor and repeat QUICK TEST. If less than 4.0 volts, go to next step.
8. Shorted VAF Sensor. Turn key OFF and wait for 10 seconds. With ECA connected, disconnect the VAF sensor. Turn key ON, leaving engine OFF. Set DVOM to 20 volt scale. Measure voltage between test pins 26 and 46. If 4.0 volts or higher, replace VAF sensor and repeat QUICK TEST. If less than 4.0 volts, go to next step.
9. With ECA disconnected, turn key OFF and wait for 10 seconds. Disconnect TPS, BPS, and VAF sensor. Set DVOM to 200 ohm scale. Measure resistance between test pin 26 and test pins 20, 40, 46, and 60. If less than 5 ohms, repair short to ground. Reconnect all sensors and repeat QUICK TEST. If problem still occurs, replace ECA. If 5 ohms or more, reconnect sensors. Replace ECA and run QUICK TEST again.

Reference Voltage Circuits. Scheme 104

TEST D - VANE AIR TEMPERATURE (VAT) SENSOR

Note. Ambient air temperature must be at least 50°F (10°C) for test results to be valid.

1. Code 24 Displayed. Make sure ambient air temperature is at least 50°F (10°C). If not, repeat QUICK TEST. If temperature is high enough, go to next step.
2. 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 4.0-volts or higher than 6.0-volts, go to «TEST C»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-c-reference-voltage) , step 1). If reading is between 4.0 and 6.0 volts, connect TPS and go to next step.
3. Turn key off and wait 10 seconds. Disconnect harness from airflow meter. Set DVOM on 200,000 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. If reading is out of range, replace airflow meter and repeat QUICK TEST.
4. Code 54 Displayed. 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 SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-off-self-test) . If code 64 is displayed, replace airflow meter. Remove jumper wire, connect airflow meter, and repeat QUICK TEST. If code 64 is not displayed, remove jumper wire and go to next step.
5. 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 25 and VAT signal at connector. Also measure resistance between test pin 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. If either reading is 5 ohms or higher, repair open circuit. Remove breakout box, connect wiring to ECA and airflow meter, then repeat QUICK TEST.
6. Code 64 Displayed. Turn key off and wait 10 seconds. Disconnect harness from airflow meter. Inspect for and repair any damaged wiring. Perform «KEY ON/ENGINE OFF SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-off-self-test) . If code 54 is displayed, replace airflow meter and connect harness. Repeat QUICK TEST. If code 54 is not displayed, go to next step.
7. 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 4.0-volts or higher than 6.0-volts, go to «TEST C»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-c-reference-voltage) , step 1). If reading is between 4.0 and 6.0 volts, connect TPS and go to next step.
8. 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 200,000 ohm scale. Measure resistance between test pin 25 and test pins 40, 46, and 60. If any reading is less than 10,000 ohms, repair shorts. Remove breakout box, connect ECA and airflow meter, then repeat QUICK TEST. If all readings are 10,000 ohms or higher, replace ECA. Remove breakout box and connect ECA. Repeat QUICK TEST.
9. Continuous Code 54 or 64 Displayed. Using CONTINUOUS MONITOR (WIGGLE) TEST, observe VOM or STAR tester LED 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. If no fault is indicated, go to next step.
10. 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. If no fault is found, go to next step.
11. Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Repeat QUICK TEST if any wiring was damaged. If wiring is good, test is completed.

VAT Sensor Circuit. Scheme 105

TEST E - AIR CHARGE TEMPERATURE (ACT) SENSOR

Note. Ambient air temperature must be greater than 50°F (10°C) for this test.

1. Code 24 Displayed. 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.
2. Turn key off and wait 10 seconds. Set DVOM on 20-volt scale and disconnect Throttle Position Sensor (TPS). Turn key on, leaving engine off. Measure voltage between VREF and signal return at TPS connector. If reading is less than 4.0-volts or higher than 6.0 volts, go to «TEST C»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-c-reference-voltage) , Step 1). If reading is between 4.0 and 6.0 volts, connect TPS and go to next step.
3. Turn key off and wait 10 seconds. Disconnect ACT sensor, set DVOM on 200,000-ohm scale, and measure ACT sensor resistance. If reading is less than 1100 ohms or more than 58,000 ohms, check function of heat stove duct valve. If valve is operating correctly, replace ACT sensor, connect ACT sensor, and repeat QUICK TEST. If reading is between 1100 and 58,000 ohms, go to next step.
4. Turn key off. Disconnect ACT sensor harness. Set DVOM on 200,000-ohm scale and run engine for 2 minutes. While engine is running, measure ACT sensor resistance. If reading is between 2400 and 29,000 ohms, replace ECA, connect ACT harness, and repeat QUICK TEST. If reading is less than 2400 ohms or more than 29,000 ohms, check function of heat stove duct valve. If valve works properly, replace ACT sensor. Repeat QUICK TEST.
5. Code 54 Displayed. 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 SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-off-self-test) . If code 64 is displayed, replace ACT sensor. Repeat QUICK TEST. If code 64 is not displayed, remove jumper wire and go to next step.
6. Turn key off and wait 10 seconds. Disconnect connectors from ECA and ACT sensor. Inspect for and repair damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200 ohm scale. Measure resistance between test pin 25 and ACT signal at ACT connector, and between test pin 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, then repeat QUICK TEST. If either reading is 5 ohms or higher, repair opens in circuit. Remove breakout box, connect ECA and ACT sensor. Repeat QUICK TEST.
7. Disconnect ACT sensor. Inspect for and repair any damaged wiring. Perform «KEY ON/ENGINE OFF SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-off-self-test) . If code 54 is displayed, replace ACT sensor, connect harness, and repeat QUICK TEST. If code 54 is not displayed, go to next step.
8. 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 4.0-volts or more than 6.0-volts, go to «TEST C»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-c-reference-voltage) , Step 1). If reading is between 4.0 and 6.0 volts, connect TPS and go to next step.
9. 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 200,000 ohm scale. Measure resistance between test pin 25 and test pins 40, 46, and 60. If any reading is less than 10,000 ohms, repair shorts. Remove breakout box, connect ECA and ACT sensor. Repeat QUICK TEST.
10. Continuous Code 54 or 64 Displayed. Using CONTINUOUS MONITOR (WIGGLE) TEST, observe VOM or STAR tester LED 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. If no fault is indicated, go to next step.
11. 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. If no fault is indicated, go to next step.
12. 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. If connectors and terminals are okay, and you are unable to duplicate fault at this time, continuous code 54 or 64 testing is complete.

Air Charge Temperature (ACT) Sensor Circuit. Scheme 106

TEST F - EGR VALVE POSITION (EVP) SENSOR & EGR CONTROL/VENT

EGRC/EGRV

1. Code 31 Displayed. Turn key off and wait 10 seconds. Disconnect and plug vacuum line at EGR valve. Perform «KEY ON/ENGINE RUNNING SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-running-self-test) . If code 31 is displayed go to next step. If code 31 is not displayed but codes 32 and 34 are, go to step 8).
2. Turn key off and wait 10 seconds. Leave EGR vacuum line disconnected and plugged. Disconnect EVP sensor harness. Set DVOM on 200,000 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. 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. 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 4.0-volts or higher than 6.0 volts, go to «TEST C»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-c-reference-voltage) , Step 1). If reading is between 4.0 and 6.0 volts, go to next step.
4. Turn key off and wait 10 seconds. Disconnect 60-pins connector at ECA and harness at EVP sensor harness. Set DVOM to 20 damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pin 27 and EVP signal at EVP connector. If reading is 5 ohms or higher, repair open in circuit. Remove breakout box, connect ECA and EVP sensor, then repeat QUICK TEST. If reading is less than 5 ohms, go to next step.
5. Turn key off and disconnect harness at EVP sensor. Install breakout box, leaving ECA disconnected. Set DVOM on 200,000 ohm scale. Measure resistance between test pin 27 and test pins 26, and 46. If any reading is less than 10,000 ohms, repair short circuit. Remove breakout box, connect ECA and EVP sensor, then repeat QUICK TEST. If all readings are 10,000 ohms or higher, go to next step.
6. 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 SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-off-self-test) . If code 31 is displayed, replace ECA. Connect original EVP sensor and EGR valve assembly. Repeat QUICK TEST. If code 31 is not displayed, go to next step.
7. 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 SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-off-self-test) . If code 31 is displayed, replace EVP sensor and repeat QUICK TEST. If code 31 is not displayed, service EGR system.
8. Codes 32, 33, or 34 Displayed. Use DVOM for this step, DO NOT use STAR 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 SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-off-self-test) 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 «TEST NN»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-nn-no-codescodes-codes) , Step 13). If DVOM reading does go high, stay in OUTPUT STATE CHECK and go to next step.
9. Turn key on, leaving engine off. Stay in OUTPUT STATE CHECK with DVOM set 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 and go to step 15). If both solenoids cycle on and off, stay in OUTPUT STATE CHECK and go to next step.
10. Turn key on, leaving engine off. Stay in 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, and leave open, vacuum vent line from EGRV solenoid. Maintain source vacuum and cycle output on and off by depressing and releasing throttle. If vacuum cycles ON and OFF in less than 2 seconds, reconnect all vacuum lines and go to step 12). If vacuum does not cycle ON and OFF in less than 2 seconds, go to next step.
11. Stay in Output State mode. Repeat procedures in step 10). If vacuum output cycles ON and OFF in less than 2 seconds, replace filter (if equipped) and/or check vent line for blockage. After repairs, reconnect all vacuum lines. Repeat QUICK TEST. If vacuum does not cycle ON and OFF in less than 2 seconds, replace solenoid assembly. Reconnect all vacuum lines. Repeat QUICK TEST.
12. Turn key OFF and wait 10 seconds. After reconnecting all vacuum lines, check ENTIRE EEC-IV vacuum line system for blockage or damage. Use VECI decal for emission schematic. If any lines are bad, repair and repeat QUICK TEST. If lines are good, go to next step.
13. With key off, disconnect EVP sensor harness. Inspect for and repair any damaged wiring. Set DVOM on 200,000 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. If reading does not slowly decrease, go to next step.
14. With key off and harness disconnected from EVP sensor. 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. If either reading changes abruptly during range of 100-5500 ohms, replace EVP sensor. Reconnect harness and EGR vacuum line. Repeat QUICK TEST.
15. 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. If both readings are between 30 and 70 ohms, reconnect solenoids and go to next step.
16. 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. If both readings are 10.5-volts or more, go to next step.
17. 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 33 and EGRV signal at EGRV solenoid connector. Measure resistance between test pin 52 and EGRC signal at EGRC solenoid connector. If either reading is 5 ohms or more, repair open circuit. Remove breakout box, connect ECA and solenoids, then repeat QUICK TEST. If both readings are less than 5 ohms, go to next step.
18. Turn key off and wait 10 seconds. Set DVOM on 200,000 ohm scale. Install breakout box, leaving ECA disconnected. Disconnect EGRC and EGRV solenoids. Measure resistance between test pin 33 and/or 52 and test pins 40, 46, and 60. If readings are less than 10,000 ohms, repair short to ground. Repeat QUICK TEST. If readings are 10,000 ohms or more, go to next step.
19. With key off, disconnect EGRC and EGRV solenoids from harness. Install breakout box, leaving ECA disconnected. Set DVOM on 200,000 ohm scale. Measure resistance between test pin 33 and test pins 37 and 57. Measure resistance between test pin 52 and test pins 37 and 57. If any reading is less than 10,000 ohms, repair short in circuit. Remove breakout box and connect ECA. Repeat QUICK TEST. If code is repeated, replace ECA. If all readings are 10,000 ohms or more, replace ECA. Remove breakout box and connect ECA. Repeat QUICK TEST.
20. Code 35 Displayed. This code indicates that engine RPM is too low for correct EGR testing. If code 12 is also displayed, go to: See: «TEST Z»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-z-idle-speed-control) , step 1) for EFI models with air by-pass. See: «TEST AA»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-aa-idle-speed-control) , step 1) for models with DC motor control. See: «TEST BB»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-bb-idle-speed-control) , Step 1) for models with throttle kicker. If code 12 is not displayed with code 35, go to next step.
21. Turn key off and wait 10 seconds. Install tachometer. Perform KOER Self-Test at 1500 RPM. Record KOER service codes. If code 35 is displayed, replace ECA and repeat QUICK TEST. If code 35 is not displayed, repeat QUICK TEST and repair codes as necessary.
22. Continuous Code 31 Displayed. Using CONTINUOUS MONITOR (WIGGLE) TEST, observe VOM or STAR tester LED 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 24).
23. 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 27 and 46. Set DVOM on 20-volt scale. Turn key on, leaving engine off. Repeat step 22) 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. 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.
24. 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. If no fault is indicated, go to next step.
25. 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. If connector and terminals are okay, fault cannot be duplicated at this time. Continuous code 31 testing is complete.

EVP-Control/Vent EGRC/EGRV Circuit. Scheme 107

TEST G - ENGINE COOLANT TEMPERATURE (ECT) SENSOR

Note. For purposes of this test, a "warmed up" engine has a coolant temperature of 50-240°F (10-116°C) for the KEY ON/ENGINE OFF SELF-TEST and 180-240°F (82-116°C) for KEY ON/ENGINE RUNNING SELF-TEST . The test procedure will be invalid outside these ranges.

1. Code 21 Displayed. Start engine and run it at 2000 RPM for 2 minutes. Check that upper radiator hose is hot and pressurized. Repeat QUICK TEST before continuing. If vehicle stalls, DO NOT service code 21 at this time, go directly to «DIAGNOSIS BY SYMPTOM TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__diagnosis-by-symptom-test) . If code 21 is not displayed, service other codes as necessary (if displayed). If code 21 appears, go to next step.
2. Turn key off and wait 10 seconds. Disconnect TPS. Set DVOM on 20-volt scale. Turn key on, leaving engine off. Measure voltage at TPS harness connector between VREF and signal return. If voltage is less than 4.0-volts or higher than 6.0-volts, go to «TEST C»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-c-reference-voltage) , step 1). If voltage is between 4 and 6 volts, reconnect TPS and go to next step.
3. Make sure engine is fully warmed up for this step. Turn key off and wait 10 seconds. Disconnect wiring harness at ECT sensor. Set DVOM on 200,000 ohm scale and measure resistance of ECT sensor. If reading is 1300-7700 ohms at engine coolant temperature of 240-140°F (116-60°C) with engine off and 1550-4550 ohms at 230-180°F (110-82°C) with engine running, replace ECA, connect ECT sensor, then repeat QUICK TEST. If readings are not correct for coolant temperature, replace ECT sensor, connect harness, and repeat QUICK TEST.
4. Code 51 Displayed. 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 SELF-TEST. If code 61 is displayed, replace ECT sensor and remove jumper wire. Reconnect harness to ECT sensor and repeat QUICK TEST. If code 61 is not displayed, go to next step.
5. 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 7. Measure resistance between signal return at ECT connector and test pin 46. If both readings are less than 5 ohms, replace ECA. Remove breakout box and connect ECA and ECT sensor. Repeat QUICK TEST. If either reading is 5 ohms or higher, repair open circuits. Remove breakout box, connect ECA and ECT sensor. Repeat QUICK TEST.
6. Code 61 Displayed. 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 SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-off-self-test) . If code 51 is displayed, replace ECT sensor, connect sensor, then repeat QUICK TEST. If code 51 is not displayed, go to next step.
7. 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 4.0-volts or higher than 6.0-volts, go to «TEST C»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-c-reference-voltage) , step 1). If voltage is between 4.0 and 6.0 volts, connect TPS and go to next step.
8. 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 200,000 ohm scale. Measure resistance between test pin 7 and test pins 40, 46, and 60. If any reading is less than 10,000 ohms, repair short circuits. Remove breakout box, connect ECA and ECT sensor, then repeat QUICK TEST. If all readings are 10,000 ohms or higher, replace ECA. Remove breakout box, connect ECA and ECT sensor. Repeat QUICK TEST.
9. Continuous Code 21 Displayed. 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 1 or more minutes. After road test, repeat «KEY ON/ENGINE OFF SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-off-self-test) . If code 21 is present in «CONTINUOUS SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__continuous-self-test-procedures) , make sure that thermostat is working properly. If thermostat functions properly, replace ECT sensor and repeat QUICK TEST. 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 Displayed. Using CONTINUOUS MONITOR (WIGGLE) TEST, observe VOM or STAR tester LED 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. If no fault is indicated, go to next step.
11. While in CONTINUOUS MONITOR (WIGGLE) TEST, observe VOM or STAR tester LED for 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. If fault is not indicated, go to next step.
12. 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. If connectors and terminals are okay, fault cannot be duplicated at this time. Continuous code 51 or 61 testing is complete.

Engine Coolant Temperature (ECT) Sensor Circuit. Scheme 108

TEST H - MANIFOLD ABSOLUTE PRESSURE (MAP)/BAROMETRIC PRESSURE

(BP) SENSOR

Note. Barometric pressure sensor output is digital and must be measured with MAP/BP tester. Perform harness check before replacing sensor.

Scheme 109

1. Code 22 Displayed, 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. (Scheme 99) Go to next step. (Scheme 109): Correct Hookup For MAP/BP Tester
2. With 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. 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. 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 «TEST C»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-c-reference-voltage), step 1).
4. 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, go to next step. If output reading is outside range, 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.
5. 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 45. If reading is less than 5 ohms, replace ECA. Connect ECA and MAP/BP sensor and repeat QUICK TEST. If reading is 5 ohms or higher, repair opens in wiring. Remove breakout box, connect ECA and MAP/BP sensor. Repeat QUICK TEST.
6. 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 200,000 ohm scale. Measure resistance between test pin 45 and test pins 26, 46, 40, and 60. If any reading is less than 10,000 ohms, repair shorts in wiring. Remove breakout box and connect ECA and MAP/BP sensor. Repeat QUICK TEST. If all readings are 10,000 ohms or higher, replace MAP/BP sensor. Remove breakout box and connect all wiring. Repeat QUICK TEST.
7. Code 22 Displayed, Engine Running. Turn key off and wait 10 seconds. Disconnect vacuum line from MAP sensor. Hook 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. If MAP sensor does hold vacuum, go to next step.
8. Turn key off and wait 10 seconds. Plug vacuum supply hose to MAP sensor. Start engine and hold in 1400-1600 RPM range. Slowly apply 15 in. Hg vacuum to MAP sensor. Perform «KEY ON/ENGINE RUNNING SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-running-self-test) while holding RPM range. Ignore all other codes at this time. If code 22 is still displayed, replace MAP sensor. Connect vacuum hose and repeat QUICK TEST. If code 22 is not displayed, check vacuum hose to sensor and repair. If hose is good, service other codes as necessary, then check engine for low vacuum condition.
9. Turn key off and wait 10 seconds, Install vacuum gauge with tee in manifold vacuum supply line near MAP sensor. Observe vacuum reading before and during DYNAMIC RESPONSE CHECK portion of test. Record service codes. If vacuum decreased 10 in. Hg or more and code 72 is not displayed, disconnect vacuum gauge and service other codes as necessary. If vacuum decreased 10 in. Hg and code 72 is displayed, replace MAP sensor and repeat QUICK TEST. If vacuum decreased less than 10 in. Hg, go to next step.
10. 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).
11. Turn key off. Disconnect MAP/BP sensor from harness. Connect MAP/BP tester between wiring harness and MAP/BP sensor. Go to next step.
12. Turn key on and measure sensor output. Compare values to wiring diagram at end of this test. If reading is within range, go to Diagnosis By Symptom Test in specific engine section at beginning of this article. If reading is out of range, replace MAP/BP sensor.
13. Continuous Code 22 Displayed. Using CONTINUOUS MONITOR (WIGGLE) TEST, observe VOM or STAR tester LED 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. If no fault is indicated, go to next step.
14. Stay in CONTINUOUS MONITOR (WIGGLE) TEST. Observe VOM or STAR tester LED 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. If no fault is indicated, go to next step.
15. 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. If connectors and terminals are okay, fault cannot be duplicated at this time. Continuous code 22 testing is complete.

MAP/BP Sensor Circuit. Scheme 110

BP SENSOR VOLTAGE OUTPUT

TEST I - KNOCK SENSOR

1. Code 25 Displayed. Have 4 oz. hammer ready. Begin Engine Running Self-Test. Tap on exhaust manifold above knock sensor with moderate strokes when Dynamic Response Signal appears. No WOT operation is required for this test. Check for code 25 in about 15 seconds and ignore all other codes at this time. If code 25 is generated, go to next step. If no code 25, knock system is working. Repeat «KEY ON/ENGINE RUNNING SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-running-self-test) and service other codes displayed.
2. Turn key OFF and wait 10 seconds. Disconnect knock sensor. Inspect for and repair any damaged wiring. With DVOM on 20 volt scale, turn key ON, leaving engine OFF. Measure voltage at knock sensor connector between sensor signal and signal return. If voltage is between 1-4 volts, go to step 6) of this test. If less than 1 volt, go to next step. If greater than 4 volts, go to step 5) of this test.
3. Turn key OFF and wait 10 seconds. Disconnect 60-pin connector at ECA. Inspect for and repair any damaged wiring. Connect breakout box and leave ECA and knock sensor disconnected. With DVOM on 200 ohm scale, measure resistance of knock sensor harness between sensor signal at connector and test pin 23 and between signal return at connector and test pin 46. If both less than 5 ohms, go to next step. If either 5 ohms or more, service open circuit and repeat QUICK TEST.
4. Turn key OFF and wait 10 seconds. Leave breakout box installed with ECA and knock sensor disconnected. With DVOM on 200,000 ohm scale, measure resistance between sensor signal at connector and test pins 40, 46 and 60. If all 10,000 ohms or greater, go to step 6) of this test. If any less than 10,000 ohms, repair harness short and repeat QUICK TEST.
5. Turn key OFF and wait 10 seconds. With equipment connected as in step 4), set DVOM on 20 volt scale. Turn key ON, leaving engine OFF. Measure voltage from test pin 23 to test pin 40. If .5 volt or more, repair short to power in knock sensor harness and repeat QUICK TEST. If less than .5 volt, go to next step.
6. Turn key OFF and wait 10 seconds. Remove breakout box and reconnect ECA. Connect equivalent knock sensor (same part number) into harness but do not install in engine. Perform «KEY ON/ENGINE RUNNING SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-running-self-test) . When Dynamic Response Signal appears, lightly tap knock sensor with 4 oz. hammer. If code 25 appears after about 15 seconds, replace ECA, remove substitute knock sensor and repeat QUICK TEST with original sensor. If code 25 does not appear within 15 seconds, install new knock sensor and repeat QUICK TEST.

Knock (Detonation) Sensor Circuits. Scheme 111

TEST J - THROTTLE POSITION SENSOR (TPS)

1. Code 23 Displayed. If Key ON/Engine OFF code 68 or Engine Running codes 31, 41, or 58 are displayed, service these codes first. If forementioned codes have been serviced or are not displayed, go to next step.
2. Check for mechanical problem of binding or sticking at throttle plate or linkage. Make sure linkage is set with throttle in closed position. If throttle plate or linkage is binding, repair problem and repeat QUICK TEST. If no mechanical problem is found, go to next step.
3. Turn key OFF and wait 10 seconds. Disconnect TPS from harness. Inspect for and repair any damaged wiring. Run Key ON/Engine OFF Self-Test. Ignore all codes except code 63 at this time. If code 63 is not displayed, go to step 5). If code 63 is displayed, go to next step.
4. Turn key OFF and wait 10 seconds. Set DVOM to 20 volt scale and disconnect TPS from harness. Inspect for and repair any damaged wiring. Turn key ON, leaving engine OFF. Measure voltage at TPS connector between VREF and signal return. If voltage is less than 4 volts or greater than 6 volts, go to «TEST C»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-c-reference-voltage) , step 1). If voltage reading is between 4-6 volts, replace TPS and adjust properly. Repeat QUICK TEST.
5. Turn key OFF and wait 10 seconds. Disconnect TPS from harness. Set DVOM to 200,000 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 47 and test pins 26 and 57. If either reading is less than 10,000 ohms, repair short in harness and repeat QUICK TEST. If both readings are 10,000 ohms or higher, replace ECA and repeat QUICK TEST.
6. Code 63 Displayed. Turn key OFF and wait 10 seconds. Disconnect TPS from harness. Connect jumper wire between VREF and TPS signal at connector. Run Key ON/Engine OFF Self-Test. If NO codes are generated, remove jumper immediately and go to step 9) of this test. If either code 53 or 23 are displayed, replace TPS. Ignore all other codes during this step. Adjust TPS correctly and repeat QUICK TEST. If neither code 53 or 23 are displayed, go to next step.
7. Turn key OFF and wait 10 seconds. Disconnect TPS from harness. Inspect for and repair any damaged wiring. Set DVOM to 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 «TEST C»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-c-reference-voltage) , step 1). If reading is between 4-6 volts, go to next step.
8. Turn key OFF and wait 10 seconds. Leave TPS disconnected. Set DVOM to 200 ohm scale and disconnect ECA. Inspect for and repair any damaged wiring. Install breakout box and connect ECA. Measure resistance between TPS signal at connector and test pin 47. If reading is 5 ohms or more, repair wiring and reconnect TPS. Remove breakout box and repeat QUICK TEST. If reading is less than 5 ohms, go to next step.
9. Turn key OFF and wait 10 seconds. Leave TPS disconnected. Disconnect ECA, inspecting and repairing wiring. Install breakout box and set DVOM to 200,000 ohm scale. Measure resistance at connector between TPS signal and ground and between TPS signal and test pin 46. If reading is less than 10,000 ohms, repair short and recheck resistance of circuit. If resistance is 10,000 ohms or more, replace ECA. Connect TPS, remove breakout box, and repeat QUICK TEST. NOTE: Code 73 in next step indicates that TPS did not exceed 25% of its rotation during Engine Response Check.
10. Code 73 Displayed. Turn key OFF. Install breakout box and set DVOM to 20 volt scale. Connect DVOM between test pins 46 and 47. Perform «KEY ON/ENGINE RUNNING SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-running-self-test) and check DVOM reading during WOT at Engine Response Check. If reading exceeds 3.5 volts, replace ECA and repeat QUICK TEST. If reading does not exceed 3.5 volts, make sure that TPS is correctly installed and adjusted. If so, replace TPS and adjust properly. Repeat QUICK TEST.
11. Continuous Code 53 or 63 Displayed. In CONTINUOUS MONITOR (WIGGLE) TEST mode, slowly open throttle to WOT and release. Lightly tap TPS and wiggle connector. If fault is indicated, go to next step. If no fault is indicated, go to step 13).
12. Turn key OFF and wait 10 seconds. Disconnect 60-pin ECA connector. Inspect for and repair any damaged wiring. Install breakout box and reconnect ECA. Stay in continous monitor (wiggle) mode. Connect DVOM between test pin 47 and test pin 46. Set DVOM to 20 volt scale. Turn key ON, leaving engine OFF. Repeat step 11). If fault occurs below 4.25 volts, inspect for and repair any damaged wiring. If wiring is good, replace TPS and repeat QUICK TEST. If fault does not occur below 4.25 volts, TPS over-travel may have caused continuous code 53. TPS is good. Go to next step to check harness integrity.
13. In Continuous Monitor (Wiggle) mode, bend and wiggle small sections of EEC-IV harness from sensor to firewall and from firewall to ECA. If fault is indicated, inspect for and repair any damaged wiring. Repeat QUICK TEST. If no fault is indicated, go to next step.
14. Turn key OFF and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Repeat QUICK TEST if repair is made. If wiring is good, fault cannot be duplicated and continuous code 53 or 63 test is complete. NOTE: In the following diagram, the wire colors for the test pins are as follows: Pin 26 = Orange Pin 46 = Black Pin 47 = Dark Green

Throttle Position Sensor (TPS) Ckt (See NOTE: above). Scheme 112

TEST K - VANE AIRFLOW (VAF) SENSOR

1. Code 26 Displayed. Code 26 indicates VAF sensor input to ECA is out of closed (Engine OFF) or idle limits (Engine OFF .15-.50 volts; Engine Idling 1.5-2.7 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 «KEY ON/ENGINE OFF SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-off-self-test) , replace airflow meter. Reinstall air cleaner and repeat QUICK TEST. If no code 26 displayed, go to next step.
2. Turn key OFF. Reinstall air filter. Check for air leaks allowing unmetered air into system between airflow meter and throttle body. Disconnect 60-pin connector at ECA. Inspect for and repair any damaged wiring. Install breakout box and connect ECA to box. Set DVOM to 20 volt scale. Turn key ON, leaving engine OFF. Place new, unsharpened wooden pencil through air inlet opening of airflow meter. Pencil must extend past both ends of airflow meter to hold vane door in open position. Measure voltage between test pins 43 and 46. If reading is 2.8-3.7 volts, airflow meter is capable of outputting acceptable signals. Code 26 has been caused by incorrect engine speed or vacuum leak. Repair problem. Remove breakout box and repeat QUICK TEST. If reading not 2.8-3.7 volts, replace airflow meter. Remove breakout box and repeat QUICK TEST.
3. Code 56 Displayed. Turn key OFF and wait 10 seconds. Disconnect harness from airflow meter. Perform Key ON/Engine OFF QUICK TEST. If code 66 is displayed, go to next step. If code 66 is not displayed, go to step 5). As disconnecting airflow meter also disconnects VAT sensor, code 54 should be displayed. Ignore all codes except VAF codes at this time.
4. Turn key OFF and wait 10 seconds. Disconnect harness from airflow meter. Inspect for and repair any damaged wiring. Turn key ON, leaving engine OFF. Set DVOM to 20 volt scale. Measure voltage at harness connector between VREF and signal return. If reading is between 4.0-6.0 volts, replace airflow meter. Reconnect harness and repeat QUICK TEST. If reading is less than 4.0 or more than 6.0 volts, go to «TEST C»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-c-reference-voltage) , step 1).
5. 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 to 200,000 ohm scale. Measure resistance between test pin 43 and test pins 26 and 57. If either reading is less than 10,000 ohms, repair short in wiring. Remove breakout box, reconnecting ECA and airflow meter. Repeat QUICK TEST. If both readings are 10,000 ohms or higher, replace ECA. Remove breakout box, reconnecting ECA and airflow meter. Repeat QUICK TEST.
6. Code 66 Displayed. 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) QUICK TEST. If no codes are displayed, remove jumper immediately and go to step 9) of this test. If code 56 is displayed, replace airflow meter. Remove jumper wire, reconnect airflow meter, and repeat QUICK TEST. If code 56 is not displayed, remove jumper and go to next step. Ignore all codes except VAF codes at this time.
7. Turn key OFF and wait 10 seconds. Leave airflow meter disconnected. Turn key ON, leaving engine OFF. Set DVOM to 20 volt scale. Measure voltage at airflow meter harness connector between VREF and signal return. If reading is below 4.0 volts or above 6.0 volts, go to «TEST C»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-c-reference-voltage) , step 1). If reading is between 4.0-6.0 volts, go to next step.
8. With key OFF and airflow meter disconnected, disconnect ECA. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM to 200 ohm scale. Measure resistance between VAF signal at airflow connector and test pin 43. If reading is 5 ohms or more, repair open circuit. Remove breakout box, reconnecting ECA and airflow meter. Repeat QUICK TEST. If reading is less than 5 ohms, go to next step.
9. Turn key OFF and wait 10 seconds. Leave ECA and airflow meter disconnected. Set DVOM to 200,000 ohm scale. Measure resistance at connector between VAF signal and signal return. Also measure resistance between VAF signal and negative battery terminal. If reading is less than 10,000 ohms, repair short. Reconnect airflow meter and repeat QUICK TEST. If reading is 10,000 ohms or more, remove breakout box. Reconnect ECA and airflow meter. Repeat QUICK TEST.
10. Code 76 Displayed. Turn key OFF and wait 10 seconds. Disconnect 60-pin ECA connector. Inspect for and repair any damaged wiring. Install breakout box and connect ECA. Set DVOM to 20 volt scale. Connect DVOM to test pins 43 and 46. Perform Engine Running Self-Test while observing DVOM. As soon as the dynamic response code 1 (or 10 on STAR tester) is displayed, perform brief WOT. Reading on DVOM should increase by more than 2.0 volts from reading before WOT. Observe service codes at end of test. If DVOM reading increased by more than 2.0 volts and code 76 is still displayed, replace ECA. Remove breakout box and repeat QUICK TEST. If DVOM reading did not increase more than 2.0 volts, check air cleaner duct for blockage. If duct is clear, replace airflow meter. If DVOM reading increased by more than 2.0 volts and code 76 is not displayed, airflow meter is good. Respond to remaining service codes that were displayed.
11. Continuous Code 56 or 66 Displayed. In Continuous Monitor (Wiggle) mode, lightly tap VAF sensor and wiggle connector. If a fault is indicated, inspect for and repair any damaged wiring. If wiring is good, replace VAF sensor and repeat QUICK TEST. If no fault is indicated, go to next step.
12. Check EEC-IV harness in Continuous Monitor (Wiggle) mode by bending and shaking small sections of the harness from sensor connector to firewall and from firewall to ECA. If fault is indicated, inspect for and repair any damaged wiring. Repeat QUICK TEST. If no fault is indicated, go to next step.
13. Turn key OFF and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Repeat QUICK TEST if wiring repair was necessary. If no wiring problem found, test is completed. Service other codes in order displayed.

VAF Sensor Circuits. Scheme 113

TEST L - EGR VALVE POSITION (EVP) EGR VALVE REGULATOR (EVR)

1. Code 31 Displayed. Turn key OFF and wait 10 seconds. Disconnect and plug EGR vacuum line at EGR valve. Perform Engine Running Self-Test. If code 31 is displayed, go to next step. If code 31 is not displayed, but codes 32 and/or 34 are, go to step 9).
2. Turn key ON, leaving engine OFF. EGR vacuum line disconnected and plugged and harness disconnected at EVP sensor. Connect vacuum pump to EGR valve. With DVOM on 200,000 ohm scale, measure resistance between EVP signal and VREF at EVP sensor while gradually increasing vacuum to 10 in. Hg. If reading gradually decreases from no more than 5500 ohms to no less than 100 ohms as vacuum is increased, go to next step. If reading is less than 100 ohms or more than 5500 ohms as vacuum is increased, replace sensor and repeat QUICK TEST. If reading does not decrease or valve does not hold vacuum, go to step 13).
3. Turn key ON, leaving engine OFF. Disconnect and plug EGR vacuum signal line. Disconnect harness at EVP sensor. With DVOM on 20 volt scale, measure voltage between EVP signal return and VREF at EVP connector. If reading is less than 4.0 volts or more than 6.0 volts, go to «TEST C»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-c-reference-voltage) , step 1). If reading is between 4.0-6.0 volts, go to next step.
4. Turn key OFF and wait 10 seconds. Disconnect EVP sensor and 60-pin ECA connectors. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM to 200 ohm scale. Measure resistance between test pin 27 and EVP signal at EVP connector. If reading is 5 ohms or more, repair open. Remove breakout box. Reconnect ECA and EVP sensor. Repeat QUICK TEST. If reading is less than 5 ohms, go to next step.
5. Leave key OFF, breakout box installed, and ECA and EVP sensor disconnected. Set DVOM to 200,000 ohm scale. Measure resistance between test pin 27 and test pins 26 and 46. If any reading is less than 10,000 ohms, repair short. Remove breakout box, reconnecting ECA and EVP sensor. Repeat QUICK TEST. If all readings are 10,000 ohms or more, go to next step.
6. Turn key OFF and wait 10 seconds. Connect known good EVP sensor and EGR valve assembly to harness. Remove breakout box and reconnect ECA. Run «KEY ON/ENGINE OFF SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-off-self-test) . If code 31 is displayed, replace ECA. Reconnect original EVP sensor and EGR valve assembly. Repeat QUICK TEST. If code 31 is not displayed, go to next step.
7. Turn key OFF and wait 10 seconds. Install original EVP sensor on known good EGR valve. Connect EVP sensor. Repeat Key ON/Engine OFF Self-Test. If code 31 is displayed, replace ECA. Connect original EVP sensor and EGR valve assembly. Repeat QUICK TEST. If code 31 is not displayed, check EGR system for problem.
8. Codes 32, 33, or 34 Displayed. Use only VOM/DVOM, not STAR tester, for this step. Turn key OFF and wait 10 seconds. Set DVOM to 20 volts scale. Connect DVOM negative test lead to STO and positive test lead to battery positive terminal. Use jumper to connect STI to signal return. Run Key ON/Engine OFF Self-Test until Continuous Code display is done. DVOM should read 0 volts. Depress and release throttle. If reading does not go to high voltage, depress throttle to WOT and release. If STO voltage does not go high, go to «TEST NN»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-nn-no-codescodes-codes) , step 13). If reading did change to high voltage, stay in Output State mode and go to next step.
9. Turn key ON, leaving engine OFF. Stay in Output State mode and set DVOM to 20 volt scale. Connect DVOM to VPWR and EVR signal circuits of EVR. Depress and release throttle several times to cycle ON and OFF. If solenoid output does not cycle ON and OFF, go to step 14). If solenoid output does cycle, stay in Output State mode and go to next step.
10. Turn key ON, leaving engine OFF and stay in Output State mode. Disconnect and plug vacuum line from bottom port of EVR solenoid and connect vacuum pump. Connect vacuum gauge to common output (top) vacuum line to EGR valve. Cycle outputs ON and OFF with throttle. Observe vacuum gauge while maintaining vacuum supply. If vacuum output does not cycle ON and OFF in less than 2 seconds, check and replace EVR filter if obstructed. If filter is good, replace EVR solenoid assembly. Reconnect all vacuum lines and repeat QUICK TEST. If vacuum output does cycle ON and OFF in less than 2 seconds, reconnect all vacuum lines and go to next step.
11. Turn key OFF and wait 10 seconds. With all vacuum lines reconnected, check entire EEC-IV vacuum line system, using VECI decal for schematic. If any vacuum lines are repaired, repeat QUICK TEST. If all lines are good, go to next step.
12. With key OFF, disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Set DVOM to 200,000 ohm scale. Disconnect vacuum line at EGR valve and connect vacuum pump to EGR valve. Measure resistance between EVP signal terminal and VREF terminal on EVP sensor while increasing vacuum to 11 in. Hg. If reading decreases gradually from a maximum of 5500 ohms to a minimum of 100 ohms, replace ECA. Reconnect EVP sensor and EGR vacuum line. Repeat QUICK TEST. If reading does not decrease gradually, go to next step.
13. With key OFF and EVP sensor harness disconnected, remove EVP sensor from EGR valve. Measure resistance between signal return and VREF terminals on EVP sensor while applying pressure to EVP sensor shaft. Look for sudden changes in resistance as shaft is slowly pushed in and released. If readings range smoothly between 5500 ohms and 100 ohms, replace EGR valve assembly. Reconnect EVP sensor and EGR vacuum supply line. Repeat QUICK TEST. If readings change abruptly between 5500 ohms and 100 ohms, replace EVP sensor. Reconnect harness and EGR vacuum supply line. Repeat QUICK TEST.
14. Turn key OFF and wait 10 seconds. With DVOM on 200 ohm scale, measure resistance of disconnected EVR solenoid. If reading is less than 30 ohms or more than 70 ohms, replace EVR solenoid assembly. Repeat QUICK TEST. If reading is between 30-70 ohms, connect EVR solenoids and go to next step.
15. Disconnect EVR solenoid from harness. Turn key ON, leaving engine OFF. Set DVOM to 20 volt scale and measure voltage between negative battery terminal and VPWR circuit to EVR solenoid. If reading is less than 10.5 volts, repair open in harness. Repeat QUICK TEST. If reading is 10.5 volts or more, go to next step.
16. Turn key OFF and wait 10 seconds. Disconnect EVR solenoid and 60-pin ECA connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM to 200 ohm scale. Measure resistance between test pin 52 and EVR signal at EVR solenoid connector. If reading is 5 ohms or more, repair open circuit. Remove breakout box and reconnect ECA. Repeat QUICK TEST. If reading is less than 5 ohms, go to next step.
17. Turn key OFF and wait 10 seconds. Leave breakout box installed and ECA disconnected. Set DVOM to 200,000 ohm scale and disconnect EVR solenoid. Measure resistance between test pin 52 and test pins 40, 46, and 60. If reading is less than 10,000 ohms, repair short to ground. Repeat QUICK TEST. If reading is 10,000 ohms or more, go to next step.
18. Turn key OFF and install breakout box, leaving ECA disconnected. Disconnect EVR solenoid. Set DVOM to 200,000 ohm scale. Measure resistance between test pin 52 and test pins 37 and 57. If any reading is less than 10,000 ohms, repair short. Remove breakout box and connect ECA and EVR solenoid. Repeat QUICK TEST. If code is repeated, replace ECA. If all readings are 10,000 ohms or more, replace ECA. Remove breakout box, reconnecting EVR solenoid and ECA. Repeat QUICK TEST.
19. Code 35 Displayed. This code indicates that engine RPM is too low for correct EGR testing. If code 12 is also displayed, go to: «TEST Z»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-z-idle-speed-control) , step 1) for EFI models with air by-pass. «TEST AA»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-aa-idle-speed-control) , step 1) for models with DC motor control. «TEST BB»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-bb-idle-speed-control) , step 1) for models with throttle kicker. NOTE: If code 12 is not displayed with code 35, go to next step.
20. Turn key OFF and wait 10 seconds. Connect tachometer. Perform «KEY ON/ENGINE RUNNING SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-running-self-test) at steady 1500 RPM. Record service codes. If code 35 is displayed, replace ECA. Repeat QUICK TEST. If code 35 is not displayed, repair codes as displayed.
21. Continuous Code 31 Displayed. Enter CONTINUOUS MONITOR (WIGGLE) TEST mode. Connect vacuum pump to EGR valve. Slowly apply 6 in. Hg vacuum to EGR valve, then release vacuum slowly and lightly tap EVP sensor. Wiggle EVP sensor connector. If fault is not indicated, go to step 23). If fault is indicated, go to next step.
22. Turn key OFF and wait 10 seconds. Disconnect 60-pin ECA connector. Inspect for and repair any damaged wiring. Install breakout box and reconnect ECA. Connect DVOM between test pin 27 and test pin 46. Set DVOM to 20 volt scale. Turn key ON, leaving engine OFF. In CONTINUOUS MONITOR (WIGGLE) TEST mode, repeat step 21). If fault occurs below 4.25 volts, disconnect EVP sensor. Inspect for and repair any damaged wiring. Repeat QUICK TEST. If wiring is not repaired, replace EVP sensor, then repeat QUICK TEST. If fault does not occur below 4.25 volts, EGR valve overshoot may have caused display of code 31. Sensor is good. Go to next step to verify integrity of harness.
23. Remain in CONTINUOUS MONITOR (WIGGLE) TEST mode. Bend or wiggle small sections of EEC-IV harness from sensor to firewall and from firewall to ECA. If fault is indicated, inspect for and repair any damaged wiring. Repeat QUICK TEST. If no fault is indicated, go to next step.
24. Turn key OFF and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Repeat QUICK TEST. If wiring is good, fault can not be duplicated at this time. Testing is completed.

EGR Valve Position (EVP) Sensor & EGR Valve Regulator (EVR) Circuits. Scheme 114

TEST M - NEUTRAL DRIVE SWITCH-A/C INPUT

1. Code 67 Displayed. When this code is displayed, determine which engine and system is being tested and proceed to step 2).
2. Turn key OFF and wait 10 seconds. Make sure heater control is in OFF position and that transaxle/transmission is in Neutral or Park. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box and reconnect ECA. Turn key ON, leaving engine OFF. Set DVOM to 20 volt scale. Measure voltage between test pin 30 and chassis ground. If less than 1.0 volts, proceed to step 4). If reading is 1.0 volts or higher, go to next step.
3. Turn key OFF and wait 10 seconds. Install breakout box and connect ECA. Locate the neutral drive switch. Disconnect harness at switch. With DVOM on 200 ohm scale, measure resistance across switch contacts. If less than 5 ohms, correct open circuit in vehicle harness and repeat QUICK TEST. If 5 ohms or more, replace neutral drive switch. Repeat QUICK TEST.
4. Reconnect neutral drive switch. Leave breakout box and ECA connected. With DVOM on 20 volt scale, turn A/C control switch OFF. Turn key ON, leaving engine OFF. Measure voltage from test pin 10 to chassis ground. (On 2.3L Turbo, check for display of Continuous Code 18.) If 1.0 volt or more, repair short to power in A/C clutch circuit and repeat QUICK TEST. If less than 1.0 volt, replace ECA and repeat QUICK TEST.
5. Turn key OFF and wait 10 seconds. Ensure that A/C is OFF (if equipped), transaxle is in Neutral, and clutch is released. Disconnect 60-pin connector at ECA. Inspect for and repair any damaged wiring. Install breakout box and reconnect ECA. With DVOM on 200 ohm scale, measure resistance between test pins 30 and 46. If resistance is less than 5 ohms, go to step 4). If 5 ohms or more, go to next step.
6. Turn key OFF. With breakout box and ECA connected, place DVOM on 200 ohm scale. Locate neutral switch (on transaxle) and clutch switch (under dash). Disconnect wiring harness from both switches. Measure resistance of each switch across terminals. If both less than 5 ohms, go to step 4) of this test. If either or both measure 5 ohms or more, replace defective switch(es). Reconnect harness and repeat QUICK TEST.
7. Turn key OFF and wait 10 seconds. Make sure A/C is OFF (if equipped). Disconnect 60-pin connector at ECA. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. With DVOM on 200 ohm scale, measure resistance between test pins 30 and 46. If less than 5 ohms, go to step 4) of this test. If 5 ohms or more, repair open circuit and repeat QUICK TEST.
8. 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. Set DVOM to 20 volt scale. Connect positive lead to test pin 30 and negative lead to test pin 46. Turn key ON, leaving engine OFF. Cycle octane switch several times while reading DVOM. If voltage changes from 0 to 5 volts, replace ECA and repeat QUICK TEST. If voltage does not change, EEC-IV system is good. Check turbo boost.

Neutral Drive-A/C Input Circuit for Models with Auto. Trans. Scheme 115

TEST N - KEY POWER CHECK

1. Turn key OFF and wait 10 seconds. Install breakout box with ECA connected. Set DVOM to 20 volt scale and connect to test pins 5 and 60. During «KEY ON/ENGINE RUNNING (KOER) SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-running-koer-self-test-procedures) , observe DVOM and record codes. If reading is above 17.5 volts, repair charging system for overcharging condition. If reading is below 17.5 volts and code 65 is displayed, replace ECA and repeat QUICK TEST. If reading is below 17.5 volts and code 65 is NOT present, go to next step.
2. Continuous Code 65 Displayed. If code 65 is displayed during «KEY ON/ENGINE OFF SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-off-self-test) , repair charging system for intermittent overcharge condition (above 17.5 volts).
3. Turn key OFF and wait 10 seconds. Disconnect ECA. Inspect for and repair any damaged wiring. Connect breakout box and reconnect ECA. Set DVOM to 20 volt scale. Measure voltage between test pins 5 and 60, then repeat KOER Self-Test. If reading stays above 7.5 volts and code 55 is displayed, replace ECA and repeat QUICK TEST. If reading stays above 7.5 volts and code 55 is NOT present, go to step 5). If reading drops below 7.5 volts, go to next step.
4. Turn key OFF. With breakout box installed and ECA connected, set DVOM to 200 ohm scale. Measure resistance between test pin 5 and key power terminal on EEC power relay. If reading is 5 ohms or less, repair undercharging condition. If reading is more than 5 ohms, repair open in key power circuit and repeat QUICK TEST.
5. Continuous Code 55 Displayed. If code 55 is not present during «KEY ON/ENGINE OFF SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-off-self-test) , charging system is good at this time. If code 55 is displayed, repair intermittent overcharging condition.

Key Power Circuits. Scheme 116

TEST O - BRAKE ON/OFF (BOO)

1. Code 74 Displayed. If brake was NOT pressed during Engine Running Self-Test, repeat test and press brake pedal once during test. If pedal was pressed, go to next step.
2. Turn key OFF and wait 10 seconds. Disconnect 60-pin ECA connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM to 20 volt scale. Measure voltage between test pin 2 and test pin 40 while applying and releasing brake. If voltage cycles, replace ECA and repeat step. If voltage does not cycle, go to next step.
3. Turn key OFF. Leave breakout box installed with ECA disconnected. Set DVOM to 200 ohm scale. Disconnect BOO circuit from 14290 (12-pin connector). Measure resistance between test pin 2 and ground. If reading is higher than 5 ohms, repair BOO circuit short to ground. If reading is not higher than 5 ohms, check brake light circuit.
4. Code 75 Displayed. Turn key OFF and wait 10 seconds. Disconnect 60-pin ECA connector. Inspect for and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM to 20 volt scale. Measure voltage between test pin 2 and test pin 40 while applying and releasing brake. If voltage cycles, replace ECA and repeat step. If voltage does not cycle, go to next step.
5. Turn key OFF. With breakout box installed and ECA disconnected, set DVOM to 200 ohm scale. Disconnect BOO circuit from 14290 harness (12-pin connector). Measure resistance between test pin 2 and ground. If reading is greater than 5 ohms, repair BOO circuit short to ground. If reading is less than 5 ohms, check brake light circuit.

Brake ON/OFF (BOO) Circuit. Scheme 117

TEST P - POWER STEERING PRESSURE SWITCH (PSPS)

1. Code 52 Displayed. Turn key OFF and wait 10 seconds. Disconnect PSPS. Jump PSPS circuit to signal return at harness. Repeat Key ON/Engine OFF Self-Test. If code 52 is not displayed, replace PSPS and repeat QUICK TEST. If code 52 is still displayed, go to next step.
2. Turn key OFF and wait 10 seconds. Disconnect PSPS and 60-pin ECA connector. Inspect for and repair any damaged wiring. Install breakout box, set DVOM to 200 ohm scale, and leave ECA disconnected. Measure resistance between test pin 46 and signal return at PSPS connector. Also measure resistance between test pin 3 (test pin 24 on 2.3L HSC/CFI models) and PSPS circuit at PSPS connector. If both readings are less than 5 ohms, replace ECA. Repeat QUICK TEST. If both readings are not less than 5 ohms, repair open in circuit. Repeat QUICK TEST.
3. Connect tachometer and start engine, allowing it to idle in Park or Neutral. Disconnect PSPS at switch. If RPM increase, replace PSPS. If RPM do not increase, go to next step.
4. Turn key OFF and wait 10 seconds. Disconnect 60-pin ECA connector. Inspect for and repair any damaged wiring. Install breakout box, leaving PSPS and ECA disconnected. Set DVOM to 200 ohm scale. Measure resistance between test pin 3 (test pin 24 on 2.3L HSC/CFI models) and test pin 46. If reading is less than 5 ohms, repair short in harness. If reading is not less than 5 ohms, replace ECA.

Power Steering Pressure Switch (PSPS) Circuit. Scheme 118

TEST T - CFI FUEL CONTROL

Note. Fuel contaminated engine oil may affect 41, 42, 43, 91, 92 and 93 service codes. If this is suspected, remove PCV from valve cover and repeat QUICK TEST. If problem corrected, change engine oil and filter.

1. Turn key OFF and wait 10 seconds. Install fuel pressure gauge. Start and run engine. Fuel pressure must be 35-45 psi (2.5-3.2 kg/cm 2 ). Pressure must remain at 35-45 psi (2.5-3.2 kg/cm 2 ) for 60 seconds after key is turned OFF. If engine has a "No Start" problem, cycling the key from OFF to ON a few times will build up fuel pressure. If fuel pressure is outside range, check electric fuel pump and fuel pressure regulator. If fuel pressure is correct, go to next step.
2. With pressure gauge installed, cycle key from OFF to ON a few times to pressurize system. Disconnect fuel pump relay. Crank engine for 5 seconds and take pressure reading immediately after finishing cranking. If pressure reading is 10-20 psi (.7-1.4 kg/cm 2 ) after 5 seconds of cranking, EEC system is not at fault for no start. If problem is rough running, missing, fuel code, or pressure is incorrect after 5 second crank, go to next step. NOTE: Make sure that fuel is of good quality and not contaminated by air or water as pressure readings may be incorrect with bad or contaminated fuel. Also, pressure drop will be greater when engine is cold than when engine is warm. If coolant is 200°F (93°C) pressure should drop approximately 10 psi (.7 kg/cm 2 ) in 5 seconds while a pressure drop of 20 psi (1.4 kg/cm 2 ) should occur in 5 seconds with engine coolant at 60°F (15.6°C).
3. Turn key OFF. Set DVOM to 200 ohm range. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box, leave ECA disconnected. Measure resistance between test pins 57 and 58 and between tests pins 57 and 59. If resistance is less than 1.5 ohms or greater than 3.5 ohms, service the harness/connectors on the suspect injector for opens or shorts. If okay, replace injector. If resistance is 1.5 to 3.5 ohms, go to next step.
4. With key OFF, reconnect ECA through breakout box. Reconnect all injectors. Connect non-powered 12 volt test light between test pins 37 and 58. Crank or start engine. Repeat procedure with test light between test pins 37 and 59. If test light does not come on during either or both tests, check for 12 volt battery power at test pins 37 and 57. If test pins 37 and 57 have 12 volt power, replace ECA and repeat QUICK TEST. If test light is very bright on either or both tests, check circuits to banks 1 and 2 for short to ground. If no short is found, replace ECA and repeat QUICK TEST. If test light glows dimly on both tests, go to next step.
5. Connect tachometer and run engine at steady 2000 RPM. Disconnect ISC and use throttle stop screw to set speed if necessary. Disconnect and reconnect one injector at a time and note RPM drop for each injector. Reset curb idle and verify ISC hookup (using VECI decal) at end of test procedure. If each injector does not produce at least 150 RPM drop when disconnected, replace faulty injector(s) and repeat QUICK TEST. If RPM drop is correct for all injectors, running or driving problem is in area common to all cylinders such as a vacuum leak or fuel contamination.
6. Code 48 Displayed. Turn OFF and wait 10 seconds. Swap injector connections. Perform «KEY ON/ENGINE RUNNING SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-running-self-test) . If code 48 is still present, return injector connections to their original position and to to next step. If not, return to QUICK TEST and address any other code and/or conditions.
7. Turn key OFF and wait 10 seconds. Disconnect left EGO sensor at sensor. Repeat «KEY ON/ENGINE RUNNING SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-running-self-test) . If code 48, go to next step. If not, go to step 12). NOTE: Areas other than EEC may cause service codes 41 and 42 to be displayed. Check for ignition caused misfires, CANP problems, or engine oil that is contaminated by fuel if service code 42 is displayed. If fuel contamination is suspected, repeat QUICK TEST after removing PCV from valve cover. If this resolves problem, replace engine oil and oil filter. Check for leaking vacuum motor, engine sealing problem, faulty EGR or PCV systems, unmetered air leak between air meter and throttle body, or a lead contaminated EGO sensor if service code 41 is displayed.
8. Always Lean: Left EGO Sensor. Turn key OFF. Set DVOM to 20 volt scale. Disconnect left EGO sensor from vehicle harness. Connect DVOM to EGO sensor and ground. Disconnect ACT sensor. Start engine and run at about 2000 RPM. If DVOM reading is greater than .5 volt within 1 minute, go to next step. If not, replace EGO sensor and repeat QUICK TEST.
9. Harness Check: Left EGO Sensor. 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. Measure resistance between test pin 49 and engine block and between left EGO sensor connector and test pin 29. If both circuits are less than 5 ohms, go to next step. If not, service as necessary and repeat QUICK TEST.
10. Short to Ground Check: Left EGO Sensor. With key OFF, ECA disconnected and breakout box installed, set DVOM to 200,000 ohm scale. Measure resistance between test pins 29 (left EGO) and 40. If reading is less than 10,000 ohms, correct cause of resistance to ground and repeat QUICK TEST. If resistance is 10,000 ohms or higher, go to next step.
11. Left EGO Sensor Lean Code Elimination. Turn key OFF. Reconnect EGO sensor. Make certain that the ACT sensor is still disconnected. Start engine and run at about 2000 RPM for 1 minute. Return to idle. Perform KOER Self-Test. If code 41, inspect for corrosion or damaged pins. If okay, replace ECA and repeat QUICK TEST. If code 41 is not present, EGO sensor is okay. Reconnect ATC and go to step 1). NOTE: Areas other than EEC may cause service codes 41 and 42 to be displayed. Check for ignition caused misfires, CANP problems, or engine oil that is contaminated by fuel if service code 42 is displayed. If fuel contamination is suspected, repeat QUICK TEST after removing PCV from valve cover. If this resolves problem, replace engine oil and oil filter. Check for leaking vacuum motor, engine sealing problem, faulty EGR or PCV systems, unmetered air leak between air meter and throttle body, or a lead contaminated EGO sensor if service code 41 is displayed.
12. Always Lean: Right EGO Sensor. Turn key OFF. Set DVOM to 20 volt scale. Disconnect right EGO sensor from vehicle harness. Connect DVOM to EGO sensor. and engine ground. Disconnect ACT sensor. If DVOM reading is greater than .5 volt within 1 minute, go to next step. If not, replace EGO sensor and repeat QUICK TEST.
13. Harness Check: Right EGO Sensor. 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. Measure resistance between test pin 44 and engine block and between left EGO sensor connector and test pin 43. If both circuits are less than 5 ohms, go to next step. If not, service as necessary and repeat QUICK TEST.
14. Short to Ground Check: Right EGO Sensor. Turn key OFF. Breakout box installed and ECA disconnected. Set DVOM to 200,000 ohms range. Measure resistance between test pins 43 and 40. If reading is 10,000 ohms or greater, go to next step. If less than 10,000, correct cause of resistance to ground and repeat QUICK TEST.
15. Right EGO Sensor Lean Code Elimination. Turn key OFF. Reconnect EGO sensor. Make certain that the ACT sensor is still disconnected. Start engine and run at about 2000 RPM for 1 minute. Return to idle. Perform KOER Self-Test. If code 91, inspect for corrosion or damaged pins. If okay, replace ECA and repeat QUICK TEST. If code 91 is not present, EGO sensor is okay. Reconnect ATC and go to step 1).
16. Always Rich: Left EGO Sensor. Turn key OFF and wait 10 seconds. Check for fuel contaminated engine oil, ignition caused misfire and CANP problems. Disconnect vehicle harness at the left EGO sensor. Using a jumper wire, ground vehicle harness EGO circuit at the EGO sensor to the engine block. Repeat «KEY ON/ENGINE RUNNING SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-running-self-test) . If codes 41/48, go to step 18). If not, go to step 17).
17. Harness Check: Left EGO Sensor. Turn key OFF and wait 10 seconds. Disconnect ECA 60-pin connecter. Inspect for and repair any damaged wiring. Install breakout box. Measure resistance between test pin 49 and left EGO ground at engine block and between left EGO harness connector and test pin 29. If both circuits are less than 5 ohms, disconnect ECA and inspect. If okay, replace ECA and repeat QUICK TEST. If both circuit are greater than 5 ohms, correct harness circuit with resistance greater than 5 ohms and repeat QUICK TEST.
18. EGO Check: Left EGO Sensor. Set DVOM to 20 volt scale. With EGO sensor disconnected from the harness, connect the DVOM from EGO sensor to engine ground. Disconnect PCV hose. Start engine and run at 2000 RPM. If the DVOM reading is less than .4 volt within 1 minute the EGO sensor is okay. Go to next step. If reading is greater, replace EGO sensor and repeat QUICK TEST.
19. Always Rich: Right EGO Sensor. Turn key OFF and wait 10 seconds. Check for fuel contaminated engine oil, ignition caused misfire and CANP problems. Disconnect vehicle harness at the right EGO sensor. Using a jumper wire, ground vehicle harness EGO circuit at the EGO sensor to the engine block. Repeat Engine Running Self-Test. If code 91, go to step 21). If not, go to step 20).
20. Harness Check: Right EGO Sensor. Turn key OFF and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box. Measure resistance between test pin 49 and left EGO ground at engine block and between left EGO harness connector and test pin 29. If both circuits are less than 5 ohms, disconnect ECA and inspect. If okay, replace ECA and repeat QUICK TEST. If both circuits are greater than 5 ohms, correct harness circuit with resistance greater than 5 ohms and repeat QUICK TEST.
21. EGO Check: Right EGO Sensor. Set DVOM to 20 volt scale. With EGO sensor disconnected from the harness, connect the DVOM from EGO sensor to engine ground. Disconnect PCV hose. Start engine and run at 2000 RPM. If the DVOM reading is less than .4 volt within 1 minute the EGO sensor is okay. Go to next step. If reading is higher, replace EGO sensor and repeat QUICK TEST.
22. Continuous Codes 41 & 42 Displayed. If code 41 appears it indicates that the fuel system was lean for more than 15 seconds, when it should have been under control of EGO sensor. If code 42 appears, it indicates that the fuel system was rich for more than 15 seconds, when it should have been under control of EGO sensor. Before attempting to correct a code 41 or 42, first diagnose all other complaints such as rough idle or missing. Areas to check to isolate fuel control problems are as follows: Unmetered Air. Vacuum or intake air leaks in canister purge system, PCV, engine sealing or air leaks between airflow meter and throttle body. EGO Sensor Fuel Fouled. If fuel fouled spark plugs are observed, make complete check of ignition system. If EGO sensor is fuel fouled (low output and/or slow response), run vehicle at high (but legal) sustained speeds. Follow speed run with a few hard accelerations to burn off contamination and restore EGO sensor to correct operation. Fuel Pressure. Perform step 1) in this test. Ignition System. If always in default spark (10 degrees), perform Computed Ignition Timing Check. Improper Fueling. Lead fouled EGO sensor. TPS. If not moving, check for mechanical damage. Connect DVOM to test pins 47 and 46. Turn key ON, leaving engine OFF. Observe DVOM while moving throttle. Reading must increase with throttle opening. If not, replace TPS as required. If, at this point, drive problem is still present, perform steps 2) through 5) only.
23. Codes 43 & 93 Displayed. Run engine at 2000 RPM for 2 minutes. Turn key OFF and wait 10 seconds. Perform «KEY ON/ENGINE RUNNING SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-running-self-test) . If code 43, go to next step. If not, service other codes as necessary.
24. Codes 43 & 93 Displayed. Check exhaust leaks at manifold or inlet pipe. If there are leaks, service and repeat QUICK TEST. If no leaks, go to next step.
25. Codes 43 & 93 Displayed. Start engine and let idle. If engine idle quality is poor during and after Quick Test, adjust idle speeds. If not, replace EGO sensor and repeat QUICK TEST.

3.8L CFI Fuel Control Circuits. Scheme 119

TEST V - FUEL PUMP CIRCUIT (INERTIA SWITCH)

1. Key ON/Engine OFF Code 87 Displayed. Install fuel pressure gauge. Check if fuel pump runs. Cycle key from OFF to ON several times WITHOUT cranking engine. Pump should operate each time key ON occurs. If so, check fuel system for problems. If not, go to next step.
2. Turn key OFF and wait 10 seconds. Disconnect 60-pin connector at ECA and inspect. Install breakout box and reconnect ECA. Turn key ON, leaving engine OFF. Set DVOM to 20 volt scale. Measure voltage between test pins 37 and 40 and between test pins 57 and 60. If either is less than 10.5 volts, go to test B. If both are 10.5 volts or more, go to next step.
3. Turn key OFF and wait 10 seconds. Leave breakout box and ECA connected. Locate and disconnect fuel pump inertia switch. Set DVOM to 200 ohm scale and measure resistance of switch. If less than 5 ohms, go to next step. If 5 ohms or more, replace inertia switch and repeat QUICK TEST.
4. Turn key ON, leaving engine OFF. Leave breakout box and ECA connected. Set DVOM to 20 volt scale. Measure voltage between chassis ground and power-to-pump(s) circuit at fuel pump inertia switch while cranking engine. If 8 volts or more during cranking, go to next step. If less than 8 volts during cranking, go to step 6).
5. Turn key ON, leaving engine OFF. Leave breakout box and ECA connected. Set DVOM to 20 volt scale. Measure voltage between chassis ground and power-to-pump(s) circuit at fuel pump(s) while cranking. If 8 volts or more during cranking, service electric fuel pump(s). If less than 8 volts during cranking, repair open in power to pump(s) circuit and repeat QUICK TEST.
6. Turn key ON, leaving engine OFF. Leave breakout box and ECA connected. Locate fuel pump relay. Set DVOM to 20 volt scale. Measure voltage between chassis ground and vehicle battery circuit at relay. If 10.5 volts or more, go to next step. If less than 10.5 volts, repair open in VPWR power circuit (between fuel pump relay and positive battery post) and repeat QUICK TEST.
7. Turn key ON, leaving engine OFF. Leave breakout box and ECA connected. Locate fuel pump relay. Set DVOM to 20 volt scale. Measure voltage between chassis ground and vehicle power circuit at fuel pump relay. If 10.5 volts or more, go to next step. If less than 10.5 volts, repair open circuit (between fuel pump relay and ECA). Repeat QUICK TEST.
8. Turn key OFF and wait 10 seconds. Leave breakout box and ECA connected. Disconnect fuel pump relay. With DVOM on 200 ohm scale, measure resistance between fuel pump circuit at pump relay and test pin 22. If less than 5 ohms, go to next step. If 5 ohms or more, repair open in fuel pump circuit. Repeat QUICK TEST.
9. Turn key OFF. Leave breakout box installed and disconnect ECA. Disconnect fuel pump relay. With DVOM on 200,000 ohm scale, measure resistance between test pin 22 and test pins 40 and 60. If 10,000 ohms or more, go to next step. If less than 10,000 ohms, repair short in fuel pump circuit. Repeat QUICK TEST.
10. Turn key OFF and wait 10 seconds. Leave breakout box installed. Leave fuel pump relay and ECA disconnected. With DVOM on 200,000 ohm scale, measure resistance between test pin 22 and test pins 37 and 57. If 10,000 ohms or more, reconnect fuel pump relay and go to next step. If less than 10,000 ohms, repair short to power in fuel pump circuit. Reconnect ECA and attempt to start engine. If engine does not start, replace ECA. Repeat QUICK TEST.
11. Leave ECA disconnected. Connect jumper wire between test pin 22 and either test pin 40 or 60. With DVOM on 20 volt scale, turn key ON, leaving engine OFF. Turn key ON, leaving engine OFF. Measure voltage from chassis ground to power to pump(s) circuit at fuel pump relay. If 10.5 volts or more, replace ECA and repeat QUICK TEST. If less than 10.5 volts, replace fuel pump relay. Reconnect ECA and repeat QUICK TEST.

Fuel Pump (Inertia Switch) Circuits. Scheme 120

TEST W - EGR ON-OFF CHECK

Note. 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.

1. Code 34 Displayed. Use only VOM/DVOM, not STAR tester, for this step. Turn key OFF and wait 10 seconds. Place DVOM on 20 volt scale. Connect negative DVOM lead to STO and positive lead to positive battery terminal. Insert jumper wire between STI and signal return circuit to enter Output State mode. Perform Key ON/Engine OFF Self-Test until end of Continuous Test Code display. DVOM will read 0 volts. Depress and release throttle and observe DVOM reading. If DVOM did not show high voltage, depress throttle to WOT and release. If output voltage does not go to high reading, go to Circuit Test NN, step 13). If DVOM registered high reading, stay in Output State mode and go to next step of this test. Leave equipment connected.
2. Set DVOM to 20 volt scale. Connect DVOM positive lead to VPWR at EGR solenoid and negative lead to EGR output circuit. Depress and release throttle several times while observing DVOM. EGR output should cycle ON and OFF as throttle is operated. If so, go to next step. If not, remove signal return jumper wire and go to step 5) of this test.
3. Disconnect DVOM and leave jumper wire installed. 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 output while maintaining vacuum at supply port. Note vacuum gauge reading. If vacuum output cycles, go to next step. If vacuum output does not cycle, replace EGR solenoid and repeat QUICK TEST.
4. Remove jumper wire, vacuum gauge and vacuum pump. With vacuum lines disconnected at EGR solenoid, start engine. If vacuum is present, EEC-IV system is not cause of problem. Check EGR system. If vacuum is not present, correct vacuum source blockage or leak and repeat QUICK TEST.
5. Turn key OFF and wait 10 seconds. Leave EGR solenoid disconnected. Set DVOM on 200 ohm scale. Measure solenoid resistance. If resistance is less than 65 ohms or more than 110 ohms, replace solenoid and repeat QUICK TEST. If resistance is between 65-110 ohms, reconnect solenoid and go to next step.
6. Turn key ON, leaving engine OFF. Set DVOM to 20 volt scale. Measure voltage at EGR solenoid connector between VPWR and ground. If less than 10.5 volts, repair open in harness and repeat QUICK TEST. If 10.5 volts or higher, go to next step.
7. Turn key OFF and wait 10 seconds. Disconnect 60-pin ECA connector. Inspect for and repair any damaged wiring. Connect breakout box and leave ECA disconnected. Set DVOM to 200 ohm scale. Measure resistance between test pin 35 and EGR circuit at connector. If 5 ohms or higher, repair open circuit and repeat QUICK TEST. If less than 5 ohms, go to next step.
8. Turn key OFF and wait 10 seconds. Place DVOM on 200,000 ohm scale. Leave breakout box installed and ECA disconnected. Disconnect EGR solenoid. Measure resistance between test pin 35 and test pins 40, 46, and 60. If 10,000 ohms or more, go to next step. If less than 10,000 ohms, repair short to ground and repeat QUICK TEST.
9. Turn key OFF and wait 10 seconds. Leave breakout box installed with ECA and EGR solenoid disconnected. With DVOM on 200,000 ohm scale, measure resistance between test pin 35 and test pins 37 and 57. If less than 10,000 ohms, repair short to power and repeat QUICK TEST. If 10,000 ohms or more, replace ECA and repeat QUICK TEST.

EGR ON/OFF Circuits. Scheme 121

TEST X - AIR MANAGEMENT SYSTEM

1. Codes 44 (94), 45 (95) and 46 (96) Displayed. Ensure correct vacuum line routing to TAB/TAD solenoids and by-pass diverter valve. Refer to VECI decal for schematic. Check for kinked or blocked vacuum lines. Check for kinked or blocked air hoses. Check for disconnected vacuum lines. If problems are detected, correct hose routing, repair faults and repeat QUICK TEST. If hoses are good and code 44 (94) is displayed, go to step 4). If code 46 (96) is displayed, go to step 3). If code 45 (95) is displayed, go to next step.
2. Code 45 (95) Displayed. This test ONLY applies to models equipped with TAD. Disconnect and plug vacuum line at diverter valve. Turn key OFF and wait 10 seconds. Repeat «KEY ON/ENGINE RUNNING SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-running-self-test) and record codes. If code 45 (95) is displayed, EEC-IV system is good. Check diverter valve and/or check valve for problem. If no code 45 (95) is displayed, go to step 4).
3. Code 46 (96) Displayed. This test ONLY applies to models equipped with TAB. Disconnect and plug vacuum line at by-pass valve. Turn key OFF and wait 10 seconds. Repeat KOER Self-Test. Record codes. If code 46 (96) is displayed, EEC-IV system is good. Check by-pass valve for problem. If no code 46 (96) is displayed, go to next step.
4. Use only VOM/DVOM, not STAR tester, for this step. Turn key OFF and wait 10 seconds. With DVOM on 20 volt scale, connect negative test lead to STO and positive test lead to battery positive terminal. Using jumper wire, connect STI to signal return. Perform Key ON/Engine OFF Self-Test until completion of Continuous Test codes. DVOM will indicate 0 volts. Depress and release throttle, DVOM reading should change to a high voltage reading. If reading changed, remain in Output State mode and go to next step. If reading did not change, depress throttle to WOT and release. If STO voltage does not go high, go to Circuit Test NN, step 13). Leave test equipment hooked up.
5. With DVOM on 20 volt scale, connect DVOM positive test lead to VPWR circuit on TAB solenoid and negative test lead to TAB output circuit. While observing DVOM depress and release throttle several times to cycle output ON and OFF. Repeat for TAD solenoid. Connect positive test lead to VPWR circuit on TAD solenoid and negative test lead to TAD output circuit. Cycle output ON and OFF. If either output does not cycle ON and OFF, remove jumper and go to step 8). If both outputs cycle ON and OFF, go to next step.
6. Connect vacuum pump to TAB solenoid vacuum supply port. Connect vacuum gauge to output port. Maintain vacuum at source while depressing and releasing throttle to cycle output ON and OFF. Observe vacuum gauge. Repeat for TAD solenoid. If either solenoid does not cycle ON and OFF, replace solenoid assembly and repeat QUICK TEST. If both solenoids cycle ON and OFF, go to next step.
7. With vacuum lines disconnected at TAB/TAD solenoid assembly, start engine and check for vacuum. If vacuum is present, EEC-IV system is good. Check thermactor valve and air pump for problem. If no vacuum is present, repair blockage as required and repeat QUICK TEST.
8. Turn key OFF, wait 10 seconds and place DVOM on 200 ohm scale. Disconnect TAB and TAD solenoid connectors. Measure solenoid resistances. If either reading is less than 50 ohms or more 100 ohms, replace TAB/TAD solenoid assembly and repeat QUICK TEST. If both readings are between 50-100 ohms, connect TAB/TAD solenoids and go to next step.
9. Turn key ON, leaving engine OFF. Set DVOM on 20V scale. Measure voltage between VPWR circuit and ground on TAB connector. Repeat for TAD solenoid. If either voltage reading is less than 10.5 volts repair harness circuit open and repeat QUICK TEST. If both readings are greater than 10.5 volts, go to next step.
10. Turn key OFF and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Connect breakout box to harness and leave ECA disconnected. With DVOM on 200 ohm scale, measure resistance between test pin 51 and TAB circuit at harness connector. Measure resistance between pin 11 and TAD circuit at harness connector. If either reading is 5 ohms or greater, repair harness open circuit and repeat QUICK TEST. If both readings are less than 5 ohms, go to next step.
11. Turn key OFF and wait 10 seconds. Set DVOM on 200,000 ohm scale. Leave breakout box installed and ECA disconnected. Disconnect TAB/TAD solenoids and measure resistance between test pins 51 and/or 11 and test pins 37 and 57. If reading is less than 10,000 ohms, repair short to power and repeat QUICK TEST. If reading is greater than 10,000 ohms, go to next step.
12. Turn key OFF and wait 10 seconds. Set DVOM on 200,000 ohm scale. Leave breakout box installed and ECA disconnected. Disconnect TAB/TAD solenoids and measure resistance between test pins 51 and/or 11 and test pins 40, 46 and 60. If reading is less than 10,000 ohms, repair circuit short. Remove breakout box, reconnect harness to ECA and repeat QUICK TEST. If code is repeated, replace ECA. If reading is 10,000 ohms or more, replace ECA. Remove breakout box, connect harness to ECA and repeat QUICK TEST.

Air Management Circuit. Scheme 122

TEST Y - CANISTER PURGE (CANP) CHECK

1. Code 85 Displayed. Use only VOM or DVOM, not STAR tester, on this step. Turn key OFF and wait 10 seconds. Set DVOM to 20 volt scale. Connect DVOM negative test lead to STO and positive test lead to positive battery terminal. Jump STI to signal return. Run «KEY ON/ENGINE OFF SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-off-self-test) until end of Continuous Codes. DVOM should indicate zero volts. Depress and release throttle. If high reading is not obtained, depress throttle to WOT and release. If STO voltage does not go high, go to «TEST NN»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-nn-no-codescodes-codes) , step 13). If voltage does go high, go to next step, leaving equipment connected.
2. Set DVOM to 20 volt scale. Connect DVOM positive test lead to VPWR on CANP solenoid and negative test lead to CANP output circuit. Depress and release throttle several times. If CANP output does not cycle, remove jumper wire from signal return and go to step 4) of this test. If output does cycle, go to next step.
3. Turn key OFF and wait 10 seconds. Disconnect vacuum hose from CANP solenoid on PCV side. Apply 16 in. Hg vacuum to solenoid. If CANP solenoid does not hold vacuum, replace it and repeat QUICK TEST. If vacuum holds, EEC-IV is good. Check fuel system.
4. Turn key OFF and wait 10 seconds. Set DVOM to 200 ohm scale. Disconnect CANP solenoid connector. Measure resistance of solenoid. If reading is below 40 ohms or above 90 ohms, replace CANP solenoid and repeat QUICK TEST. If reading is between 40-90 ohms, reconnect solenoid and go to next step.
5. Turn key ON, leaving engine OFF. Set DVOM to 20 volt scale. Measure voltage at connector between VPWR and ground. If reading is less than 10.5 volts, repair open circuit and repeat QUICK TEST. If reading is 10.5 volts or more, go to next step.
6. Turn key OFF and wait 10 seconds. Disconnect 60-pin ECA connector. Inspect for and repair any damaged wiring. Connect breakout box, leaving ECA disconnected. Set DVOM to 200 ohm scale. Measure resistance between test pin 35 (test pin 32 on all 1.6L engines) and CANP signal at connector. If reading is 5 ohms or more, repair open circuit and repeat QUICK TEST. If reading is less than 5 ohms, go to next step.
7. Turn key OFF and wait 10 seconds. Leave breakout box connected and ECA disconnected. Disconnect CANP solenoid. Set DVOM to 200,000 ohm scale. Measure resistance between test pin 35 (test pin 32 on all 1.6L engines) and test pins 40, 46, and 60. If reading is less than 10,000 ohms, repair short to power and repeat QUICK TEST. If reading is 10,000 ohms or greater, go to next step.
8. Turn key OFF and wait 10 seconds. Leave breakout box installed and both ECA and CANP solenoid disconnected. Measure resistance between test pin 35 (test pin 32 on all 1.6L engines) and test pins 37 and 57. If reading is less than 10,000 ohms, repair short to ground and repeat QUICK TEST. If code is repeated, replace ECA and repeat QUICK TEST. If reading is 10,000 ohms or more, remove breakout box. Replace ECA and repeat QUICK TEST.

Canister Purge (CANP) Circuit. Scheme 123

TEST Z - IDLE SPEED CONTROL (BY-PASS AIR)

Note. If engine is running rough or has rough idle, correct before running test. Causes may be in ignition system, fuel system or EGR system.

1. Code 12 Displayed. Turn key OFF. Disconnect Idle Speed Control (ISC) harness. With DVOM on 200 ohm scale, measure resistance of ISC solenoid. If resistance is between 7-13 ohms, go to next step. If resistance less than 7 ohms or more than 13 ohms, replace ISC solenoid and repeat QUICK TEST.
2. Turn key OFF. Leave ISC harness disconnected. With DVOM on 200,000 ohm scale, check for short from either ISC pin to ISC housing. If more than 10,000 ohms, go to next step. If less than 10,000 ohms, replace ISC solenoid and repeat QUICK TEST.
3. Leave ISC harness disconnected. Turn key ON, leaving engine OFF. Place DVOM on 20 volt scale. Connect positive lead of DVOM to vehicle power circuit of ISC harness and negative lead to ground. If 10.5 volts or more, go to next step. If less than 10.5 volts, repair open in circuit and repeat QUICK TEST.
4. Turn key OFF. Leave ISC harness disconnected. Disconnect 60-pin connector at ECA. Inspect for and repair any damaged wiring. Connect breakout box and leave ECA disconnected. With DVOM on 200 ohm scale measure resistance of ISC harness from ISC circuit to test pin 21. If less than 5 ohms, go to next step. If 5 ohms or more, repair open circuit and repeat QUICK TEST.
5. With same connections as in step 4), turn key OFF and wait 10 seconds. Place DVOM on 200,000 ohm scale. Measure resistance between test pin 21 and test pins 40, 46, and 60. If 10,000 ohms or more, go to next step. If less than 10,000 ohms, repair short to ground and repeat QUICK TEST.
6. Turn key OFF and wait 10 seconds. Leave breakout box installed. Leave ECA and ISC solenoid disconnected. With DVOM on 200,000 ohm scale, measure resistance between test pin 21 and test pin 37. If less than 10,000 ohms, repair short to power and repeat QUICK TEST. If 10,000 ohms or more, go to next step.
7. With key OFF, reconnect ECA and ISC; leave breakout box installed. With vehicle prepared for Quick Test, place DVOM on 20 volt scale. Connect DVOM between test pins 21 and 40. Start engine and observe DVOM. If meter reading varies during Quick Test, replace ISC actuator and repeat QUICK TEST. If meter reading does not vary, disconnect ECA. Inspect for and repair any damaged wiring. If wiring is good, replace ECA and repeat QUICK TEST.
8. Code 13 Displayed. Disconnect ISC harness. Connect tachometer and repeat «KEY ON/ENGINE RUNNING SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-running-self-test) . At end of test, record service codes for future use. If engine speed remains below 1500 RPM during test, replace ECA and repeat QUICK TEST. If engine speed does not remain below 1500 RPM, check engine vacuum hoses for proper connections and routing. Ensure throttle plate is fully closed and throttle linkage is not binding. If no mechanical problems appear, replace ISC actuator. Repeat QUICK TEST.

ISC (BY-PASS AIR) Circuits. Scheme 124

TEST AA - IDLE SPEED CONTROL (DC MOTOR/IDLE TRACKING SWITCH (ITS) ASSEMBLY)

1. Key ON/Engine OFF (KOEO) Code 68 Displayed. Turn key OFF and wait 10 seconds. Move throttle away from Idle Speed Control (ISC) motor shaft to simulate NO throttle contact. Repeat «KEY ON/ENGINE OFF SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-off-self-test) and note codes. If code 68 is displayed, go to step 3). If code 68 is not displayed, go to next step. Ignore all other codes at this time.
2. Turn key OFF and wait 10 seconds. Install breakout box, leaving ECA disconnected. Connect jumper wire between test pins 41 and 1 and between test pin 21 and ground. If ISC DC motor retracts, check ISC mechanical adjustments. If motor does not retract, go to step 5).
3. Turn key OFF and wait 10 seconds. Disconnect harness at ISC motor. Connect jumper between connector pins 3 and 4 to simulate closed contact condition. Perform «KEY ON/ENGINE OFF SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-off-self-test) . If code 68 is not displayed, replace ISC DC motor and repeat QUICK TEST. If code 68 is displayed, go to next step.
4. Turn key OFF and wait 10 seconds. Disconnect 60-pin ECA connector. Inspect for and repair any damaged wiring. Connect breakout box and leave ECA disconnected. With harness disconnected at ISC, place DVOM on 200,000 ohm scale. Measure resistance between test pin 28 and idle tracking switch (ITS) circuit at ISC connector. Also measure resistance between test pin 46 and signal return at ISC connector. If either reading is 5 ohms or more, repair circuit. Repeat QUICK TEST. If both readings are less than 5 ohms, replace ECA. Repeat QUICK TEST.
5. Turn key OFF and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Connect breakout box, leaving ECA disconnected. Disconnect ISC motor harness and set DVOM to 200 ohm scale. Measure resistance between test pin 41 and ISC ground circuit and between test pin 21 and ISC power circuit at ISC connector. If either reading is 5 ohms or more, repair wiring and repeat QUICK TEST. If both readings are less than 5 ohms, go to next step.
6. Turn key ON, leaving engine OFF. Leave breakout box connected and ECA disconnected. Leave harness disconnected from ISC motor and set DVOM to 20 volt scale. Measure voltage between test pin 41 and test pins 40 and 60. Also measurevoltage between test pin 21 and test pins 40 and 60. If any reading is 1 volt or more, repair short to power. Repeat QUICK TEST. If code 12 is still displayed, replace ECA and repeat QUICK TEST. If all readings are less than 1 volt, go to next step.
7. Turn key OFF and wait 10 seconds. Leave breakout box installed with ECA and ISC motor disconnected. Set DVOM to 200,000 ohm scale. Measure resistance between test pin 41 and test pins 40, 46 and 60. Also measure resistance between test pin 21 and test pins 40, 46, and 60. If any reading is 10,000 ohms or less, repair bad circuit. Repeat QUICK TEST. If code 12 is still displayed, replace ECA and repeat QUICK TEST. If all readings are more than 10,000 ohms, go to next step.
8. Turn key OFF and wait 10 seconds. Set DVOM to 20 volt scale, leaving breakout box installed with ECA and ISC motor disconnected. Connect positive test lead to test pin 1 and negative test lead to ground. If reading is less than 10.5 volts, repair open in KAPWR circuit. Repeat QUICK TEST. If code 12 is still displayed, go to next step. If reading is 10.5 volts or more, go to next step.
9. Turn key OFF and wait 10 seconds. Leave breakout box installed and ECA disconnected. Connect ISC motor. Jump wire test pin 21 to test pin 1 and test pin 41 to ground. If DC motor shaft does not extend 2 in. (5 cm.) or more, replace DC motor. Repeat QUICK TEST. If motor shaft does extend far enough, go to next step.
10. Turn key OFF and wait 10 seconds. Leave breakout box installed and ECA disconnected. Jump wire test pin 41 to test pin 1 and test pin 21 to ground. If shaft does not retract, replace motor. Repeat QUICK TEST. If shaft does retract, go to next step.
11. Turn key OFF and wait 10 seconds. Leave breakout box installed and ECA disconnected. Jump wire test pin 21 to test pin 1 and test pin 41 to ground. If shaft does not extend, replace motor and repeat QUICK TEST. If shaft does extend, replace ECA and repeat QUICK TEST.
12. Code 58 Displayed. Turn key OFF and wait 10 seconds. Press on ISC motor shaft to simulate throttle contact. Run Key ON/Engine OFF Self-Test while maintaining pressure on shaft. If code 68 is displayed, go to step 5). If code 68 is not displayed, go to next step. Ignore all other codes at this time.
13. Turn key OFF and wait 10 seconds. Leave breakout box connected and ECA disconnected. Jump wire test pin 41 to test pin 1 and test pin 21 to ground. If motor shaft retracts, check ISC motor adjustments. If shaft does not retract, go to next step.
14. Turn key OFF and wait 10 seconds. Disconnect harness from ISC. Run Key ON/Engine OFF Self-Test. If code 68 is displayed, replace DC motor and repeat QUICK TEST. If code 68 is not displayed, go to next step. Ignore all other codes during this step.
15. Turn key OFF and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Connect breakout box, leaving ECA disconnected. Disconnect ISC and set DVOM to 200,000 ohm scale. Measure resistance between test pin 28 and test pins 40, 46, and 60. If any reading is less than 10,000 ohms, repair short to ground. Repeat QUICK TEST. If all readings are 10,000 ohms or more, replace ECA. Repeat QUICK TEST.
16. Code 12 Displayed. If codes 58, 68, 31, or 41 are also displayed, go to «KEY ON/ENGINE RUNNING SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-running-self-test) results for correct test. If these codes are not displayed, go to next step.
17. Check throttle plates and linkages for binding. If vehicle has speed control, make sure that no binding occurs in speed control linkage. If mechanical repair is made, repeat QUICK TEST. If no problem is found with linkages or throttle plates, go to next step.
18. Turn key OFF and wait 10 seconds. Leave breakout box installed and ECA disconnected. Jump wire test pin 21 to test pin 1 and test pin 41 to ground. If motor shaft does not extend, replace DC motor and repeat QUICK TEST. If shaft does extend, replace ECA and repeat QUICK TEST.
19. Code 13 Displayed. This code is displayed if engine is not returning to proper idle RPM. Prepare vehicle for normal operation. Turn A/C OFF and deactivate Self-Test mode. Start and run engine. Run at idle for 30 seconds, then partial throttle for 5 seconds, then return to idle for 30 seconds. Repeat this sequence for 3 minutes. If idle speed is erratic, check for: vacuum leaks or any of codes 22, 31, 41, or 58 being displayed. Repair codes or leaks before proceeding. If idle speed is not erratic, go to next step.
20. Check throttle plate linkages for sticking or binding. Check choke for sticking or binding. Make sure throttle does not hang on high cam step. If any fault is found, repair and repeat QUICK TEST. If no fault is found, go to next step.
21. Run «KEY ON/ENGINE OFF SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-off-self-test) and record On Demand codes. If code 68 is displayed, go to step 1) of this test. If code 68 is not displayed, check anti-diesel speed adjustments.

DC Motor/Idle Tracking Switch Circuit. Scheme 125

TEST BB - IDLE SPEED CONTROL (THROTTLE KICKER)

1. Check vacuum line routing to throttle kicker (TK) solenoid. Refer to VECI decal. Check for kinked or blocked vacuum lines. Check for kinked or blocked air hoses. Check for disconnected vacuum lines. If problems are detected, correct routing or faults and repeat QUICK TEST. If items are okay, repair code 12 and go to next step.
2. Apply 20 in. Hg. vacuum to TK solenoid. If vacuum does not hold, replace solenoid and repeat QUICK TEST. If vacuum holds, go to next step.
3. While applying 20 in. Hg vacuum to TK solenoid, repeat «KEY ON/ENGINE RUNNING SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-running-self-test) . If code 12 is displayed, EEC-IV system is good. Check idle adjustment. If no code 12 is displayed, go to next step.
4. Use only VOM/DVOM, not STAR tester, for this step. Turn key OFF, wait 10 seconds and place DVOM on 20 volt scale. Connect DVOM negative test lead to STO and positive test lead to battery positive terminal. Using jumper wire, connect STI to signal return. Perform «KEY ON/ENGINE OFF SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-off-self-test) until end of Continuous Test codes. DVOM will read 0 volts. Depress and release throttle while observing DVOM reading. DVOM reading should change to a high reading. If DVOM did not register a high reading, depress throttle to WOT and release. If STO voltage does not go high, go to «TEST NN»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-nn-no-codescodes-codes) , step 13). Leave test equipment hooked up. If DVOM reading was high, stay in Output State mode and go to next step.
5. With DVOM on 20 volt scale, connect positive test lead to VPWR on solenoid and negative test lead to TK output circuit on solenoid. While observing DVOM, depress and release throttle several times to cycle output ON and OFF. If output does not cycle ON and OFF, go to step 8). If output cycles ON and OFF, go to next step.
6. Connect vacuum pump to TK solenoid vacuum supply port and connect vacuum gauge to output port. While depressing and releasing throttle, to cycle output ON and OFF, apply and maintain minimum of 6 in. Hg vacuum to solenoid. Observe vacuum gauge. If vacuum output does not cycle ON and OFF, replace throttle kicker solenoid and repeat QUICK TEST. If output cycles ON and OFF, go to next step.
7. Disconnect vacuum lines at TK solenoid and start engine. If vacuum is present, EEC-IV system is good. Check idle adjustment. If no vacuum is present, repair cause of vacuum loss and repeat QUICK TEST.
8. Turn key Off, wait 10 seconds and place DVOM on 200 ohm scale. Disconnect TK solenoid connector and measure solenoid resistance. If resistance is less than 50 ohms or more than 100 ohms, replace TK solenoid and repeat QUICK TEST. If resistance is between 50-100 ohms, connect TK solenoid and go to next step.
9. Turn key ON, leaving engine OFF. Place DVOM on 20 volt scale. Measure voltage between VPWR and ground at TK solenoid harness connector. If voltage reading is less than 10.5 volts, repair open circuit and repeat QUICK TEST. If voltage reading is 10.5 volts or greater, go to next step.
10. Turn key OFF and wait 10 seconds. Disconnect 60-pin connectors at ECA. Inspect for and repair any damaged wiring. Connect breakout box to harness and leave ECA disconnected. With DVOM on 200 ohm scale, measure resistance between test pin 53 and TK circuit at harness connector. If reading is 5 ohms or more, repair open circuit and repeat QUICK TEST. If reading is less than 5 ohms, go to next step.
11. Turn key OFF and wait 10 seconds. Leave breakout box installed and ECA disconnected. Disconnect TK solenoid. Place DVOM on 200,000 ohm scale, and measure resistance between test pin 53 and test pins 40, 46, and 60. If reading is less than 10,000 ohms, repair short to ground and repeat QUICK TEST. If reading is 10,000 ohms or more, go to next step.
12. Turn key OFF and wait 10 seconds. Leave breakout box installed with ECA and TK solenoid disconnected. With DVOM on 200,000 ohm scale, measure resistance between test pin 53 and test pins 37 and 57. If reading is 10,000 ohms or more, replace ECA. Remove breakout box, connect harness to ECA and repeat QUICK TEST. If reading is less than 10,000 ohms, repair short to power and repeat QUICK TEST. If code is repeated, replace ECA.

Idle Speed Control (Throttle Kicker) Circuit. Scheme 126

TEST CC - INLET AIR SOLENOID (IAS)

1. Locate and disconnect Air Charge Temperature (ACT) sensor. Start vehicle. If inlet air door on air cleaner closes, IAS is functioning correctly. Check non-EEC related areas. If inlet air door does not close, go to next step.
2. With key off, disconnect both vacuum hoses from IAS. Connect both vacuum hoses and start vehicle. If inlet air door closes, connect vacuum hose at source and go to step 4). If inlet air door does not close, go to next step.
3. Turn key off. Connect vacuum pump to inlet air valve vacuum hose and apply vacuum. If inlet air door closes, verify proper vacuum source. If inlet air door does not close, check inlet air duct and valve assembly.
4. Turn key off and wait 10 seconds. Disconnect IAS solenoid connector. With DVOM on 200-ohm scale, measure IAS solenoid resistance. If reading is less than 65 ohms or higher than 110 ohms, replace IAS solenoid and repeat QUICK TEST. If reading is between 65 and 110 ohms, connect IAS solenoid and go to next step.
5. Turn key on, leaving engine off. With DVOM on 20-volt scale, measure voltage between VPWR circuit at IAS solenoid and ground. If voltage reading is less than 10.5-volts, repair open circuit in harness and repeat QUICK TEST. If voltage reading is 10.5 volts or higher, go to next step.
6. 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. Measure resistance between test pin 59 and IAS circuit at harness connector. If reading is 5 ohms or higher, repair open circuit and repeat QUICK TEST. If reading is less than 5 ohms, go to next step.
7. Turn key off and wait 10 seconds. Leave breakout box installed and ECA disconnected. Disconnect IAS solenoid. Set DVOM on 200,000-ohm scale. Measure resistance between test pin 59 and test pins 40, 46, and 60. If any reading is less than 10,000 ohms, repair short to ground and repeat QUICK TEST. If all readings are 10,000 ohms or higher, go to next step.
8. Turn key off and wait 10 seconds. Leave breakout box installed and ECA and IAS solenoid disconnected. Set DVOM on 200,000-ohm scale. Measure resistance between test pin 59 and test pins 37 and 57. If any reading is less than 10,000 ohms, repair short to power and repeat QUICK TEST. If all readings are 10,000 ohms or higher, go to next step.
9. Turn key off. Connect IAS solenoid. Leave breakout box installed and ECA disconnected. Install a jumper wire between test pin 59 and 40. Start engine. If inlet air door closes, replace ECA. If inlet air door does not close, replace IAS solenoid.

Inlet Air Solenoid (IAS) Circuit. Scheme 127

TEST DD - VARIABLE VOLTAGE CHOKE (VVC)

1. Use only VOM/DVOM 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 SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-off-self-test) until end of CONTINUOUS SELF-TEST codes (DVOM reads zero volts). 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 «TEST NN»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-nn-no-codescodes-codes) , step 13). Leave test equipment hooked up.
2. Turn key on, leave engine Off. Set DVOM on 20-volt scale. Connect DVOM positive lead to choke circuit on choke cap and negative lead to ground. While observing DVOM, depress and release throttle several times to cycle choke output on and off. If output cycles, repair choke assembly. If choke output does not cycle, remove jumper wire and go to next step.
3. Turn key off and wait 10 seconds. With DVOM on 200-ohm scale, measure resistance between battery negative terminal and pin 1 at VVC relay harness connector. If reading is 5 ohms or higher, repair harness circuit and repeat QUICK TEST. If reading is less than 5 ohms, go to next step.
4. Turn key off and wait 10 seconds. Disconnect VCC relay. With DVOM on 200-ohm scale, measure resistance between pin 3 of VVC relay connector and choke connector at choke cap. If reading is higher than 5 ohms, service open in choke circuit. If reading is not higher than 5 ohms, go to next step.
5. Turn key on, leaving engine off. Leave VCC relay disconnected. With DVOM on 20-volt scale, measure voltage between pin 1 and 5, and between pin 1 and 4 of VVC relay harness connector. If reading is less than 10.5-volts, repair open in choke power circuit and repeat QUICK TEST. If reading is 10.5-volts or higher, replace choke relay.
6. Turn key off. Leave VCC relay disconnected. With DVOM on 200,000-ohm scale, measure resistance at VVC relay between pin 2 and 4. If reading is not 1600 to 2000 ohms, replace choke relay. If reading is 1600 to 2000 ohms, go to next step.
7. Turn key off. Leave VVC relay disconnected. Turn key on, leaving engine off. With DVOM on 20-volt scale, measure voltage between pin 4 at VVC relay connector and engine block ground. If reading is not higher than 10-volts, repair VPWR circuit and repeat QUICK TEST. If reading is higher than 10-volts, go to next step.
8. 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 VVC relay disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pin 55 and VVC circuit at relay harness connector. If reading is 5 ohms or higher, repair circuit and repeat QUICK TEST. If reading is less than 5 ohms, go to next step.
9. Turn key off and wait 10 seconds. Leave breakout box installed and ECA and VVC relay disconnected. Set DVOM on 200,000-ohm scale. Measure resistance between test pin 55 and test pins 40, 46, and 50. If any reading is less than 10,000 ohms, repair short(s) in harness and repeat QUICK TEST. If all readings are 10,000 ohms or higher, go to next step.
10. Turn key off and wait 10 seconds. Leave breakout box installed and ECA and VVC relay disconnected. Set DVOM on 200,000-ohm scale. Measure resistance between test pin 55 and test pins 1, 37, and 57. If all readings are 10,000 ohms or higher, replace ECA and repeat QUICK TEST. If any reading is less than 10,000 ohms, repair short to power and repeat QUICK TEST. If code is repeated, replace ECA.

Variable Voltage Choke (VVC) Circuits. Scheme 128

TEST EE - TEMPERATURE COMPENSATED PUMP (TCP)

1. Use only VOM/DVOM, not STAR 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 SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-off-self-test) until end of CONTINUOUS SELF-TEST codes (DVOM reads zero volts). 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 «TEST NN»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-nn-no-codescodes-codes) , step 13). Leave test equipment hooked up. If reading changes to high voltage, remain in OUTPUT STATE CHECK and go to next step.
2. With DVOM set on 20-volt scale, connect DVOM positive lead to VPWR circuit on TCP solenoid and negative test lead to TCP circuit at solenoid. Depress and release throttle several times to cycle TCP on and off. If TCP does not cycle, remove jumper wire from STI and go to step 5). If TCP cycles, go to next step.
3. Install vacuum pump to TCP solenoid vacuum supply port and vacuum gauge to output port. Apply a minimum of 6 in. Hg. With vacuum applied, cycle TCP on and off by depressing and releasing throttle while observing vacuum gauge. If vacuum output does not cycle, replace TCP solenoid and repeat QUICK TEST. If vacuum output cycles, go to next step.
4. With vacuum lines disconnected at TCP solenoid, start engine and check for vacuum. If vacuum is present, EEC-IV system is okay. Check TCP solenoid. If no vacuum is present, remove vacuum source blockage or repair vacuum leak and repeat QUICK TEST.
5. Turn key off and wait 10 seconds. Set DVOM on 200-ohm scale. Disconnect TCP solenoid connector and measure solenoid resistance. If reading is less than 50 ohms or higher than 100 ohms, replace TCP solenoid and repeat QUICK TEST. If reading is between 50 and 100 ohms, connect TCP solenoid and go to next step.
6. Turn key on, leave engine off. With DVOM on 20-volt scale, measure voltage at TCP solenoid harness connector between VPWR circuit and ground. If reading is 10.5-volts or less, repair open circuit in harness and repeat QUICK TEST. If reading is 10.5-volts or higher, go to next step.
7. 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. Measure resistance between test pin 54 and TCP circuit at harness connector. If reading is 5 ohms or higher, repair open circuit in harness. Repeat QUICK TEST. If reading is less than 5 ohms, go to next step.
8. Turn key off and wait 10 seconds. Leave breakout box installed and ECA disconnected. Disconnect TCP solenoid. Set DVOM on 200,000-ohm scale. Measure resistance between test pin 54 and test pins 40, 46, and 60. If any reading is less than 10,000 ohms, repair short to ground and repeat QUICK TEST. If all readings are 10,000 ohms or more, go to next step.
9. Turn key off and wait 10 seconds. Leave breakout box installed and ECA and TCP solenoid disconnected. Set DVOM on 200,000-ohm scale. Measure resistance between test pin 54 and test pins 37 and 57. If all readings are 10,000 ohms or higher, replace ECA and repeat QUICK TEST. If any reading is less than 10,000 ohms, repair short to power and repeat QUICK TEST. If code is repeated, replace ECA.

Temperature Compensated Pump (TCP) Circuit. Scheme 129

TEST FF - SHIFT INDICATOR LIGHT (SIL)

1. Use only VOM/DVOM, not STAR tester, for this step. Turn key off and wait 10 seconds. Put transmission in Neutral. 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 SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-off-self-test) until end of CONTINUOUS SELF-TEST codes (DVOM reads zero volts). 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 step 7). Leave test equipment hooked up. If reading changes to high voltage, remain in OUTPUT STATE CHECK and go to next step.
2. Set DVOM on 20-volt scale. Connect DVOM positive test lead to battery positive terminal and negative test lead to pin 1 on dimmer relay. Depress and release throttle several times to cycle relay on and off. If relay does not cycle, go to step 5). If relay cycles, go to next step.
3. Set DVOM on 20-volt scale. Connect DVOM positive test lead to battery positive terminal and negative test lead to pin 2 on dimmer relay. Depress and release throttle several times to cycle relay on and off. If relay does not cycle, remove jumper wire and replace dimmer relay. If relay does cycle, remove jumper wire and go to next step.
4. Turn key off and wait 10 seconds. With DVOM set to 200-ohm scale, measure resistance between pin 2 of dimmer relay and SIL bulb. If reading is less than 5 ohms, replace SIL bulb. If reading is 5 ohms or more, repair open circuit in harness. Repeat QUICK TEST.
5. Set DVOM on 20-volt scale. Connect DVOM positive test lead to battery positive terminal and negative test lead to SIL circuit of top gear switch. Depress and release throttle several times to cycle SIL circuit on and off. If SIL circuit cycles, repair open circuit in harness and repeat QUICK TEST. If SIL circuit does not cycle, go to next step.
6. Set DVOM on 20 volt scale. Connect DVOM positive test lead to positive battery terminal and negative test lead to STO circuit of top gear switch. Depress and release throttle several times to cycle STO circuit on and off. If STO circuit cycles, replace top gear switch. If STO does not cycle, repair open circuit in harness and repeat QUICK TEST.
7. Use only VOM/DVOM, not STAR tester, for this step. Turn key off and wait 10 seconds. Put transmission in top gear. 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 SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-off-self-test) until end of CONTINUOUS SELF-TEST codes (DVOM reads zero volts). Depress and release throttle while watching DVOM reading. If reading changed to high voltage, check SIL bulb and fuse No. 15. If bulb and fuse are good, repair short to ground in SIL circuit. If reading did not change to high voltage, go to CIRCUIT TEST NN, step 13).

All Other Shift Indicator Light (SIL) Circuits. Scheme 130

Scheme 131

1. Use only VOM/DVOM, not STAR 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. Jump STI to signal return. Run key ON/Engine OFF Self-Test until completion of Continuous Codes. DVOM should read zero volts. Depress and release throttle. If reading did not change to high voltage, depress throttle to WOT and release. If reading still does not go to high voltage, go to «TEST NN»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-nn-no-codescodes-codes), step 13). If voltage goes high, remain in Output State mode and go to next step.
2. Turn key on, leaving engine off. Disconnect ECA 60-pin connector. Inspect for and repair any damaged wiring. Install breakout box and connect ECA to box. Place A/C switch on A/C position and set DVOM on 20-volt scale. Connect DVOM positive test lead to test pin 37 and negative test lead to test pin 54. Depress and release throttle several times while watching DVOM. If A/C clutch output cycles, EEC-IV system is okay. Check A/C system operation. If A/C clutch output does not cycle, remove jumper wire and go to next step.
3. On vehicles using A/C Fan/Control Module (1.6L EFI/Turbo), go to next step. On vehicles using WAC relay (all other models), go to step 9).
4. Turn key off and wait 10 seconds. Set DVOM on 200-ohm scale. Measure resistance between fan control module connector and battery ground. If reading is 5 ohms or more, repair harness and repeat QUICK TEST. If reading is less than 5 ohms, go to next step.
5. Turn key on, leave engine off. Set DVOM on 20-volt scale. Measure voltage between ignition circuit and ground circuit on fan control module connector. If reading is less than 10.5-volts, repair open in ignition circuit and repeat QUICK TEST. If reading is 10.5 volts or more, go to next step.
6. 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. Measure resistance between test pin 54 (test pin 53 on 2.3L engines) and WAC circuit at fan control module connector. If reading is 5 ohms or more, repair WAC circuit and repeat QUICK TEST. If reading is less than 5 ohms, go to next step.
7. Turn key off and wait 10 seconds. Leave breakout box installed and ECA disconnected. Set DVOM on 200,000-ohm scale. Measure resistance between test pin 54 (test pin 53 on 2.3L engines) and test pins 40, 46, and 60. If reading is 10,000 ohms or more, replace ECA and repeat QUICK TEST. If reading is less than 10,000 ohms, go to next step.
8. Turn key off and wait 10 seconds. Leave breakout box installed and ECA disconnected. Disconnect fan control module. Set DVOM on 200,000-ohm scale. Measure resistance between test pin 54 (test pin 53 on 2.3L engines) and test pins 40, 46, and 60. If all readings are 10,000 ohms or more, replace fan control module and repeat QUICK TEST. If any reading is less than 10,000 ohms, repair short in harness and repeat QUICK TEST. (Scheme 131): WOT A/C Cutout Circuits
9. Turn key off and wait 10 seconds. Set DVOM on 200-ohm scale. Disconnect WAC relay and measure relay resistance. If reading is less than 50 ohms or more than 70 ohms, replace WAC relay and repeat QUICK TEST. If reading is between 50 and 70 ohms, connect WAC relay and go to next step.
10. Turn key on, leaving engine off. Set DVOM on 20-volt scale. Connect DVOM positive test lead to VPWR circuit and negative test lead to ground. Measure VPWR voltage at WAC relay. If reading is less than 10.5-volts, repair open in harness and repeat QUICK TEST. If reading is 10.5-volts or more, go to next step.
11. 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. Measure resistance between test pin 54 and WAC circuit at relay connector. If reading is 5 ohms or more, repair open in harness and repeat QUICK TEST. If reading is less than 5 ohms, go to next step.
12. Turn key off and wait 10 seconds. Leave breakout box installed and ECA disconnected. Set DVOM on 200,000-ohm scale. Measure resistance between test pin 54 and test pins 40, 46, and 60. If any reading is less than 10,000 ohms, repair short to ground and repeat QUICK TEST. If all readings are 10,000 ohms or more, go to next step.
13. Turn key off and wait 10 seconds. Leave breakout box installed, ECA disconnected, and DVOM on 200,000-ohm scale. Disconnect WAC solenoid. Measure resistance between test pin 54 and test pins 37 and 57. If reading is 10,000 ohms or more, replace ECA and repeat QUICK TEST. If reading is less than 10,000 ohms, repair short to power and repeat QUICK TEST.
14. 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. Measure voltage between test pin 10 and 40. If reading fluctuates from 4.0 to 10.5 volts as A/C switch is cycled, replace ECA and repeat QUICK TEST. If reading does not fluctuate, go to next step.
15. Turn key off and wait 10 seconds. Set DVOM on 200-ohm scale. Measure resistance between ACC test pin 10 and A/C clutch. If reading is 5 ohms or more, repair harness and repeat QUICK TEST. If reading is less than 5 ohms, EEC-IV is okay. Check A/C system.

TEST II - EXHAUST HEAT CONTROL (EHC)

1. Use only VOM/DVOM, not STAR tester, for this step. Turn key OFF and wait 10 seconds. Set DVOM to 20 volt scale. Connect negative lead of DVOM to STO and positive lead to positive battery terminal. Jumper STI to signal return. Run «KEY ON/ENGINE OFF SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-off-self-test) until end of continuous codes. DVOM should read 0 volts. Depress and release throttle while watching DVOM reading. If reading changes to high voltage, remain in Output State check and go to next step. 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 NN, step 13). Leave equipment hooked up.
2. Set DVOM set to 20 volt scale. Measure voltage between VPWR and EHC circuit at EHC solenoid. While observing DVOM, depress and release throttle several times to cycle EHC output ON and OFF. If DVOM reading shows EHC output cycling, go to next step. If EHC output does not show cycling on DVOM, remove jumper wire and go to step 5).
3. Install vacuum pump to exhaust heat solenoid vacuum supply port and install vacuum gauge to output port. Apply 6 in. Hg, minimum. With vacuum applied, observe vacuum gauge while cycling outputs ON and OFF by depressing and releasing throttle. If vacuum output cycles ON and OFF, go to next step. If vacuum output does not cycle ON and OFF, replace solenoid and repeat QUICK TEST.
4. With vacuum lines disconnected at EHC solenoid, start engine and check for vacuum. If vacuum is present, EEC-IV system is good, check EHC. If no vacuum is present, remove vacuum source blockage or repair vacuum leak and repeat QUICK TEST.
5. Turn key OFF and wait 10 seconds. Set DVOM to 200 ohm scale. Disconnect EHC solenoid connector and measure solenoid resistance. If resistance is between 50-100 ohms, connect EHC solenoid and go to next step. If resistance is less than 50 ohms or greater than 100 ohms, replace HEC solenoid and repeat QUICK TEST.
6. Turn key ON, leaving engine OFF. With DVOM on 20 volt scale, measure voltage at EHC solenoid harness connector between VPWR circuit and ground. If voltage reading is 10.5 volts or less, repair open circuit in harness and repeat QUICK TEST. If voltage reading is 10.5 volts or greater, go to next step.
7. Turn key OFF and wait 10 seconds. Disconnect 60-pin ECA connector. Inspect for and repair any damaged wiring. Connect breakout box, leaving ECA disconnected. Set DVOM to 200 ohm scale. Measure resistance between test pin 55 and EHC circuit at harness connector. If resistance reading is 5 ohms or greater, repair open circuit in harness and repeat QUICK TEST. If resistance reading is less than 5 ohms, go to next step.
8. Turn key OFF and wait 10 seconds. Leave breakout box connected and ECA disconnected. Disconnect EHC solenoid. Set DVOM to 200,000 ohm scale. Measure resistance between test pin 55 and test pins 40, 46, and 60. If resistance is less than 10,000 ohms, go to next step. If resistance is 10,000 ohms or greater, replace ECA and repeat QUICK TEST.
9. Turn key OFF and wait 10 seconds. Leave breakout box connected and ECA and EHC solenoid disconnected. Set DVOM to 200,000 ohm scale. Measure resistance between test pin 55 and test pins 37 and 57. If resistance is 10,000 ohms or greater, replace ECA and repeat QUICK TEST. If resistance is less than 10,000 ohms, repair short to power and repeat QUICK TEST. If code is repeated, replace ECA.

Exhaust Heat Control Circuit. Scheme 132

TEST JJ - CONVERTER CLUTCH OVERRIDE (CCO)

1. Turn key OFF and wait 10 seconds. Set DVOM to 200 ohm scale. Disconnect CCO solenoid connector and measure solenoid resistance. If resistance is between 26 and 40 ohms, reconnect solenoid and go to next step. If resistance is less than 26 ohms or greater than 40 ohms, replace CCO solenoid and repeat QUICK TEST.
2. Turn key ON, leaving engine OFF. With DVOM on 20 volt scale, measure voltage at CCO solenoid connector between VPWR circuit and ground. If voltage reading is 10.5 volts or less, repair open circuit in harness and repeat QUICK TEST. If voltage reading is 10.5 volts or greater, go to next step.
3. Turn key OFF and wait 10 seconds. Disconnect 60-pin ECA connector. Inspect for and repair any damaged wiring. Connect breakout box, leaving ECA disconnected. Set DVOM to 200 ohm scale. Measure resistance between test pin 53 and CCO circuit at solenoid harness connector. If resistance reading is 5 ohms or greater, repair open circuit in harness and repeat QUICK TEST. If resistance reading is less than 5 ohms, go to next step.
4. Turn key OFF and wait 10 seconds. Leave breakout box connected and ECA disconnected. Disconnect CCO solenoid. Set DVOM to 200,000 ohm scale. Measure resistance between test pin 55 and test pins 40, 46, and 60. If resistance readings are less than 10,000 ohms, repair short to ground and repeat QUICK TEST. If resistance readings are 10,000 ohms or greater, go to next step.
5. Turn key OFF and wait 10 seconds. Leave breakout box connected and ECA and CCO solenoid disconnected. Set DVOM to 200,000 ohm scale. Measure resistance between test pin 55 and test pins 37 and 57. If resistance is 10,000 ohms or greater, replace ECA and repeat QUICK TEST. If resistance is less than 10,000 ohms, repair short to power and repeat QUICK TEST. If code is repeated, replace ECA.

CCO Circuit. Scheme 133

TEST KK - DYNAMIC RESPONSE

Code 77 Displayed. This code appeared because the system failed to recognize a brief WOT after Dynamic Response Code during Engine Running Self-Test. If code 77 is still present, replace ECA and repeat QUICK TEST. If no code 77, Dynamic Response Test is passed. Repair any service codes received as required.

TEST LL - IGNITION DIAGNOSTIC MONITOR (IDM)

1. Continuous Code 18 Displayed. Turn key OFF and wait 10 seconds. Disconnect E-Core ignition connector from core. Disconnect 60-pin ECA connector. Inspect for and repair any damaged wiring. Connect breakout box, leaving ECA disconnected. Set DVOM to 200,000 ohm scale. Measure resistance between test pin 4 and negative terminal on ignition coil. If reading is less than 20,000 ohms or greater than 24,000 ohms, repair open circuit and repeat QUICK TEST. If reading is between 20,000-24,000 ohms, go to next step.
2. Turn key OFF and wait 10 seconds. Leave breakout box installed and ECA disconnected. With DVOM on 200,000 ohm scale, measure resistance between test pin 4 and test pins 40, 46, and 60. If reading is less than 10,000 ohms, repair short to ground and repeat QUICK TEST. If reading is 10,000 ohms or more, go to next step.
3. Turn key OFF and wait 10 seconds. Deactivate Self-Test. Connect VOM or STAR tester and start CONTINUOUS MONITOR (WIGGLE) TEST PROCEDURES. While lightly tapping on TFI module and wiggling TFI harness connector, observe VOM or STAR tester for fault indication. If fault is indicated, disconnect TFI harness. Inspect for and repair any damaged wiring. If okay, check TFI ignition system. If no fault indicated, go to next step.
4. While still in Continuous Monitor mode, observe VOM or STAR tester for fault while wiggling, shaking, or bending small sections of harness while working way to firewall. Repeat process from firewall to ECA. Perform this test to check on faults in the following circuits: PIP Open/Shorted to Ground - Check circuit at Test Pin 56. SPOUT Shorted to Ground - Check circuit at Test Pin 36. Ignition Ground Open - Check circuit at Test Pin 16. IDM Open/Shorted to Ground/Power - Check circuit at Test Pin 4. Test above circuits individually if necessary to isolate fault. If fault is indicated, isolate and repair problem and repeat QUICK TEST. If no fault indicated, go to next step.
5. Turn key OFF and wait 10 seconds. Disconnect 60-pin ECA connector. Inspect for and repair any damaged wiring. Repeat QUICK TEST. If connectors and terminals are okay, unable to duplicate fault at this time. Reconnect ECA.

Ignition Circuits. Scheme 134

TEST MM - SPARK TIMING CHECK

1. If spark advance was not 27-33° in Engine Running Self-Test, place system in Self-Test. System returns to normal 2 minutes after last Self-Test service code is displayed. Spark timing is locked at base timing plus 20°F3° BTDC when Key On/Engine Running Self-Test is activated. VECI decal (in engine compartment) will show base timing.
2. Connect timing light to engine. Locate spark output (SPOUT) connector and open the connection. Start engine and check base timing. Base timing is 10° (F3°) BTDC except on 1.6L Turbo models which have a base timing of 8°(F3°) BTDC. If timing is correct, go to step 3). If timing is not correct, reconnect SPOUT circuit and set base timing. After timing is adjusted, repeat Engine Running Self-Test and check spark advance.
3. Turn key OFF and wait 10 seconds. Disconnect 60-pin connector at ECA. Inspect for and repair any damaged wiring. Connect breakout box. Turn key ON, leaving engine OFF. With DVOM on 20 volt scale, measure voltage between test pins 37 and 40 and between test pins 57 and 60. If either reading is less than 10.5 volts, go to Circuit Test B, step 1). If both readings are 10.5 volts or more, go to next step.
4. Turn key OFF and wait 10 seconds. Disconnect harness connector at TFI module. With DVOM on 200 ohm scale, measure SPOUT circuit between SPOUT pin (pin 2) on TFI harness connector and test pin 36. If 5 ohms or less, go to next step. If more than 5 ohms, repair open circuit. Reconnect SPOUT connector and check timing as described in step 1).
5. Install breakout box, leave TFI harness disconnected. With key OFF, place DVOM on 200 ohm scale. Measure resistance between test pin 16 and TFI harness connector ignition ground pin (pin 6). If less than 5 ohms, go to Circuit Test A, step 7). If 5 ohms or more, repair harness as required and repeat QUICK TEST.

Spark Advance Circuit. Scheme 135

TEST NN - NO CODES/CODES CODES NOT LISTED

1. Turn key OFF and wait 10 seconds. Place DVOM on 20 volt scale. Disconnect throttle position sensor (TPS). Turn key ON, leaving engine OFF. Measure voltage at TPS harness connector between VREF and signal return circuit in Self-Test connector. If less than 4 volts or more than 6 volts, go to to «TEST C»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-c-reference-voltage) , step 1). If between 4 and 6 volts, reconnect TPS and go to next step.
2. Turn key OFF and wait 10 seconds. Disconnect 60-pin connector at ECA to inspect and repair. Install breakout box, leaving ECA disconnected. Set DVOM on 200 ohm scale. Measure resistance between Self-Test input from Self-Test pigtail to test pin 48. If less than 5 ohms, go to next step. If 5 ohms or more, repair open in circuit.
3. Measure resistance between Self-Test output at Self-Test connector and test pin 17. If less than 5 ohms, go to next step. If 5 ohms or more, repair open in circuit.
4. Turn key OFF. Measure resistance between EGO sensor ground point on engine and test pin 49. If 5 ohms or more, repair EGO sensor ground wire or open circuit bad connection. If less than 5 ohms, go to next step.
5. Set DVOM to 200 ohm scale. Measure resistance between Self-Test output at Self-Test connector and ground at engine block. If resistance is greater than 5 ohms, replace ECA and repeat QUICK TEST. If resistance is lower than 5 ohms, go to next step.
6. If vehicle is NOT equipped with shift indicator light, repair short to ground in Self-Test output circuit and repeat QUICK TEST. If vehicle has shift indicator light, go to «TEST FF»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__test-ff-shift-indicator-light) , step 7).
7. Continuous Code 15 Displayed. Code 15 is recorded any time power is lost to Keep Alive Memory circuit. Clear continuous codes, repeat Key ON/Engine OFF Self-Test, and note any continuous codes. If code 15 is present, go to next step. If no code 15, test is complete.
8. Ensure EEC components are properly connected and wiring does not contact, or lie near, ignition components or wires. Relocate EEC wiring away from ignition components and repeat «KEY ON/ENGINE OFF SELF-TEST»(/ford/thunderbird/ix-1983-1988/remont/testing-diagnostics/#38l-cfi-tests__key-onengine-off-self-test) . If code 15, go to next step. If no code 15, test is complete.
9. Check power circuit to Keep Alive Memory circuit for voltage. Turn key OFF and wait 10 seconds. Disconnect 60-pin connector at ECA and check both connector terminals and ECA pins for damage. Connect breakout box, leaving ECA disconnected. With DVOM on 20 volt scale, connect positive lead to test pin 1 and negative lead to test pin 40 or 60. Turn key ON and observe voltage reading. If less than 10 volts, service open to Keep Alive Memory circuit and repeat QUICK TEST. If 10 volts or more, replace ECA and repeat QUICK TEST.
10. Engine Stalls Routine. Perform diagnosis of non-EEC related components and repair as required. Check all vacuum lines, electrical connections and routing. Diagnose engine functions as on a vehicle without EEC. After correcting faults, go to next step.
11. Turn key OFF and wait 10 seconds. Install tachometer. Start engine and attempt to maintain engine at 2000 RPM for 2 minutes. If 2000 RPM can be maintained, go to Circuit Test A, step 13). If 2000 RPM can NOT be maintained, go to next step.
12. With engine at operating temperature and tachometer installed, turn key OFF and wait 10 seconds. Perform Engine Running Self-Test while maintaining 2000 RPM engine speed. If test is passed (code 11) or any service codes are recorded, treat codes as described for Engine Running Self-Test. If no codes are recorded, go to step 1) of this test.
13. Output State Check Not Functioning. Turn key OFF and wait 10 seconds. Perform Key ON/Engine OFF Self-Test and leave key ON to enter Output State mode. If codes 23, 53, 63 or 68 are present in On Demand Test results, treat codes as described for Key ON/Engine OFF Self-Test. If no codes are received, go to step 1) of this test. If code 11 is received, go to next step.
14. Check throttle and linkages for sticking or binding. Repair any mechanical problems and repeat QUICK TEST. If no sticking or binding is found in throttle or linkages, replace throttle position sensor (TPS) and repeat QUICK TEST.

Circuits Used In Test NN. Scheme 136

TEST OO - ERRATIC IGNITION

1. Code 14 Displayed. This code indicates 2 successive erratic profile ignition pickup (PIP) pulses were input to ECA from the distributor, resulting in possible engine miss or stall. Check EEC and ignition systems for loose wires and connections, arcing secondary ignition components (coil, cap, wires, etc.), or an on-board 2-way radio. Make sure radio antenna and power leads are routed properly. If any of the above are present, repair as necessary and repeat QUICK TEST. If none are present, go to next step.
2. Turn key OFF and wait 10 seconds. Deactivate Self-Test. Connect VOM or STAR tester and enter Engine Running Continuous Monitor Test. While lightly tapping on TFI module and distributor and wiggling TFI harness connector, observe VOM or STAR for fault indication. If fault is indicated, disconnect and inspect wiring. If wiring is good, check TFI ignition system. If no fault is indicated, go to next step.
3. Remain in Continuous Monitor Mode, observing VOM or STAR, while wiggling, shaking, or bending small sections of harness from TFI module to firewall. Also check harness from firewall to ECA. Isolate the PIP circuit for this test, if required. If fault is indicated, isolate and repair problem and repeat QUICK TEST. If no fault indicated, go to next step.
4. Turn key OFF and wait 10 seconds. Disconnect 60-pin connector at ECA. Inspect for and repair any damaged wiring, then repeat QUICK TEST. If pins and terminals are good and fault in EEC-IV system cannot be duplicated at this time, check TFI ignition system.

WIRING DIAGRAMS

See also:
• TEST A
• TEST G
• TEST H
• TEST J
• TEST E
• TEST F
• TEST M
• TEST AA
• TEST X
• TEST GG
• TEST V
• TEST II
• TEST OO
• TEST LL
• TEST N
• DIAGNOSIS BY SYMPTOM TEST
• TEST NN
• TEST T
• TEST I
• TEST F
• TEST KK
• TEST Y
• TEST C
• TEST B
• KEY ON/ENGINE OFF SELF-TEST
• KEY ON/ENGINE RUNNING SELF-TEST
• TEST Z
• TEST BB
• CONTINUOUS SELF-TEST
• KEY ON/ENGINE RUNNING (KOER) SELF-TEST