Engine Controls - Tests W/codes - 1.9l Ford Escort V

INTRODUCTION

Perform all steps in BASIC TESTING article in this section. If no fault is found while performing BASIC TESTING , proceed with self-diagnostics. If no service code or only pass codes are found during self-diagnostics, proceed to TESTS W/O CODES article in this section for diagnosis by symptoms.

DIAGNOSTIC FORMATS

There are 2 diagnostic formats used to test and service the EEC-IV system: QUICK TEST and CIRCUIT TESTS. QUICK TEST allows the technician to identify problems, and retrieve and record service codes. CIRCUIT TESTS check circuits, sensors and actuators.

If vehicle passes QUICK TEST, and there are no driveability symptoms or intermittent faults, the EEC-IV system is okay. Problem exists elsewhere.

Before starting any CIRCUIT TEST, follow all steps under QUICK TEST to find the correct CIRCUIT TEST.

SERVICE CODES

There are 3 types of service codes retrieved during KOEO SELF-TEST and KOER SELF-TEST: KOEO, KOER and Continuous Memory codes. See QUICK TEST for self-test procedures. Codes may be cleared from ECA memory after they have been recorded or repaired. See CLEARING CODES.

KOEO & KOER Codes (Hard Faults)

These codes indicate faults are present at time of testing. See appropriate chart under SERVICE CODE DEFINITION CHARTS for definitions of codes. A hard fault may cause CHECK ENGINE or SERVICE ENGINE SOON light to illuminate and remain on until fault is repaired. If KOEO or KOER codes are retrieved during KOEO SELF-TEST or KOER SELF-TEST, use appropriate KOEO SELF-TEST CODES or KOER SELF-TEST CODES chart under SERVICE CODE REFERENCE CHARTS to select the correct CIRCUIT TEST for testing and repair.

Continuous Memory Codes (Soft Faults)

These codes indicate a fault that may or may not be present at the time of testing, and are used to diagnose intermittent problems. See appropriate charts under SERVICE CODE DEFINITION CHARTS for definitions of codes. Continuous Memory Codes are retrieved during the KOEO SELF-TEST. Some codes may illuminate the CHECK ENGINE or SERVICE ENGINE SOON light. The corresponding soft trouble code will be retained in the ECA memory. If the fault does not reoccur within 40 warm-up cycles (80 cycles on some models), ECA will automatically clear the code.

Service codes may be cleared from memory by the technician. See CLEARING CODES. Intermittent faults may be caused by a sensor, connector or wiring-related problems. See INTERMITTENTS in TESTS W/O CODES article.

RETRIEVING CODES

Service codes are retrieved from the EEC-IV system through the self-test connector. Various methods and test equipment may be used to access these codes. The following test equipment may be used

1. Analog Volt-Ohmmeter (VOM)
2. "Scan" Tool
3. STAR Series Tester
4. In-Dash CHECK ENGINE or SERVICE ENGINE SOON Light

SELF-TEST CONNECTOR LOCATIONS

CLEARING CODES

To clear codes from ECA memory, start KOEO SELF-TEST. When service codes appear on test equipment or CHECK ENGINE light, disconnect jumper wire from Self-Test Input (STI) connector. If using STAR Series Tester, unlatch center button. This procedure erases Continuous Memory Codes from ECA memory. If problem has not been corrected, or fault is still present, hard code will immediately be reset in ECA memory.

KOEO & KOER SELF-TEST CODES

All service codes are 2 or 3-digit numbers. Codes are outputted, one digit at a time, by ECA. See appropriate chart under SERVICE CODE DEFINITION CHARTS for definitions of codes. These codes indicate current faults in the system, and should be serviced in the order of appearance. Use appropriate chart under SERVICE CODE REFERENCE CHARTS to find the correct CIRCUIT TEST. Codes are shown as voltage pulses (needle sweeps) on an analog Volt/Ohmmeter (VOM). (Scheme 1)

If using VOM, pay careful attention to the length of pauses in order to read codes correctly. There is a 1/2-second pause between number of sweeps in a digit, and a 2-second pause between the digits in a code. There is a 4-second pause between each code. KOEO codes are separated from Continuous Memory codes by a 6-second delay, a single 1/2-second sweep (Separator) and another 6-second delay. Record codes in the order received.

If using "Scan" Tool, it will count the pulses and display them as a digital code. The STAR Series Tester will add a zero (0) to single-digit Separator Code (10) and Dynamic Response Code (10). The Dynamic Response Code is displayed in KOER SELF-TEST. (Scheme 1)

If using CHECK ENGINE light, service codes are displayed as flashes.

Separator Pulse

A single 1/2-second separator pulse is issued 6-9 seconds after last KOEO code. Then 6-9 seconds after the single 1/2-second separator pulse, Continuous Memory Codes (soft faults) are displayed. Some digital test equipment may display the separator code as a 10 instead of a 1.

Pass Codes

A Code 11 or 111 indicates there are no service codes recorded in that portion of the test, and system passes that portion of the test. If Code 11 or 111 is not received in KOEO SELF-TEST, codes received during KOER SELF-TEST may not be valid. It is very important that Code 11 or 111 (pass code) be observed in KOEO SELF-TEST. A Code 11-1-11 or 111-1-111 output during KOEO SELF-TEST indicates there is no KOEO code or Continuous Memory Code recorded. The separator code may appear as a 10 instead of a 1 on some test equipment.

Continuous Memory Codes

These codes result from information stored by ECA during continuous self-test monitoring. Codes are displayed in KOEO SELF-TEST, after separator pulse code. Use these codes for diagnosis ONLY when KOEO SELF-TEST and KOER SELF-TEST result in Code 11 or 111 (pass code), and all steps under QUICK TEST are successfully completed. (There are few exceptions which may be checked after KOEO codes have been repaired). These codes indicate faults recorded within the last 40 engine starts. The fault may or may not be currently present. See appropriate chart under SERVICE CODE DEFINITION CHARTS for definitions of codes.

Fast Codes

At the start of KOEO SELF-TEST, and after Wide Open Throttle (WOT) request in KOER SELF-TEST, there is an output from the ECA known as Fast Codes. These are short bursts of information used by manufacturer during assembly. With most equipment, these code bursts are not visible; as the entire code sequence lasts less than 1/2 second. If this fluctuation is visible on test equipment, ignore it.

Scheme 1

Scheme 2

Scheme 3

DESCRIPTION

The following procedures are functional tests of EEC-IV system. There are 7 basic test steps. These test steps must be carefully followed in sequence, otherwise misdiagnosis or replacement of non-faulty components may result.

1. Visual Check & Vehicle Preparation
2. Equipment Hookup
3. Key On Engine Off (KOEO) Self-Test
4. Computed Timing Check
5. Key On Engine Running (KOER) Self-Test
6. Continuous Monitor Mode (Wiggle Test)
7. Intermittents & Diagnosis By Symptom

DIAGNOSTIC AIDS

After all tests, servicing or repairs have been completed, repeat QUICK TEST procedure to ensure all EEC-IV systems work properly and service codes are no longer present.

VISUAL CHECK & VEHICLE PREPARATION

Complete all steps in BASIC TESTING article before proceeding to next test step. Ensure vacuum hoses are connected correctly and EEC-IV wiring harnesses are connected.

EQUIPMENT HOOKUP

Apply parking brake, and place shift lever in Park (A/T) or Neutral (M/T). Block drive wheels. Turn off all electrical loads. Connect appropriate test equipment to vehicle as follows.

Analog Volt-Ohmmeter (VOM)

1) Turn ignition switch to OFF position. Set VOM at 0-15V DC range, and connect positive lead of VOM to positive battery terminal.

2) Connect negative VOM lead to Self-Test Output (STO) terminal of self-test connector. (Scheme 2) Connect timing light, and go to KOEO SELF-TEST. Activate KOEO SELF-TEST by connecting jumper wire from Self-Test Input (STI) pigtail to signal return terminal of self-test connector with ignition on.

"Scan" Tool

Follow manufacturer's instructions to hook up equipment and record service codes.

STAR Series Tester

Turn ignition to OFF position. Connect color-coded adapter cable leads to diagnostic tester. Connect 2 service connectors of adapter cable to vehicle self-test connector and STI pigtail connector. Connect timing light. Go to KOEO SELF-TEST.

CHECK ENGINE Or SERVICE ENGINE SOON Light (MIL)

With ignition on, connect a jumper wire between Self-Test Input (STI) pigtail and signal return terminal of self-test connector. No additional special equipment hookup is required.

KOEO SELF-TEST

Start engine and allow to idle until vehicle reaches operating temperature. If engine does not start or stalls after starting, continue KOEO SELF-TEST. DO NOT depress throttle on gasoline-engine vehicles. Turn ignition off and wait 10 seconds. Activate self-test procedure by using a jumper wire or appropriate test equipment. Turn ignition on, leaving engine off. Record all KOEO and Continuous Memory Codes.

If a Code 11 or 111 (pass code) is not received in the KOEO portion of the test, service the KOEO codes. See appropriate chart under SERVICE CODE REFERENCE CHARTS. If the ECA will not output codes, go to TEST QA, step 1. If service codes are received, check the following procedures

1. If CHECK ENGINE or SERVICE ENGINE SOON light is on when vehicle arrived for service, use recorded Continuous Memory Codes and appropriate chart under SERVICE CODE REFERENCE CHARTS before addressing any other symptoms.
2. On all vehicles, except vehicles with Distributorless Ignition System (DIS) or Electronic Distributorless Ignition System (EDIS), if engine runs or idles rough, go to TEST S, step 2. On vehicles with DIS or EDIS, use recorded Continuous Memory Codes and appropriate chart under SERVICE CODE REFERENCE CHARTS.
3. On DIS and EDIS vehicles, perform only the following. If Continuous Memory Codes 45, 46, 48, 215, 216, 217, 232 or 238 are received during KOEO SELF-TEST, see appropriate system in the SYSTEM/COMPONENT TESTS article. If Codes 45, 46, 48, 215, 216, 217, 232 or 238 were not received, go to TEST S, step 2.
4. On all vehicles, except vehicles with EDIS, if vehicle has a no-start condition, go to TEST A, step 1. On vehicles with EDIS, go to TEST AA, step 1.
5. If vehicle displays a Code 11 or 111 (pass code) and does not have any of the symptoms described in previous steps, go to COMPUTED TIMING CHECK.

COMPUTED TIMING CHECK

Turn ignition off and wait 10 seconds. Using jumper wire or test equipment, activate KOER SELF-TEST. Start engine and check for the following

1. If engine starts and stalls, or stalls during self-test, go to TEST S, step 1.
2. If Code 98 or 998 is displayed, it indicates EEC-IV system is operating in Failure Mode Effects Management (FMEM). Vehicle cannot be diagnosed in KOER SELF-TEST; rerun KOEO SELF-TEST.
3. Check computed timing after the last service code has been displayed. The timing will remain fixed for 2 minutes after the last code has been received, unless self-test is deactivated.
4. Computed timing, at the crankshaft, should equal the base timing (see vehicle emission decal) plus 20 degrees BTDC. This timing may vary 3 degrees (+/-). If computed timing is within specification, perform KOER SELF-TEST. If timing is not within specification, go to step 2 of TEST PC (vehicles with EDIS), step 2 of TEST PB (vehicles with DIS), or Step 2) of TEST PA (vehicles with TFI).

DO NOT enter this test sequence until a Code 11 or 111 (pass code) has been received in KOEO SELF-TEST. If system has not passed KOEO SELF-TEST, code recorded in KOER SELF-TEST may not be valid.

Deactivate self-test by removing and reconnecting jumper wire, or by procedure specified by test equipment in use. Start and run engine for 2 minutes at 2000 RPM to warm-up Heated Exhaust Gas Oxygen (HEGO) sensor. Turn engine off and wait 10 seconds. Activate KOER SELF-TEST using a jumper wire or appropriate procedure for test equipment used. Start engine. Record all service codes displayed. Check the following items

1. If engine starts and stalls, or stalls during self-test, go to TEST S, step 1.
2. If vehicle is equipped with a Brake On/Off (BOO) switch, brake pedal MUST be depressed and released AFTER the ID code portion of test.
3. On vehicles with Power Steering Pressure Switch (PSPS), turn steering wheel at least 1/2 turn and release within 1-2 seconds after the ID code portion of test.
4. On vehicles with E4OD transmissions, the Overdrive Cancel Switch (OCS) MUST be cycled after the ID code portion of the test.
5. When the Dynamic Response Code appears, perform a brief Wide Open Throttle (WOT). DO NOT perform WOT unless requested.
6. If Code 98 or 998 is displayed, it indicates EEC-IV system is operating in Failure Management Effects Mode (FMEM) and vehicle has not passed KOEO SELF-TEST. Vehicle cannot be diagnosed while in FMEM mode. See Code 98 or 998 in appropriate CONTINUOUS MEMORY CODE chart under SERVICE CODE REFERENCE CHARTS.
7. If a Code 11 or 111 (pass code) is received during KOER SELF-TEST, service Continuous Memory Codes received in KOEO SELF-TEST. See appropriate CONTINUOUS MEMORY CODE chart.
8. If a Code 11 or 111 (pass code) is received during the Continuous Memory Code portion of KOEO SELF-TEST (Code 11-1-11) or (11-1-111), and no driveability problem exists, EEC-IV testing is complete. If driveability problems are still present, go to TESTS W/O CODES article in this section.
9. If KOER codes are present, refer to appropriate KOER SELF-TEST CODES chart under SERVICE CODE REFERENCE CHARTS. If system will not output codes, go to TEST QA, step 1.

CONTINUOUS MONITOR MODE (WIGGLE TEST)

The Continuous Monitor Mode allows technician to attempt a recreation of intermittent fault while monitoring the system. This mode, also called the wiggle test, may be used in both KOEO SELF-TEST and KOER SELF-TEST. The CIRCUIT TESTS specify the use of this procedure to identify intermittent faults in specific circuits or components.

KOEO Wiggle Test Procedure

Connect test equipment. (Scheme 2) Turn ignition on and activate self-test with jumper lead or diagnostic tester. Wait 10 seconds, deactivate, and then reactivate self-test. Wiggle test mode is now activated. Tap, move and wiggle the suspected sensor and/or harness area. If a fault is detected, a service code may be stored in memory and indicated at the diagnostic tester or "Scan" tool. Record or retrieve code and perform test indicated by appropriate CONTINUOUS MEMORY CODES chart under SERVICE CODE REFERENCE CHARTS.

KOER Wiggle Test Procedure

Connect test equipment. (Scheme 2) Turn ignition off and wait 10 seconds. Start engine. Activate self-test with jumper lead or diagnostic tester. Wait 10 seconds, deactivate, and then reactivate self-test. DO NOT turn engine off. KOER wiggle test mode is now activated. Tap, move and wiggle the suspected sensor and/or harness area. If a fault is detected, a service code may be stored in memory and indicated at the diagnostic tester or "Scan" tool. Record or retrieve code and perform test indicated in appropriate CONTINUOUS MEMORY CODES chart under SERVICE CODE REFERENCE CHARTS.

INTERMITTENT & DIAGNOSIS BY SYMPTOMS

See TESTS W/O CODES article in this section.

ADDITIONAL SYSTEM FUNCTIONS

A number of additional diagnostic system features are available to help technicians diagnose driveability problems and test EEC-IV systems.

CHECK ENGINE/SERVICE ENGINE SOON/MALFUNCTION INDICATOR LIGHT (MIL)

The MIL is intended to alert driver of certain malfunctions in the EEC-IV system.

The light may also be used to retrieve service codes stored in ECA. When hooked up for KOEO SELF-TEST or KOER SELF-TEST, light will retrieve all codes, not just Continuous Memory Codes which turn on light during vehicle operation.

If the light comes on during vehicle operation, it should be serviced and inspected as soon as possible. It is not necessary to immediately turn off engine; vehicle can still be driven and does not need to be towed.

If the light comes on then goes off while in operation, the code causing light to illuminate will be stored in ECA memory as a Continuous Memory Code.

Light should come on when ignition is turned on and go out when engine is started. If hard fault codes are not present, ECA turns out the light when it receives a Profile Ignition Pick-Up (PIP) signal. If light never comes on, see SYMPTOMS in the TESTS W/O CODES article.

Output State Check

The Output State Check is used as an aid in servicing output actuators associated with EEC-IV system. It allows technicians to energize and de-energize most of the system output actuators on command. This mode is entered from the KOEO SELF-TEST, after all codes have been received. Leave self-test activated and depress throttle to initiate test sequence. Each time throttle is depressed and released, the output actuators will change state (from on to off, or off to on).

Failure Mode Effects Management (FMEM), Code 98 or 998

The FMEM mode allows system operation when sensor(s) fails or transmits signals which are out of normal operating range. When this happens, ECA substitutes a mid-range signal for the defective sensor(s) while continuing to monitor the sensor(s). If the faulty sensor's signals return to normal operating range, the ECA will use those signals. A Code 98 or 998 will be displayed when the FMEM mode is in effect.

Hardware Limited Operational Strategy (HLOS)

If a number of system or sensor failures are present, and the ECA is not receiving enough information to operate, ECA will switch to HLOS mode. ECA will output fixed values to allow operation of vehicle. Driveability concerns will be present. ECA will not output service codes in this mode.

Cylinder Balance Test

This test helps identify a weak or noncontributing cylinder in engines with sequential PFI fuel systems. The ECA shuts off fuel supply to each injector and measures RPM drop. It computes the variation between cylinders and identifies the weak ones. This test mode is entered from the KOER SELF-TEST, after all codes have been displayed. Within 2 minutes after codes have been displayed, lightly depress throttle (a 2-3 degree throttle angle is required, NOT a wide open throttle). After a brief stabilizing period, ECA will activate the test procedure. The test will be repeated if the throttle is depressed within 2 minutes of the final code output. During the 2nd and 3rd test sequence, the percentage of allowable variation between cylinders is reduced. Service codes displayed during this test identify the weak or non-contributing cylinder. See CYLINDER BALANCE TEST SERVICE CODES table to identify the cylinder number corresponding to the service code displayed. If Code 90 is displayed during this test, it indicates a passing result. If Code 77 is displayed, repeat cylinder balance test. If throttle is moved during this test, Code 77 will appear, indicating that test is not completed. Total test time is about 3 minutes.

CYLINDER BALANCE TEST SERVICE CODES

SUMMARY

If no service code (or pass code 11-1-11 or 111-1-111) is present, but driveability problem still exists, proceed to TESTS W/O CODES article for diagnosis by symptom (i.e. ROUGH IDLE, NO START, etc.), or intermittent diagnosis procedures.

KOEO CODE-TO-TEST MENU - 1.9L

KOEO SELF-TEST - CIRCUIT TEST & STEP MENU

KOER CODE-TO-TEST MENU - 1.9L

KOER SELF-TEST - CIRCUIT TEST & STEP MENU

CONTINUOUS CODE-TO-TEST MENU - 1.9L

CONTINUOUS MEMORY - CIRCUIT TEST & STEP

"CHECK ENGINE"/"SERVICE ENGINE SOON" MIL ACTIVATING CODES

1.9L SPFI-MA SERVICE CODE DEFINITIONS

PFI SERVICE CODE DEFINITIONS

HOW TO USE CIRCUIT TESTS

Note. A breakout box, connected to vehicle harness at the ECA, is necessary to perform most circuit tests. References to Test Pin No. found in CIRCUIT TEST steps refer to test terminals on the manufacturer's breakout box. Circuit diagrams at the beginning of each test identify circuit and wire colors.

1) Ensure all non-EEC related faults found while performing steps in BASIC TESTING article have been corrected. DO NOT perform any CIRCUIT TEST unless specifically instructed by a QUICK TEST procedure. FOLLOW EACH TEST STEP IN ORDER UNTIL FAULT IS FOUND. DO NOT replace any part unless directed to do so. When more than one code is received, start with the first code displayed.

2) CIRCUIT TESTS check electrical circuits to make sure they are okay before replacing sensors or any other components. Always test circuits for continuity between sensor and ECA. Test all circuits for short to power, opens, or short to ground. Voltage Reference (VREF) and Voltage Power (VPWR) circuits should be tested with KOEO, or as specified in CIRCUIT TESTS.

3) DO NOT measure voltage or resistance at ECA, or connect any test light unless specified in testing procedure. All measurements are made by probing REAR of connector. Isolate both ends of a circuit and turn ignition off whenever checking for shorts or continuity, unless stated otherwise.

4) Disconnect solenoids and switches from harness before measuring continuity, resistance, or applying voltage. After each repair, check all component connections and repeat CIRCUIT TEST.

5) An open circuit is defined as a resistance reading of greater than 5 ohms. This specification tolerance may be too high for some items in the EEC-IV system. If resistance approaches 5 ohms, always clean the suspected connector and coat with protective dielectric silicone grease. A short is defined as a resistance reading of less than 10 k/ohms to ground, unless stated otherwise in the CIRCUIT TEST.

6) On CIRCUIT TEST H and CIRCUIT TEST J (Fuel Control), to prevent replacement of good components, be aware that the following non-EEC related areas may also be the cause of problem. These areas include ignition coil, distributor cap and rotor, spark plug wires, fouled spark plugs, canister purge problems, EGR valve and gasket, air filter, poor power and ground circuits, fuel pressure, intake and exhaust manifold leaks, engine not at normal operating temperature, and problems with PCV valves or fuel-contaminated engine oil.

Fuel-contaminated engine oil may affect some codes. If this is suspected, remove PCV valve from valve cover and repeat QUICK TEST. If problem is corrected, change engine oil and filter.

On CIRCUIT TEST H and CIRCUIT TEST J (Fuel Control), vacuum leaks in non-EEC related areas may also cause Code 41 or 91 to be displayed. Check the following: unmetered air leaks between airflow meter and throttle body, vacuum motors, engine seals, EGR system, PCV system, Canister Purge (CANP) and HEGO sensor. Code 42 or 92 may be caused by fuel-contaminated engine oil, ignition misfire, EGR system or CANP problems.

Note. In the following tests, circuit diagrams and illustrations are courtesy of Ford Motor Co.

CIRCUIT TESTS are grouped as follows

1. A-C - No Start & Voltage Tests
2. DA-DR - Input Sensor Tests
3. FD-FF - Additional Input Component Tests
4. G-J Fuel - Control Systems
5. KC-X - ECA (Processor) Output Tests

TEST AA - NO START (EDIS IGNITION SYSTEMS)

Enter this CIRCUIT TEST only when all steps under QUICK TEST have been successfully completed and the engine still does not start, or when directed here from another test or chart.

This test is intended to diagnose only the following EEC-IV ignition systems and circuits

1. Spark (ECA Controlled)
2. Wiring Harness Circuits (PIP, IGN GND & VPWR)
3. ECA

EDIS Module Circuits (1.9L SPFI-MA). Scheme 4

TEST PINS & WIRE COLOR IDENTIFICATION

To prevent replacement of good components, be aware that the following non-EEC related areas and components may be the cause of problem

1. Fuel Quality & Quantity
2. Ignition (General Condition)
3. Engine Mechanical Components
4. Starter & Battery Circuits
5. Variable Reluctance Sensor (VRS)
6. EDIS Module
7. Coil Packs

1) Starting System Ensure fuel pump inertia switch is closed (button pushed in). Try to start engine. If engine does not crank, check vehicle starting and charging systems. If engine cranks, go to next step.

2) Check VREF Signal At TPS Ensure fuel pump inertia switch is set (button pushed in). Turn ignition off and wait 10 seconds. Set DVOM on 20-volt scale and disconnect Throttle Position Sensor (TPS). Turn ignition on, leaving engine off. Measure voltage at TPS harness connector between VREF and SIG RTN. If reading is less than 4 volts or more than 6 volts, go to TEST C, step 1. If reading is between 4 and 6 volts, reconnect TPS and go to next step.

TPS Harness Connectors. Scheme 5

3) Check For Spark At Plugs Disconnect any spark plug wire and connect spark tester between plug wire and engine ground. Crank engine and check for spark. If spark is present and consistent, connect spark plug wire and go to next step. If there is no spark, check ignition system. Refer to the SYSTEM/COMPONENT TESTS article in this section.

4) Check Ignition Ground Continuity Turn ignition off and wait 10 seconds. Disconnect and inspect ECA 60-pin connector. Install breakout box, leaving ECA disconnected. Disconnect EDIS module. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 16 at breakout box and IGN GND circuit at EDIS module vehicle harness connector. If resistance is more than 5 ohms, repair open in circuit and repeat QUICK TEST. If reading is less than 5 ohms, go to next step.

5) Check PIP For Short To Power Turn ignition off and wait 10 seconds. With breakout box installed, disconnect ECA. Disconnect EDIS module. Set DVOM on 20-volt scale. Measure voltage between test pin No. 56 at breakout box and battery negative post. If voltage is greater than 7 volts, repair short to power. Remove breakout box and rerun QUICK TEST. If voltage is NOT greater than 7 volts, go to next step.

6) Check PIP Circuit Continuity Turn ignition off and wait 10 seconds. With breakout box installed, disconnect ECA. Disconnect EDIS module. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 56 at breakout box and PIP circuit at EDIS module vehicle harness connector. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair open circuit. Remove breakout box, reconnect all components and rerun QUICK TEST.

7) Check PIP Circuit For Shorts to Ground Turn ignition off and wait 10 seconds. With breakout box installed, reconnect ECA. Disconnect EDIS module. Set DVOM on 200-k/ohm scale. Measure resistance between test pin No. 56 (PIP) and test pins No. 16, 40, 46 and 60 for short to ground. If any reading is less than 10 k/ohms, repair short in harness and repeat QUICK TEST. If engine still does not start, go to next step. If all readings are 10 k/ohms or more, go to next step.

8) Isolate Shorts In ECA Turn ignition off and wait 10 seconds. With breakout box installed, connect ECA to breakout box. Disconnect EDIS module. Set DVOM on 200-k/ohm scale. Measure resistance between test pin No. 56 (PIP) and test pins No. 37 and 57 for short to power. Measure resistance between test pin No. 56 and test pins No. 40 and 60 for short to ground. If all readings are less than 20 k/ohms or greater than 150 k/ohms, problem is in EDIS system. Replace ECA and repeat QUICK TEST. If any reading is 20-150 k/ohms go to next step.

9) Check PIP Signal Turn ignition off and wait 10 seconds. With breakout box installed, disconnect ECA. Reconnect EDIS module. Set DVOM on 20-volt scale. Measure voltage between test pin No. 56 and test pin No. 16 at breakout box. Crank engine and record reading. If voltage is less than 3 volts or greater than 7 volts, remove breakout box and rerun QUICK TEST. If voltage is 3-7 volts, replace EDIS module and go to next step.

10) Fuel Pump Check Connect pressure gauge to vehicle. Note initial pressure reading. Pressurize fuel system by turning ignition on for one second and observe pressure gauge. Turn ignition off and wait 10 seconds. Repeat sequence 5 times. If pressure increases, go to TEST S, step 1. If pressure does not increase, check fuel pump and system for mechanical problems.

Enter this CIRCUIT TEST only when directed by TEST C, TEST J, TEST PA, TEST PB or TEST PC.

Power Relay Circuits. Scheme 6

TEST PIN WIRE COLOR IDENTIFICATION

To prevent replacement of good components, be aware that the following non-EEC related areas may be the cause of problem: battery cables and ground straps, voltage regulator, alternator or ignition switch. This test is intended to diagnose the ECA, power relay, battery voltage and the following harness circuits

1. Signal Return
2. STO
3. STI
4. PWR GND
5. VPWR
6. KAPWR
7. VREF
8. Ignition

1) Battery Voltage Check Turn ignition on, leaving engine off. Set DVOM on 20-volt scale and measure voltage across battery terminals. If reading is less than 10.5 volts, service or replace discharged battery. If reading is 10.5 volts or more, go to next step.

2) Check Continuity Of PWR GND Circuit Turn ignition off and wait 10 seconds. Inspect ECA connector and pins. Install breakout box, leaving ECA connected. Set DVOM on 200-ohm scale and measure resistance between test pins No. 40 and 60 at breakout box and battery negative post. If readings are greater than 5 ohms, repair open in PWR GND circuit. Remove breakout box, reconnect components and repeat QUICK TEST. If both readings are less than 5 ohms, go to next step.

3) Check For Open Between SIG RTN & PWR GND Circuits At ECA With breakout box installed and ECA connected, turn ignition off and wait 10 seconds. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 46 and test pins No. 40 and 60 at breakout box. If both readings are less than 5 ohms, go to next step. If readings are greater than 5 ohms, disconnect ECA connector and inspect for corrosion or damaged pins. Repair as necessary. If fault is still present, replace ECA and repeat QUICK TEST.

4) Check Continuity Of SIG RTN Circuit With breakout box installed and ECA connected, turn ignition off and wait 10 seconds. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 46 at breakout box and SIG RTN circuit at self-test connector. If resistance is greater than 5 ohms, repair open in SIG RTN circuit. Remove breakout box, reconnect components and repeat QUICK TEST. If reading is less than 5 ohms, remove breakout box, connect ECA and go to next step.

5) Check KAPWR Circuit Voltage At EEC Power Relay Turn ignition on, leaving engine off. With ECA connected, set DVOM on 20-volt scale. Measure voltage between battery negative post and KAPWR circuit at EEC power relay harness connector. If reading is less than 10.5 volts, check KAPWR circuit from EEC power relay to battery positive post for open circuit. If reading is 10.5 volts or more, go to next step.

6) Check Ignition Circuit Voltage At EEC Power Relay Turn ignition on, leaving engine off. Ensure ECA is connected. Set DVOM on 20-volt scale. Measure voltage between battery negative post and IGNITION circuit at EEC power relay vehicle harness connector. If reading is less than 10.5 volts, check for open in ignition switch circuits. Repair wiring and repeat QUICK TEST. If reading is 10.5 volts or more, go to next step.

7) Check PWR GND Circuit Continuity Turn ignition off and wait 10 seconds. With ECA connected and DVOM on 200-ohm scale, measure resistance between battery negative post and PWR GND circuit at EEC power relay vehicle harness connector. If resistance is 5 ohms or more, repair wiring in ground circuit. Repeat QUICK TEST. If reading is less than 5 ohms, go to next step.

8) Check VPWR Circuit At EEC Power Relay Turn ignition on, leaving engine off. With ECA connected and DVOM on 20-volt scale, measure voltage between battery negative post and VPWR circuit at EEC power relay vehicle harness connector. If reading is 10.5 volts or more, repair open or short to ground in VPWR circuit between ECA and EEC power relay. Reconnect components and repeat QUICK TEST. If reading is less than 10.5 volts, replace EEC power relay. Repeat QUICK TEST.

Perform this test when a check for VREF signal has failed in sensor input TEST DA-through-TEST DR, or when directed by TEST A or TEST QA.

This circuit test is intended to diagnose only the ECA, SIG RTN, VREF, TP, EVP, PFE, DPFE, MAP and BP circuits.

Reference Voltage Circuits. Scheme 7

TEST PIN WIRE COLOR IDENTIFICATION

1) Check Battery Power Circuit Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair as necessary. Install breakout box, leaving ECA connected. Turn ignition on, leaving engine off. Set DVOM on 20-volt scale and measure voltage between test pin No. 37 and SIG RTN/PWR GND circuit of self-test connector. Record reading. Measure voltage across battery terminals. Record reading. If both readings are less than 10.5 volts, or if they differ by more than one volt, reconnect sensor (if applicable). Go to step 1 of TEST B. If reading is 10.5 volts or more and does not differ from one another by more than one volt, go to next step.

2) Check VREF Voltage With breakout box installed and ECA connected, turn ignition on, leaving engine off. Set DVOM on 20-volt scale and measure voltage between test pins No. 26 and 46 at breakout box. If reading is 6 volts or more, go to step 4. If reading is 4 volts or less, go to step 5. If reading is 4-6 volts, go to next step.

3) Check VREF & SIG RTN Circuit Continuity With breakout box installed and ECA disconnected, turn ignition off. If directed here by a sensor test, ensure sensor is disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 26 and VREF circuit terminal at vehicle harness connector of applicable sensor. Measure resistance between test pin No. 46 and SIG RTN circuit terminal at vehicle harness connector of applicable sensor. If both readings are less than 5 ohms, VREF voltage is okay. Remove breakout box, reconnect components and sensor, and repeat QUICK TEST. If any reading is 5 ohms or more, repair open in VREF or SIG RTN circuit. Remove breakout box, reconnect components and repeat QUICK TEST.

4) Check For Excess VREF Circuit Voltage Turn ignition off and wait 10 seconds. With breakout box installed, disconnect ECA and "Scan" tool or STAR tester (if applicable). Turn ignition on, leaving engine off. Set DVOM on 20-volt scale and measure voltage between test pin No. 26 and battery ground. If reading is less than 0.5 volt, replace ECA, remove breakout box, reconnect components and repeat QUICK TEST. If reading is 0.5 volt or more, repair short to battery power in EEC vehicle harness. Remove breakout box, reconnect components and repeat QUICK TEST. Replace ECA if fault still occurs.

5) Check For Shorted TPS Sensor Turn ignition off and wait 10 seconds. With breakout box installed and ECA connected, disconnect Throttle Position Sensor (TPS) from vehicle harness. Turn ignition on, leaving engine off. Set DVOM on 20-volt scale and measure voltage between test pins No. 26 and 46. If reading is 4 volts or more, replace TPS, remove breakout box, reconnect components and repeat QUICK TEST. If voltage is less than 4 volts on vehicles with EVP/PFE sensor, go to next step. If reading is less than 4 volts on all other models, go to step 7.

6) Check For Shorted EVP/PFE/DPFE Sensor Turn ignition off and wait 10 seconds. With breakout box installed and ECA connected, disconnect EVP/PFE/DPFE sensor. Turn ignition on, leaving engine off. Set DVOM on 20-volt scale. Measure voltage between test pins No. 26 and 46. If reading is 4 volts or more, replace EVP/PFE/DPFE sensor and repeat QUICK TEST. If reading is less than 4 volts, reconnect EVP/PFE/DPFE sensor and go to next step.

7) Check For Shorted MAP/BP Sensor All vehicles not equipped with a MAP/BP sensor, except 1.9L SPFI-MA vehicles with A/T, go to step 9). On 1.9L SPFI-MA vehicles with A/T, go to next step. Turn ignition off and wait 10 seconds. With breakout box installed and ECA connected, disconnect MAP/BP sensor. Set DVOM on 20-volt scale. With ignition on and engine off, measure voltage between test pins No. 26 and 46. If reading is 4 volts or more, replace MAP/BP sensor. Remove breakout box, reconnect components and repeat QUICK TEST. If reading is less than 4 volts, reconnect MAP/BP sensor.

Note. There is a break in the step numbering sequence at this point, skipping from step 7 to step 9. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

9) Check VREF Circuit For Short To Ground With breakout box installed and ECA disconnected, turn ignition off and wait 10 seconds. Disconnect TPS, MAP/BP, EVP/PFE/DPFE and 4EAT module (if equipped). Set DVOM on 200-ohm scale. Measure resistance between test pin No. 26 and test pins No. 20, 40, 46 and 60. If any resistance is less than 5 ohms, repair short to ground. Remove breakout box, connect all sensors and repeat QUICK TEST. If original problem still exists, replace ECA and repeat QUICK TEST. If reading is 5 ohms or more, connect sensors, replace ECA and repeat QUICK TEST.

Perform this test only when directed by QUICK TEST. Ambient air temperature must be at least 50°F (10°C) to receive valid input from ACT and VAT sensors. Engine coolant temperature must be greater than 50°F (10°C) to pass KOEO SELF-TEST and greater than 180°F (82°C) to pass KOER SELF-TEST. Voltage values in this test are based on a 5-volt VREF signal. Values may vary up to 15% due to sensor and VREF variations. For test results to be valid, avoid performing test in unusually hot or cold conditions.

This circuit test is intended to diagnose the following components and circuits

1. ACT Sensor
2. ECT Sensor
3. Vehicle Harness Circuits (ACT, ECT & SIG RTN)
4. ECA

Temperature Sensor Circuits. Scheme 8

TEST PIN WIRE COLOR IDENTIFICATION

Temperature Sensors Resistance & Voltage Charts. Scheme 9

To prevent replacing good components, ensure the following non-EEC areas or components are not the cause of problem

1. Coolant Level Low
2. Cooling System, Water Pump or Fan
3. Electro Drive Cooling Fan
4. Engine Operating Temperature Low
5. Engine Oil Level Low
6. Thermostat
7. Heat Riser Duct Valve
8. Air Cleaner Duct
9. Ambient Temperature Too Low

1) Code 21/116 Or 24/114: Check Installation & Operation Of Temperature Sensor Codes 21/116 (ECT) or 24/114 (ACT) indicates that the corresponding sensor is out of self-test range. Correct range for measurement is .3-3.7 volts. Check for the following possible causes

1. Low Ambient Temperature (Less Than 50°F)
2. Low Coolant Level
3. Faulty Harness Connector
4. Faulty Sensor
5. ACT sensor improperly mounted in air cleaner

If vehicle cannot be started, go to step 3. If vehicle stalls, or starts then dies, go to TEST S, step 1. Run engine for 2 minutes at 2000 RPM. Ensure upper radiator hose is hot and pressurized. Repeat QUICK TEST. If Codes 21, 24, 114 or 116 is present, go to next step. If none of these codes is present, service other codes as necessary.

2) Check VREF Circuit Voltage at TPS Turn ignition off and wait 10 seconds. Set DVOM on 20-volt scale. Disconnect Throttle Position Sensor (TPS). With ignition on and engine off, measure voltage at TPS vehicle harness connector between VREF and SIG RTN. If reading is less than 4 volts or more than 6 volts, go to TEST C, step 1. If reading is 4-6 volts, reconnect TPS and go to next step.

3) Check Temperature Sensor Resistance With Engine Off Turn ignition off and wait 10 seconds. Disconnect suspected sensor. Set DVOM on 200-k/ohm scale. Measure resistance between sensor signal circuit and SIG RTN circuit at sensor. See TEMPERATURE SENSORS RESISTANCE & VOLTAGE CHART in this circuit test for resistance specifications.

If resistance is within specification, perform the following step as applicable.

1. For ECT sensor with a no-start condition, go to TEST A, step 1. DO NOT service code 21/116 at this time.
2. For all others, go to next step.

If resistance is not within specification, replace suspected sensor. Reconnect vehicle harness and rerun QUICK TEST.

4) Check Resistance Of Temperature Sensor With Engine Running If engine has cooled down, warm engine before measuring ECT sensor resistance. Check for an open thermostat. Turn ignition off and wait 10 seconds. Disconnect suspected sensor. Run engine at 2000 RPM for 2 minutes. Set DVOM on 200-k/ohm scale. Measure resistance between sensor signal circuit and SIG RTN circuit at temperature sensor. See TEMPERATURE SENSORS RESISTANCE & VOLTAGE CHART in this circuit test for resistance specifications. If resistance is within specification, replace ECA; reconnect components and repeat QUICK TEST. If sensor is not within specification, replace ECT sensor. Reconnect components and repeat QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 4 to step 10. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

10) Code 51/118 Or 54/113: Induce Opposite Code (61/117 Or 64/112) Code 51/118 (ECT) or 54/113 (ACT) and 58 (VAT) indicate that the corresponding sensor signal is greater than the self-test maximum. Maximum signal voltage for ECT and ACT sensors is 4.6 volts. Maximum signal voltage for VAT sensors is 3.5 volts. Possible causes for excess voltage signals are as follows

1. Open circuit in vehicle harness (ACT or ECT)
2. Faulty connection
3. Faulty sensor
4. Faulty ECA

Turn ignition off and wait 10 seconds. Disconnect suspected temperature sensor. Connect a jumper wire between sensor signal circuit and SIG RTN circuit at temperature sensor vehicle harness connector. Perform KOEO SELF-TEST. See KEY ON ENGINE OF (KOEO) SELF-TEST under QUICK TEST. If Code 61, 64, 112 or 117 is displayed, replace suspected sensor. Remove jumper wire, reconnect vehicle harness and repeat QUICK TEST. If Code 61, 64, 112 or 117 is not displayed, remove jumper wire and go to next step.

11) Check Continuity Of Sensor Signal & SIG RTN Circuits Turn ignition off and wait 10 seconds. Ensure suspected temperature sensor is disconnected. Disconnect ECA 60-pin connector. Check for damaged wiring and repair as necessary. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 7 (ECT sensor) or test pin No. 25 (ACT sensor) at breakout box and sensor signal circuit at sensor vehicle harness connector. Also measure resistance between test pin No. 46 and SIG RTN circuit at sensor vehicle harness connector. If both readings are less than 5 ohms, replace ECA. Remove breakout box, reconnect components and rerun QUICK TEST. If either reading is 5 ohms or more, repair open circuits. Remove breakout box, reconnect components and rerun QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 11 to step 20. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

20) Code 61/117 or 64/112: Induce Opposite Code (51/118 or 54/113) Code 61/117 (ECT) or 64/112 (ACT) indicates that sensor signal is less than the self-test minimum. Minimum signal for ACT and ECT sensor is 0.2 volt. Minimum signal for VAT sensor is 0.35 volt. Possible causes for this fault are as follows

1. Circuit grounded in vehicle harness (ACT or ECT)
2. Faulty sensor
3. Faulty ECA
4. Faulty connection

Turn ignition off and wait 10 seconds. Disconnect vehicle harness connector from suspected sensor. Check for damaged wiring and repair as necessary. Repeat KOEO SELF-TEST. If code 51, 54, 113 or 118 is displayed, replace sensor and connect harness. Repeat QUICK TEST. If code 51, 54, 113 or 118 is not displayed, go to next step.

21) Check VREF Circuit Voltage at TPS Turn ignition off and wait 10 seconds. Set DVOM on 20-volt scale. Disconnect TPS. With ignition on and engine off, measure voltage between VREF and SIG RTN at TPS vehicle harness connector. If reading is less than 4 volts or more than 6 volts, go to TEST C, step 1. If reading is 4-6 volts, connect TPS and go to next step.

TPS Connectors. Scheme 10

22) Check Temperature Sensor Signal For Shorts to Ground Turn ignition off and wait 10 seconds. Disconnect suspected sensor. Disconnect ECA 60-pin connector. Check for damaged wiring and repair as necessary. Install breakout box, leaving ECA disconnected. Set DVOM on 200-k/ohm scale. Measure resistance between test pin No. 7 (ECT) or test pin No. 25 (ACT) and test pins No. 40, 46, and 60. If any reading is less than 10 k/ohms, repair short circuit. Remove breakout box, reconnect components and repeat QUICK TEST. If all readings are 10 k/ohms or more, replace ECA. Remove breakout box and reconnect components. Repeat QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 22 to step 90. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

90) Continuous Memory Code 51/118, 54/113, 61/117 or 68/112: Check Sensor A Continuous Memory Code 51/118 and 54/113 indicates that sensor signal is greater than the self-test maximum of 4.6 volts. The code is set during normal driving conditions.

Continuous Memory Code 61/117 and 64/112 indicates that sensor signal is less than the self-test minimum of 0.2 volt. The code is set during normal driving conditions.

Possible causes for these faults are as follows

1. Faulty sensor
2. Open or grounded circuit in harness
3. Faulty ECA

SENSOR CODES

Sensor Circuit Fault. Scheme 11

Enter KOEO wiggle test mode. See CONTINUOUS MONITOR MODE (WIGGLE TEST) under QUICK TEST. Observe VOM or diagnostic tester for indication of fault while tapping sensor lightly and wiggling sensor connector. If fault is indicated, disconnect and inspect connector and terminals. If connector and terminals are okay, replace sensor, clear continuous memory and repeat QUICK TEST. If fault is not indicated, go to next step.

91) Check EEC-IV Vehicle Harness While in CONTINUOUS MONITOR MODE (WIGGLE TEST), observe VOM or diagnostic tester while wiggling and bending EEC-IV harness from sensor to cowl, a small section at a time. Also check harness from cowl to ECA. If fault is indicated, isolate fault and repair as necessary. Clear continuous memory and repeat QUICK TEST. If no fault is found, go to next step.

92) Inspecting ECA & Vehicle Harness Connectors Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect both connector and connector terminals for obvious damage. If connectors and terminals are damaged, repair as necessary and repeat QUICK TEST. If connectors and terminals are okay, and fault cannot be duplicated at this time, clear codes and repeat QUICK TEST. See INTERMITTENTS in TESTS W/O CODES article.

Perform this test when directed by QUICK TEST. This test procedure is intended to diagnose only the MAF, ECA and vehicle harness circuits (VPWR, PWR GND, MAF and MAF RTN).

To prevent replacement of good components, be aware that the following non-EEC related areas may be the cause of problem

1. Air cleaner element
2. Inlet air duct
3. Throttle body

Mass Airflow Sensor (MAF) Circuits. Scheme 12

TEST PIN WIRE COLOR IDENTIFICATION

MAF SIGNAL VOLTAGE

MAF signal voltage is typical for A/T vehicles at normal operating temperature. Voltage signal may vary due to engine load and temperature.

1) Code 26/159: Check VPWR Circuit Voltage Code 26/159 indicates MAF sensor voltage is out of self-test range. If code is received during KOEO SELF-TEST, it indicates voltage exceeded the .70-volt test range. If Code 26/159 is received during KOER SELF-TEST, it indicates voltage is not within .20-1.50 volt operating range. Possible causes for this fault are as follows: faulty MAF sensor or faulty ECA.

Code 26/159 may be caused by the use of a garage exhaust ventilation system. Ensure vehicle is vented to outside atmosphere before repeating QUICK TEST.

Turn ignition off and disconnect MAF sensor. Set DVOM on 20-volt scale. Turn ignition on, leaving engine off. Measure voltage between VPWR circuit at MAF sensor vehicle harness connector and battery negative post. If voltage is greater than 10.5 volts, go to next step. If voltage is not greater than 10.5 volts, repair open in VPWR circuit and rerun QUICK TEST.

2) Check MAF Sensor Ground With ignition on and engine off, and MAF sensor disconnected, set DVOM on 20-volt scale. Measure voltage between VPWR circuit and PWR GND circuit at MAF sensor connector. If voltage is greater than 10.5 volts, go to next step. If voltage is less than 10.5 volts repair open PWR GND circuit. Connect MAF sensor and rerun QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 2 to step 10. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

10) Code 66/157 Or 72/129: Check Continuity Of MAF Signal & VPWR Circuits Code 66/157 indicates that MAF signal was less than .40 volt sometime during last 80 warm-up cycles. Code 72/129 indicates insufficient MAF change during DYNAMIC RESPONSE TEST. Possible causes for this fault are as follows

1. Open MAF Circuit
2. Open VPWR Circuit To MAF Sensor
3. Open PWR GND Circuit To MAF Sensor
4. Open MAF RTN Circuit To MAF Sensor
5. MAF Circuit Shorted To Ground
6. Faulty ECA Or MAF Sensor
7. Air Leak Before Or After MAF Sensor
8. MAF Sensor Disconnected

Ensure ignition is off. Disconnect and inspect 60-pin connector at ECA. Service as necessary. Disconnect MAF sensor and install breakout box; leave ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between VPWR circuit at MAF sensor vehicle harness connector and test pins No. 37 and 57 at breakout box.

Measure resistance between MAF circuit at MAF sensor vehicle harness connector and test pin No. 50 at breakout box. If both resistances are less than 5 ohms, go to next step. If either resistance is greater than 5 ohms, remove breakout box and repair open circuit. Reconnect all components and rerun QUICK TEST.

11) Check MAF Circuit For Shorts To Ground & MAF RTN Circuit With ignition off and MAF sensor disconnected, set DVOM on 200-k/ohm scale. Disconnect ECA 60-pin connector. Inspect connector and terminals. Install breakout box, leaving ECA disconnected.

Measure resistance between test pin No. 50 and test pins No. 9, 40, and 60 at breakout box.

If all resistances are greater than 10 k/ohms, go to next step. If resistance in any circuit is less than 10 k/ohms, repair short circuit. Remove breakout box, reconnect components and repeat QUICK TEST.

12) Check Continuity Of PWR GND Circuit Ensure ignition is off. Disconnect MAF sensor. Set DVOM on 200-ohm scale. Measure resistance between PWR GND circuit at MAF sensor vehicle harness connector and battery negative post. If resistance is less than 10 ohms, go to next step. If resistance is greater than 10 ohms, repair open circuit. Reconnect all components and repeat QUICK TEST.

13) Check Continuity Of MAF RTN Circuit With ignition off and MAF sensor disconnected, set DVOM on 200-ohm scale. Disconnect ECA 60-pin connector and inspect pins. Install breakout box; leave ECA disconnected.

Measure resistance between MAF RTN circuit at MAF sensor vehicle harness connector and test pin No. 9 at breakout box. If resistance is less than 5 ohms, go to next step. If resistance is more than 5 ohms, repair open circuit. Remove breakout box, reconnect components and repeat QUICK TEST.

14) Check MAF Signal For Short To Ground With ignition off, breakout box installed and ECA connected, disconnect MAF sensor. Set DVOM on 200-k/ohm scale.

Measure resistance between test pin No. 50 and test pins No. 9, 40 and 60 at breakout box.

If resistances are greater than 10 k/ohms, go to next step. If all resistances are less than 10 k/ohms, replace ECA. Remove breakout box, reconnect components and repeat QUICK TEST.

15) Check MAF Circuit Output With ignition off, install breakout box. Ensure ECA and MAF are connected. Set DVOM on 20-volt scale. Start engine.

Measure voltage between test pin No. 50 at breakout box and battery negative post.

If voltage is .36-1.5 volts, replace ECA; remove breakout box, reconnect components and repeat QUICK TEST. If voltage is not .36-1.5 volts, replace MAF sensor; remove breakout box, reconnect components and repeat the QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 15 to step 20. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

20) Code 56/158: Repeat Self-Test With MAF Sensor Disconnected With ignition off, disconnect MAF sensor from vehicle harness. Start engine and allow to idle for one minute. Turn ignition off. Repeat KOEO SELF-TEST. See KEY ON ENGINE OFF (KOEO) SELF-TEST under QUICK TEST. If Code 66 or 157 is present, replace MAF sensor and rerun QUICK TEST. If Code 66 or 157 is not present, go to next step.

21) Check MAF Circuit For Short To VPWR With ignition off, disconnect MAF sensor and ECA. Disconnect ECA 60-pin connector and inspect for damaged or corroded terminals. Repair as necessary. Set DVOM on 200-k/ohm scale. Measure resistance between MAF and VPWR circuits at MAF sensor vehicle harness connector. If resistance is greater than 10 k/ohms, replace ECA; remove breakout box, reconnect components and repeat QUICK TEST. If resistance is less than 10 k/ohms, repair short circuit; remove breakout box, reconnect components and repeat QUICK TEST.

Perform this test when directed by QUICK TEST or TEST S. Barometric pressure sensor output is digital and must be measured with an oscilloscope or MAP/BP tester.

To prevent replacement of good components, be aware that the following non-EEC related areas may be the cause of problem

1. Unusually High Or Low Atmospheric Barometric Pressure
2. Kinked Or Blocked Vacuum Lines
3. Engine Mechanical Condition (Valves, Vacuum Leaks, Valve Timing, EGR Valve, etc.)

This test is intended to diagnose the following

1. MAP/BP Sensor
2. Vehicle Harness Circuits (VREF, MAP/BP SIG & SIG RTN)
3. MAP Vacuum Line
4. ECA

MAP/BP Circuits & Tester Hookup. Scheme 13

TEST PIN WIRE COLOR IDENTIFICATION

MAP SENSOR SPECIFICATIONS

MAP/BP SENSOR SPECIFICATIONS

1) Code 22/126: Check For Power to MAP/BP Sensor Code 22/126 indicates MAP/BP sensor is out of self-test voltage range (1.4-1.6 volts). The following are possible causes of this code

1. MAP/BP Signal Circuit Open Between Sensor And ECA
2. MAP/BP Signal Circuit Shorted To VREF, SIG RTN Or Ground
3. Faulty MAP/BP Sensor
4. Vacuum Trapped At MAP/BP Sensor
5. High Atmospheric Pressure
6. Faulty ECA
7. VREF Circuit Open At Sensor
8. SIG RTN Open At Sensor

Turn ignition off. Disconnect MAP/BP sensor from vehicle 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.

Turn ignition on. If Red light or no light is on, then VREF is either too high or too low. Go to next step. If Green light is on, VREF is okay. Go to step 3.

2) Check For Power At Sensor Vehicle Harness Connector With MAP/BP sensor and MAP/BP tester connected, turn ignition on. Disconnect MAP/BP sensor. If only Green light on tester is lit, VREF is correct; replace MAP/BP sensor and repeat QUICK TEST. If Green light is not on, remove MAP/BP tester; reconnect MAP/BP sensor and go to TEST C, step 1.

3) Check MAP/BP Sensor Output With MAP/BP tester connected and ignition on, measure sensor output voltage. If output voltage is within range, for altitude in which vehicle is being tested, remove MAP/BP tester and go to next step. If output reading is outside range, remove MAP/BP tester and go to step 5.

If possible, measure output voltage several known good MAP/BP sensors on available vehicles. The average voltage reading will be typical for your location on date of testing.

MAP SENSOR VOLTAGE OUTPUT

4) Check Continuity Of MAP/BP SIG Circuit Turn ignition off and wait 10 seconds. Disconnect MAP/BP sensor from vehicle harness. Disconnect ECA 60-pin connector. Inspect for damaged wiring and repair as necessary. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between MAP/BP SIG circuit at sensor vehicle harness connector and test pin No. 45. If reading is less than 5 ohms, replace ECA. Reconnect components and repeat QUICK TEST. If reading is 5 ohms or higher, repair open circuit. Remove breakout box, reconnect components and repeat QUICK TEST.

5) Check MAP/BP SIG Circuit For Shorts To VREF, SIG RTN & Ground Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for damaged wiring and repair as necessary. Install breakout box, leaving ECA disconnected. Disconnect harness at MAP/BP sensor. Set DVOM on 200-k/ohm scale. Measure resistance between test pin No. 45 and test pins No. 26, 46, 40 and 60. If any reading is less than 10 k/ohms, repair short circuit. Remove breakout box and reconnect all components. Repeat QUICK TEST. If all readings are 10 k/ohms or more, replace MAP/BP sensor. Remove breakout box and connect all wiring. Repeat QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 5 to step 7. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

7) KOER Code 22/126: Check For EGR-Related Codes KOER Code 22/126 indicates MAP/BP signal is out of self-test range during KOER SELF-TEST. Check for Codes 31, 32, 33, 34, 35, 326, 327, 328, 332, 334, 336 or 337. If codes are present, go to appropriate KOER SELF-TEST CODES under SERVICE CODE REFERENCE CHARTS to find the proper CIRCUIT TEST. If codes are not present, go to next step.

8) Check MAP Sensor Operation Turn ignition off and wait 10 seconds. Disconnect vacuum hose from MAP sensor. Connect vacuum pump to MAP sensor and apply 18 in. Hg to sensor. If sensor does not hold vacuum, replace sensor; connect vacuum line and repeat QUICK TEST. If MAP sensor holds vacuum, release vacuum and go to next step.

9) Attempt To Eliminate Code 22/126 Turn ignition off and wait 10 seconds. Plug vacuum hose going to MAP sensor. Start engine and run at 1400-1600 RPM. Slowly apply 15 in. Hg to MAP sensor. With engine operating under these conditions, perform KOER SELF-TEST. Check for Code 22/126; disregard any other codes at this time. If Code 22/126 is still present, replace MAP sensor. If Code 22/126 is no longer displayed, inspect vacuum hose going to MAP sensor. If hose is okay, service other codes at this time. If no other code is present, check engine mechanical condition for cause of low vacuum.

10) Code 72/129: Repeat Dynamic Response (Goose) Test Code 72/129 indicates MAP sensor output did not change enough during dynamic response (Goose) test. Possible causes for this code are as follows

1. System failed to detect partial Wide Open Throttle (WOT)
2. Incorrect MAP sensor vacuum line routing
3. Faulty MAP sensor

Repeat KOER SELF-TEST. Ensure complete WOT is performed during dynamic response portion of test. If KOER Code 72/129 is still present, go to next step. If code is not present, service other codes as necessary.

11) Code 81/128: Check Vacuum Hoses Continuous memory code 81/128 indicates MAP sensor vacuum has not changed more than 2 in. Hg during normal vehicle operation. Possible causes for this code are as follows

1. MAP sensor vacuum supply hose is improperly routed, blocked or is leaking.
2. MAP sensor is leaking. - With ignition off, check vacuum lines for correct routing. Refer to Vehicle Emission Control Identification (VECI) decal. Check for disconnections, kinks or blockage. Repair vacuum lines as necessary and repeat QUICK TEST. If vacuum lines are okay, go to next step.

12) Check MAP Sensor Operation Turn ignition off and wait 10 seconds. Disconnect vacuum supply hose from MAP sensor. Install vacuum pump to MAP sensor. Apply 18 in. Hg to MAP sensor. If MAP sensor holds vacuum, release vacuum and go to next step. If sensor does not hold vacuum, replace MAP sensor; reconnect components and repeat QUICK TEST.

13) Ensure Vacuum To MAP Sensor Decreases During Dynamic Response (Goose) Test Turn ignition off and wait 10 seconds. Use a "T" fitting to install a vacuum gauge in the intake manifold MAP sensor supply line. Perform KOER SELF-TEST while observing vacuum gauge. If vacuum decreases by more than 10 in. Hg during dynamic response (Goose) test, remove gauge and replace MAP sensor; rerun QUICK TEST. If vacuum does not decrease by 10 in. Hg or more, EEC-IV system is okay; repair engine mechanical components as necessary to increase engine vacuum.

Note. There is a break in the step numbering sequence at this point, skipping from step 13 to step 90. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

90) Continuous Memory Code 22/126: Operate MAP/BP Sensor Continuous Code 22/126 indicates MAP/BP sensor was out of self-test range (1.4-1.6 volts) during normal driving conditions. Possible causes for this code are as follows

1. Faulty MAP/BP Sensor
2. Faulty wiring harness or connectors
3. Unusually high or low barometric pressure

While in KOEO wiggle test (see CONTINUOUS MONITOR MODE (WIGGLE TEST) under QUICK TEST), observe test equipment while performing the following

1. Connect a vacuum pump to MAP/BP sensor.
2. Slowly apply 25 in. Hg to sensor.
3. Slowly bleed off vacuum from sensor.
4. Lightly tap on sensor (to simulate road shock).
5. Wiggle sensor connector.

If a fault is indicated, disconnect sensor and inspect connectors. Repair as necessary. If connectors are okay, replace MAP/BP sensor. Rerun QUICK TEST. If a fault is not indicated, go to next step.

91) Check EEC-IV Vehicle Harness Stay in KOEO wiggle test. Observe VOM or diagnostic tester for indication of fault while shaking, bending or wiggling small sections of harness from sensor connector to firewall. Check harness from firewall to ECA in same manner. If fault is indicated, isolate fault in harness and repair as necessary. Clear codes and repeat QUICK TEST. If no fault is indicated, go to next step.

92) Check ECA & Vehicle Harness Connectors Turn ignition 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 Memory Code 22/126 testing is complete. Refer to INTERMITTENTS in the TESTS W/O CODES article.

Perform this test only when directed by QUICK TEST.

TPS Circuits. Scheme 14

TEST PIN WIRE COLOR IDENTIFICATION

TPS Specification Charts. Scheme 15

2.3L TPS SPECIFICATIONS TABLE. Scheme 16

The normal range of throttle angle measurement for TPS is 0-8. degrees. To pass QUICK TEST procedure, the range of throttle rotation (in degrees) must be within 3% of specification.

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault

1. Idle Speed
2. Throttle Stop Adjustment
3. Binding Throttle Shaft Or Linkage
4. Cruise Control Linkage

1) Code 23/121: Check For Other Codes Code 23/121 indicates TPS rotational setting may be out of self-test range. See TPS SPECIFICATION CHARTS. Possible causes for this fault are as follows

1. Binding Throttle Linkage
2. TPS not seated correctly
3. Faulty TPS
4. Faulty ECA

If you are at this step to service a KOEO Code 23/121, check for Code 31/327 in KOER SELF-TEST. If any of these codes is present, return to appropriate KOEO SELF-TEST CODES or KOER SELF-TEST CODES chart under SERVICE CODE REFERENCE CHARTS; proceed as directed to Code 31/327. If these codes are not present, go to next step.

2) Code 23/121: Check For Stuck Throttle Plate Code 23/121 indicates Throttle Position Sensor (TPS) rotational setting may be out of self-test range. Possible causes for this fault are as follows

1. Binding Throttle Linkage
2. TPS not seated correctly
3. Faulty TPS
4. Faulty ECA

Inspect throttle body and linkage for binding or sticking. Ensure linkage is in throttle-closed position. If throttle plate or linkage is binding, check for binding throttle or cruise control linkage, vacuum line or harness interference, etc. Repair any problem and repeat QUICK TEST. If no mechanical problem is found, go to next step.

3) Code 53/112: Attempt to Generate Code 63/122 Code 53/112 indicates TPS signal is greater than self-test maximum value. Possible causes for this fault are as follows

1. TPS not seated properly
2. Faulty TPS Sensor
3. VREF circuit shorted in vehicle harness
4. Faulty ECA

Turn ignition off and wait 10 seconds. Disconnect TPS from vehicle harness at throttle body. Inspect and repair any damaged wiring or connector pins. Disconnect both 4EAT module vehicle harness connectors on 1.9L SPFI-MA with auto. trans. Repeat KOEO SELF-TEST. Ignore all other codes at this time. If Code 63/122 is not displayed, go to step 6. If Code 63/122 is displayed, go to next step.

4) Check VREF Circuit Voltage Turn ignition off and wait 10 seconds. Set DVOM on 20-volt scale. Disconnect TPS and both 4EAT module vehicle harness connectors. With ignition on and engine off, measure voltage between VREF and SIG RTN at TPS vehicle harness connector. If reading is less than 4 volts or more than 6 volts, reconnect sensor and go to TEST C, step 1. If reading is between 4 and 6 volts, go to next step (1.9L SPFI-MA Escort).

5) Check For Shorted 4EAT Transmission Module All 1.9L SPFI-MA have a TP input circuit to 4EAT module. This test verifies that TP circuit is not shorted inside 4EAT module. With ignition off, reconnect TP sensor. Ensure both 4EAT module vehicle harness connectors are disconnected. Repeat KOEO SELF-TEST. If Code 53/123 is present (ignore other codes at this time), replace TPS and repeat QUICK TEST. If Code 53/123 is not present, service transmission components as necessary.

6) Checking TP Circuit For Short To Power Turn ignition off and wait 10 seconds. Disconnect TPS from harness. Set DVOM on 200-k/ohm scale. Disconnect ECA 60-pin connector. Inspect and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Measure resistance between test pin No. 47 and test pins No. 26 and 57. If either reading is less than 10 k/ohms, repair short in harness; connect components and repeat QUICK TEST. If both readings are 10 k/ohms or more, replace ECA; reconnect components and repeat QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 6 to step 10. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

10) Code 63/122: Attempt To Generate Code 53/123 or 23/121 Code 63/122 indicates TP signal is less than minimum self-test value. Refer to TPS SPECIFICATION CHART at beginning of this circuit test. Possible causes for this fault are as follows

1. TPS not seated correctly
2. Faulty TPS
3. Open circuit in vehicle harness
4. Grounded circuit in vehicle harness
5. Faulty ECA

Turn ignition off and wait 10 seconds. Disconnect TPS from harness. Install a jumper wire between VREF and TP circuit at TPS vehicle harness connector. Perform KOEO SELF-TEST. If no codes are generated, immediately remove jumper wire and go directly to step 13 (1.9L SPFI-MA with auto. trans. Check for Codes 53/123 or 23/121 (ignore all other codes at this time). If Codes 53/123 or 23/121 are not present, remove jumper wire, and go to next step. If either Code 53/123 or 23/121 is displayed, replace TPS; remove jumper and repeat QUICK TEST.

11) Check VREF Circuit Voltage Turn ignition off and wait 10 seconds. Disconnect TPS from vehicle harness. Inspect and repair any damaged wiring. Set DVOM on 20-volt scale. With ignition on and engine off, measure voltage between VREF and SIG RTN circuits at TPS vehicle harness connector. If reading is less than 4 volts or more than 6 volts, go to TEST C, step 1. If reading is between 4 and 6 volts, reconnect all components and go to next step.

12) Check TPS Circuit Continuity Turn ignition off and wait 10 seconds. Leave TPS disconnected. Set DVOM on 200-ohm scale and disconnect ECA 60-pin connector. Inspect and repair any damaged wiring. Install breakout box and connect ECA. Measure resistance between TP circuit at TPS vehicle harness connector and test pin No. 47. If reading is 5 ohms or more, repair open circuit. Remove breakout box, reconnect all components and repeat QUICK TEST. If reading is less than 5 ohms, go to step 14.

13) Check For Shorted 4EAT Module All 1.9L SPFI-MA have a TP input circuit to 4EAT module. This test verifies that TP circuit is not shorted inside the 4EAT module. With ignition off, reconnect TP sensor. Ensure both 4EAT module vehicle harness connectors are disconnected. Repeat KOEO SELF-TEST. If Code 63/122 is present (ignore other codes at this time), disconnect TPS, and go to next step. If Code 63/122 is not present, service transmission components as necessary.

14) Check TP Circuit For Shorts To Ground Turn ignition off and wait 10 seconds. Leave TPS disconnected. Ensure both 4EAT module vehicle harness connectors are disconnected (if applicable). Disconnect ECA 60-pin connector. Inspect and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200-k/ohm scale. Measure resistance between test pin No. 47 and test pins No. 40, 46 and 60. If any reading is less than 10 k/ohms, repair short circuit; reconnect all components and repeat QUICK TEST. If all readings are 10 k/ohms or more, replace ECA. Remove breakout box, reconnect all components and repeat QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 14 to step 20. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

20) KOER Code 73/167: Perform Correct Dynamic Response (Goose) Test At Wide Open Throttle (WOT) KOER Code 73/167 indicates TPS did not exceed 25% of its rotation during dynamic response check portion of KOER SELF-TEST. A complete WOT must be performed during dynamic response check portion. Run KOER SELF-TEST. Ensure WOT is performed during dynamic response portion of test. If Code 73/167 is still present, go to next step. If code is not present, system is unable to duplicate Code 73/167 at this time. Service any other KOER codes at this time. If no other KOER code is present, testing is complete.

21) Check TPS Movement During Dynamic Response Test Turn ignition off and disconnect ECA 60-pin connector. Inspect and repair any damaged wiring. Install breakout box and connect ECA. Set DVOM on 20-volt scale. Connect DVOM between test pins No. 46 and 47. Perform KOER SELF-TEST and ensure a proper WOT is performed. Monitor DVOM reading during dynamic response check. If reading exceeds 3.5 volts, replace ECA; remove breakout box, reconnect all components and repeat QUICK TEST. If reading does not exceed 3.5 volts, ensure TPS is correctly installed and adjusted. If TPS is correctly installed and adjusted, replace TPS. Repeat QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 21 to step 90. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

90) Continuous Memory Code 53/123: Monitor TPS Circuit Under Simulated Road Shock Conditions Enter KOEO wiggle test (see CONTINUOUS MONITOR MODE (WIGGLE TEST) under QUICK TEST); observe DVOM or diagnostic tester for indication of fault while slowly opening throttle to WOT. Slowly bring throttle to closed position, and lightly tap TPS and wiggle harness connector. This test checks for open or short in TPS, connectors and vehicle harness. If no fault is indicated, go to step 92. If fault is indicated, go to next step.

91) Measure TP Circuit Voltage While Exercising TPS Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect and repair any damaged wiring. Install breakout box, leaving ECA connected. Stay in KOEO wiggle test (as in previous step). Connect DVOM between test pins No. 47 and 46. Set DVOM on 20-volt scale. With ignition on and engine off, observe DVOM and repeat step 90. If fault occurs at less than 4.25 volts, inspect TPS connectors and terminals. If connectors and terminals are okay, replace TPS; clear codes and repeat QUICK TEST. If fault does not occur at less than 4.25 volts, TPS over-travel may have caused Continuous Memory Code 53/123. TPS is okay, go to next step to check harness.

92) Check EEC-IV Vehicle Harness While in KOEO wiggle test (CONTINUOUS MONITOR MODE), shake, bend and wiggle small sections of EEC-IV harness from TPS vehicle harness connector to firewall, and from firewall to ECA. If fault is indicated, isolate fault in wiring and repair as necessary. Clear codes and repeat QUICK TEST. If no fault is indicated, go to next step.

93) Check ECA & Harness Connectors Turn ignition 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; clear Continuous Memory Codes and repeat QUICK TEST. If connectors and terminals are okay, fault cannot be duplicated at this time. Continuous Memory Code 53/123 testing is complete.

94) Continuous Memory Code 63/122: Monitor TP Circuit Under Simulated Road Shock Conditions Enter KOEO wiggle test. See CONTINUOUS MONITOR MODE (WIGGLE TEST) under QUICK TEST. Observe VOM or diagnostic tester for indication of fault while performing the following

1. Slowly open throttle to WOT.
2. Slowly bring throttle to closed position.
3. Lightly tap TPS and wiggle connector.

This test checks for open or short in TPS, connectors and vehicle harness. If fault is indicated, disconnect TPS. Inspect connectors and terminals. If connectors and terminals are okay, replace TPS. Clear Continuous Memory Codes and repeat QUICK TEST. If no fault is indicated, go to next step.

95) Check EEC-IV Vehicle Harness While in KOEO wiggle test (CONTINUOUS MONITOR MODE), shake, bend and wiggle small sections of EEC-IV harness from TPS sensor vehicle harness connector to firewall, and from firewall to ECA. If fault is indicated, isolate fault in wiring and repair as necessary. Clear Continuous Memory Codes and repeat QUICK TEST. If no fault is indicated, go to next step.

96) Check ECA & Harness Connectors Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect both connectors and terminals for damage. If connectors and terminals are damaged, repair as necessary. Clear Continuous Memory Codes and repeat QUICK TEST. If connectors and terminals are okay, fault cannot be duplicated at this time. Continuous Memory Code 63/122 testing is complete.

Perform this test only when instructed during QUICK TEST, or when directed by other test procedures.

This CIRCUIT TEST is intended to diagnose the following

1. VREF, PFE, SIG RTN, EVR and VPWR harness circuits
2. PFE sensor
3. EVR solenoid
4. EGR valve assembly
5. ECA
6. Vacuum lines and tubes of EVR and PFE

PFE Valve, DPFE Sensor & EVR Solenoid Circuits. Scheme 17

TEST PIN WIRE COLOR IDENTIFICATION

PFE SENSOR SPECIFICATIONS

DPFE SENSOR SPECIFICATIONS

To prevent replacement of good components, be aware that the following non-EEC components may be at fault

1. Faulty or damaged EGR valve
2. Restricted exhaust system
3. Damaged vacuum reservoir or canister

1) Code 31/327: Generate Code 35/337 Code 31/327 indicates PFE/DPFE sensor signal is less than self-test minimum of 0.2 volt. Possible causes for this fault are as follows

1. Faulty PFE sensor
2. Open harness circuits
3. Shorted harness circuits
4. Faulty ECA

Turn ignition off. Disconnect PFE/DPFE harness at sensor. Install a jumper wire between VREF circuit and PFE/DPFE circuit at PFE/DPFE sensor vehicle harness connector. Perform KOEO SELF-TEST. Check for Code 35/337. Ignore all other codes at this time. If no code is displayed, immediately remove jumper wire and go directly to step 4. If Code 35/337 is displayed, remove jumper wire and replace PFE/DPFE sensor. Repeat QUICK TEST. If Code 35/337 is not displayed, remove jumper wire and go to next step.

2) Measure VREF Circuit Voltage With ignition off and PFE/DPFE sensor disconnected, set DVOM on 20-volt scale. With ignition on and engine off, measure voltage at PFE/DPFE sensor vehicle harness connector between VREF and SIG RTN circuits. If reading is less than 4 volts or more than 6 volts, go to TEST C, step 1. If reading is between 4 and 6 volts, go to next step.

3) Check PFE/DPFE Circuit Continuity With ignition off and PFE sensor disconnected, set DVOM on 200-ohm scale. Disconnect ECA 60-pin connector. Inspect and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Measure resistance between PFE/DPFE circuit (at PFE/DPFE sensor vehicle harness connector) and test pin No. 27. If resistance is 5 ohms or more, repair open circuit. Connect PFE/DPFE sensor and remove breakout box. Repeat QUICK TEST. If reading is less than 5 ohms, go to next step.

4) Check PFE Circuit For Shorts To Ground & SIG RTN With ignition off and PFE/DPFE sensor disconnected, install breakout box; leave ECA disconnected. Set DVOM on 200-k/ohm scale. Measure resistance between PFE/DPFE circuit (at vehicle harness connector) and test pins No. 40 and 60 (at breakout box). Measure resistance between PFE/DPFE circuit (at PFE/DPFE sensor vehicle harness connector) and test pin No. 46. If either reading is less than 10 k/ohms, repair short circuit. Connect PFE/DPFE and remove breakout box. Repeat QUICK TEST. If both readings are 10 k/ohms or more, replace ECA. Reconnect all components and remove breakout box. Repeat QUICK TEST.

5) Code 35/337: Generate Code 31/327 Code 35/337 indicates PFE/DPFE sensor signal is greater than self-test maximum of 4.8 volts. Possible causes for this fault are as follows: a faulty PFE/DPFE sensor, shorted vehicle harness circuits, or faulty ECA. Turn ignition off and disconnect PFE/DPFE sensor. Inspect and repair any damaged wiring. Repeat KOEO SELF-TEST. Check for Code 31/327. Ignore all other codes at this time. If Code 31/327 is not displayed, proceed to step 7. If Code 31 is displayed, go to next step.

6) Measure VREF Circuit Voltage With ignition off and PFE/DPFE sensor disconnected, set DVOM on 20-volt scale. Turn ignition on, leaving engine off. Measure voltage at PFE/DPFE sensor vehicle harness connector between VREF circuit and SIG RTN circuit. If reading is 4).

7) Check PFE/DPFE Circuit For Shorts To Power With ignition off and PFE/DPFE harness disconnected, disconnect ECA 60-pin connector. Inspect and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200-k/ohm scale. Measure resistance between test pin No. 27 and test pins No. 26, 37 and 57. If any reading is less than 10 k/ohms, repair short. Connect PFE/DPFE and remove breakout box. Repeat QUICK TEST. If all readings are 10 k/ohms or more, replace ECA. Connect PFE/DPFE and remove breakout box. Repeat QUICK TEST.

8) Code 34/335: Verify KOER Codes Code 34/335 indicates PFE/DPFE sensor is out of self-test range (2.6-4.2 volts), and PFE/DPFE sensor may be faulty. PFE/DPFE system can detect lack of pressure in exhaust system. An efficient garage exhaust ventilation system, installed during KOEO SELF-TEST, may cause PFE/DPFE sensor to generate Code 34/335. Remove exhaust ventilation system and retest. If Code 34/335 is not displayed, service other codes displayed during KOEO SELF-TEST; if no code is displayed, continue with QUICK TEST. If Code 34/335 is displayed, go to next step.

9) Check PFE/DPFE Sensor Pressure Input Hose Remove pressure feed tube from PFE/DPFE sensor. Inspect complete tube, including PFE/DPFE inlet, for blockage. If blockage is found, repair as necessary. Repeat QUICK TEST. If no blockage is found, go to next step.

10) Measure VREF Circuit Voltage Turn ignition off and disconnect PFE/DPFE sensor. Inspect and repair any damaged wiring. Set DVOM on 20-volt scale. Turn ignition on, leaving engine off. Measure voltage at PFE/DPFE sensor vehicle harness connector between VREF and SIG RTN circuit. If reading is 4-6 volts, replace PFE/DPFE sensor. Repeat QUICK TEST. If reading is NOT 4-6 volts, go to TEST C, step 1.

11) Code 84/558: Measure EVR Solenoid Resistance Code 84/558 indicates failure in EVR solenoid circuit. Possible causes for this fault are as follows: faulty EVR solenoid, open or shorted harness circuit, or faulty ECA. Turn ignition off. Set DVOM on 200-ohm scale. Disconnect EVR solenoid connector and measure solenoid resistance. If reading is NOT 25-70 ohms, replace EVR solenoid assembly. Repeat QUICK TEST. If reading is 25-70 ohms, go to next step.

12) Check VPWR Circuit Voltage With ignition on and engine off, and EVR solenoid disconnected from harness, set DVOM on 20-volt scale. Measure voltage between negative battery terminal and VPWR circuit at EVR solenoid vehicle harness connector. If reading is less than 10.5 volts, repair open circuit. Repeat QUICK TEST. If reading is 10.5 volts or more, go to next step.

13) Check Continuity Of EVR Circuit Turn ignition off and disconnect EVR solenoid from harness. Disconnect ECA 60-pin connector. Inspect and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 33 and EVR circuit at EVR solenoid vehicle harness connector. If resistance is 5 ohms or more, repair open circuit. Connect EVR solenoid and remove breakout box. Repeat QUICK TEST. If reading is less than 5 ohms, go to next step.

14) Check EVR Circuit For Shorts To Power Or Ground Turn ignition off. Install breakout box, leaving ECA disconnected. Disconnect EVR solenoid. Set DVOM on 200-k/ohm scale. Measure resistance between test pin No. 33 and test pins No. 37, 57, 40 and 60 at breakout box. If any reading is less than 10 k/ohms, repair short circuit. Remove breakout box. Connect ECA and EVR solenoid. Repeat QUICK TEST. If code is repeated, replace ECA. If all readings are 10 k/ohms or more, replace ECA. Remove breakout box. Reconnect ECA and EVR solenoid. Repeat QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 14 to step 20. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

20) Code 32/326: Verify KOER Codes Code 32/326 indicates EGR valve is not fully seated. Possible causes for this fault are as follows

1. Obstructed vacuum line
2. Contaminated EVR filter
3. Faulty EGR valve
4. Faulty EVR solenoid

The PFE/DPFE system can detect lack of pressure in exhaust system. An efficient garage exhaust ventilation system, installed during KOER SELF-TEST, may cause PFE/DPFE sensor to generate Code 32/326. Temporarily remove exhaust ventilation system and retest. If Code 32/326 is not displayed, service other codes displayed during KOER SELF-TEST; if no code is displayed, continue with QUICK TEST. If Code 32/326 is present, go to next step.

21) Code 31/327: Separate EVR From PFE Code 31/327 indicates PFE/DPFE sensor signal is less than self-test minimum of 3.25 volts. Turn ignition off. Disconnect and plug EGR valve vacuum hose. Perform KOER SELF-TEST. If Codes 31/327 or 32/326 are present, go to next step. If codes are not present, EVR filter or solenoid is contaminated. Replace EVR solenoid. Reconnect all components and repeat QUICK TEST.

22) Check PFE/DPFE Sensor Supply Tube For Blockage With ignition off, check PFE/DPFE sensor supply tube for blockage or leaks; repair as necessary. Connect all lines and repeat QUICK TEST. If no fault is found, service or diagnose faulty EGR system.

Note. There is a break in the step numbering sequence at this point, skipping from step 22 to step 25. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

25) Codes 34/336 & 35/337: Check PFE/DPFE Input Pressure Code 34/336 indicates PFE/DPFE voltage is too high (possibly because of excessive exhaust backpressure for PFE). Code 35/337 indicates PFE/DPFE circuit voltage is excessively higher than self-test maximum. Possible causes for these codes are as follows

1. Exhaust system blocked
2. PFE/DPFE sensor faulty
3. Faulty ECA

Turn ignition off. Disconnect and inspect PFE/DPFE inlet hose(s) for damage; repair or replace hose(s) as necessary. Reconnect hose(s) and return to QUICK TEST. If hose(s) is okay, install "T" fitting into PFE/DPFE inlet hose and connect vacuum/pressure gauge to "T" fitting. Start engine. Open and close throttle while observing vacuum/pressure gauge. If vacuum/pressure gauge does not fluctuate, check exhaust system for restriction. If vacuum/pressure gauge fluctuates, remove vacuum/pressure gauge and go to next step.

26) Check PFE/DPFE Sensor Output With Engine Idling With ignition off, disconnect PFE/DPFE sensor. Set DVOM on 20-volt scale. Start engine, let idle and measure sensor output voltage. If voltage is 2.5-3.5 volts, go to next step. If voltage is NOT 2.5-3.5 volts, replace sensor and rerun QUICK TEST.

27) Check PFE/DPFE Harness Continuity Ensure ignition is off. Disconnect PFE/DPFE sensor connector. Set DVOM on 200-k/ohm scale. Disconnect ECA 60-pin connector. Inspect and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Measure resistance between PFE/DPFE circuit (at PFE/DPFE sensor vehicle harness connector) and test pin No. 27. Measure resistance between PFE/DPFE SIG RTN circuit (at PFE/DPFE sensor vehicle harness connector) and test pin No. 46. If each resistance is less than 10 k/ohms, repair short circuit. Remove breakout box, reconnect all components and rerun QUICK TEST. If each resistance is greater than 10 k/ohms, go to next step.

28) Check PFE/DPFE Harness Circuit For Short To Power Ensure ignition is off. Disconnect PFE/DPFE sensor connector. Set DVOM on 200-k/ohm scale. Disconnect ECA 60-pin connector. Inspect and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Measure resistance between test pin No. 27 and test pins No. 26, 37 and 57. If each resistance is greater than 10 k/ohms, replace ECA. Remove breakout box, reconnect all components and rerun QUICK TEST. If each resistance is less than 10 k/ohms, repair short. Remove breakout box, reconnect all components and rerun QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 28 to step 30. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

30) Code 33/332: Verify Vacuum At EGR Valve Code 33/332 indicates PFE/DPFE sensor input did not change after EVR solenoid received signal from ECA to open EGR valve. Possible causes for this fault are as follows

1. Vacuum hose leaks
2. Obstructed vacuum hose
3. Faulty EVR solenoid
4. Faulty PFE/DPFE sensor
5. Faulty EGR valve

Turn ignition off and wait 10 seconds. Using a vacuum "T", connect vacuum gauge at EGR valve. Perform KOER SELF-TEST while observing vacuum gauge. Disregard code output at this time. If vacuum reading is greater than 1 in. Hg, go to step 36. If vacuum reading is 1 in. Hg or less, remove vacuum gauge and go to next step.

31) Check Vacuum Input To EVR Solenoid Turn ignition off and wait 10 seconds. Using a vacuum "T", connect vacuum gauge between manifold vacuum source and EVR solenoid input port. Start engine, let idle and observe vacuum gauge. If vacuum is present, go to next step. If vacuum is not present, replace vacuum line between EVR solenoid and vacuum source. Rerun QUICK TEST.

32) Enter Output State Check Turn ignition off and wait 10 seconds. Disconnect speed control servo electrical connector (if equipped). Set DVOM to 20-volt scale. Connect DVOM negative lead to self-test connector STO circuit, and positive lead to battery positive terminal. Install jumper wire between STI circuit and SIG RTN of self-test connector.

Perform KOEO SELF-TEST until Continuous Memory Codes appear. DVOM will indicate less than 1.0 volt when test is complete. When test is complete, depress and release throttle. If voltage increases, remain in Output State Check and go to next step. If voltage does not increase, depress throttle to WOT and release. If STO voltage does not go high, leave equipment installed and go to TEST QC step 1.

33) Check EVR Solenoid Electrical Operation With ignition on and engine off, disconnect EVR solenoid harness connector. Set DVOM to 20-volt scale. Connect DVOM positive lead to VPWR circuit, and negative lead to EVR signal circuit at EVR solenoid vehicle harness connector. Observe DVOM. Depress and release throttle several times to cycle output. If EVR solenoid circuit voltage does not cycle above 0.5 volt, remove jumper wire and go to next step. If EVR circuit voltage cycles above 0.5 volt, replace EVR solenoid and rerun QUICK TEST.

34) Check Continuity Of EVR Solenoid Circuit Turn ignition off and wait 10 seconds. Set DVOM on 200-ohm scale. Disconnect ECA 60-pin connector. Inspect and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Measure resistance between test pin No. 33 and EVR signal circuit at vehicle harness connector. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair open circuit. Remove breakout box, reconnect all components and rerun QUICK TEST.

35) Check For EVR Signal Circuit Shorts Turn ignition off and wait 10 seconds. Set DVOM on 200-k/ohm scale. Disconnect ECA 60-pin connector. Inspect and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Measure resistance between test pin No. 33 and test pins No. 40, 46, 60, 37 and 57. If all resistances are less than 10 k/ohms, repair short circuit(s). Remove breakout box, reconnect all components and rerun QUICK TEST. If all resistances are greater than 10 k/ohms, replace ECA. Remove breakout box, reconnect all components and rerun QUICK TEST.

36) Check Vacuum At PFE/DPFE Pressure Inlet Hose(s) Turn ignition off and wait 10 seconds. Using a vacuum "T", connect vacuum gauge at PFE/DPFE inlet hose(s). Start engine, let idle and observe vacuum gauge. If vacuum is not present, remove vacuum gauge and go to next step. If vacuum is present, remove vacuum gauge. If hose(s) are damaged, replace hose(s) and rerun QUICK TEST. If hose(s) are okay, go to step 38.

37) Check EGR Valve Operation With ignition off, disconnect vacuum hose at EGR valve. Connect vacuum pump to EGR valve. While observing EGR valve, slowly apply 10 in. Hg. EGR valve should begin to open with a very small amount of vacuum (1-1.5 in. Hg), and should be fully open with about 4 in. Hg. If EGR opens freely and smoothly, replace source vacuum hose; remove vacuum pump and rerun QUICK TEST. If EGR valve does not open freely and smoothly, service or replace EGR valve.

38) Attempt To Generate KOEO Code 35/337 Turn ignition off and wait 10 seconds. Disconnect PFE/DPFE sensor. Install jumper wire between PFE/DPFE circuit and VREF circuit at PFE/DPFE sensor vehicle connector. Perform KOEO SELF-TEST. If no code is generated, remove jumper wire immediately and go directly to step 39.

39) Measure VREF Circuit Voltage Turn ignition off and wait 10 seconds. Disconnect PFE/DPFE sensor. Set DVOM to 20-volt scale. With ignition on and engine off, measure voltage between VREF circuit and SIG RTN circuit at PFE/DPFE sensor vehicle harness connector. If voltage is 4-6 volts, go to next step. If voltage is NOT 4-6 volts, go to TEST C step 1.

40) Check PFE/DPFE Harness Circuit Continuity Turn ignition on and wait 10 seconds. Set DVOM to 200-ohm scale. Disconnect PFE/DPFE sensor. Disconnect ECA 60-pin connector. Inspect and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Measure resistance between PFE/DPFE circuit at PFE/DPFE sensor vehicle harness connector and test pin No. 27 of breakout box. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair open circuit. Remove breakout box, reconnect all components and rerun QUICK TEST.

41) Check PFE/DPFE Harness Circuit For Shorts Turn ignition off and wait 10 seconds. Disconnect PFE/DPFE sensor. Install breakout box, leaving ECA disconnected. Set DVOM to 200-k/ohm scale. Measure resistance between PFE/DPFE circuit (at PFE/DPFE sensor vehicle harness connector) and test pins No. 40 and 60.

Measure resistance between PFE/DPFE circuit (at PFE/DPFE sensor vehicle harness connector) and test pin No. 46. If all resistances are less than 10 k/ohms, repair short. Remove breakout box, connect all components and rerun QUICK TEST. If all resistances are greater than 10 k/ohms, replace ECA. Remove breakout box, connect all components and rerun QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 41 to step 90. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

90) Continuous Memory Code 31/327 Or 35/337: Testing the PFE/DPFE Sensor Code 31/327 or 35/337 indicates PFE/DPFE sensor signal was either less than, Code 31/327, or greater than, Code 35/337, the self-test voltage during vehicle operation. Possible causes for this fault are as follows: damaged connectors or terminals, open or grounded vehicle harness, or faulty PFE/DPFE sensor.

Enter KOEO wiggle test (see CONTINUOUS MONITOR MODE (WIGGLE TEST) under QUICK TEST). Observe VOM or diagnostic tester for indication of fault while performing the following steps. Connect a vacuum pump to PFE/DPFE sensor and slowly apply 5 in. Hg to sensor. Slowly bleed vacuum off PFE/DPFE sensor. Lightly tap on PFE/DPFE sensor and wiggle PFE/DPFE connector. If fault is indicated, disconnect harness and inspect connector. If connector and terminals are okay, replace PFE/DPFE sensor. Clear codes and repeat QUICK TEST. If no fault is indicated, go to next step.

PFE Harness Circuit. Scheme 18

91) Check EEC-IV Vehicle Harness With vehicle still in KOEO wiggle test, observe VOM or diagnostic tester for fault indication; grasp the vehicle harness near sensor connector, then wiggle, shake or bend small sections of harness, working your way toward firewall. Also wiggle, shake or bend harness from firewall to ECA. If fault is indicated, isolate fault and repair as necessary. Repeat QUICK TEST. If fault is not indicated, go to next step.

92) Check ECA & Vehicle Harness Connectors Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect both connector and terminals for damage. Repair as necessary. Clear codes and repeat QUICK TEST. If connector and terminals are okay, fault is intermittent and cannot be duplicated at this time. Clear codes and repeat QUICK TEST.

93) Continuous Memory Code 34/336: Check PFE Supply Tube For Blockage Code 34 indicates PFE sensor was restricted sometime during vehicle operation. Turn ignition off. Remove PFE sensor and inspect sensor supply inlet for liquids or any type of blockage. Inspect PFE supply tube at EGR valve base for liquids or blockage. If supply tube is blocked, clean or service as necessary. Clear codes and repeat QUICK TEST. If supply tube is not blocked, fault is intermittent and cannot be duplicated at this time. Clear codes and repeat QUICK TEST.

94) Continuous Memory Code 32/326: Check EGR Valve Operation Code 32/326 indicates EGR valve was not fully seated sometime during vehicle operation. Possible causes for this fault are as follows

1. Obstructed vacuum hose
2. Contaminated EVR filter
3. Faulty EGR valve

Turn ignition off. Connect vacuum pump to EGR valve and apply 10 in. Hg. While observing EGR valve, release vacuum, and repeat step if necessary. If EGR valve does not operate smoothly, service or replace EGR valve; clear codes and repeat QUICK TEST. If EGR valve works smoothly, go to next step.

95) Inspect Vacuum Lines Between EVR Solenoid & EGR Valve Inspect EGR valve vacuum supply line from EVR solenoid to EGR valve for kinks or obstructions. If vacuum supply line is blocked, repair as necessary. Clear codes and repeat QUICK TEST. If vacuum supply line is okay, go to next step.

96) Inspect EVR Solenoid Filter Carefully check EVR filter for contamination or obstructions. If EVR filter is contaminated, replace filter; clear codes and repeat QUICK TEST. If EVR filter is not contaminated, fault is intermittent and cannot be duplicated at this time. Continuous Memory Code 32/326 testing is complete.

97) Attempt To Remove Drive Symptom Turn ignition off and wait 10 seconds. Disconnect and plug EGR valve vacuum line at EGR valve. Start engine and let idle. If engine runs smoothly and does not stall, turn engine off. Remove plug from vacuum line and go to next step. If engine runs rough or stalls, turn engine off. Remove plug from vacuum line and reconnect line to EGR valve. Problem cannot be identified at this time. Check for faulty EGR valve. Clear continuous memory codes and rerun QUICK TEST.

98) Rerun Self-Test With EGR Valve Vacuum Line Disconnected Turn ignition off and wait 10 seconds. Disconnect and plug EGR valve vacuum line at EGR valve. Perform KOEO SELF-TEST. If code(s) 31, 32, 326 or 327 is present, go to next step. If code(s) 31, 32, 326 or 327 is not present, replace EVR solenoid. Reconnect components and rerun QUICK TEST.

99) Check PFE/DPFE Sensor Pressure Inlet Hose(s) For Blockage Turn ignition off and wait 10 seconds. Check PFE/DPFE sensor pressure input hose(s) for obstructions and/or leaks, and repair obstructions and/or leaks as necessary; reconnect vacuum hose(s) and rerun QUICK TEST. If hose(s) is okay, service or replace EGR valve.

100) Continuous Memory Code 33/332: Check for proper EGR Valve Operation Code 33/332 indicates EGR valve did not open occasionally, when required, during vehicle operation. Possible causes for this fault are as follows

1. Faulty EGR valve
2. Shorted or open harness circuit.

Turn ignition off. Connect vacuum pump to EGR valve. While observing EGR valve, slowly apply 10 in. Hg. EGR valve should begin to open at 1-1.5 in. Hg, and should fully open at 4 in. Hg. If EGR valve does not move freely and smoothly, service exhaust gas recirculation system; clear codes and repeat QUICK TEST. If EGR valve moves freely and smoothly, go to next step.

101) Check EVR Harness With ignition off, disconnect ECA 60-pin connector. Inspect and repair any damaged wiring. Install breakout box and connect ECA to box. Enter OUTPUT STATE CHECK mode. See ADDITIONAL SYSTEM FUNCTIONS. Set DVOM on 20-volt scale. Connect DVOM negative test lead to test pin No. 40 at breakout box, and DVOM positive test lead to test pin No. 33. Move throttle, if necessary, to indicate 10.5 volts or more and maintain position. While observing DVOM, grasp harness closest to EVR connector. Wiggle, shake or bend small sections of harness, and work your way to firewall. Lightly tap EVR solenoid to simulate road vibration. If DVOM reads 10.5 volts or less, isolate fault and repair as necessary. Clear codes and repeat QUICK TEST. If DVOM reads 10.5 volts or more, fault cannot be duplicated at this time. Continuous Memory Code 33/332 testing is complete.

102) Continuous Memory Code 336: Check Pressure Sensor Output Voltage Code 336 indicates that during normal vehicle operation, ECA detected an input voltage that is higher than expected from DPFE sensor. Voltages greater than 0.7 volt from sensor will cause code.

Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect and repair any damaged wiring. Install breakout box and connect ECA to box. Set DVOM to 20-volt scale. Start engine and let idle. Measure voltage between test pin No. 27 and test pin No. 46. If voltage is greater than 0.7 volt, service DPFE sensor. Remove breakout box, reconnect components and rerun QUICK TEST. If voltage is less than 0.7 volt, fault is intermittent and cannot be duplicated at this time. Clear codes and repeat QUICK TEST.

Perform this test when instructed by QUICK TEST, or when directed by other test procedures.

To prevent replacement of good components, be aware that a damaged EGR valve may be the cause of problem.

This CIRCUIT TEST is intended to diagnose the following

1. EVP sensor
2. VREF, EVP, SIG RTN, EVR, and VPWR harness circuits
3. EVR solenoid
4. EGR valve assembly
5. ECA
6. EGR and EVR vacuum lines

EVP Sensor & EVR Solenoid Circuits. Scheme 19

TEST PIN WIRE COLOR IDENTIFICATION

1) Code 31/327: Generate Code 35/337 Code 31/327 indicates EVP sensor signal is less than self-test minimum of 0.2 volt. Possible causes for this fault are as follows

1. Faulty EVP sensor
2. Open or grounded harness
3. Faulty ECA

Turn ignition off and wait 10 seconds. Disconnect EVP harness at sensor. Install a jumper wire between VREF circuit and EVP circuit at EVP sensor vehicle harness connector. Repeat KOEO SELF-TEST. Check for code 35. Ignore all other codes at this time. If Code 35/337 is displayed, remove jumper and replace EVP sensor. Repeat QUICK TEST. If Code 35/337 is not displayed, remove jumper wire and go to next step.

2) Check VREF Circuit Voltage With ignition on and engine off, and EVP sensor disconnected, set DVOM on 20-volt scale. Disconnect ECA 60-pin connector. Inspect and repair any damaged wiring. Measure voltage at EVP sensor vehicle harness connector between VREF circuit and SIG RTN circuit. If reading is NOT 4-6 volts, go to TEST C, step 1. If reading is 4-6 volts, go to next step.

3) Check EVP Circuit Continuity Turn ignition off and wait 10 seconds. Disconnect EVP sensor and set DVOM on 200-ohm scale. Disconnect ECA 60-pin connector. Inspect and repair any damaged wiring. Install breakout box, and connect ECA to box. Measure resistance between EVP circuit at EVP sensor vehicle harness connector and test pin No. 27. If reading is 5 ohms or more, repair open circuit. Connect EVP sensor and remove breakout box. Repeat QUICK TEST. If reading is less than 5 ohms, go to next step.

4) Check EVP Circuit For Shorts To Ground With ignition off and EVP sensor disconnected, leave breakout box installed and ECA disconnected. Set DVOM on 200-k/ohm scale. Measure resistance between test pin No. 27 and test pins No. 40, 46 and 60. If any reading is less than 10 k/ohms, repair short circuit. Reconnect all components and remove breakout box. Repeat QUICK TEST. If all readings are 10 k/ohms or more, replace ECA. Connect EVP and remove breakout box. Repeat QUICK TEST.

5) Code 35/337: Generate Code 31/327 Code 35/337 indicates EVP sensor signal is greater than self-test maximum of 4.81 volts. Possible causes for this fault are as follows

1. Faulty EVP sensor
2. Short to power in vehicle harness

Turn ignition off and wait 10 seconds. Disconnect EVP sensor. Inspect and repair any damaged wiring. Perform KOEO SELF-TEST. Check for Code 31/327. Ignore all other codes at this time. If Code 31/327 is not displayed, go to step 7. If Code 31/327 is displayed, go to next step.

6) Check VREF Circuit Voltage With EVP harness disconnected, set DVOM on 20-volt scale. With ignition on and engine off, measure voltage at EVP sensor vehicle harness connector between VREF circuit and SIG RTN circuit. If reading is 4-6 volts, replace EVP sensor. Repeat QUICK TEST. If reading is NOT 4-6 volts, go to TEST C, step 1.

7) Check EVP Circuit For Short To Power Turn ignition off and disconnect EVP sensor. Disconnect ECA 60-pin connector. Inspect and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200-k/ohm scale. Measure resistance between test pin No. 27 and test pins No. 26 and 57. If either reading is less than 10 k/ohms, repair short in harness. Connect EVP sensor and remove breakout box. Repeat QUICK TEST. If both readings are 10 k/ohms or more, replace ECA. Reconnect EVP sensor and remove breakout box. Repeat QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 7 to step 10. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

10) Code 84/558: Check EVR Solenoid Resistance Code 84/558 indicates fault in EVR solenoid circuit. Possible causes for this fault are as follows

1. Faulty EVR solenoid
2. Shorted or open harness

Turn ignition off and wait 10 seconds. Set DVOM on 200-ohm scale. Disconnect EVR solenoid connector and measure solenoid resistance. If reading is not within specification, replace EVR solenoid assembly and repeat QUICK TEST. See EVR SOLENOID RESISTANCE table for specification. If reading is within specification, go to next step.

EVR SOLENOID RESISTANCE

11) Check VPWR Circuit Voltage Leave EVR solenoid disconnected and set DVOM on 20-volt scale. Turn ignition on, leaving engine off. Measure voltage between negative battery terminal and VPWR circuit at EVR solenoid vehicle harness connector. If reading is less than 10.5 volts, repair VPWR open circuit. Reconnect components and repeat QUICK TEST. If reading is 10.5 volts or more, go to next step.

12) Check EVR Circuit Continuity With ignition off and EVR solenoid disconnected, disconnect ECA 60-pin connector. Inspect and repair any damaged wiring. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 33 and EVR circuit at EVR solenoid vehicle harness connector. If reading is 5 ohms or more, repair open circuit. Reconnect all components and remove breakout box. Repeat QUICK TEST. If reading is less than 5 ohms, go to next step.

13) Check EVR Circuit For Shorts To Power Or Ground With ignition off, breakout box installed and ECA disconnected, disconnect EVR solenoid. Set DVOM on 200-k/ohm scale. Measure resistance between test pin No. 33 and test pins No. 37, 40, 46, 57 and 60 at breakout box. If any reading is less than 10 k/ohms, repair short circuit. Remove breakout box and reconnect all components. Repeat QUICK TEST; if code is repeated, replace ECA. If all readings are 10 k/ohms or more, replace ECA. Remove breakout box and reconnect all components. Repeat QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 13 to step 20. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

20) KOEO Code 34/334: Check For Code 84/558 KOEO Code 34/334 indicates EGR valve and/or EVP is not fully seated in the closed position. EVP voltage signal, in the closed position, is greater than self-test maximum of 0.67 volt. Because of the preload on the installed EVP sensor, it is very difficult to determine if EGR valve is seated, or EVP sensor is in contact with EGR valve. Possible causes for this fault are as follows

1. Poor continuity at EVP sensor
2. Non-seated EGR valve
3. Faulty EGR valve
4. Faulty EVP sensor

Turn ignition off and wait 10 seconds. Check for Code 84/558 in KOEO SELF-TEST. If Code 84/558 is present, go to step 10 of this circuit test. If Code 84/558 is not displayed, go to next step.

21) Check EVP Sensor & EGR Valve Operation Turn ignition off and wait 10 seconds. Disconnect EVP sensor. Inspect harness and connector and service as necessary. Remove vacuum line from EGR valve. To test operation of EGR valve, apply and release vacuum to valve using a vacuum pump, or manually depress and release diaphragm. Connect vacuum line to EGR valve, and connect connector to EVP sensor. Repeat KOEO SELF-TEST and KOER SELF-TEST. If Code 34/334 is still displayed, go to next step. If Code 34/334 is not displayed, the original code was set by a faulty connection or a sticking EGR valve. Testing of EGR valve is complete.

22) Check EVR Solenoid Operation Turn ignition off and wait 10 seconds. Install vacuum gauge at EGR valve vacuum hose. Start engine and let idle. If vacuum at EGR valve is less than 2.5 in. Hg at normal operating temperature, remove vacuum gauge and go to next step. If vacuum at EGR valve is greater than 2.5 in. Hg at normal operating temperature, original code 34/334 is caused by a stuck open EVR solenoid. Replace EVR solenoid and rerun QUICK TEST.

23) Substitute EVP Sensor On Original EGR Valve Turn ignition off and wait 10 seconds. Install a known good EVP sensor on original EGR valve. Perform KOEO SELF-TEST. If Code 34/334 is present, check EGR valve for mechanical fault. If Code 34/334 is not present, service or replace original EVP sensor. Repeat QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 23 to step 25. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

25) KOEO & KOER Code 32/238: Checking EVP Sensor & EGR Valve Operation Code 32/238 indicates EGR valve and/or EVP sensor signal voltage is less than closed position minimum (0.29 volt). Preload on EVP sensor makes it difficult to determine whether EGR valve has malfunctioned, or EVP sensor has abnormally high resistance. Possible causes for this fault are as follows

1. Poor continuity at EVP sensor connector
2. Non-seated or faulty EGR valve
3. Faulty EVP sensor

Turn ignition off and wait 10 seconds. Disconnect EVP sensor. Inspect connector and harness for damage, and service as necessary. Remove vacuum line from EGR valve. To test operation of EGR valve, apply and release vacuum to valve using vacuum pump, or manually depress and release diaphragm. Connect vacuum line to EGR valve, and connect connector to EVP sensor. Repeat KOEO SELF-TEST and KOER SELF-TEST. If Code 32/328 is still present, go to next step. If Code 32/328 is not displayed, the original code is set by a faulty connection or a sticking EGR valve. Testing of EGR valve is complete.

26) Substitute EVP Sensor On Original EGR Valve Turn ignition off and wait 10 seconds. Install a known good EVP sensor on original EGR valve. Perform KOEO SELF-TEST. If Code 32/328 is present, check EGR valve for mechanical malfunction. If Code 32/328 is not present, replace original EVP sensor. Repeat QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 26 to step 40. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

40) KOER Code 33/332: Check Vacuum At EGR KOER Code 33/332 indicates EVP sensor input did not change after ECA signaled operation of EGR. Because a Code 84 was not received in KOEO SELF-TEST, EVR solenoid electrical function is okay. The lack of Code 32/328 or 34/334 indicates EVP sensor is within closed position specifications. Possible causes for this fault are as follows

1. Leaking vacuum hose
2. Restricted vacuum hose
3. Restricted EVR solenoid filter
4. Faulty EGR valve

Turn ignition off. Disconnect vacuum line from EGR valve. Connect a vacuum gauge at open end of line. Perform KOER SELF-TEST and observe vacuum gauge. If reading is greater than 1.5 in. Hg, remove vacuum gauge and go to step 43. If reading is not greater than 1.5 in. Hg, remove vacuum gauge and reconnect EGR valve vacuum line; go to next step.

41) Verify Vacuum Supply To EVR Solenoid Turn ignition off. Disconnect vacuum source to EVR solenoid. Install vacuum gauge at source vacuum hose. Start engine and check vacuum. If reading is 10 in. Hg or more, go to next step. If reading is less than 10 in. Hg, check vacuum hose to EVR solenoid. Replace if necessary. Repeat QUICK TEST.

42) Check Vacuum Hose Between EVR Solenoid & EGR Valve Carefully check vacuum line for cracks, loose connections, blockage, kinks and leaks. If vacuum hose is faulty, replace hose. Connect new vacuum hose and repeat QUICK TEST. If vacuum hose is okay, check EVR solenoid filter for obstructions. Replace as necessary. If filter is okay, replace EVR solenoid. Connect all vacuum hoses and repeat QUICK TEST.

43) Check EVP Sensor & EGR Valve Operation Turn ignition off and wait 10 seconds. Disconnect EVP sensor. Inspect connector and harness for damage and service as necessary. Remove vacuum line from EGR valve. Test EGR valve operation by applying vacuum or manually depressing and releasing diaphragm. Connect vacuum line to EGR valve, and connect connector to EVP sensor. Repeat KOEO SELF-TEST and KOER SELF-TEST. If Code 33/332 is still present, go to next step. If Code 33/332 is not displayed, the original code is set either by poor continuity at EVP sensor connector, or sticking EGR valve. Testing of EGR valve is complete.

44) Verify EGR Valve Vacuum Control With ignition off, disconnect EGR valve vacuum supply. Connect vacuum gauge to EGR valve and apply 2-3 in. Hg for 2 minutes. If EGR holds vacuum, reconnect supply line and go to next step. If EGR valve does not hold vacuum, service or replace EGR valve.

45) Substitute Known Good EVP Sensor On Original EGR Valve Turn ignition off and wait 10 seconds. Install a known good EVP sensor on original EGR valve. Perform KOER SELF-TEST. If Code 33/332 is present, check EGR valve and/or system for mechanical malfunction. If Code 33/332 is not present, service or replace original EVP sensor. Repeat QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 45 to step 50. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

50) Code 34/334: Check EGR Valve Operation In KOER SELF-TEST With EGR Vacuum Disconnected KOER Code 34/334 indicates EVP voltage is greater than closed position self-test limit (0.67 volt). Possible causes for this fault are as follows

1. Obstructed EVR solenoid filter
2. Faulty EVR solenoid
3. Faulty EGR valve
4. Faulty EVP sensor

Turn ignition off. Disconnect and plug EGR valve vacuum hose. Perform KOER SELF-TEST. If Code 34/334 is not present, check EVR solenoid filter for obstructions. Replace as necessary. If filter is okay, replace EVR solenoid. Connect all vacuum hoses and repeat QUICK TEST. If Code 34/334 is present, go to next step.

51) Check EVP Sensor Resistance While Applying Vacuum To EGR Valve Turn ignition off and wait 10 seconds. Disconnect harness from EVP sensor. Inspect connectors for damaged pins or corrosion. Repair as necessary. Set DVOM on 200-k/ohm scale. Disconnect vacuum hose to EGR valve and connect vacuum pump to valve. Measure resistance at EVP sensor between EVP circuit and VREF circuit while gradually increasing vacuum to 10 in. Hg. If reading decreases from no more than 5500 ohms to no less than 100 ohms, check EGR valve for mechanical malfunction and service or replace as necessary. If reading does not change as indicated, replace EVP sensor. Reconnect vacuum hose and rerun QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 51 to step 90. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

90) Continuous Memory Code 32/328: Check EVP Signal Voltage While Operating EVP Sensor Code 32/328 indicates either EGR valve closed further than normal with engine at idle and at normal operating temperature, or EVP sensor has failed with an intermittent low-voltage spike symptom. Possible causes for this fault are as follows

1. Obstructed vacuum valve
2. Faulty EVP sensor
3. EGR valve

Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect and repair any damaged wiring. Install breakout box and connect ECA. Disconnect vacuum hose at EGR valve. Connect a vacuum pump to EGR valve. Set DVOM on 20-volt scale. With ignition on and engine off, measure voltage between test pins No. 27 and 46 while slowly applying 6 in. Hg to EGR valve. Slowly bleed vacuum off EGR valve and lightly tap on EVP sensor to simulate road shock. If voltage drops to less than .24 volt, EGR valve may have caused Code 32/328. Clear Continuous Memory Codes. Check EGR valve for mechanical malfunction. If all readings are greater than .24 volt, go to next step.

91) Continuous Memory Code 32/31 (328/327): Check EVP Sensor While In Continuous Monitor Mode Code 31/327 indicates that sometime during vehicle operation, EVP signal was out of self-test range. Possible causes for this fault are as follow

1. Faulty EVP sensor
2. Open or shorted circuit

With DVOM connected as in previous step, enter KOEO wiggle test. See CONTINUOUS MONITOR MODE (WIGGLE TEST) under QUICK TEST. Connect vacuum pump to EGR valve. Observe DVOM while performing the following procedures. If a fault is indicated, go to next step. If fault is not indicated, go to step 93.

1. Very slowly, apply 6 in. Hg to EGR valve.
2. Slowly bleed off vacuum from EGR valve while tapping on EVP sensor to simulate road shock.
3. Wiggle EVP sensor connector.

Checking EVP Harness Circuit. Scheme 20

92) Measure EVP Signal Voltage While Exercising EVP Sensor Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector and terminals for obvious damage. If connector and terminals are damaged, repair as necessary. Install breakout box and reconnect ECA. Set DVOM on 20-volt scale and connect DVOM between test pins No. 27 and 46. Re-enter KOEO wiggle test. See CONTINUOUS MONITOR MODE (WIGGLE TEST) under QUICK TEST. Observe DVOM while repeating test step 91. If fault occurs at less than 4.25 volts, disconnect and inspect connector. If connector is okay, replace EVP sensor. Clear codes and repeat QUICK TEST. If fault does not occur at less than 4.25 volts, go to next step.

93) Continuous Memory Code 31/327 And/Or 35/337: Check EEC-IV Harness Code 31/327 indicates either an open in EVP or VREF circuits, or a short to SIG RTN with engine at idle and at normal operating temperature. Code 35/337 indicates a short to VREF and/or VPWR, or an open in SIG RTN with engine at idle and at normal operating temperature.

Enter KOEO wiggle test. See CONTINUOUS MONITOR MODE (WIGGLE TEST) under QUICK TEST. Observe VOM or diagnostic tester for fault indication and grasp harness near sensor; wiggle, shake or bend small section of EEC-IV harness, and work toward dash panel. Wiggle, shake or bend harness from firewall to ECA. If fault is indicated, isolate fault and repair wiring harness as required. Clear codes and repeat QUICK TEST. If fault is not found, go to next step.

EVP Harness Faults. Scheme 21

94) Check ECA & Harness Connectors Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector and terminals for obvious damage. If connector and terminals are damaged, repair as necessary. Clear codes and repeat QUICK TEST. If connector and terminals are okay, fault cannot be duplicated at this time. Clear codes. Check EGR valve for mechanical fault.

95) Continuous Memory Code 33/332: Leak Test Code 33/332 indicates EGR valve did not open with engine at normal operating temperature and with EVR solenoid signal present. Possible causes of this fault are as follows

1. Obstructed or cracked vacuum line
2. Open circuit
3. Faulty EGR valve

Turn ignition off and wait 10 seconds. Disconnect vacuum hose at EGR valve and connect vacuum pump to valve. Apply 20 in. Hg to EGR valve. If EGR valve opens and holds vacuum, remove vacuum pump and reconnect EGR valve; go to next step. If EGR valve does not function as described, remove pump and reconnect EGR valve. Clear codes and service or replace EGR valve as necessary.

96) EVR Solenoid Check Using Continuous Monitor Mode (Wiggle Test), observe VOM or diagnostic tester for fault indication. Grasp harness close to EVR solenoid connector and wiggle, shake or bend a small section of harness, and work toward ECA. Inspect connectors and terminals for obvious damage. If fault is indicated, isolate fault and repair as necessary. Clear codes and repeat QUICK TEST. If fault is not indicated, fault cannot be duplicated at this time. Clear codes and repeat QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 96 to step 98. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

98) Continuous Memory Code 34/334: Check EVP Resistance While Applying Vacuum To EGR Valve Code 34/334 indicates EGR valve was open with engine idling at normal operating temperature. Possible causes for this fault are as follows

1. Faulty EVR filter
2. Faulty EVR solenoid
3. Faulty EGR valve

Turn ignition off and disconnect EVP sensor. Inspect connector for obvious damage. Place DVOM on 200-k/ohm scale. Disconnect vacuum hose to EGR valve and connect vacuum pump to valve. Measure resistance at EVP sensor between EVP circuit and VREF circuit at sensor while increasing vacuum to 10 in. Hg. If reading does not decrease gradually from maximum of 5500 ohms to minimum 100 ohms, remove vacuum pump and reconnect all components. Clear codes and check EGR valve for mechanical malfunction. If reading gradually decreases from maximum of 5500 ohms to minimum of 100 ohms, remove vacuum pump and reconnect all components. Go to next step.

99) EVR Check Turn ignition off. Disconnect vacuum hose from EGR valve and plug hose. Perform KOER SELF-TEST. If Code 34/334 is present, check EVR filter for obstructions. Replace as necessary. If filter is okay, replace EVR solenoid. Connect all vacuum hoses and repeat QUICK TEST. If Code 34/334 is not present, fault cannot be duplicated at this time. Clear codes and repeat QUICK TEST. Testing is complete.

Perform this test when directed by QUICK TEST.

This CIRCUIT TEST is intended to diagnose the following

1. VSS harness circuits
2. Vehicle Speed Sensor (VSS)
3. ECA

Vehicle Speed Sensor Circuit. Scheme 22

TEST PIN WIRE COLOR IDENTIFICATION

Preliminary Instructions (A/T Vehicles)

Record and clear Continuous Memory Codes. Warm engine to normal operating temperature. In Low gear, accelerate hard to 25 MPH and coast down to a stop. Shut off engine. Perform KOEO SELF-TEST. Go to step 1.

Preliminary Instructions (M/T Vehicles)

Record and clear Continuous Memory Codes. Warm engine to normal operating temperature. Start in first gear, shift to second gear and accelerate moderately to 40 MPH. Coast down to idle and stop. Shut engine off. Perform KOEO SELF-TEST and record Continuous Memory Codes. Go to step 1.

1) Continuous Memory Code 29/452 Code 29/452 indicates there is insufficient input to ECA from VSS. Possible causes for this code are as follows

1. Faulty VSS
2. Open or shorted circuit
3. Faulty ECA

Perform appropriate drive cycle procedure. See PRELIMINARY INSTRUCTIONS (A/T VEHICLES) or PRELIMINARY INSTRUCTIONS (M/T VEHICLES). If Code 29/452 is still present, go to the next step. If code is not present or complaint cannot be verified, fault cannot be duplicated at this time. Clear codes and see INTERMITTENTS in the TESTS W/O CODES article in this section.

2) Check VSS Circuit Continuity Turn ignition off and wait 10 seconds. Remove ECA 60-pin connector and inspect for damaged pins, corrosion, or loose wires. Repair as necessary. Install breakout box. With ECA and VSS disconnected, set DVOM on 200-ohm scale. Measure resistance between test pin No. 3 at breakout box and VSS DIF (+) circuit at VSS vehicle harness connector. Also measure resistance between test pin No. 6 at breakout box and VSS DIF (-) circuit vehicle harness connector. If both readings are 5 ohms or less, go to next step. If readings are 5 ohms or more, service open circuit in VSS wiring harness. After repairs, reconnect all components and repeat step 1.

Checking VSS Circuits. Scheme 23

3) Check VSS Circuits For Shorts To Power Or Ground Turn ignition off. With ECA and VSS disconnected, install breakout box. Set DVOM on 200-k/ohm scale. On 1.9L MA PFI vehicles with A/T, disconnect both 4EAT transmission module vehicle harness connectors. Measure resistance between test pin No. 3 and test pins No. 37, 40 and 6. If all readings are greater than 500 ohms, remove breakout box and reconnect components; go to step 5 (1.9L SPFI-MA with auto. trans. If any reading is less than 500 ohms, repair short(s) in VSS wiring harness and reconnect components. After repairs, repeat step 1.

4) Checking VSS Resistance Turn ignition off and wait 10 seconds. Disconnect VSS. Set DVOM on 2-k/ohm scale. Measure resistance across vehicle speed sensor. If reading is 190-250 ohms, replace ECA. Remove breakout box, reconnect components and repeat step 1. If reading is NOT 190-250 ohms, replace vehicle speed sensor and repeat appropriate drive cycle procedure.

5) Check For Shorted 4EAT Module The 1.9L MA PFI A/T has a VSS circuit input to 4EAT module. This test checks VSS circuit to ensure it is not shorted inside 4EAT module. With ignition off, install breakout box, leaving ECA disconnected. Disconnect VSS. Set DVOM on 200-k/ohm scale. Measure resistance between test pin No. 3 and test pins No. 6, 37 and 40. If each resistance is greater than 500 ohms, reconnect ECA and go back to step 4. If each resistance is not greater than 500 ohms, check for fault in 4EAT transmission system.

Enter this CIRCUIT TEST only when instructed during QUICK TEST. This test is intended to diagnose only the following

1. Harness circuit (CID + and CID -)
2. CID sensor
3. ECA

CID Harness Circuits (1.9L SPFI-MA). Scheme 24

1) Continuous Memory Code 19/214: Check CID Sensor Resistance Code 19/214 indicates error has been detected in CID sensor input signal. The error could be due to a hard fault or an intermittent condition. On 1.9L MA PFI engines, CID sensor is a Variable Reluctance (VR) device used for fuel injection synchronization. Possible causes for this fault are as follows

1. Open or shorted harness
2. Faulty CID sensor
3. Faulty ECA

With ignition off, disconnect CID sensor (located on back of cylinder head coil pack). Set DVOM on 200-k/ohm scale. Measure resistance of CID sensor. If resistance is 300-750 ohms, go to next step. If resistance is not 300-750 ohms, replace CID sensor and repeat QUICK TEST.

2) Check Continuity Of CID Circuits With ignition off, and CID sensor disconnected, disconnect ECA 60-pin connector. Inspect and repair any corroded or damaged pins. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 41 and CID (+) circuit at CID sensor vehicle harness connector. Measure resistance between test pin No. 42 and CID (-) at CID sensor vehicle harness connector. If each resistance is less than 5 ohms, go to next step. If each resistance is not less than 5 ohms, repair open circuit as necessary; remove breakout box and reconnect all components. Repeat QUICK TEST.

Checking CID Sensor Harness Circuit. Scheme 25

3) Check CID Circuit For Shorts With ignition off and breakout box installed, ensure ECA and CID sensor are disconnected. Set DVOM on 200-k/ohm scale. Measure resistance between test pin No. 41 and test pins No. 42, 37, 57, 40 and 60. Measure resistance between test pin No. 42 and test pins No. 37, 57, 40 and 60. If each resistance is greater than 10 k/ohms, go to next step. If resistances are not greater than 10 k/ohms, repair short circuit; remove breakout box and reconnect all components. Repeat QUICK TEST.

4) Check For Shorts In ECA With ignition off, install breakout box and reconnect ECA. Disconnect CID sensor. Set DVOM on 200-k/ohm scale. Measure resistance between test pin No. 41 and test pins No. 42, 37, 57, 40 and 60. Measure resistance between test pin No. 42 and test pins No. 37, 57, 40 and 60. If each resistance is greater than 500 ohms, go to next step. If resistances are not greater than 500 ohms, replace ECA; remove breakout box and reconnect all components. Repeat QUICK TEST.

5) Check CID Sensor Output With ignition off, breakout box installed and ECA connected, reconnect CID sensor. Set DVOM on AC 5-volt scale. Start engine. Measure voltage between test pins No. 41 and 42 while varying engine RPM. If voltage varies, go to next step. If voltage does not vary, replace CID sensor; remove breakout box and reconnect components. Repeat QUICK TEST.

6) Attempt To Regenerate Code 19/214 With ignition on and engine off, clear Continuous Memory Codes. Start engine. Rev engine to greater than 1500 RPM for 10 seconds 2 or 3 times. Turn ignition off. Repeat KOEO SELF-TEST. If Continuous Memory Code 19/214 is still present, replace ECA; remove breakout box, reconnect all components and repeat QUICK TEST. If code is not present, Code 19/214 is an intermittent fault. Check vehicle harness for intermittent opens or shorts. See INTERMITTENTS in the TESTS W/O CODES article in this section.

Note. There is a break in the step numbering sequence at this point, skipping from step 6 to step 10. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

10) Continuous Memory Code 19/214: Check CID Signal At ECA Code 19/214 indicates an error has been detected on CID sensor signal. Error could be due to a hard fault or an intermittent condition. Possible causes for this code are as follows

1. Open or shorted vehicle harness
2. Faulty CID sensor
3. Faulty DIS module (if equipped)
4. Faulty ECA

Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect and repair any corroded or damaged pins. Install breakout box and connect ECA to breakout box. Set DVOM on AC 5-volt scale. With ignition on and engine running, measure voltage between test pin No. 24 and test pin No. 40 while varying engine RPM. If AC voltage varies more than 0.2 volt, go back to step 6. If voltage does not vary more than 0.2 volt, go to next step.

11) Check CID Circuit Continuity To ECA With ignition off, breakout box installed and ECA disconnected, disconnect camshaft sensor. Set DVOM to 200-ohm scale. Measure resistance between test pin No. 24 and CID circuit at camshaft/crankshaft sensor vehicle harness connector.

12) Check CID circuit For Short To Power With ignition off, breakout box installed and ECA disconnected, disconnect camshaft sensor. Set DVOM to 20-volt scale. With ignition on and engine off, measure voltage between test pin No. 24 and test pin No. 40. If voltage is less than one volt, go to next step. If voltage is greater than one volt, repair short to power. Remove breakout box, reconnect all components and rerun QUICK TEST.

13) Check CID Circuit For Short To Ground With ignition off, breakout box installed and ECA disconnected, disconnect camshaft sensor Set DVOM to 200-k/ohm scale. Measure resistance between test pin No. 24 and test pins No. 16, 40 and 46. If each resistance is greater than 10 k/ohms, problem is with DIS; reconnect all components and go to the SYSTEM/COMPONENT TESTS article in this section. If each resistance is less than 10 k/ohms, repair open in CID circuit. Remove breakout box, reconnect all components and rerun QUICK TEST.

14) Check For Shorts In ECA With ignition off, breakout box installed and ECA connected, disconnect camshaft sensor. On DIS equipped vehicles, disconnect DIS module pins No. 1-6 connector. Set DVOM to 20-k/ohm scale. Measure resistance between test pin No. 24 and test pins No. 37, 57, 40, 46 and 60. If each resistance is greater than 500 ohms, replace CID sensor. Remove breakout box, reconnect all components and rerun QUICK TEST. If each resistance is less than 500 ohms, replace ECA. Remove breakout box, reconnect all components and rerun QUICK TEST.

Perform this test when instructed during QUICK TEST, or when directed by other test procedures.

This test is intended to diagnose only the following

1. MAP/BP Sensor
2. Throttle Position Sensor (TPS)
3. Mass Airflow (MAF) Sensor
4. Air Charge Temperature (ACT) Sensor
5. Fuel Injectors

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: excessive blow-by, PCV malfunction, vacuum leak, fuel pressure or throttle linkage sticking or binding.

1) Throttle Position Sensor Integrity Code 121 indicates TPS is inconsistent with MAF value. Code 124 indicates TPS value is higher than expected. Code 125 indicates TPS value is lower than expected.

Turn ignition off. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Install breakout box and connect ECA. Set DVOM on 20-volt scale. Connect DVOM to test pins No. 47 and 46. Operate throttle slowly to WOT, and slowly release to closed position. See TEST DH for schematics and specific engine values. If there are any sudden voltage variations, ensure TPS is properly installed on throttle body. If TPS is properly installed, replace TPS; remove breakout box, reconnect all components and rerun QUICK TEST. If there are no sudden voltage variations, go to step 6 (for Continuous Memory Code 121), or go to next step (for all other codes).

2) Check Throttle Body Check throttle and/or speed control linkage for binding and smooth operation. Inspect throttle body for contamination. Check engine vacuum hoses. Refer to VECI decal for proper vacuum hose routing. Check for air leak between ISC solenoid and MAF sensor. If all checks reveal no problems, go to next step. If problems are found, repair as necessary; remove breakout box, reconnect all components and rerun QUICK TEST.

3) Check MAP/BP Sensor Output Refer to TEST DF for schematic. With MAP/BP tester connected and ignition on, measure sensor output voltage. If voltage output is within range at specific altitude, remove MAP/BP tester and go to next step. See MAP SENSOR VOLTAGE OUTPUT table for specification. If output reading is outside range, replace MAP/BP sensor; remove tester, reconnect all components and rerun QUICK TEST.

If possible, measure several known good MAP/BP sensors on available vehicles. Average voltage reading will be typical for your location on date of testing.

MAP SENSOR VOLTAGE OUTPUT

4) Check ACT Sensor Ensure ambient temperature is greater than 50°F before performing this test. Check and repair any air leaks in front of ACT sensor. Turn ignition off. Install breakout box and connect ECA to breakout box. Set DVOM to 20-volt scale. See TEST DF for schematic. Connect DVOM to test pins No. 25 and 46. Start engine and let idle. Observe voltage as engine warms up. If voltage does not decrease smoothly and stabilize after engine reaches operating conditions, replace ACT sensor; remove breakout box and rerun QUICK TEST. If voltage decreases smoothly and stabilizes when engine reaches operating conditions, system is operating properly at this time. Reconnect all components and rerun QUICK TEST.

5) Visual Inspection Of MAF Sensor Code 184 indicates MAF sensor value is higher than expected. Code 185 indicates MAF sensor value is lower than expected. Turn ignition off. Check for air leaks between ISC solenoid and MAF sensor. Inspect MAF sensor for oil contamination caused by excessive blow-by or malfunctioning PCV. If problems are found, repair as necessary; clear codes and rerun QUICK TEST. If all checks are okay, go to step 8.

6) Check MAF Sensor Turn ignition off. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Install breakout box and connect ECA. Set DVOM on 20-volt scale. Start engine and allow to idle until engine reaches normal operating temperature. Measure voltage between MAF signal and test pin 40/60 of breakout box.

If voltage is within acceptable range, system is operating normally at this time. See INTERMITTENTS in the TESTS W/O CODES article in this section. If voltage is not within acceptable range, replace MAF sensor. See MAF SENSOR DATA table for specification. Reconnect all components and rerun QUICK TEST.

MAF Sensor Graph. Scheme 26

MAF SENSOR DATA

7) Visual Vacuum Checks Code 186 indicates pulse width is longer than expected (rich). Code 187 indicates pulse width is shorter than expected (lean). Inspect air cleaner and air inlet duct; replace or repair an necessary. Check for unmetered air between MAF sensor and ISC bypass solenoid. Check all engine vacuum hoses for damage, leaks, blockage and proper routing. Make necessary repairs and rerun QUICK TEST. If all items are okay, go to next step.

8) Check Fuel Pressure Turn ignition off. Install fuel pressure gauge. Ensure fuel pressure regulator is connected to manifold vacuum (if applicable). Start engine and run at idle. If fuel pressure is within specifications, go to next step. For fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS article. If fuel pressure is not within specifications, repair fuel pump or fuel pressure regulator as necessary.

9) Check Systems Ability To Hold Fuel Pressure Turn ignition on, leaving engine off. If fuel pressure remains at specification for 60 seconds, go to next step (for SEFI), or go to TEST H, step 7 (for EFI). If fuel pressure does not remain at specification, repair fuel delivery system as necessary.

10) Cylinder Balance Test Run KOER SELF-TEST. After last repeated code, wait 5-10 seconds then "goose" throttle lightly (not wide-open throttle). This will activate cylinder balance test. If code 90 is present after test, go back to step 5. If code 90 is not present after test, go to TEST H, step 4.

TEST H - FUEL CONTROL

Note. For fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS article.

Perform this test when instructed during QUICK TEST, or when directed by other test procedures.

See HOW TO USE CIRCUIT TESTS under CIRCUIT TESTS before performing this test. Fuel contaminated engine oil may affect Codes 41/172, 91/136, 42/173 or 92/137. If this is suspected, remove PCV valve from valve cover and repeat QUICK TEST. If problem is corrected, change engine oil and filter.

Use this test to diagnose only the following components

1. HEGO sensor
2. HEGO signal and ground circuit
3. HEGO sensor connection
4. Vacuum systems
5. Fuel injector
6. ECA
7. Electrical circuits (HEGO GND, HEGO, INJ 1-8, VPWR and SIG RTN)

To prevent replacement of good components, be aware that the following non-EEC areas may be the cause of driveability concerns

1. Ignition coil, distributor cap or rotor
2. Faulty or fouled spark plugs or wires
3. Faulty CANP system
4. Distributorless Ignition System (DIS)
5. EGR valve and gasket
6. Air filter
7. Fuel or engine oil contamination
8. Poor electrical ground
9. Faulty fuel pressure
10. Intake or exhaust system leaks
11. Engine below normal operating temperature

INDIVIDUAL INJECTOR RESISTANCE (1)

TEST PIN WIRE COLOR IDENTIFICATION

TEST PIN WIRE COLOR IDENTIFICATION

Test Schematic (1.9L SPFI-MA). Scheme 27

1) Check For Contaminated Engine Oil Turn ignition off. Remove PCV valve from valve cover. Inspect valve cover hole and PCV for damage, sludge build up, blockage and movement of valve plunger. Repair as necessary. Perform KOER SELF-TEST. If vehicle is a no start, KOER codes 41/172, 91/136, 42/173 or 92/137, or Continuous Memory Codes 176, 177, 144/41, 91/139, 171, 175, 174 or 178 are set, reinstall PCV valve and go to next step. If no code is set, change engine oil and filter; reinstall PCV valve. Drive vehicle for 5 miles at 55 MPH. Rerun QUICK TEST.

2) Check Fuel Pressure Turn ignition off and wait 10 seconds. Install fuel pressure gauge. Ensure manifold vacuum supply is connected to fuel pressure regulator (if equipped). Run engine at idle and check fuel pressure. If vehicle will not start, cycle ignition on and off several times. For fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS article. If vehicle is a no start, cycle ignition on and off several times. If fuel pressure is within specification, go to next step. If pressure is not to specification, remove fuel pressure gauge. Repair electric fuel pump or fuel pressure regulator.

3) Check Systems Ability To Hold Fuel Pressure Turn ignition on, leaving engine off. If fuel pressure remains at specification for 60 seconds, go to next step (for no starts), go to step 5 (for EFI), or go to step 6 (for SEFI). If fuel pressure is not as described, repair fuel delivery system as necessary.

4) Fuel Delivery Test Ensure fuel is of good quality. With ignition off, install fuel pressure gauge and pressurize fuel system as in step 1. Disconnect inertia switch. Crank engine for 5 seconds. If fuel pressure drop is greater than 5 psi after 5 seconds of cranking, EEC-IV system is not the cause of no-start condition. Check additional no-start tests in the H - TESTS W/O NO CODES article in this section. If fuel pressure drop is less than 5 psi, remove fuel pressure gauge and reconnect inertia switch; go to step 7 (for EFI), or step 8 (for SEFI).

Note. There is a break in the step numbering sequence at this point, skipping from step 4 to step 7 Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

7) Check Injector & Harness Resistance: EFI Engines Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect pins for damage. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance of injector banks between test pins No. 37 and 58 (injector bank No. 1 or 59 (injector bank No. 2 at breakout box. Record resistance. Refer to appropriate INJECTOR BANK RESISTANCE table in this circuit test. If each resistance is within specifications for appropriate engine, go to step 12. If resistance is not as specified, repair open circuit on VPWR circuit (for no start), or go to step 9 (for all other conditions).

8) Check Injector & Harness Resistance: SEFI Engines Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect pins for damage. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure and record resistance between suspected injector circuit test pin and test pin No. 37. For no starts, measure and record resistance between any injector circuit test pin and test pin No. 37. Refer to appropriate INJECTOR BANK RESISTANCE table in this circuit test. If each resistance is within specifications for appropriate engine, go to step 12. If resistance is not as specified, repair open circuit on VPWR circuit (for no start), or go to step 9 (for all other conditions).

9) Check Continuity Of Fuel Injector Harness Turn ignition off and wait 10 seconds. Install breakout box, leaving ECA disconnected. Disconnect injector vehicle harness connector at injectors. Set DVOM to 200-ohm scale. Measure resistance between test pin No. 37/57 at breakout box and VPWR pin at each injector vehicle harness connector. See appropriate TEST SCHEMATIC in this circuit test. Measure resistance between injector test pin(s) at breakout box and the same injector circuit signal pin at each injector vehicle harness connector. If each resistance is less than 5 ohms, go to next step. If each resistance is greater than 5 ohms, repair open circuit. Remove breakout box, reconnect all components and drive vehicle for 5 miles at 55 MPH. Rerun QUICK TEST.

10) Check Injector Harness Circuit For Short To Power Or Ground Turn ignition off and wait for 10 seconds. With breakout box installed and ECA disconnected, disconnect fuel injector vehicle harness. See appropriate TEST SCHEMATIC in this circuit test. Set DVOM to 200-k/ohm scale. Measure resistance between injector test pin(s) and test pins No. 37/57, 40, 46 and 60. Measure resistance between injector test pin(s) at breakout box and chassis ground. If each resistance is greater than 10 k/ohms, replace injector per cylinder balance test service code and rerun QUICK TEST (for SEFI), or go to next step (for EFI). If each resistance is less than 10 k/ohms, repair short. Remove breakout box, reconnect all components and drive vehicle for 5 miles at 55 MPH. Rerun QUICK TEST.

11) Isolate Faulty Injector Circuit Turn ignition off. Install breakout box and disconnect ECA. Disconnect all injectors on suspected bank. With DVOM set on 200-ohm scale, connect one injector and measure resistance between test pins No. 37 and 58 or 59. Disconnect injector and repeat process for all other injectors. See appropriate INDIVIDUAL INJECTOR RESISTANCE table for specifications. If all injectors are within specifications, go to step 12. If injectors are not as specified, remove breakout box. Reconnect ECA and injectors. Repair open or short in injector harness. If circuit is okay, replace injector. Drive vehicle for 5 miles at 55 MPH. Rerun QUICK TEST.

12) Check Injector Drive Signal With ignition off and breakout box installed, connect ECA to breakout box. Use a non-powered 12-volt test light and connect as follows

1. EFI Engines - Connect test light between test pins No. 37 and 58 at breakout box. Connect light between test pins No. 37 and 59 at breakout box.
2. Sequential PFI Engines (SPFI) - Connect test light between test pin No. 37 and the suspected injector(s) test pin at breakout box.

Crank or start engine. If test light glows dimly, system is operating properly. remove breakout box and reconnect ECA. Clean and test injectors. Drive vehicle for 5 miles at 55 MPH. Rerun QUICK TEST.

If test light does not glow dimly (no light/bright light), check injector circuit for shorts to ground. If system is okay, remove breakout box and replace ECA. Remove breakout box and reconnect all components. Drive vehicle for 5 miles at 55 MPH. Rerun QUICK TEST.

13) Check Thermactor Operation If vehicle is equipped with Pulse-Air or does not have Thermactor System, ignore this step and go to next step. With dual HEGO, code 41/172 refers to right or rear HEGO, and code 91/136 or 176 refers to left or front HEGO. A HEGO that is always lean could be caused by Thermactor air being diverted upstream from HEGO sensor. Turn ignition off and wait 10 second. Disconnect Thermactor air hose(s) from Thermactor pump. Run KOER SELF-TEST. If codes 41/172, 91/136 or 176 are present, reconnect Thermactor air hose(s) and go to next step. If codes 41/172, 91/136 or 176 are not present, repair thermactor system as necessary.

14) Check HEGO Integrity A HEGO sensor that is always lean, slow to switch or does not switch could be caused by the following

1. Moisture inside HEGO sensor, or harness connector causing a short to ground
2. HEGO sensor coated with containments
3. HEGO circuit open
4. HEGO circuit shorted to ground

Turn ignition off and wait 10 seconds. Inspect HEGO harness for chaffing, burns or other indications of damage; repair or replace as necessary. Inspect HEGO sensor and connector for signs of water entry; repair or replace as necessary. Start engine and run at 2000 RPM for 2 minutes. Turn ignition off and wait 10 seconds. Run KOER SELF-TEST. If fault codes are present, go to next step (for MAP sensor-equipped vehicles), or step 16 (for MAF sensor-equipped vehicles). If no code is present, go to step 21.

15) Checking HEGO Sensor On Engines With MAP Sensors Turn ignition off and set DVOM on 20-volt scale. Disconnect appropriate HEGO sensor from vehicle harness. Connect DVOM to HEGO SIGNAL lead at sensor connector and battery negative terminal (3-wire HEGO). Connect DVOM to HEGO SIGNAL and HEGO GND leads at sensor connector (4-wire HEGO). Disconnect and plug vacuum line MAP sensor. Start engine and apply 10-14 in Hg to Manifold Absolute Pressure (MAP) sensor. Run engine at 2000 RPM for 2 minutes. If reading is greater than 0.5 volt within 2 minutes, go to step 17. If reading is less than 0.5 volt within 2 minutes, replace HEGO sensor; reconnect MAP and rerun QUICK TEST.

Vacuum or air leaks in non-EEC-IV related areas may cause Code 41 or 91. Check the following areas: leaking vacuum actuator (A/C control motor, etc.) engine seals, EGR system, PCV system and lead contamination of HEGO sensor.

Checking HEGO Sensor. Scheme 28

16) Check HEGO Sensor On Engines With MAF Sensor The purpose of this test is to verify HEGO sensor can generate a voltage signal of greater than 0.5 volt during KOER SELF-TEST. With ignition off and DVOM set on 20-volt scale, disconnect appropriate HEGO sensor from harness. Depending on type of sensor (3 wires or 4 wires), connect DVOM as follows

1. 4-Wire HEGO Sensors - Connect DVOM between HEGO SIGNAL and HEGO GND at HEGO sensor connector.
2. 3-Wire HEGO Sensors - Connect DVOM to HEGO SIGNAL at sensor and battery negative terminal.

Rerun KOER SELF-TEST and monitor HEGO sensor voltage. If voltage is greater than 0.5 volt, go to next step. If voltage is less than 0.5 volt, replace HEGO sensor and rerun QUICK TEST.

Vacuum or air leaks in non-EEC-IV related areas may cause Code 41 or 91. Check the following areas: leaking vacuum actuator (A/C control motor, etc.) engine seals, EGR system, PCV system and lead contamination of HEGO sensor.

17) Check Continuity Of HEGO SIGNAL & HEGO GROUND Circuits Turn ignition off. Install breakout box, leaving ECA disconnected. Disconnect suspected HEGO sensor from vehicle harness. Inspect both ends of connector for damage or pushed-out pins, moisture, corrosion, loose wires or other damage. Repair as necessary. Set DVOM on 200-ohm scale. Measure resistance between HEGO SIGNAL (test pin No. 29) at breakout box and HEGO SIGNAL at vehicle harness connector.

On 3-Wire HEGO sensors, measure resistance between HEGO GROUND test pin at breakout box and battery negative terminal.

On 4-Wire HEGO sensors, measure resistance between HEGO GROUND test pin at breakout box and HEGO GND at vehicle harness connector. Where applicable, measure resistance between HEGO GND and SIG RTN at breakout box.

If each resistance is less than 5 ohms, go to next step. If each resistance is greater than 5 ohms, repair open circuit. Remove breakout box and reconnect all components. Drive vehicle for 5 minutes at 55 MPH. Rerun QUICK TEST.

18) Check HEGO Circuit For Short To Ground Turn ignition off. Leave breakout box installed and ECA disconnected. Disconnect HEGO sensor and set DVOM on 200-k/ohm scale. Measure resistance between HEGO SIGNAL (test pin No. 29) and test pins No. 40, 46 and 49 at breakout box. If any reading is less than 10 k/ohms, repair short to ground; remove breakout box, reconnect all components and repeat QUICK TEST. If reading is 10 k/ohms or more, go to next step.

19) Check HEGO Sensor For Short To Ground With ignition off, breakout box installed and ECA disconnected, set DVOM to 200-k/ohm scale. Disconnect HEGO sensor. Measure resistance between PWR GND and HEGO SIGNAL at HEGO sensor connector. If resistance is less than 10 k/ohms, replace HEGO sensor and remove breakout box; reconnect all components, drive vehicle for 5 miles at 55 MPH and repeat QUICK TEST. If resistance is greater than 10 k/ohms, perform the following procedure as applicable.

1. For codes 144/41, 139/91, 171, 174, 175 or 178, go to step 90.
2. On engines with MAP sensor, go to step 20.
3. On engines with MAF sensor, remove breakout box. Reconnect HEGO sensor and replace ECA. Drive vehicle for 5 miles at 55 MPH. Rerun QUICK TEST.

20) Attempt To Eliminate Code 41/172, 91/136 Or 176: Engines With MAP Sensor Turn ignition off. Install breakout box; reconnect ECA and HEGO sensor. Ensure MAP sensor vacuum hose is disconnected and plugged. Apply 10-14 in. Hg to MAP sensor. Start and run engine at 2000 RPM for 2 minutes. Allow engine to return to idle. Perform KOER SELF-TEST. If you are here for Continuous Memory Codes, vehicle has to be driven 5 miles at 55 MPH. If Code 41/172, 91/136 or 176 is still present, remove breakout box. Reconnect ECA and MAP sensor vacuum line. If engine still runs rough, go to TEST S, step 2. If engine does not run rough, replace ECA; drive vehicle 5 miles at 55 MPH then repeat QUICK TEST.

If Code 41/172, 91/136 or 176 is not present, remove breakout box and reconnect ECA and MAP sensor vacuum hose. HEGO input circuit and fuel delivery are okay; fault is in area common to all areas. Service as necessary.

21) Check Resistance Of HEGO Heating Element Turn ignition off. Disconnect suspected HEGO sensor. Inspect both ends of connector for damaged or pushed-out pins, moisture, corrosion, loose wires or other damage. Repair as necessary. Set DVOM on 200-ohm scale. Measure resistance between KPWR circuit and PWR GND circuit at HEGO sensor connector. Hot to warm resistance should be 5.0-30.0 ohms. Room temperature resistance is 2.0-5.0 ohms. If resistance is within specification, go to next step. If resistance is not as specified, replace HEGO sensor and repeat QUICK TEST.

Checking HEGO Sensor. Scheme 29

22) Check For Power At HEGO Harness Connector With ignition on and engine off, and HEGO disconnected, set DVOM on 20-volt scale. Measure voltage between KEY POWER circuit and PWR GND circuit at HEGO vehicle harness connector. If voltage is greater than 10.5 volts, HEGO system and fuel delivery are okay; HEGO sensor may have cooled before KOER SELF-TEST. If driveability symptom persists, fault is in area common to all cylinders, such as air or vacuum leaks, fuel contamination, EGR, MAP, etc. If voltage is less than 10.5 volts, go to next step.

Identifying HEGO Sensor Harness Connector. Scheme 30

23) Check Continuity Of Power Ground Circuit Turn ignition off and wait 10 seconds. Disconnect HEGO sensor and set DVOM on 200-ohm scale. Measure resistance between PWR GND circuit at HEGO vehicle harness connector and battery negative post. If resistance is less than 5 ohms, repair open in KEY POWER circuit. Reconnect HEGO and rerun QUICK TEST. If resistance is more than 5 ohms, reconnect HEGO sensor and repair open in PWR GND circuit. Reconnect HEGO sensor and rerun QUICK TEST.

24) Check HEGO SIGNAL For Short To Power On dual HEGO systems, Code 42/173 refers to right (or rear) side HEGO, and Code 92/137 or 177 refers to left (or front) side HEGO. Turn ignition off and wait 10 seconds. Disconnect appropriate HEGO sensor. Set DVOM on 20-volt scale. With ignition on and engine off, measure voltage between HEGO SIG and PWR GND at HEGO vehicle harness connector. If reading is less than .5 volt, go to step 26. If reading is NOT less than 0.5 volt, go to next step.

25) Check For Short To Power Turn ignition off. Disconnect HEGO sensor. Inspect both ends of connector for damaged or pushed-out pins, moisture, corrosion, loose wires or other damage. Repair as necessary. Set DVOM on 200-k/ohm scale. Disconnect ECA 60-pin connector. Install breakout box, leaving ECA disconnected. Measure resistance between KEY POWER circuit and HEGO SIG circuit at breakout box.

If reading is greater than 10 k/ohms, replace ECA. Remove breakout box and reconnect all components. Drive vehicle for 5 miles at 55 MPH. Rerun QUICK TEST.

If reading is less than 10 k/ohms, repair short circuit. Remove breakout box and reconnect all components. Drive vehicle for 5 miles at 55 MPH. Rerun QUICK TEST.

26) Check HEGO Sensor For Short To Ignition Run Circuit Turn ignition off and wait 10 seconds. Disconnect HEGO. Set DVOM to 200-k/ohm scale. Measure resistance between KEY POWER circuit and HEGO SIG circuit at HEGO sensor connector.

If resistance is greater than 10 k/ohms, go to next step for codes 42/173, 92/137 or 177. For codes 171, 174, 175 or 178, go to step 28 (MAP sensor), or step 30 (MAF sensor).

If resistance is less than 10 k/ohms, replace HEGO sensor. Drive vehicle for 5 miles at 55 MPH and rerun QUICK TEST.

27) Attempt To Generate Code 41/172, 91/136 Or 176 The following non-EEC areas may cause these codes: fuel-contaminated engine oil, ignition misfire and faulty CANP system. Turn ignition off and wait 10 seconds. Disconnect appropriate HEGO sensor. Using jumper wire, connect HEGO SIG circuit at HEGO vehicle harness connector to battery negative terminal. Repeat KOER SELF-TEST.

If Code 41/172, 91/136 or 176 is present, remove jumper wire and go to next step for engines with MAP. For all other engines, go to step 30.

If Codes 41/172, 91/136 or 176 is not present, remove jumper wire. Disconnect ECA connector and inspect for damage. If connector is okay, replace ECA. Drive vehicle for 5 miles at 55 MPH. Repeat QUICK TEST.

Because MAP sensor has a large influence on fuel control, Code 42/172 or 91/136 may be caused by a faulty MAP sensor, even though Code 22/126 has not been set. The next 2 steps test the MAP vacuum circuit.

28) Check MAP Sensor For Vacuum Leaks Turn ignition off and wait 10 seconds. Disconnect vacuum hose from MAP sensor and connect vacuum pump to sensor. Apply 18 in Hg to MAP sensor. If sensor holds vacuum, release vacuum and go to next step. If sensor does not hold vacuum, replace MAP sensor. Remove vacuum pump. Connect vacuum hose and reconnect HEGO. Drive vehicle for 5 miles at 55 MPH. Repeat QUICK TEST.

29) Check For Loss Of Vacuum To MAP Sensor Using vacuum "T", connect vacuum gauge in intake manifold vacuum hose at MAP sensor. Start engine and note vacuum reading at a stable idle. Turn ignition off and wait 10 seconds. Remove "T" and vacuum gauge. Reconnect hose to MAP sensor. Connect vacuum gauge at a different intake manifold location. Start engine and note vacuum reading. If readings do not differ by more than 1 in. Hg, go to next step. If readings differ by more than 1 in. Hg, inspect vacuum hoses for leaks, kinks, or blockage. Repair as necessary. Reconnect all components and drive vehicle for 5 miles at 55 MPH. Rerun QUICK TEST.

30) HEGO Sensor Check Turn ignition off and wait 10 seconds. Disconnect HEGO sensor. Set DVOM on 20-volt scale. For 4-Wire HEGO, connect DVOM to HEGO SIGNAL and HEGO GND at HEGO sensor connector. For 3-Wire HEGO, connect DVOM to HEGO SIGNAL at HEGO sensor connector and battery negative post. Remove a vacuum hose to create vacuum leak, which will cause HEGO sensor to go lean. Start engine and run at approximately 2000 RPM. DVOM should indicate less than 0.4 volt within 30 seconds. If voltage is not as specified, replace HEGO sensor. Reconnect vacuum hoses and drive vehicle for 5 miles at 55 MPH. Repeat QUICK TEST. If voltage is as specified, go to next step.

Note. There is a break in the step numbering sequence at this point, skipping from step 30 to step 90. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

90) Check Continuous Monitor Mode Turn ignition off and wait 10 seconds. Ensure engine is at normal operating temperature. Start engine and run at 2000 RPM for 2 minutes then return to idle. Enter KOER wiggle test. See CONTINUOUS MONITOR MODE (WIGGLE TEST) under QUICK TEST. While observing DVOM or "Scan" Tool, wiggle, shake or bend small sections of EEC-IV wiring harness from HEGO sensor to ECA. Wiggle, shake or bend small sections of EEC-IV wiring harness from HEGO GND to ECA. If no fault is indicated, remain in CONTINUOUS MONITOR MODE and go to next step. If fault is indicated, isolate and repair fault as necessary. Clear codes, remove breakout box and reconnect all components. Rerun QUICK TEST.

91) Continuous Monitor Test Drive Check While still in KOER wiggle test, test drive vehicle for 5 miles at 55 MPH with minimum road load. Drive an additional 5 miles at 55 MPH over rough roads. If possible, drive vehicle through a pool of water to shower HEGO sensor and connector. If fault is indicated, isolate fault and repair as necessary. Clear codes and remove breakout box. Rerun QUICK TEST. If no codes are indicated, exit KOER wiggle test and go to next step.

92) Check HEGO Switching Turn ignition off and wait 10 seconds. Inspect EEC-IV wire harness for proper routing and insulation. Check for burnt, chaffed or intermittently shorted or open wires. Repair as necessary. Disconnect ECA 60-pin connector and inspect for damaged or pushed-out pins, corrosion, loose wires or other damage; repair as necessary. Install breakout box and connect ECA to breakout box. Connect analog voltmeter to suspected HEGO sensor test pin and HEGO GND at breakout box. Test drive vehicle for 5 miles at 55 MPH while observing voltmeter. HEGO should switch from .3 volt to .9 volt within 3 seconds. If HEGO does not switch as described, replace HEGO sensor. Remove breakout box, reconnect all components and rerun QUICK TEST. If HEGO switches as described, fault cannot be identified or duplicated at this time. See INTERMITTENTS in the TESTS W/O CODES article in this section.

TEST HA - ADAPTIVE FUEL

Note. For fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS article.

Perform this test when directed by QUICK TEST.

The ECA uses Adaptive Fuel logic primarily to compensate for normal variability in fuel system components. If fuel system appears to be too rich or too lean, adaptive fuel will make a corresponding shift in fuel delivery calculations to compensate and remove bias.

MAP SENSOR VOLTAGE OUTPUT

If possible, measure several known good MAP/BP sensors on available vehicles. Average voltage reading will be typical for your location on date of testing.

1) Continuous Memory Codes 181, 183, 189 Or 192: Is Vehicle SEFI or EFI? This test identifies areas that could cause HEGO sensor to detect excessive oxygen, resulting in adaptive fuel enriching the system to compensate. Excessive oxygen will be detected with lean conditions and certain rich conditions.

For vehicles with dual HEGO sensors, a related fuel code from both HEGO sensors could indicate a problem that is common to all cylinders. If a code is present from only one HEGO, this may help isolate a problem or be an early indication of a common problem.

1. Code 183 - Indicates the single right or rear HEGO detected a problem, and adaptive fuel rich limit has been reached at idle.
2. Code 192 - Indicates the left or front HEGO detected a problem, and adaptive fuel rich limit has been reached at idle.
3. Code 181 - Indicates the single right or rear HEGO detected a problem, and adaptive fuel rich limit has been reached.
4. Code 189 - Indicates the left or front HEGO detected a problem, and adaptive fuel rich limit has been reached.

Ensure a pass code (111) is received during both KOEO SELF-TEST and KOER SELF-TEST. Whenever a repair is made, clear Keep-Alive Memory (KAM). If driveability symptoms are not present, be aware of other temporary conditions that may have set this code, such as vehicle is out of fuel or fuel is contaminated.

If vehicle is SEFI equipped, go to next step. If vehicle is not SEFI equipped, go to step 3.

2) Run Cylinder Balance Test Run KOER SELF-TEST. After last repeated code, wait 5-10 seconds then "goose" throttle lightly (not WOT). Cylinder balance test will be activated. If Code 90 is present, go to next step. If Code 90 is not present, go to step 35.

3) Check For Vacuum/Air Induction Leaks Check all vacuum hose and connections for leaks or damage. Check air induction system for leak or damage. If leak or damage is found, repair as necessary; clear KAM and rerun QUICK TEST. If leak or damage is not found, go to next step.

4) Check For Low Fuel Pressure Turn ignition off and wait 10 seconds. Install fuel pressure gauge. Cycle ignition from off to run 2 to 3 times. Observe KOEO fuel pressure. Start engine, observe and record KOER fuel pressure. For fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS article. If fuel pressure is within specifications, go to next step. If fuel pressure is not within specifications, repair fuel system as necessary. Clear KAM and rerun QUICK TEST.

5) Check Systems Ability To Hold Fuel Pressure With fuel pressure gauge installed, cycle ignition from off to on 2 to 3 times to pressurize fuel system (do not start engine). If fuel pressure remains at specifications for 60 seconds, go to next step (MAP/BP-equipped vehicles), or step 7 (all other vehicles). If fuel pressure does not remain at specifications for 60 seconds, visually inspect fuel system for leaks and repair as necessary. Clear KAM and rerun QUICK TEST.

6) Check MAP/BP Frequency Turn ignition off and wait 10 seconds. Connect MAP/BP tester to MAP/BP sensor. Turn ignition on. Refer to MAP SENSOR VOLTAGE OUTPUT table at beginning of this circuit test. If MAP/BP voltage is within specifications, go to next step. If voltage is not within specifications, check wiring to MAP/BP sensor for corrosion, high resistance or other damage; repair as necessary. Clear KAM and rerun QUICK TEST. If wiring is okay, replace MAP/BP sensor; clear KAM and rerun QUICK TEST.

7) Check For Proper Battery Voltage To Fuel Injectors Turn ignition on, leaving engine off. Set DVOM to 20-volt scale. Measure and record voltage across battery terminals. Disconnect any fuel injector harness connector. Measure and record voltage between VPWR circuit at fuel injector vehicle harness connector and battery negative terminal. If both voltage readings are within one volt of each other, go to next step. If voltage readings differ by more than one volt, fuel injectors are not getting proper battery voltage. Isolate and repair problem. Clear KAM and rerun QUICK TEST.

8) Ensure CANP Solenoid Is Not Stuck Closed Enter Output State Check. Disconnect hose to manifold vacuum at CANP solenoid. Check for blockage and repair or replace hose as necessary. With outputs off, apply 16 in. Hg. vacuum to manifold vacuum side of CANP. Depress throttle to cycle outputs on. If vacuum releases, reconnect vacuum hose to CANP and go to next step (thermactor-equipped vehicles), or step 26 (all other vehicles). If vacuum does not release, repeat this step to verify results. If vacuum will not release, check canister and vacuum hose to canister for blockage; repair as necessary. If canister and hose are okay, replace CANP solenoid; clear KAM and rerun QUICK TEST.

9) Check Thermactor System For Upstream Air Leak Check thermactor air control and vacuum control valves. See SYSTEM/COMPONENT TESTS article. If air control valve is operating properly, go to step 25. If air control valve is not operating properly, repair or replace valve as necessary. Clear KAM and rerun QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 9 to step 15. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

15) Continuous Memory Codes 179, 182, 188 Or 191: Is Vehicle SEFI or EFI? This test identifies areas that could cause engine to run rich, resulting in adaptive fuel reducing the system to compensate.

For vehicles with dual HEGO sensors, a related fuel code from both HEGO sensors could indicate a problem that is common to all cylinders. If a code is present from only one HEGO, this may help isolate a problem or it may be an early indication of a common problem.

1. Code 182 Indicates the single right or rear HEGO detected a problem, and adaptive fuel lean limit has been reached at idle.
2. Code 191 - Indicates the left or front HEGO detected a problem, and adaptive fuel lean limit has been reached at idle.
3. Code 179 - Indicates the single, right or rear HEGO detected a problem, and adaptive fuel lean limit has been reached.
4. Code 188 - Indicates the left or front HEGO detected a problem, and adaptive fuel lean limit has been reached.

Ensure a pass code (111) is received during both KOEO SELF-TEST and KOER SELF-TEST. Whenever a repair is made, clear Keep-Alive Memory (KAM).

If vehicle is SEFI equipped, go to next step. If vehicle is not SEFI equipped, go to step 17.

16) Run Cylinder Balance Test Run KOER SELF-TEST. After last repeated code, wait 5-10 seconds then "goose" throttle lightly (not WOT). Cylinder balance test will be activated. If Code 90 is present, go to next step. If Code 90 is not present, go to step 35.

17) Check For Low Fuel Pressure Turn ignition off and wait 10 seconds. Install fuel pressure gauge. Cycle ignition from off to run 2 to 3 times. Observe KOEO fuel pressure. Start engine, observe and record KOER fuel pressure. For fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS article. If fuel pressure is within specifications, go to next step. If fuel pressure is not within specifications, check condition of fuel pressure regulator vacuum hose, fuel return line and fuel pressure regulator. Repair fuel system as necessary. Clear KAM and rerun QUICK TEST.

18) Check Systems Ability To Hold Fuel Pressure With fuel pressure gauge installed, cycle ignition from off to on 2 to 3 times to pressurize fuel system (do not start engine). If fuel pressure remains at specifications for 60 seconds, go to next step (MAP/BP-equipped vehicles), or step 20 (all other vehicles). If fuel pressure does not remain at specifications for 60 seconds, visually inspect fuel system for leaks and repair as necessary. Clear KAM and rerun QUICK TEST.

19) Check MAP/BP Frequency Turn ignition off and wait 10 seconds. Connect MAP/BP tester to MAP/BP sensor. Turn ignition on. Refer to MAP SENSOR VOLTAGE OUTPUT table in this circuit test. If MAP/BP voltage is within specifications, go to next step. If voltage is not within specifications, check wiring to MAP/BP sensor for corrosion, high resistance or other damage; repair as necessary. Clear KAM and rerun QUICK TEST. If wiring is okay, replace MAP/BP sensor; clear KAM and rerun QUICK TEST.

20) Check Throttle Body And Air Induction System Check throttle body and air induction system for contamination, obstruction, etc. Repair or clean as necessary. Clear KAM and rerun QUICK TEST. If throttle body and air induction system are okay, go to next step.

21) Ensure CANP Will Hold Vacuum Turn ignition off and wait 10 seconds. Disconnect vacuum hose to manifold vacuum at CANP solenoid. Apply 16 in. Hg vacuum to manifold side of CANP solenoid. If solenoid holds vacuum for 20 seconds, reconnect vacuum hose and go to next step. If solenoid does not hold vacuum for 20 seconds, replace CANP solenoid. Clear KAM and rerun QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 21 to step 25. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

25) Check PCV Valve Turn ignition off and wait 10 seconds. Remove PCV valve and shake. If PCV valve rattles freely when shaken, go to next step. If PCV valve does not rattle, replace PCV valve. Clear KAM and rerun QUICK TEST.

26) Check HEGO Heater Circuit Turn ignition off and wait 10 seconds. Disconnect HEGO sensor(s). Set DVOM to 200-ohm scale. measure resistance between KEY POWER circuit and PWR GND circuit at HEGO sensor connector(s). Resistance should be 2 ohms (room temperature), or 35 ohms (hot).

Turn ignition on, leaving engine off. Set DVOM to 20-volt scale. Measure voltage between KEY POWER circuit and PWR GND circuit at HEGO sensor connector(s). Voltage should be 10.5 volts. If HEGO circuits check okay, go to next step. If HEGO circuits are not okay, isolate problem and repair as necessary. Clear KAM and rerun QUICK TEST.

27) Inspect HEGO Sensor For Contamination Remove HEGO sensor(s) from exhaust manifold. Visually inspect for contamination or other damage. If HEGO sensor(s) appears okay, go to next step (vehicles with EGR), or step 30 (all other vehicles). If HEGO sensor(s) is not okay, replace HEGO sensor; clear KAM and rerun QUICK TEST.

28) Verify Excessive Vacuum Is Not At EGR Valve During Idle Disconnect vacuum line at EGR valve. Connect vacuum gauge to EGR vacuum line. Start engine and let idle. If vacuum reading is less than 2.5 in. Hg, go to next step. If vacuum reading is greater than 2.5 in. Hg, check EVR solenoid filter for obstructions and repair as necessary. If EVR filter is okay, replace EVR solenoid; reconnect all components, clear KAM and rerun QUICK TEST.

29) Verify EGR Valve Is Fully Seated Inspect EGR valve to ensure proper seating. If EGR valve is fully seated, reconnect vacuum line to EGR valve and go to next step. If EGR Valve is not fully seated, service or replace EGR valve as necessary; clear KAM and rerun QUICK TEST.

30) Check Cooling System Ensure cooling system is in good condition and all components are operating properly. If cooling system is okay, go to next step. If system is not okay, repair as necessary. Clear KAM and rerun QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 30 to step 35. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

35) Check Ignition System Ensure ignition system is operating properly. Scope check engine spark plug, coil, secondary wires, distributor cap, rotor, timing, etc. If ignition system is operating properly, go to next step. If system is not operating properly, make necessary repairs. Clear KAM and rerun QUICK TEST.

36) Flow Check Injectors Flow check fuel injectors. See FUEL CONTROL in the SYSTEM/COMPONENT TESTS article in this section. If injectors are okay, go to next step. If injectors are not okay, clean or replace injectors as necessary. Clear KAM and rerun QUICK TEST.

37) Check Cylinder Compression Check cylinder compression. See MECHANICAL INSPECTION in BASIC TESTING article in this section. If cylinder compression is not within specifications, service or repair engine as necessary. After servicing engine, clear KAM and rerun QUICK TEST. If cylinder compression is within specifications, go to the next step.

Note. There is a break in the step numbering sequence at this point, skipping from step 37 to step 40.Break is due to previous chart references to these testing procedures. No test procedures have been omitted. The following road test is a suggested optional procedure. Follow all applicable safety procedures and traffic laws. This road test requires another person to accompany the driver. The accompanying person can make measurements, observe changes and record notes. If for some reason this test is not performed, go to the TESTS W/O CODES article in this section for other possible causes.

40) Road Test Vehicle The purpose of this test is to identify areas of concern by monitoring certain controlled parameters, while trying to recreate a driveability or MIL light symptom. To prepare for road test, do the following

1. Install fuel pressure gauge.
2. Install MAP/BP tester.
3. Disconnect ECA 60-pin connector; install breakout box and reconnect ECA to breakout box.
4. Connect "T" vacuum gauge into manifold vacuum line.
5. Have DVOM, writing materials and appropriate schematics or pin voltage charts on hand.

With ignition on and negative lead of DVOM connected to battery negative terminal, ensure the following signals are correct

1. POWERS: KAPWR (pin No. 1) is greater than 10.5 volts, VPWR (pins No. 37/57) is greater than 10.5 volts and VREF (pin No. 26) is 4-6 volts.
2. GROUNDS: PWR GND (pins No. 40/60), SIG RTN (pin No. 46) and IGN GND (pin No. 16) are 0-.5 volt.
3. OPTIONAL GROUNDS: HEGO GND (pin No. 49), CSE GND (pin No. 20) and MAF RTN (pin No. 9 or 15).

Drive vehicle and attempt to induce symptom. Information provided by customer may help when trying to recreate symptom. When symptom occurs, the accompanying passenger should observe and record changes in EEC-IV signals. Information about the symptom, operating condition value of EEC-IV signal and any other information available should be recorded on paper for analysis. If unable to duplicate symptom during road test, it is still useful to verify that EEC-IV values are in expected range.

Once road test has been completed, analyze results to locate and repair exact fault causing symptom. If problem cannot be identified, go to the TESTS W/O CODES article in this section for other possible causes of symptom.

Perform this test when instructed by QUICK TEST, or when directed by other test procedures.

This test is intended to diagnose only the following

1. Fuel Pump Relay
2. Inertia Switch
3. Harness Circuits (BATT +, VPWR, FUEL PUMP, GND & POWER To PUMP)
4. ECA

Fuel Pump Circuit. Scheme 31

TEST PIN WIRE COLOR IDENTIFICATION

1) No Fuel Pump Pressure: Check Fuel Pump Electrical Operation Turn ignition from OFF to RUN position several times (DO NOT turn to START position). If fuel pumps run briefly each time ignition is turned to RUN position, fuel pump circuit is okay. If fuel pumps do not run, go to next step.

2) Check For VPWR To ECA With ignition off, install breakout box and reconnect ECA. Set DVOM on 20-volt scale. Turn ignition on, leaving engine off. Measure voltage between test pins No. 37 and 40 at breakout box. Measure voltage between test pins No. 57 and 60 at breakout box. If both voltage readings are greater than 10.5 volts, go to step 3. If voltage is not greater than 10.5 volts, go to TEST B, step 1.

3) Check Voltage To POWER-TO-PUMP(s) Circuit With Key On Engine Off (KOEO), breakout box installed and ECA connected, set DVOM on 20-volt scale. Measure voltage between chassis ground and POWER-to-PUMP circuit at fuel pump relay while cranking engine. If reading is less than 8 volts, go to next step. If reading is 8 volts or more, check the following: open in POWER-to-PUMP circuit, open in fuel pump, and open fuel pump ground circuit.

4) Checking BATT (+) Circuit To Fuel Pump Relay Turn ignition on, leaving engine off. Leave breakout box installed and ECA connected. Locate fuel pump relay. Set DVOM on 20-volt scale. Measure voltage between chassis ground and BATT (+) circuit at fuel pump relay. If reading is less than 10.5 volts, repair open in BATT (+) circuit between fuel pump relay and battery positive post. Repeat QUICK TEST. If reading is 10.5 volts or greater, go to next step.

5) Check Voltage At POWER-TO-PUMP(s) Circuit With ignition off, breakout box installed and ECA connected, set DVOM on 20-volt scale. Connect jumper wire from test pin No. 22 to test pin No. 40 or 60 at breakout box. Turn ignition on, leaving engine off. Measure voltage between chassis ground and POWER-to-PUMP circuit at fuel pump relay. If voltage is greater than 10.5 volts, replace ECA. Remove breakout box and rerun QUICK TEST. If voltage is less than 10.5 volts, replace fuel pump relay. Remove breakout box, reconnect ECA and rerun QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 5 to step 7. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

7) Code 87/556: Checking VPWR Circuit To Fuel Pump Relay Code 87/556 indicates a fuel pump primary circuit failure. Possible causes for this fault are as follows

1. Inertia switch not reset or electrically open
2. Open or shorted circuit
3. Faulty fuel pump relay
4. Faulty ECA

Turn ignition on, leaving engine off. Set DVOM on 20-volt scale. Disconnect fuel pump relay. Measure voltage between chassis ground and VPWR circuit at fuel pump relay. If reading is 10.5 volts or more, go to next step. If reading is less than 10.5 volts, ensure inertia switch is on. If inertia switch will not reset, replace switch. If switch is okay, repair open in VPWR circuit between EEC power relay and fuel pump relay. Reconnect fuel pump relay and repeat QUICK TEST.

8) Check Fuel Pump Relay Turn ignition off and wait 10 seconds. Disconnect fuel pump relay. With DVOM on 200-ohm scale, measure resistance between VPWR pin and Fuel Pump circuit pin at fuel pump relay. Resistance should be 40-85 ohms.

Set DVOM to 20-k/ohm scale. Measure resistance between Fuel Pump circuit pin and both POWER-to-PUMP and BATT (+) pins at fuel pump relay. Both resistances should be greater than 10 k/ohms. If all resistances are as specified, go to next step. If resistances are not as specified, replace fuel pump relay and rerun QUICK TEST.

Fuel Pump Relay Connector. Scheme 32

9) Check For Short To Power With ignition off, disconnect 60-pin ECA connector and fuel pump relay. Install breakout box and leave ECA disconnected. Set DVOM on 20-volt scale. Turn ignition on. Measure voltage between test pin No. 22 and battery negative terminal. If voltage is less than one volt, go to next step. If voltage is not less than one volt, repair short circuit. Reconnect ECA and attempt to start vehicle. If vehicle fails to start, replace ECA. Rerun QUICK TEST.

10) Check For Shorts To Ground Turn ignition off and wait 10 seconds. Leave breakout box installed and ECA disconnected. Disconnect fuel pump relay. With DVOM on 200-k/ohm scale, measure resistance between test pin No. 22 and test pins No. 40 and 60. If reading is less than 10 k/ohms, repair short in FUEL PUMP circuit. Remove breakout box and reconnect all components. Repeat QUICK TEST. If reading is 10 k/ohms or more, go to next step.

11) Check Fuel Pump Circuit Continuity Turn ignition off. Leave breakout box installed and ECA disconnected. Set DVOM to 200-ohm scale. Disconnect fuel pump relay. Measure resistance between fuel pump circuit at fuel pump relay vehicle harness connector and test pin No. 22 at breakout box. If resistance is less than 5 ohms, replace ECA. Reconnect fuel pump relay and rerun QUICK TEST. If resistance is greater than 5 ohms, repair open circuit. Remove breakout box, reconnect all components and rerun QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 11 to step 20. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

20) Code 95/542: Does Engine Start? A KOEO Code 95/542 indicates one of the following conditions has occurred

No Starts

1. Inertia switch not reset or electrically open
2. Open circuit in or between ECA and fuel pump
3. Faulty ground connection at fuel pump

Vehicle Starts

1. Fuel pump secondary circuit shorted to power
2. Fuel pump relay contacts always closed
3. Open in Fuel Pump Monitor (FPM) circuit between ECA and connection to POWER-to-PUMP circuit
4. HEGO short to power (dual HEGO applications)
5. Faulty ECA

If engine starts, go to next step. If engine does not start, go to step 25.

21) Verify Fuel Pump Is Off Turn ignition on and wait 5 seconds. Listen for fuel pump noise. If fuel pump is off, go to step 23. If fuel pump is on, go to next step.

22) Check For Fuel Pump Relay Always Closed Turn ignition off. Disconnect fuel pump relay. Turn ignition on. If fuel pump is off with relay disconnected, replace fuel pump relay and rerun QUICK TEST. If Fuel pump is on with relay disconnected, repair short to power in POWER-to-PUMP/FPM circuit. (For vehicles with relay block, also check fuel pump prime plug circuit.) Rerun QUICK TEST.

23) Check Continuity Of Fuel Pump Monitor (FPM) Circuit Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Install breakout box and leave ECA disconnected. Disconnect fuel pump relay. Set DVOM on 200-ohm scale and measure resistance between test pin No. 19 at breakout box and POWER-to-PUMP circuit at fuel pump relay vehicle harness connector. If resistance is less than 5 ohms, go to step 35 (dual HEGO vehicles), or replace ECA, remove breakout box, reconnect fuel pump relay and rerun QUICK TEST (all other vehicles). If resistance is greater than 5 ohms, repair open circuit; remove breakout box, reconnect all components and rerun QUICK TEST.

Fuel Pump Relay Vehicle Harness Connector. Scheme 33

Note. There is a break in the step numbering sequence at this point, skipping from step 23 to step 25. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

25) Check Inertia Switch Turn ignition off and wait 10 seconds. Locate and disconnect fuel pump inertia switch. Ensure switch is reset. Set DVOM on 200-ohm scale. Measure resistance of fuel pump inertia switch (on Escort and Tracer, measure resistance between GND pin and FP pin). If resistance is less than 5 ohms, reconnect switch and check for open in POWER-to-PUMP circuit, poor fuel pump ground or open in fuel pump. If resistance is not less than 5 ohms, replace or reset inertia switch. Repeat QUICK TEST.

Inertia Switch (Escort & Tracer). Scheme 34

Note. There is a break in the step numbering sequence at this point, skipping from step 25 to step 30. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

30) Code 96/543: Engine Does Not Start Code 96/543 indicates fuel pump secondary circuit failure between BATT (+) supply and FPM connection to POWER-to-PUMP circuit. The following are possible causes for this fault.

No Start

1. Open circuit between BATT (+) supply and FPM connection to POWER-to-PUMP circuit
2. Fuel pump relay contacts are always open

Engine Starts

1. HEGO short to power (Dual HEGO vehicles)
2. Faulty ECA

If engine starts, go to step 35 (for dual HEGO vehicles) or replace ECA and rerun QUICK TEST (for all other vehicles). If engine does not start, go to next step.

31) Check For BATT (+) To Fuel Pump Relay With ignition off, set DVOM on 20-volt scale. Connect DVOM between BATT (+) circuit at fuel pump relay and battery negative post. If voltage is greater than 10.5 volts, go to next step. If voltage is less than 10.5 volts, check integrity of fuse/fusible link for BATT (+) supply to fuel pump relay. If fuse/fusible is okay, repair open circuit in BATT (+) circuit. Rerun QUICK TEST.

32) Check For Voltage At POWER-TO-PUMP Circuit Turn ignition off and wait 10 seconds. Set DVOM to 20-volt scale. Connect DVOM between POWER-to-PUMP circuit at fuel pump relay and battery negative terminal. Observe DVOM while activating fuel pump relay (turn ignition to RUN position for one second, then turn ignition off for 10 seconds; repeat 5 times). If voltage is greater than 10.5 volts for about one second after key is turned to RUN position, go to next step. If voltage is not as specified, disconnect fuel pump relay. Inspect for damaged pins, corrosion, loose pins or other damage. Repair as necessary. If okay, replace fuel pump relay and rerun QUICK TEST.

33) Check POWER-To-PUMP Circuit Continuity Turn ignition off and wait 10 seconds. Set DVOM to 200-ohm scale. Disconnect fuel pump relay. Measure resistance between POWER-to-PUMP circuit at fuel pump relay vehicle harness connector and battery negative terminal. If resistance is less than 10 ohms, replace ECA. Reconnect relay and rerun QUICK TEST. If resistance is greater than 10 ohms, repair open circuit in POWER-to-PUMP circuit between FPM splice and fuel pump relay. Rerun QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 33 to step 35. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

Due to the internal circuitry of ECA, a left/front HEGO signal short to power could produce a code 95/542 or 96/543.

35) Check Left/Front HEGO Sensor For Short To Power Turn ignition off and wait 10 seconds. Set DVOM to 200-k/ohm scale. Disconnect left or front HEGO sensor. Measure resistance between HEGO signal pin and KEY POWER pin at HEGO sensor connector. Is resistance is greater than 10 k/ohms, go to next step. If resistance is less than 10 k/ohms, replace HEGO sensor and rerun QUICK TEST. Clear Keep-Alive Memory (KAM).

HEGO Sensor Connector. Scheme 35

36) Check HEGO Circuit For Short To Power Turn ignition off and wait 10 seconds. Set DVOM to 20-volt scale. Disconnect left or front HEGO. Disconnect ECA 60-pin connector and inspect for damaged or pushed-out pins, corrosion, loose wire ore other damage. Leave ECA disconnected. Turn ignition on and measure voltage between HEGO signal at HEGO vehicle harness connector and chassis ground. If voltage is less than 2 volts, replace ECA; reconnect HEGO sensor and rerun QUICK TEST. If voltage is greater than 2 volts, repair short circuit. Reconnect ECA and HEGO sensor. Rerun QUICK TEST and clear KAM.

HEGO Sensor Vehicle Harness Connector. Scheme 36

Note. There is a break in the step numbering sequence at this point, skipping from step 36 to step 90. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

90) Continuous Memory Code 95/542: Check EEC-IV Harness Code 95/542 indicates one of the following conditions has occurred intermittently

1. Open circuit in or between fuel pump and FPM circuit at ECA
2. Faulty ground circuit at fuel pump
3. FPM or POWER-to-PUMP circuit short to power
4. Fuel pump relay contacts stuck open
5. FUEL PUMP circuit is activated when ECA expects circuit to be off.

Start engine and perform wiggle test on vehicle harness to fuel pump, and to pump ground circuit harness. See CONTINUOUS MONITOR MODE (WIGGLE TEST) under QUICK TEST. Lightly tap inertia switch and pump to simulate road shock. Check for engine miss or stumble while performing test. With ignition off, check harness connectors for corrosion or damage. Isolate and repair any faults; clear Code 95/542 and rerun QUICK TEST. If no fault is found, go to next step.

91) Check FPM Circuit Turn ignition off. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Install breakout box and leave ECA disconnected. With Key On Engine Off (KOEO), connect a test light between test pin No. 19 and test pin No. 37 at breakout box. With test light lit, perform wiggle test on FPM circuit between pump and monitor. Light should go out if fault is found during wiggle test. Isolate and repair any found faults; remove test set-up and rerun QUICK TEST. If no fault is found, go to next step.

92) Check For Shorts To Power With KOEO, breakout box installed and ECA disconnected, connect a test light between test pin No. 19 and test pin No. 40. Observe test light; perform wiggle test on FPM circuit and POWER-to-PUMP circuit. Lightly tap fuel pump relay to simulate road shock. If light comes on, it indicates fault exists; isolate and repair as necessary. Remove test set-up and rerun QUICK TEST. If no fault is found, go to step 96 (dual HEGO-equipped vehicles), or step 99 (all others).

93) Continuous Memory Code 96/543: Check For Continuous Memory Code 87/556 If Code 87 or 556 is present, go to step 95. If code 87 or 556 is not displayed, go to next step.

94) Check EEC-IV Harness A Continuous Memory Code 96/543, without an accompanying Continuous Memory Code 87/556, indicates that during vehicle operation, one of the following conditions has occurred

1. An open in BATT (+) circuit between BATT (+) and fuel pump relay
2. Fuel pump relay contacts open
3. Open in POWER-to-PUMP circuit from fuel pump relay to FPM splice (if applicable)
4. Left/front HEGO circuit short to power (dual HEGO)

With engine running, attempt to cause a miss or stumble while performing wiggle test on pump harness and connectors. With ignition off, inspect all fuel pump connectors and BATT (+) for damage or corrosion. If fault is found, isolate and repair as necessary. Clear Continuous Memory Codes and rerun QUICK TEST. If no fault is found, under certain conditions, a Continuous Memory Code 95/543 may have been set without a Continuous Memory Code 87/556, even though a fault has occurred in fuel pump primary circuit. Go to next step.

95) Continuous Code 87/556: Check EEC-IV Harness A Continuous Memory Code 87 or 556 indicates primary fuel pump circuit has failed during vehicle operation. Possible causes for this fault are as follows

1. Open in VPWR circuit between EEC power relay and fuel pump relay
2. Open coil in fuel pump relay
3. Open in fuel pump circuit (pin 22)
4. Faulty inertia switch

With engine running, attempt to cause a miss or stumble while performing wiggle test on VPWR circuit between EEC power relay and fuel pump relay. Wiggle fuel pump circuit harness (test pin No. 22) between ECA and fuel pump relay. Lightly tap fuel pump relay to simulate road shock. With ignition off, inspect ECA 60-pin connector for damage or corrosion. If fault is found, isolate and repair as necessary. Rerun QUICK TEST. If no fault is found, go to next step (dual HEGO-equipped vehicles), or if fault may not be duplicated at this time (all others), go to step 99.

Due to internal circuitry of ECA, an intermittent left/front HEGO signal short to power could produce a Continuous Memory Code 95/542 or 96/543.

96) Check Left/Front HEGO Circuit For Short To Power Turn ignition off. Install breakout box and leave ECA disconnected. Connect test light between left/front HEGO test pin and pin No. 40 at breakout box. See schematic at beginning of TEST H for appropriate HEGO test pin No. Perform wiggle test on left/front HEGO circuit to ECA. Lightly tap HEGO sensor to simulate road shock. If light goes on, it indicates fault exists; isolate and repair as necessary. Remove test set-up, clear Keep-Alive Memory (KAM) and rerun QUICK TEST. If no fault is indicated, go to next step.

Note. There is a break in the step numbering sequence at this point, skipping from step 96 to step 99. Break is due to previous chart references to these testing procedures. No test procedures have been omitted. This road test is a suggested optional procedure. Follow all applicable safety procedures and traffic laws. This road test requires another person to accompany the driver. The accompanying person can make measurements, observe changes and record notes. If for some reason this test is not performed, go to the TESTS W/O CODES article in this section for other possible causes.

99) Road Test Vehicle This test identifies areas of concern by monitoring certain controlled parameters while trying to recreate a driveability or MIL light symptom. To prepare for road test, do the following

1. Install fuel pressure gauge.
2. Install MAP/BP tester.
3. Disconnect ECA 60-pin connector; install breakout box and reconnect ECA to breakout box.
4. Connect "T" vacuum gauge into manifold vacuum line.
5. Have DVOM, writing materials and appropriate schematics or pin voltage charts on hand.

With ignition on and negative lead of DVOM connected to battery negative terminal, ensure the following signals are correct

1. POWERS: KAPWR (pin No. 1) is greater than 10.5 volts, VPWR (pins No. 37/57) is greater than 10.5 volts, and VREF (pin No. 26) is 4-6 volts.
2. GROUNDS: PWR GND (pins No. 40/60), SIG RTN (pin No. 46) and IGN GND (pin No. 16) are 0-.5 volt.
3. OPTIONAL GROUNDS: HEGO GND (pin No. 49), CSE GND (pin No. 20) and MAF RTN (pin No. 9 or 15).

Drive vehicle and attempt to induce symptom. Information provided by customer may help when trying to recreate symptom. When symptom occurs, the accompanying passenger should observe and record changes in EEC-IV signals. Information about the symptom, operating condition value of EEC-IV signal and any other information available should be recorded on paper for analysis. If unable to duplicate symptom during road test, it is still useful to verify that EEC-IV values are in expected range.

Once road test has been completed, analyze results to locate and repair fault causing the symptom. If problem cannot be identified, go to the TESTS W/O CODES article in this section for other possible causes of symptom.

Perform this test when instructed by QUICK TEST, or when directed by other test procedures. If engine is running rough or has rough idle, correct these conditions before performing test. Causes may be in ignition system, fuel system or EGR system. This test is intended to diagnose only the following

1. RPM during Self-Test mode
2. ISC solenoid
3. Harness circuits (ISC and VPWR)
4. Faulty ECA

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault

1. Engine temperature not up to operating temperature
2. Engine over operating temperature
3. A/C input (electrical problem)
4. Incorrect idle speed or throttle stop adjustment
5. Faulty cruise control linkage

Idle Speed Control (Air By-Pass) Circuit. Scheme 37

TEST PIN WIRE COLOR IDENTIFICATION

1) Code 12/412: Check For RPM Drop Code 12/412 indicates that during KOER SELF-TEST, engine RPM could not be controlled within the upper RPM limit of self-test. Possible causes for this fault are as follows

1. Open or shorted circuit
2. Sticking or binding throttle linkage
3. Incorrect idle adjustment
4. Throttle body or ISC solenoid contaminated
5. Faulty ISC solenoid
6. Faulty ECA
7. Non-ECC mechanical faults that could affect RPM

Turn ignition off. Connect engine tachometer and start engine. Disconnect Idle Speed Control (ISC) harness. If RPM drops or engine stalls, go to next step. If RPM doesn't drop or engine doesn't stall, go to step 3.

2) Check For EGR Codes If EGR service codes 31/327, 32/326/328, 33/332 or 34/336/334 are displayed, reconnect ISC solenoid. Go to appropriate KOER SELF-TEST CODES chart under SERVICE CODE REFERENCE CHARTS, and perform appropriate CIRCUIT TEST. If these codes are not displayed, go to next step.

3) Check For Other EEC-IV Codes If Codes 22/126, 41/172, 42/173, 91/136 or 92/137 are displayed, reconnect ISC solenoid. Go to appropriate KOER SELF-TEST CODES chart under SERVICE CODE REFERENCE CHARTS, and perform the appropriate CIRCUIT TEST. If these codes are not displayed, go to next step.

4) Measure ISC Solenoid Resistance Turn ignition off. Disconnect ISC solenoid. Set DVOM on 200-ohm scale, and measure resistance of ISC solenoid. Connect DVOM positive (+) lead to VPWR terminal and DVOM negative lead to ISC terminal, as ISC solenoid is equipped with a diode. If resistance is 7-13 ohms, go to next step. If resistance is NOT 7-13 ohms, replace ISC solenoid and repeat QUICK TEST.

ISC Solenoid Connector. Scheme 38

5) Check For Internal Short To ISC Solenoid Case With ignition off and ISC solenoid disconnected, set DVOM on 200-k/ohm scale. Measure resistance from either ISC terminal pin to ISC solenoid housing. If reading is greater than 10 k/ohms, go to next step. If reading is 10 k/ohms or less, replace ISC solenoid. Repeat QUICK TEST.

6) Check VPWR Circuit Voltage Leave ISC harness disconnected. With KOEO, set DVOM on 20-volt scale. Measure voltage between VPWR circuit at ISC harness connector and battery ground terminal. If reading is less than 10.5 volts, repair open in circuit and repeat QUICK TEST. If reading is 10.5 volts or more, go to next step.

7) Check ISC Circuit Continuity Turn ignition off and wait 10 seconds. Leave ISC solenoid disconnected. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair as necessary. Install breakout box, leaving ECA disconnected. With DVOM on 200-ohm scale, measure resistance between test pin No. 21 and ISC circuit at ISC vehicle harness connector. If reading is greater than 5 ohms, repair open circuit; remove breakout box, reconnect all components and repeat QUICK TEST. If reading is less than 5 ohms, go to next step.

8) Check ISC Circuit For Short To Ground Turn ignition off and wait 10 seconds. Leave ISC solenoid disconnected. Install breakout box, leaving ECA disconnected. Set DVOM on 200-k/ohm scale. Measure resistance between test pin No. 21 and test pins No. 40, 46 and 60. If any reading is less than 10 k/ohms, repair short to ground and repeat QUICK TEST. If all readings are 10 k/ohms or more, go to next step.

9) Check ISC Circuit For Short To Power Turn ignition off and wait 10 seconds. Leave breakout box installed. Leave ECA and ISC solenoid disconnected. Set DVOM on 200-k/ohm scale. Measure resistance by connecting DVOM negative lead to test pin No. 21 and positive lead to test pin No. 37. If reading is greater than 10 k/ohms, go to next step. If reading is 10 k/ohms or less, repair short circuit and remove breakout box. Reconnect all components and repeat QUICK TEST. If code or symptom is still present, replace ECA.

10) Check ISC Signal From ECA With ignition off, reconnect ECA and ISC. Leave breakout box installed and set DVOM on 20-volt scale. Connect DVOM between test pins No. 21 and 40. Start engine and observe DVOM while slowly increasing RPM to 3000 RPM. If DVOM voltage reading is 3.0-11.5 volts, go to next step. If DVOM voltage reading does not vary, replace ECA and repeat QUICK TEST.

11) Check Base Idle Verify base idle speed. See ON-VEHICLE ADJUSTMENTS article. If base idle speed is within specifications, remove ISC solenoid and inspect for contamination; service as necessary. Rerun QUICK TEST. If code or symptom is still present, replace ISC solenoid.

If curb idle speed is incorrect, reset idle speed to specification. Rerun QUICK TEST. If unable to set idle to specification, go to next step.

12) Check Faults Which Affect Idle Speed Check the following mechanical items for faults

1. Throttle linkage and/or cruise control linkage (sticking or binding)
2. Throttle body (contamination)
3. Vacuum hoses (check emission decal)
4. Check for leaks around ISC solenoid (gaskets, etc.)

If all of these items are okay, remove ISC solenoid and inspect for contamination. Service as necessary and rerun QUICK TEST. If code or symptom is still present, replace ISC. If any of these items are faulty, service as necessary. Remove breakout box. Reconnect components and rerun QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 12 to step 15. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

15) Code 13/411: Verify Idle Speed Is Within Specification Code 13/411 indicates that during KOER SELF-TEST, engine RPM could not be controlled within the lower RPM limit of self-test. Possible causes for this fault are as follows

1. Incorrect idle setting
2. Vacuum leaks
3. Sticking or binding throttle linkage
4. Throttle plates open
5. Incorrect ignition timing (TFI ignition only)
6. Throttle body or ISC solenoid contamination
7. ISC circuit shorted to ground
8. Faulty ISC solenoid

If all of the mentioned components are okay and idle is set to specification, remove ISC solenoid and inspect for contamination; service as necessary and rerun QUICK TEST. If code or symptom is still present, replace ISC solenoid. If idle speed is not set to specification, reset and rerun QUICK TEST. If idle speed cannot be reset to specification, go to next step.

16) Check For Conditions Affecting Idle Speed Check the following mechanical components

1. Engine vacuum hoses (refer to emission decal)
2. Throttle linkage and/or cruise control linkage (sticking or binding)
3. Ensure throttle plates are fully closed
4. Induction system (vacuum leaks)
5. Throttle body (contamination)
6. Ensure base ignition timing is to specification on emission decal (TFI vehicles only)

If everything check okay, go to next step. If fault is found, service as necessary and rerun QUICK TEST.

17) Check For Internal Short To ISC Solenoid Case With ignition off and ISC solenoid disconnected, set DVOM on 200-k/ohm scale. Measure resistance from either ISC terminal pin to ISC solenoid housing. If reading is greater than 10 k/ohms, go to next step. If reading is 10 k/ohms or less, replace ISC solenoid. Repeat QUICK TEST.

18) Check ISC Circuit For Short To Ground Turn ignition off and wait 10 seconds. Leave ISC solenoid disconnected. Disconnect ECA 60-pin connector. Inspect for damaged or corroded terminal pins; service as necessary. Install breakout box, leaving ECA disconnected. Set DVOM on 200-k/ohm scale. Measure resistance between test pin No. 21 and test pins No. 40, 46 and 60. If any reading is less than 10 k/ohms, repair short to ground and remove breakout box. Reconnect components and repeat QUICK TEST. If all readings are 10 k/ohms or more, go to next step.

19) Check ISC Signal From ECA With ignition off, connect ECA and ISC. Leave breakout box installed and set DVOM on 20-volt scale. Connect DVOM between test pins No. 21 and 40. Start engine and observe DVOM while slowly increasing and decreasing engine RPM. If DVOM voltage reading varies, remove ISC solenoid and inspect for contamination; service as necessary and rerun QUICK TEST. If code or symptom is still present, replace ISC solenoid. If DVOM voltage does not vary, replace ECA and rerun QUICK TEST.

Perform this test only when Code 83/563 or 88/564, is displayed during QUICK TEST or directed here by a driveability symptom. This test is intended to diagnose only the following components or circuits

1. Harness circuits (EDF, HEDF, EDF POWER-TO-FAN, HEDF POWER-TO-FAN, IGN START/RUN and GND)
2. EDF and HEDF relays
3. Cooling fan
4. ECA

EDF/HEDF Circuit. Scheme 39

TEST PIN IDENTIFICATION

1) Code 83/563 or 88/564: Check For IGNITION START/RUN Voltage At EDF/HEDF Relay Code 83/563 indicates faulty HEDF primary circuit. Code 88/564 indicates faulty EDF primary circuit. Possible causes for these faults are as follows

1. Open or shorted circuit
2. Faulty fan relay
3. Faulty ECA

With ignition off, disconnect EDF and HEDF relays. Set Digital Volt-Ohmmeter (DVOM) on 20-volt scale. With KOEO, measure voltage between IGN START/RUN circuit (at EDF/HEDF relay vehicle harness connector) and chassis ground. If voltage is greater than 10.5 volts, go to next step. If voltage is not as specified, repair open circuit. Reconnect relays. Go to QUICK TEST.

2) Enter Output State Check Use an analog Volt-Ohmmeter (VOM) or DVOM for this test. Turn ignition off and wait 10 seconds. Set DVOM on 20-volt scale. Disconnect electrical connector on speed control servo (if equipped). Connect DVOM negative lead to STO at self-test connector, and positive lead to battery positive post. Jumper STI or SIG RTN at the self-test connector. Perform KOEO SELF-TEST until Continuous Memory Code output is complete. See KOEO SELF-TEST under QUICK TEST. When DVOM indicates less than one volt, depress and release throttle. If voltage increases to greater than 10.5 volts, stay in output state check and go to next step. If voltage does not increase to at least 10.5 volts, depress throttle to wide open throttle and release. If STO voltage increases to specification, leave equipment connected and go to TEST QC, step 2.

3) Check For EDF/HEDF Circuit Cycling With vehicle still in output state check, disconnect EDF or HEDF relay. Set DVOM on 20-volt scale. Connect DVOM positive test lead to IGN START/RUN circuit and negative test lead to EDF or HEDF circuit at relay vehicle harness connector. Depress throttle to cycle off outputs. Observe DVOM and depress throttle again. For EDF, wait until CHECK ENGINE light flashes once (about 10 seconds). For HEDF, wait until CHECK ENGINE light flashes twice (about 15 seconds). Release throttle. EDF/HEDF output is now on. To cycle off output, depress and release throttle. If voltage cycles (about a 1-volt change), replace EDF or HEDF relay. Remove jumper and repeat QUICK TEST. If voltage does not cycle, remove jumper and go to next step.

4) Check Continuity of EDF/HEDF Circuit Turn ignition off and disconnect EDF or HEDF relay. Disconnect ECA 60-pin connector. Inspect for corroded or damaged connector pins and repair as necessary. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Perform the following appropriate check

1. Code 83/563 - Measure resistance between test pin No. 31 at breakout box and HEDF circuit at HEDF relay vehicle harness connector.
2. Code 88/564 - Measure resistance between test pin No. 35 at breakout box and EDF circuit at EDF relay vehicle harness connector.

If resistance is less than 5 ohms, go to next step. If is not less than 5 ohms, repair open circuit. Remove breakout box and reconnect all components. Rerun QUICK TEST.

5) Check EDF/HEDF Circuit For Short To Power With breakout box installed, leave ECA disconnected. Disconnect EDF or HEDF relay. Set DVOM on 20-volt scale. Turn ignition on. Measure voltage between test pin No. 31 (HEDF) or 32 (EDF) at the breakout box and battery negative terminal. If voltage is less than one volt, go to next step. If voltage is not less than one volt, repair short circuit. Remove breakout box and reconnect all components. Rerun QUICK TEST. If code is still present, replace ECA.

6) Check EDF/HEDF Circuit For Short To Ground With ignition off, install breakout box, leaving ECA disconnected. Disconnect EDF or HEDF relay. Set DVOM on 200-k/ohm scale. Measure resistance between test pin No. 31 (HEDF) or 35 (EDF) and test pins No. 40 and 60 at breakout box. If resistance is greater than 10 k/ohms, replace ECA. Remove breakout box, reconnect all components and repeat QUICK TEST. If resistance is less than 10 k/ohms, repair short circuit. Remove breakout box, reconnect all components and repeat QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 6 to step 10. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

10) Low-Speed (EDF) And/Or High-Speed (HEDF) Cooling Fan Does Not Operate: Check For Voltage To EDF Relay With ignition off, disconnect EDF relay. Set DVOM on 20-volt scale. Turn ignition on. Measure voltage between HEDF relay pin (at EDF relay vehicle harness connector) and battery negative terminal. If voltage is greater than 10.5 volts, go to step 13. If voltage is not greater than 10.5 volts, go to next step.

EDF Relay Vehicle Harness Connector. Scheme 40

11) Check For Voltage To HEDF Relay With ignition off, disconnect EDF and HEDF relays. Set DVOM on 20-volt scale. Turn ignition on. Measure voltage between ignition relay input terminal (at HEDF relay vehicle harness connector) and battery negative terminal. If voltage is greater than 10.5 volts, go to next step. If voltage is not greater than 10.5 volts, check operation of ignition relay. If relay is okay, repair open circuit. Reconnect EDF and HEDF relays. Re-evaluate symptoms.

HEDF Relay Vehicle Harness Connector. Scheme 41

12) Check Continuity Between EDF & HEDF Relays With ignition off, disconnect EDF and HEDF relays. Set DVOM on 200-ohm scale. Measure resistance between HEDF input terminal (at EDF relay vehicle harness connector) and the output to EDF terminal (at HEDF relay vehicle harness connector). If resistance is less than 5 ohms, replace HEDF relay. Reconnect all components. Re-evaluate symptom. If resistance is greater than 5 ohms, repair open circuit. Reconnect all components. Re-evaluate symptom.

EDF & HEDF Relay Harness Connectors. Scheme 42

13) Check Circuits From EDF Relay To Fan With ignition off, disconnect EDF relay. Install a jumper wire between HEDF relay pin and POWER-TO-FAN pin at EDF relay vehicle harness connector. Turn ignition on. If fan operates, remove jumper and go to step 16. If fan does not operate, remove jumper wire and go to next step.

EDF Relay Vehicle Harness Connector. Scheme 43

14) Check EDF POWER-TO-FAN Circuit Continuity With ignition off, disconnect EDF relay and cooling fan. Set DVOM on 200-ohm scale. Measure resistance between EDF POWER-TO-FAN output terminal (at EDF vehicle harness connector) and EDF POWER-TO-FAN input pin (at cooling fan vehicle harness connector). If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair open circuit. Reconnect all components. Re-evaluate driveability symptoms.

EDF & Cooling Fan Vehicle Harness Connector. Scheme 44

15) Check Cooling Fan Ground Circuit With ignition off, disconnect EDF relay. Disconnect cooling fan. Set DVOM to 200-ohm scale. Measure resistance between GND circuit (at cooling fan vehicle harness connector) and battery negative terminal. If resistance is less than 5 ohms, replace cooling fan. Reconnect all components. Recheck symptom. If resistance is greater than 5 ohms, repair open circuit. Reconnect all components and recheck symptom.

16) Check Circuits From HEDF Relay To Fan With ignition off, disconnect EDF relay. Disconnect ECU 60-pin connector. Inspect for damaged or pushed out terminals, corrosion and loose wires. Repair as necessary. Install a breakout box and leave ECU disconnected. Install a jumper wire between test pin No. 31 and test pin No. 40 of the breakout box. Turn ignition on. If fan runs at high speed, replace EDF relay. Remove breakout box. Recheck symptom. If fan does not run at high speed, remove jumper wire and go to next step.

17) Check HEDF Power-To-Fan Voltage At Fan With ignition off, disconnect HEDF relay and cooling fan. Install a jumper wire between test pin No. 31 and test pin No. 40 of breakout box. Turn ignition on. Measure voltage between HEDF POWER-TO-FAN circuit (at cooling fan vehicle harness connector) and battery negative terminal. If voltage is greater than 10.5 volts, replace cooling fan. Remove breakout box. Reconnect components and recheck symptom. If voltage is less than 10.5 volts, remove jumper wire and go to next step.

Cooling Fan Vehicle Harness Connector. Scheme 45

18) Check HEDF POWER-TO-FAN Circuit Continuity Turn ignition off. Install a breakout box. Disconnect ECA. Disconnect cooling fan, HEDF and EDF relays. Set DVOM on 200-ohm scale. Measure resistance between HEDF POWER-TO-FAN output terminal (at HEDF vehicle harness connector) and HEDF POWER-TO-FAN input terminal (at cooling fan vehicle harness connector). If resistance is less than 5 ohms, replace HEDF relay. Reconnect all components. Recheck system operation. If resistance is greater than 5 ohms, repair open circuit. Reconnect all components and recheck system operation.

HEDF Relay Vehicle Harness Connector. Scheme 46

Note. There is a break in the step numbering sequence at this point, skipping from step 18 to step 25. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

25) Low Speed (EDF) or High Speed (HEDF) Cooling Fan Always On: Ensure Ignition Relay Opens Turn A/C off during this test. Check cooling fan with ignition in OFF and ON positions. If cooling fan is always on with ignition off, but operates normally with ignition on, ensure IGNITION relay contacts are always closed. If relay is okay, check circuit from IGNITION relay to fan relays for a short to BATT (+). If system does not operate as described, go to next step.

26) Check For Relay Always Closed Turn ignition off and disconnect EDF relay. Turn ignition on. If fan continues to run, go to next step. If fan does not continue to run, replace EDF relay and recheck system operation.

27) Check HEDF Relay Turn ignition off. Disconnect EDF and HEDF relay. Turn ignition on. If fan continues to run, go to next step. If does not continue to run, replace HEDF relay. Reconnect EDF relay. Recheck system operation.

28) Check EDF POWER-TO-FAN Circuit For Short to Power Turn ignition off. Disconnect EDF and HEDF relays. Disconnect cooling fan. Set DVOM on 20-volt scale. Turn ignition on. Measure voltage between EDF POWER-TO-FAN circuit (at cooling fan vehicle harness connector) and battery negative terminal. If voltage is greater than one volt, repair short to power in EDF POWER-TO-FAN circuit. Reconnect all components. Recheck system operation. If voltage is not greater than one volt, repair short to power in HEDF POWER-TO-FAN circuit. Reconnect all components. Recheck system operation.

Cooling Fan Vehicle Harness Connector. Scheme 47

Perform this test only when directed here by a driveability symptom. This test is intended to diagnose only the following

1. Harness circuits (SIL)
2. Top gear switch
3. SIL dimmer relay
4. SIL bulb and SIL circuit fuse

Shift Indicator Light (SIL) Circuits (1.9L SPFI-MA). Scheme 48

1) Check SIL Operation Inspect SIL while driving vehicle. SIL should turn on when optimum-shift RPM for each gear is reached. Light should be off in highest gear. If SIL light is always on, check for short to ground in SIL circuit. If light is always off, check for open in SIL circuit. If light is always on, go to step 10 (1.9L SPFI-MA). If light is NOT always on, go to next step.

2) Check SIL Circuit Fuse Turn ignition off and wait 10 seconds. Remove and inspect SIL fuse. If fuse is okay, reconnect and go to next step. If fuse is blown, repair short to ground between fuse and SIL bulb. Replace fuse and check SIL operation.

3) Check SIL Bulb With ignition off, remove and inspect SIL bulb. If bulb is okay, go to step 15 (1.9L SPFI-MA engines). If bulb has failed, replace bulb and check SIL operation.

4) Check Continuity Of SIL Dimmer Relay With ignition off, disconnect SIL dimmer relay. Set DVOM on 200-ohm scale. Measure resistance between pins No. 3 and 5 on SIL dimmer relay. If resistance is less than 5 ohms, go to next step. If resistance is more than 5 ohms, replace SIL dimmer relay and check operation.

5) Check SIL Dimmer Relay Function With ignition off, disconnect SIL dimmer relay. Apply 12 volts across pins No. 1 and 2 of SIL dimmer relay. With DVOM on 200-ohm scale, measure resistance between pins No. 3 and 5 on SIL dimmer relay. If resistance is 40-55 ohms, go to next step. If resistance is not 40-55 ohms, replace SIL dimmer relay and retest operation.

6) Check Voltage At SIL Dimmer Relay With Key On Engine Off (KOEO), disconnect SIL dimmer relay. Set DVOM on 20-volt scale. Measure voltage between test pin No. 5 of SIL dimmer relay harness connector and battery negative post. If voltage is greater than 5 volts, reconnect relay and go to next step. If voltage is less than 5 volts, repair circuit between SIL fuse and SIL dimmer relay. Recheck SIL operation.

7) Check Voltage At Top Gear Switch With KOEO, disconnect top gear switch. Set DVOM on 20-volt scale. Measure voltage between SIL dimmer relay side of top gear switch vehicle harness connector and battery negative post. If voltage is greater than 5 volts, go to next step. If voltage is less than 5 volts, repair circuit between high gear switch and dimmer relay. Check SIL operation.

8) Check Operation Of Top Gear Switch Turn ignition off and wait 10 seconds. Disconnect top gear switch. Set DVOM on 200-ohm scale. Measure resistance of top gear switch while shifting transmission from highest gear to next lower gear. If switch opens and closes, go to next step. If circuit does not open and close, replace switch and check operation.

9) Check Continuity Of SIL Circuit Turn ignition off and disconnect top gear switch. Disconnect ECA 60-pin connector. Inspect for corroded or damaged connector pins and repair as necessary. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 53 and ECA side of top gear switch vehicle harness connector. If resistance is less than 5 ohms, reconnect top gear switch; shift transmission into high gear and go to next step. If resistance is more than 5 ohms, repair open circuit between high gear switch and ECA. Remove breakout box, reconnect all components and verify operation of SIL.

10) Check SIL Circuit For Short To Ground Turn ignition off and place transmission in highest gear. Set DVOM on 200-k/ohm scale and install breakout box, leaving ECA disconnected. Measure resistance between test pin No. 53 and test pin No. 60. If resistance is less than 10 k/ohms, repair short between high gear switch and ECA. If resistance is greater than 10 k/ohms, replace ECA. Remove breakout box and rerun QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 10 to step 15). Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

15) Check For Voltage To SIL Socket Turn ignition off and remove SIL bulb. Place transmission in any gear except top gear. Set DVOM on 20-volt scale. With KOEO, measure voltage between power contact at SIL socket and chassis ground. If voltage is greater than 10.5 volts, go to step 17. If voltage is not greater than 10.5 volts, reconnect SIL bulb and go to next step.

16) Check Operation Of Top Gear Switch Top gear switch is normally closed, and is in IGNITION RUN circuit to SIL bulb. The top gear switch should only be open when vehicle is shifted into top gear. With ignition off and transmission in any gear except top gear, disconnect top gear switch. Set DVOM on 200-ohm scale. Measure resistance of top gear switch. If resistance is less than 5 ohms, repair open in IGNITION RUN circuit to SIL bulb socket, and verify SIL operation. If resistance is not less than 5 ohms, replace top gear switch and verify SIL operation.

17) Check Continuity Of SIL Circuit Turn ignition off and remove SIL bulb. Disconnect ECA 60-pin connector. Inspect for corroded or damaged connector pins and repair as necessary. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 53 and SIL circuit contact at SIL bulb socket. If resistance is less than 5 ohms, replace ECA; remove breakout box, reconnect SIL bulb and verify SIL operation. If resistance is not less than 5 ohms, repair open circuit; remove breakout box, reconnect all components and verify SIL operation.

18) Operation Of 3.8L SC SIL On 3.8L SC, SIL will come on and a chime will sound when ignition is in RUN position and engine is off. Depending on the transmission type, SIL and chime will also activate under the following conditions

1. Greater than 93 MPH (4000 RPM) in third gear for A/T
2. Greater than 121 MPH (4300 RPM) in fourth gear for M/T

When this happens, EEC will take necessary action to prevent engine damage from overheating. If coolant gets too hot, or vehicle remains at high speed for 60 seconds, EEC will shut off 3 injectors until a safe operating speed is reached, or transmission is upshifted to higher gear. EEC action is independent of SIL and warning chime, and will occur regardless of these circuits malfunction. If SIL is always on, go to step 23. If SIL is always off, go to next step.

19) Check SIL Circuit Fuse Turn ignition off and wait 10 seconds. Remove and inspect SIL fuse. If fuse is okay, reconnect and go to next step. If fuse is blown, repair short to ground between fuse and SIL bulb. Replace fuse and check SIL operation.

20) Check SIL Bulb With ignition off, remove and inspect SIL bulb. If bulb is okay, go to step 21. If bulb has failed, replace bulb and check SIL operation.

21) Check For Voltage To SIL Socket Turn ignition off and remove SIL bulb. Set DVOM on 20-volt scale. With KOEO, measure voltage between power contact at SIL socket and chassis ground. If voltage is greater than 10.5 volts, go to next step. If voltage is not greater than 10.5 volts, repair open circuit in ignition START RUN circuit to SIL bulb socket.

22) Check Continuity Of SIL Circuit Turn ignition off and remove SIL bulb. Disconnect ECA 60-pin connector. Inspect for corroded or damaged connector pins and repair as necessary. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 53 and SIL circuit contact at SIL bulb socket. If resistance is less than 5 ohms, replace ECA, remove breakout box and reconnect SIL bulb. If resistance is more than 5 ohms, repair open circuit; remove breakout box, reconnect all components and verify operation of SIL.

23) Check SIL Circuit For Short To Ground Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for corroded or damaged connector pins and repair as necessary. Turn ignition on, leaving engine off. If SIL is on with ECA disconnected, repair short to ground between SIL bulb and ECA; reconnect ECA and verify operation of SIL. If SIL is not on with ECA disconnected, replace ECA and verify operation of SIL.

Perform this test when diagnosing a symptom. To prevent replacing good components, check the following non-EEC components and systems

1. Refrigerant charge
2. Low ambient temperature (less than 45°F)

This test is intended to diagnose only the following

1. Harness circuits (WAC, VPWR, GND, POWER to CLUTCH, and ACD)
2. WAC relay
3. A/C fan controller
4. ECA

WOT A/C Cut-Out Circuits (Escort & Tracer). Scheme 49

TEST PIN WIRE COLOR IDENTIFICATION

1) No A/C: Check For Voltage At A/C Clutch Check all A/C related fuses in fuse panel before proceeding with this test. Use only DVOM for this step; DO NOT use diagnostic tester. With ignition off, disconnect A/C clutch harness connector. Turn A/C switch to A/C position. Turn blower switch to any position (Escort and Tracer only). Set DVOM on 20-volt scale. Start engine and wait 10 seconds. Measure voltage between power side of A/C clutch vehicle harness connector and negative battery terminal. If voltage is greater than 10.5 volts, EEC-IV system is okay; diagnose A/C system. If voltage is less than 10.5 volts, go to next step.

2) Check Continuity Of POWER-To-CLUTCH Circuit Turn ignition off and wait 10 seconds. Set DVOM on 200-ohm scale. Disconnect A/C clutch harness and harness from WAC relay or A/C fan controller. Measure resistance between power side of A/C clutch vehicle harness connector and POWER-to-CLUTCH circuit terminal pin at WAC relay or A/C fan controller vehicle harness connector. If resistance is less than 5 ohms, reconnect A/C clutch and go to next step. If resistance is more than 5 ohms, service open circuit and retest system.

3) Check For Power On A/C Demand Circuit With KOEO and WAC relay or A/C fan controller disconnected, turn on A/C switch. Set DVOM to 20-volt scale. Perform the following procedure

1. Turn blower motor switch on (any speed). Measure voltage between A/C relay input terminal pin at WAC relay vehicle harness connector and chassis ground.

If voltage is greater than 10.5 volts, go to step 5. If voltage is less than 10.5 volts, go to next step. If components are okay, repair open circuit. Reconnect all components. Recheck system.

4) Check Continuity Between WAC Relay & A/C Relay With ignition off, disconnect WAC and A/C relays. Set DVOM on 200-ohm scale. Measure resistance between A/C relay output to WAC relay circuit (at A/C relay vehicle harness connector) and A/C relay input (at WAC relay vehicle harness connector). If resistance is less than 5 ohms, reconnect WAC relay; diagnose A/C system. If resistance is greater than 5 ohms, repair open circuit; reconnect relays and recheck system operation.

5) Check WAC Circuit For Short To Ground Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector and WAC relay or A/C fan controller. Inspect and repair any damaged wiring. Leaving ECA disconnected, set DVOM on 200-k/ohm scale. Measure resistance between WAC circuit at WAC relay or A/C fan controller and chassis ground. If resistance is greater than 10 k/ohms, go to next step. If resistance is less than 10 k/ohms, repair short; reconnect all components and recheck system operation.

6) Check For Voltage At ACCS Input To ECA Turn ignition off and wait 10 seconds. Disconnect WAC relay and A/C fan controller. Disconnect ECA and install breakout box, leaving ECA disconnected. Set A/C switch to A/C position. Turn blower switch to any position (Escort and Tracer only). Set DVOM to 20-volt scale. With KOEO, measure voltage between test pin No. 10 and test pin No. 40 at breakout box. If voltage is greater than 10.5 volts, go to step 9. If voltage is less than 10.5 volts, repair open circuit; remove breakout box, reconnect all components and recheck system operation.

Note. There is a break in the step numbering sequence at this point, skipping from step 7 to step 9. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

9) Check WAC Relay Or A/C Fan Controller Turn ignition off and wait 10 seconds. Leave ECA disconnected and reconnect WAC relay or A/C fan controller. Disconnect A/C clutch. Set DVOM on 20-volt scale. On Escort and Tracer, turn blower switch on to any speed. With KOEO and A/C on, measure voltage between power side of A/C clutch vehicle harness connector and battery negative terminal. If voltage is greater than 10.5 volts, replace ECA; reconnect A/C clutch and retest system. If voltage is less than 10.5 volts, replace WAC relay or fan controller; reconnect all components and recheck system.

Note. There is a break in the step numbering sequence at this point, skipping from step 9 to step 15. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

15) No A/C Output At WOT Enter OUTPUT STATE CHECK; see ADDITIONAL SYSTEM FUNCTIONS. Use a VOM or DVOM for this test. Turn ignition off and wait 10 seconds. Disconnect speed control servo electrical connector (if equipped). Set DVOM on 20-volt scale. Connect DVOM negative test lead to STO at self-test connector and positive lead to positive battery terminal. Jumper STI to SIGNAL RETURN at self-test connector. Perform KOEO SELF-TEST until Continuous Memory Code output is completed. Meter will indicate less than one volt when test is complete. Depress and release throttle. If voltage increases to greater than 10.5 volts, remain in OUTPUT STATE CHECK and go to the next step. If voltage does not increase to 10.5 volts, depress throttle to WOT and release. If STO voltage does not go high, leave test equipment connected and go to TEST QC, step 2.

16) Check For VPWR To Relay With vehicle in OUTPUT STATE CHECK, disconnect harness from WAC relay and set DVOM on 20-volt scale. Measure voltage between VPWR circuit (IGN RUN circuit for 1.9L SPFI-MA) at WAC relay vehicle harness connector and chassis ground. If voltage is greater than 10.5 volts, go to next step. If voltage is less than 10.5 volts, repair open circuit between power relay and WAC relay (IGN RUN circuit between WCA relay and joint box on Escort and Tracer). Remove test equipment and retest system.

17) Check WAC System For Cycling With vehicle in OUTPUT STATE CHECK, reconnect WAC relay and set DVOM on 20-volt scale. Connect positive test lead to VPWR circuit (IGN RUN circuit for Escort and Tracer) and negative test lead to WAC circuit at WAC relay vehicle harness connector. Check DVOM while depressing and releasing throttle several times to cycle output on and off. If voltage cycles from high to low, replace WAC relay; remove jumper and retest system. If voltage does not cycle, remove test leads; reconnect speed control servo and go to next step.

18) Check Resistance Of WAC Relay Coil Turn ignition off and wait 10 seconds. Disconnect WAC relay. Set DVOM to 200-ohm scale. Measure resistance between WAC pin and VPWR pin (IGN RUN on Escort and Tracer) on WAC relay. If resistance is 40-100 ohms, go to next step. If resistance is NOT 40-100 ohms, replace WAC relay and retest system.

19) Check Continuity Of WAC Circuit Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect and repair any damaged wiring. Install breakout box, leaving ECA and WAC relay disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 54 and WAC circuit at WAC relay vehicle harness connector. If reading is 5 ohms or more, repair open circuit; remove breakout box, reconnect all components and retest system. If reading is less than 5 ohms, go to next step.

20) Check WAC Circuit For Short To Power Turn ignition off and wait 10 seconds. Leave breakout box installed and ECA and WAC relay disconnected. Set DVOM on 200-k/ohm scale. Measure resistance between test pin No. 54 and test pins No. 37 and 57. If all readings are 10 k/ohms or more, replace ECA; reconnect WAC relay and retest system. If any reading is less than 10 k/ohms, repair short circuit. Reconnect all components and retest system. If symptom is still present, replace ECA.

21) Check WAC Cycling With vehicle in OUTPUT STATE CHECK, disconnect A/C fan controller and set DVOM on 20-volt scale. Connect DVOM positive test lead to ignition run circuit and negative test lead to WAC circuit at A/C fan controller harness connector. Check DVOM while depressing and releasing throttle several times to cycle system. If voltage does not cycle, remove jumper; reconnect components and go to next step. If voltage cycles from high to low, replace A/C fan controller. Reconnect components and retest system.

22) Check Continuity Of WAC Circuit Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect and repair any damaged wiring. Install breakout box, leaving ECA and fan controller disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 54 and WAC circuit at WAC relay vehicle harness connector. If reading is less than 5 ohms, go to next step. If reading is 5 ohms or more, repair open in harness; remove breakout box, reconnect all components and retest system.

23) Check WAC Circuit For Short To Power Turn ignition off and wait 10 seconds. Install breakout box, leaving ECA and A/C fan controller disconnected. Set DVOM on 200-k/ohm scale. Measure resistance between test pin No. 54 and test pins No. 37 and 57 at breakout box. If all readings are greater than 10 k/ohms, replace ECA; reconnect A/C fan controller and retest system. If any reading is 10 k/ohms or less, repair short to power and retest system; if symptom is still present, replace ECA.

Note. There is a break in the step numbering sequence at this point, skipping from step 23 to step 30. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

30) Cycle A/C Demand Switch Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect for corroded or damaged connector pins and repair as necessary. Install breakout box, leaving ECA disconnected. Set DVOM on 20-volt scale. With KOEO, connect DVOM positive test lead to test pin No. 43 and negative test lead to test pin No. 40. If voltage goes high and low as switch is cycled, go to step 44. If voltage does not cycle, go to next step.

31) Check Continuity Of A/C Demand (ACD) Circuit Turn ignition off and wait 10 seconds. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 43 at breakout box and A/C demand switch. If resistance is greater than 5 ohms, repair open in ACD circuit and rerun QUICK TEST. If resistance is less than 5 ohms, EEC-IV system is okay. Remove breakout box and reconnect components. Diagnose A/C system.

Note. There is a break in the step numbering sequence at this point, skipping from step 31 to step 35. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

35) Check A/C Demand (ACD) Circuit For Short To Power With ignition off, disconnect WAC relay or A/C fan controller. Disconnect ECA 60-pin connector. Inspect for corroded or damaged connector pins and repair as necessary. Install breakout box, leaving ECA disconnected.

With A/C demand switch in OFF position, set DVOM on 20-volt scale. With KOEO, measure voltage between test pin No. 43 at breakout box and chassis ground. If voltage is less than one volt, EEC-IV system is okay; remove breakout box, reconnect all components and diagnose A/C system. If voltage is greater than one volt, check operation of A/C demand switch.

If switch operation is okay, repair short circuit. Remove breakout box, reconnect all components and retest system.

Note. There is a break in the step numbering sequence at this point, skipping from step 35 to step 40. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

Before entering this test, ensure A/C selector is off (and shift selector is in PARK for AXODE and E4OD vehicles). If A/C was on, rerun QUICK TEST. If Code 67 or 79/539 is present, continue with this test.

40) Check A/C Input Code 79/539 indicates ACCS input to ECA was high during self-test. Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector; inspect for corroded or damaged connector pins and repair as necessary. Install breakout box, leaving ECA disconnected. Set DVOM to 20-volt scale. With KOEO, measure voltage between test pin No. 10 at breakout box and chassis ground. If voltage is greater than one volt, repair short to power in A/C circuit. Remove breakout box, reconnect all components and rerun QUICK TEST. If voltage is less than one volt, replace ECA, reconnect all components and rerun QUICK TEST.

41) Check For Short To Power In ECA Turn ignition off and wait 10 seconds. Install breakout box, leaving ECA disconnected. Disconnect A/C clutch connector. Set DVOM to 20-volt scale. With KOEO, measure voltage between test pins No. 10 and 40. If voltage is greater than one volt, replace ECA; reconnect A/C clutch and rerun QUICK TEST. If voltage is less than one volt, diagnose transmission.

Note. There is a break in the step numbering sequence at this point, skipping from step 41 to step 43. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

A low idle with A/C on may be caused by the ECA not receiving or recognizing A/C input from pin No. 10.

43) Check A/C Input Circuit Turn A/C switch to A/C position. Turn blower motor switch on lowest speed for Escort, Tracer and Probe. Perform KOEO SELF-TEST. If Code 67 or 79/539 is present, ECA is receiving and recognizing A/C input from pin No. 10. Check for other possible cause of low idle. If Code 67 or 79/539 is not present, go to next step.

44) Check A/C Input Circuit Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Install breakout box, leaving ECA disconnected. Set DVOM to 20-volt scale. Turn A/C on. With KOEO, measure voltage between test pins No. 10 and 40.

If voltage is greater than 10.5 volts, replace ECA. Remove breakout box, reconnect all components and rerun QUICK TEST.

If voltage is less than 10.5 volts, repair open A/C circuit. Remove breakout box, reconnect all components and rerun QUICK TEST.

Enter this test when directed by QUICK TEST. This test is intended to diagnose only the following systems or components

1. Harness circuits (SIG RTN and OCT ADJ)
2. Octane shorting bar connector

Octane Adjust Circuit. Scheme 50

TEST PIN WIRE COLOR IDENTIFICATION

The purpose of the Octane Adjust Shorting Bar is to provide optimum spark advance for the fuel used. If vehicle engine detonates (spark knock), remove Octane Shorting Bar. This retards spark advance about 3 to 4 degrees. If vehicle continues to detonate, use fuel with a higher octane rating.

1) Code 57/341: Inspect Octane Adjust In-Line Connector Code 57/431 indicates Octane Adjust Shorting Bar is not in, or OCT ADJ circuit is open. Turn ignition off and wait 10 seconds. Inspect Octane Adjust in-line connector. If shorting bar has been removed, return to QUICK TEST for complete diagnosis. If shorting bar is in place, go to next step.

2) Check Octane Adjust Circuit Continuity There should be continuity from OCT ADJ circuit, through in-line connector and shorting bar, to SIG RTN circuit. Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector; inspect for corroded or damaged connector pins and repair as necessary. Install breakout box, leaving ECA disconnected. Set DVOM to 200-ohm scale. Measure resistance between test pin No. 46 and OCT ADJ test pin at breakout box. If resistance is less than 5 ohms, replace ECA. Remove breakout box and rerun QUICK TEST. If resistance is greater than 5 ohms, repair open OCT ADJ circuit, shorting bar or SIG RTN circuit. Remove breakout box and rerun QUICK TEST.

3) Check For Code 11 Start engine and let idle at operating temperature. Turn ignition off and wait 10 seconds. Enter KOEO SELF-TEST. If Code 11 or 111 is present, go to next step. If Code 11 or 111 is not present, use higher octane fuel or check for other possible causes for Code 57/341; for all other codes, return to QUICK TEST.

4) Verify In-Line Shorting Bar Is Installed Turn ignition off and wait 10 seconds. Inspect Octane Adjust in-line connector. If shorting bar is installed, go to next step. If shorting bar is not installed, go to step 7.

5) Verify Drive Concern Turn ignition off and wait 10 seconds. Locate and remove shorting bar. Test drive vehicle to verify complaint. If symptom is present, go to next step. If symptom is not present, EEC is okay; testing is complete.

6) Rerun KOEO SELF-TEST Verify engine is at normal operating temperature. Turn ignition off and wait 10 seconds. Enter KOEO SELF-TEST. If Code 57 or 341 is present, use higher octane fuel; testing is complete. If Code 57 or 341 is not present, go to next step.

7) Check Octane Adjust Circuit For Short To Ground Turn ignition off and wait 10 seconds. Install breakout box and leave ECA disconnected. Set DVOM to 200-k/ohm scale. Measure resistance between OCT ADJ circuit at in-line connector and test pins No. 40 and 60 at breakout box.

If resistance is less than 10 k/ohms, repair short circuit; remove breakout box and rerun QUICK TEST. If each resistance is greater than 10 k/ohms, use higher octane fuel. If fuel is okay, check for other causes of symptoms.

Perform this test only when instructed by QUICK TEST, or directed here by a driveability symptom. This test is intended to diagnose only the following components or circuits

1. Harness circuits (VPWR and IAC)
2. IAC solenoid
3. ECA

To prevent replacing good components, check the following non-EEC areas for faults

1. Vacuum tank leaks
2. Vacuum hose leaks

IAC Circuit. Scheme 51

1) Code 81: Check IAC Solenoid Resistance Code 81 indicates IAC solenoid output voltage did not change when IAC was activated during KOEO SELF-TEST. Possible causes for this fault are as follows

1. IAC circuit open
2. IAC shorted or disconnected
3. ECA output driver open or grounded

Turn ignition off and wait 10 seconds. Set DVOM on 200-ohm scale and disconnect IAC solenoid connector from harness. Measure resistance between IAC and VPWR circuits of solenoid at solenoid terminals. If resistance is 50-100 ohms, go to next step. If resistance is NOT 50-100 ohms, replace solenoid and rerun QUICK TEST.

IAC Solenoid. Scheme 52

2) Check Voltage Of VPWR Circuit With Key On Engine Off (KOEO), disconnect IAC solenoid. Set DVOM on 20-volt scale. Measure voltage between VPWR circuit of IAC solenoid vehicle harness connector and battery negative post. If voltage is greater than 10.5 volts, go to next step. If voltage is less than 10.5 volts, reconnect IAC solenoid, repair open circuit in harness and rerun QUICK TEST.

3) Check Continuity Of IAC Solenoid Circuit Turn ignition off and wait 10 seconds. Disconnect 60-pin ECA connector. Inspect pins for corrosion or damage, and service as necessary. Install breakout box, leaving ECA and IAC solenoid disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 32 at breakout box and IAC solenoid vehicle harness connector. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair open circuit. Remove breakout box, reconnect all components and repeat QUICK TEST.

4) Check For Short To Ground Turn ignition off and wait 10 seconds. With breakout box installed and ECA disconnected, set DVOM on 200-k/ohm scale. Disconnect IAC solenoid. Measure resistance between test pin No. 32 and test pins No. 40, 46 and 60 at breakout box. If resistance is greater than 100 k/ohms, go to next step. If resistance is less than 100 k/ohms, repair short circuit, reconnect components and repeat QUICK TEST.

5) Check IAC Circuit For Short To Power Turn ignition off and wait 10 seconds. With breakout box installed and ECA disconnected, set DVOM on 200-k/ohm scale. Disconnect IAC solenoid. Measure resistance between test pin No. 32 and test pins No. 37 and 57 at breakout box. If resistance is greater than 100 k/ohms, replace ECA. Remove breakout box, reconnect components and repeat QUICK TEST. If resistance is less than 100 k/ohms, repair short circuit, reconnect components and retest. If fault is still present, replace ECA.

6) Check Front & Rear Intake Air Valves With ignition off, disconnect vacuum lines from both intake air valves. Check each air valve with a vacuum pump. Apply 10 in. Hg vacuum. If both valves hold vacuum, go to next step. If valves do not hold vacuum, replace valve(s) as necessary. Reconnect all components and rerun QUICK TEST.

Intake Air Valve Locations. Scheme 53

7) Check Operation Of Both Intake Air Valve Systems With ignition off, apply 10 in. Hg to each air valve. If both valves and mechanical linkage move in response to the applied vacuum, go to next step. If valves and linkage are faulty, service as necessary and rerun QUICK TEST.

8) Check Vacuum To Both Intake Air Valves With ignition off, check vacuum lines from air valves to IAC solenoid. Inspect lines for damage or blockage. If vacuum lines are okay, go to next step. If vacuum lines are damaged or blocked, service as necessary and retest.

Vacuum Line Routing. Scheme 54

9) Check Vacuum Source To IAC Solenoid Disconnect IAC solenoid vacuum supply hose from intake manifold. Start engine and check vacuum at disconnected manifold hose. If vacuum is present at hose, replace IAC solenoid and rerun QUICK TEST. If vacuum is not present, check supply hose to IAC solenoid. Service as necessary and rerun QUICK TEST.

IAC Solenoid Vacuum Hose. Scheme 55

Perform this test only when directed by QUICK TEST. To prevent replacing good components, be aware that the following non-EEC related areas may be the cause of problem

1. Technician testing EEC system did not perform brief Wide Open Throttle (WOT) after Dynamic Response Code.
2. Faulty mechanical engine components
3. Engine did not go over 2000 RPM during WOT

This test is intended to diagnose only the following

1. Throttle movement (minimum 3/4 throttle)
2. RPM increase is greater than 2000 RPM

If throttle is snapped open briefly, it may not be sufficient to pass WOT test. Ensure throttle is depressed fully to WOT, and engine speed exceeds 2000 RPM.

Code 77/538 Displayed: System Failed To Recognize WOT Test - Rerun KOER SELF-TEST as follows

1. Start engine
2. Activate KOER SELF-TEST
3. Observe ID Code 2 (Code 0 with STAR tester)
4. Observe Dynamic Response Code 1 (Code 0 with STAR tester)
5. Perform brief WOT
6. Testing is complete, KOER code output begins

If Code 77/538 is still displayed, replace ECA and rerun QUICK TEST. If Code 77/538 is no longer present, vehicle has passed dynamic response test; service other codes as necessary.

Perform this test only when instructed by QUICK TEST, or when directed by TEST QA.

To prevent replacing good components, be aware that the following non-EEC related areas may be the cause of problem

1. Fuse, bulb or socket

This test is intended to diagnose only the following

1. STO/MIL circuit (except 1.9L PFI)
2. ECA
3. Data Communications Link (DCL)

"CHECK ENGINE" Light Circuit. Scheme 56

Data Communication Link (DCL) Circuit. Scheme 57

TEST PIN WIRE COLOR IDENTIFICATION

1) Malfunction Indicator Light (MIL) Always On If vehicle will not start, go to TEST A, step 1. Service all other KOEO and Continuous Memory Codes before proceeding with this test. Turn ignition off. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Connect DVOM between test pins No. 17 and 40 at breakout box. If resistance is greater than 5 ohms, replace ECA; remove breakout box and rerun QUICK TEST. If reading is less than 5 ohms, repair short between test pin No. 17 and self-test connector or CHECK ENGINE light. Remove breakout box, reconnect all components and repeat QUICK TEST.

Note. There is a break in the step numbering sequence at this point, skipping from step 1 to step 4. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

4) Malfunction Indicator Light (MIL) Never On: Check Continuity Of STO/MIL Circuit If vehicle will not start, go to TEST A, step 1. Turn ignition on; leave engine off. Set DVOM on 20-volt scale. Measure voltage between battery negative terminal to ground side of MIL fuse. If voltage is greater than 10.5 volts, go to step 6. If voltage is less than 10.5 volts, go to next step.

5) Check For Voltage At Fuse Set DVOM on 20-volt scale. With Key On Engine Off (KOEO), measure voltage from battery negative post to hot side of MIL fuse. If voltage is greater than 10.5 volts, repair fuse or open circuit. Reconnect ECA and verify repair by turning ignition to RUN position. If voltage is not greater than 10.5 volts, repair MIL/VBAT circuit. Reconnect ECA and verify repair by turning ignition to RUN position.

6) Check Continuity Of VBAT Circuit Turn ignition off. Set DVOM to 200-k/ohm scale. Measure resistance between MIL fuse (at ground side) and MIL bulb socket (VBAT side). If resistance is greater than 10 k/ohms, repair open circuit in MIL circuit. Verify repair by turning ignition to RUN position. If resistance is less than 10 k/ohms, go to next step.

7) Check MIL Bulb Response To Grounding Turn ignition off. Attach one end of jumper wire to negative battery terminal or chassis ground. Attach other end of jumper wire to ground side of MIL bulb socket. Turn ignition to RUN position. If MIL light comes on, turn ignition off. Remove jumper wire and go to next step. If MIL light does not come on, turn ignition off and remove jumper wire. Replace MIL bulb socket. Turn ignition to RUN position to verify operation.

8) Check Continuity Of MIL Circuit Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Install breakout box and leave ECA disconnected. Set DVOM to 200-ohm scale. Measure resistance between test pin No. 17 at breakout box and MIL. If resistance is less than 5 ohms, replace ECA. Remove breakout box. Verify operation by turning ignition switch to RUN position. If resistance is greater than 5 ohms, repair open MIL circuit. Turn ignition switch to RUN position to verify operation.

Note. There is a break in the step numbering sequence at this point, skipping from step 8 to step 10. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

10) CHECK ENGINE Or SERVICE ENGINE SOON Light Intermittent, Check For Intermittent Short From STO To Ground If vehicle does not start, go to TEST A, step 1. The light comes on when a Continuous Memory Code is present. Service all Continuous Memory Codes before proceeding. If no codes are outputted, proceed with this test. Enter KOEO wiggle test. See CONTINUOUS MONITOR MODE (WIGGLE TEST) under QUICK TEST. Observe DVOM for indication of fault while performing wiggle test on harness in the following areas

1. From self-test connector to dash panel
2. Dash panel to ECA
3. Dash panel to Malfunction Indicator Light (MIL).

If a fault is indicated, repair as necessary and rerun QUICK TEST. If a fault is not indicated, then fault cannot be duplicated at this time. Testing for this fault is complete.

Note. There is a break in the step numbering sequence at this point, skipping from step 10 to step 15. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

15) CHECK ENGINE Or SERVICE ENGINE SOON Light Flashes With Erratic Idle: Check STI Circuit For Short To Ground Vehicle symptoms indicate STI is grounded and ECA is performing self-test without tester installed. With ignition off, disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair as necessary. Set DVOM on 200-k/ohm scale. Measure resistance between STI connector and engine block ground. If resistance is less than 10 k/ohms, repair short circuit. Reconnect ECA and retest. If resistance is not less than 10 k/ohms, reconnect ECA. Verify symptom and test for other rough idle symptoms.

Note. There is a break in the step numbering sequence at this point, skipping from step 15 to step 20. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

20) CHECK ENGINE Message Displayed If vehicle will not start, go to TEST A, step 1. Perform KOEO SELF-TEST. If result is Code 11-10-11 (pass code), repair fault in electronic message center Data Communications Link (DCL). If pass code is not displayed, service codes as required in self-test procedures.

Note. There is a break in the step numbering sequence at this point, skipping from step 20 to step 25. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

25) Continuous Memory Code 529: CHECK ENGINE Or CHECK DCL Message Displayed Codes 529 and 533 indicate circuit failure has occurred on Data Communications Link (DCL). These codes can occur alone or in conjunction with another code. "CHECK ENGINE" or CHECK DCL message will be displayed under the following conditions

1. Code 529 indicates ECA or Data Communicator Link (DCL) circuit failure.
2. Code 533 indicates Data Communication Link to Electronic Instrument Cluster circuit failure.

If vehicle does not start, go to TEST A, step 1. If vehicle starts, clear Continuous Memory codes. Wait 5 minutes then rerun KOEO SELF-TEST. If result is Code 11-10-11 (pass code), repair fault in electronic message center Data Communications Link (DCL). If pass code is not displayed, service codes as described in self-test procedures.

Perform this test when directed by QUICK TEST. This test is intended to diagnose only the EEC-IV portion of ignition system. For additional information on ignition system and component testing, see the SYSTEM/COMPONENT TESTS article.

To prevent replacing good components, be aware that the following non-EEC related areas may be at fault

1. EDIS ignition module
2. EDIS coil packs
3. Spark plugs and/or high tension cables
4. Variable reluctance sensor
5. Secondary ignition component arcing

This test is intended to diagnose the following circuits and components

1. IDM and SAW Harness circuit
2. ECA assembly

IDM Circuit Schematic (1.9L SPFI-MA). Scheme 58

TEST PIN WIRE COLOR IDENTIFICATION

1) Continuous Memory Code 14/211: Erratic Ignition Code 14/211 indicates 2 successive erratic Profile Ignition Pick-Up (PIP) pulses occurred, resulting in a possible engine miss or stall. Possible causes for this fault are as follows

1. Loose wires or connectors
2. Arcing secondary ignition components
3. On-board transmitter equipment (2-way radio)

Repair any problems in listed items as necessary; clear code and rerun QUICK TEST. If problem is not found in items listed, go to step 4.

2) Code 16/226: IDM Circuit Failure Code 16/226 indicates ECA did not receive IDM signal from EDIS module in KOEO SELF-TEST. Possible causes for this problem are as follows

1. Open or short in IDM or IGN GND circuit harness
2. Faulty EDIS module - If engine starts, go to next step. If engine does not start, diagnose EDIS system.

3) Continuous Memory Code 18/212: Check For Other Codes Code 18/212 indicates loss of IDM input signal to ECA. Possible causes for this fault are as follows

1. Open or shorted harness
2. Faulty EDIS module
3. Faulty ECA

If Continuous Memory Code 45, 46, 48, 215, 216 or 217 is present, see testing procedure for EDIS in the SYSTEM/COMPONENT TESTS article in this section. If Code 45, 46, 48, 215, 216 or 217 is not present, go to next step.

4) Continuous Memory Codes 18/212: Check IDM Circuit Continuity Turn ignition off and wait 10 seconds. Disconnect EDIS module. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair as necessary. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 4 at breakout box and EDIS module harness connector pin No. 2. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair open circuit. Remove breakout box and reconnect all components. Clear codes and rerun QUICK TEST.

5) Check IDM Circuit For Short To Ground Turn ignition off and wait 10 seconds. Disconnect EDIS module connector. Install breakout box and leave ECA disconnected. With DVOM on 200-k/ohm scale, measure resistance between test pin No. 4 and test pins No. 40, 46 and 60. If readings are 10 k/ohms or more, go to next step. If any reading is less than 10 k/ohms, remove breakout box and repair short to ground in IDM circuit. Reconnect all components and rerun QUICK TEST.

6) Check IDM Circuit For Shorts To Power (Except VREF Circuit) With ignition off, install breakout box. Disconnect ECA and EDIS module. Measure voltage between test pin No. 4 and test pins No. 40 and 60. To check for short to VBAT, turn ignition off. To check for short to VPWR, turn ignition on. If voltage is less than 10.5 volts, go to next step. If any reading is greater than 10.5 volts, repair short circuit. Remove breakout box and reconnect all components. Rerun QUICK TEST.

7) Check IDM Circuit For Short To VREF & PIP Turn ignition off. Install breakout box, leaving ECA disconnected. Disconnect EDIS module. Set DVOM to 200-k/ohm scale.

To check for shorts to VREF, measure resistance between test pins No. 36 and 26 at breakout box. To test for shorts to PIP, measure resistance between test pins No. 36 and 56 at breakout box.

If each resistance is greater than 10 k/ohms, go to next step. If resistance is not greater than 10 k/ohms, repair short circuit. Remove breakout box, reconnect all components and repeat QUICK TEST.

During this test, when 4-wire HEGO is connected to vehicle harness, a short to SIGRTN (pin No. 46) may be indicated along with an actual short to PWR GND.

8) Check ECA For Short To Ground Turn ignition off and wait 10 seconds. Disconnect EDIS module. Install breakout box and connect ECA. With DVOM on 200-k/ohm scale, measure resistance between test pin No. 4 and test pins No. 16, 20 (If equipped), 40, 46 and 60. If readings are 10 k/ohms or more, reconnect components and go to next step. If any reading is less than 10 k/ohms, replace ECA. Reconnect all components and rerun QUICK TEST.

9) Check EDIS Module Turn ignition off and wait 10 seconds. Enter KOER wiggle test. See CONTINUOUS MONITOR MODE (WIGGLE TEST) under QUICK TEST. Observe VOM or diagnostic tester for indication of fault while lightly tapping on EDIS module to simulate road shock. Wiggle all EDIS harness connectors. If fault is indicated, go to next step. If fault is not indicated, disconnect and inspect EDIS harness connectors and terminals for damage. If connectors and terminals are okay, check ignition system. See the SYSTEM/COMPONENT TESTS article in this section. If ignition is okay, replace ECA.

10) Check EEC-IV Harness Remain in CONTINUOUS MONITOR MODE (WIGGLE TEST). Wiggle, shake or bend small sections of harness, working from EDIS connectors to firewall. Observe VOM or diagnostic tester for indication of fault. Repeat process from firewall to ECA. This test checks for the following circuit faults

1. PIP Open/Shorted To Ground (check at test pin No. 56)
2. SAW Shorted To Ground (check at test pin No. 36)
3. Ignition Ground Open (check at test pin No. 16)
4. IDM Open To Ground (check at test pin No. 4)
5. IDM Shorted To Power (check at test pin No. 4)

Perform CONTINUOUS MONITOR MODE (WIGGLE TEST) on these circuits, one at a time, to isolate fault. If fault is indicated, isolate fault and repair harness. Repeat QUICK TEST. If no fault is indicated, go to next step.

11) Check ECA & Harness Connectors Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion or loose wires. If connector is damaged, repair as necessary; clear codes and repeat QUICK TEST. If connector is okay, perform appropriate procedure listed as follows, based on the Continuous Memory Code displayed

1. Code 14/211 - Erratic ignition fault in EEC system cannot be duplicated. Remove breakout box and reconnect all components. Diagnose EDIS ignition system.
2. Code 18/212 - Replace ECA. Remove breakout box and reconnect all components. Start and run engine for about one minute, then rerun QUICK TEST.

Perform this test when checking computed timing, or when directed by QUICK TEST. This test is intended to diagnose the following

1. Harness circuit (SAW)
2. Base timing
3. Faulty ECA

To prevent replacing good components, be aware that the following non-EEC related areas may be at fault

1. Basic engine condition (valves, vacuum leaks, valve timing, EGR valve, etc.)
2. EDIS module
3. Distributor

IDM Circuit (1.9L SPFI-MA). Scheme 59

TEST PIN WIRE COLOR IDENTIFICATION

1) KOER Code 18/213: Check Computed Spark Timing Code 18/213 indicates SAW circuit is open or shorted to ground or VBAT. Possible causes for this fault are as follows

1. Open or shorted harness circuit
2. Faulty ECA
3. Faulty EDIS module

Activate KOER SELF-TEST. Check and record timing while in KOER SELF-TEST. Self-test mode locks timing during testing, and during 2 minutes after last code is displayed. Computed timing during these 2 minutes is equal to base timing plus 20 degrees (+/- 3 degrees). If computed timing is correct, restart KOER SELF-TEST. If timing is not to specification, go to next step.

2) Check Base Timing Turn ignition off and wait 10 seconds. Locate in-line SAW connector, and open connection. Start engine and check base timing. Use specification on VECI decal. If base timing is correct, reconnect SAW and go to next step. If base timing is incorrect, diagnose ignition system, as base timing is not adjustable. See the SYSTEM/COMPONENT TESTS article in this section.

3) Check For Power To ECA Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair as necessary. Install breakout box, leaving ECA disconnected. With KOEO and DVOM on 20-volt scale, measure voltage between test pins No. 37 and 40, and between test pins No. 57 and 60 at breakout box. If either reading is less than 10.5 volts, go to TEST B, step 1. If both readings are 10.5 volts or more, go to next step.

4) Check SAW Circuit For Continuity Turn ignition off and wait 10 seconds. Install breakout box. Disconnect ECA and EDIS module. With DVOM on 200-ohm scale, measure resistance between test pin No. 36 at breakout box and SAW terminal at EDIS module vehicle harness connector. If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, repair open circuit. Reconnect all components and check timing as described in step 1.

Module Connector. Scheme 60

5) Check SAW Circuit For Shorts To Power (Except VREF Circuit) With ignition off, install breakout box. Disconnect ECA and EDIS module. Measure voltage between test pin No. 36 and test pins No. 40 and 60. To check for short to VBAT, turn ignition off. To check for short to VPWR, turn ignition on.

If voltage is less than 10.5 volts, go to next step. If any reading is greater than 10.5 volts, repair short circuit. Remove breakout box and reconnect all components. Rerun QUICK TEST.

6) Check SAW Circuit For Shorts To VREF, GROUND And PIP Turn ignition off and wait 10 seconds. Set DVOM to 200-k/ohm scale. Install breakout box, leaving ECA and EDIS module disconnected.

To check for shorts to ground, measure resistance between test pin 36 and test pins No. 16, 20 (if equipped), 40, 46 and 60. To check for shorts to VREF, measure resistance between test pin 36 and test pin No. 26. To check for shorts to PIP circuit, measure resistance between test pin No. 36 and test pin No. 56.

If each resistance is greater than 10 k/ohms, go to next step. If resistance is less than 10 k/ohms, repair short circuit. Remove breakout box, reconnect all components and rerun QUICK TEST.

During this test, when 4-wire HEGO is connected to vehicle harness, a short to SIG RTN (pin No. 46) may be indicated along with an actual short to PWR GND.

7) Check SAW Voltage at ECA With ignition off and breakout box installed, connect ECA to breakout box. Reconnect EDIS module. Ensure timing switch on breakout box is in DIST position. Set DVOM on 20-volt AC scale. With KOER, measure voltage between test pin No. 36 and battery negative post. If AC voltage is NOT .3-2 volts on 1.9L SPFI-MA engines, replace ECA .Remove breakout box and repeat QUICK TEST. If AC voltage is .3-2 volts on 1.9L SPFI-MA engines, EEC-IV system is okay; remove breakout box, reconnect ECA and check ignition system. See the SYSTEM/COMPONENT TESTS article.

Perform this test when directed by QUICK TEST or other test procedures. This test is intended to diagnose only the following

1. ECA
2. EEC power relay
3. Harness circuits (SIG RTN, STO, STI, VPWR, VREF)

No Codes/Codes Not Listed Circuits. Scheme 61

TEST PIN WIRE COLOR IDENTIFICATION

After-market devices, such as alarm system, may cause self-test to abort if wiring is connected to certain EEC components. If a device is installed, disconnect it completely from EEC system. Before continuing with this circuit test, restore EEC circuits to original and rerun QUICK TEST.

1) Check VREF Voltage At Self-Test Connector Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair as necessary. Install breakout box and connect ECA. Set DVOM on 20-volt scale. With Key On Engine Off (KOEO), measure voltage between test pin No. 26 and SIG RTN at self-test connector. If reading is NOT 4-6 volts, go to TEST C, step 1. If reading is 4-6 volts, go to next step.

2) Check STI Circuit Continuity Turn ignition off and wait 10 seconds. With breakout box installed and ECA disconnected, set DVOM on 200-ohm scale. Measure resistance between test pin No. 48 at breakout box and Self-Test Input (STI) at self-test connector pigtail. If reading is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in circuit; remove breakout box and reconnect ECA. Rerun QUICK TEST.

3) Check STO Circuit Continuity With breakout box installed and ECA disconnected, set DVOM on 200-ohm scale. Measure resistance between test pin No. 17 at breakout box and Self-Test Output (STO) at self-test connector. If reading is less than 5 ohms, go to next step. If reading is 5 ohms or more, repair open circuit; remove breakout box and reconnect ECA. Rerun QUICK TEST.

4) Check EGO Signal For Short To Power With breakout box installed, ECA disconnected and DVOM on 20-volt scale, measure voltage between HEGO SIGNAL test pin No. 29 or 44 and test pin No. 40 or 60 (refer to schematic at beginning of TEST H). If voltage is greater than 2 volts, go to next step. If voltage is less than 2 volts, go to step 6.

5) Isolate Short To Harness Or HEGO Sensor With breakout box installed and ECA disconnected, set DVOM to 20-volt scale. Disconnect HEGO (bank No. 1) sensor connector. With KOEO, measure voltage between HEGO SIGNAL test pin No. 20 or 44 and test pin No. 40 or 60 (refer to schematic at beginning of TEST H). If voltage is greater than 2 volts, repair short to power in HEGO SIGNAL circuit. Remove breakout box, reconnect all components and rerun QUICK TEST. If voltage is less than 2 volts, replace HEGO sensor (bank No. 1). Remove breakout box, reconnect all components and rerun QUICK TEST.

6) Check STO Circuit For Short To Ground With breakout box installed and ECA disconnected, set DVOM on 200-k/ohm scale. Measure resistance between STO at self-test connector and engine block ground. If reading is greater than 10k/ohms, go to next step. If resistance is less than 10 k/ohms, repair STO or MIL/SIL circuit for short to ground. Reconnect ECA and repeat QUICK TEST.

7) Check If Power Relay Always On With ignition off, install breakout box, leaving ECA disconnected. Set DVOM on 20-volt scale. Connect DVOM between test pin No. 37 or 57 and pin No. 40 or 60. Turn ignition on then off. Wait 10 seconds. If reading does not change from 10.5 volts (or more) to less than one volt, go to next step. If reading changes from 10.5 volts (or more) to less than one volt, go to step 8.

8) Check VPWR Circuit For Short To Power With ignition off, breakout box installed and EEC power relay or Integrated Relay Controller Module (IRCM) disconnected, set DVOM on 20-volt scale. Ensure ECA is disconnected. Connect DVOM to test pin No. 37 or 57 and test pin No. 40 or 46 at breakout box. If voltage is greater than one volt, repair short to VPWR circuit. Remove breakout box, reconnect ECA and rerun QUICK TEST. If voltage is less than one volt, replace EEC-IV power relay or IRCM. Remove breakout box, reconnect ECA and rerun QUICK TEST.

9) Check Malfunction Indicator Light (MIL) Function If MIL is always on, go to TEST ML, step 1. If MIL is always off, go to TEST ML, step 4. If MIL is working normally, replace ECA and repeat QUICK TEST.

Perform this test when directed by QUICK TEST. This test is intended to diagnose only the following components or systems

1. ECA
2. Harness circuits (KAPWR)

EEC Power Relay Circuit. Scheme 62

TEST PIN WIRE COLOR IDENTIFICATION

1) Continuous Memory Code 15/512 Displayed Code 15/512 indicates ECA is experiencing power interruption in its Keep-Alive Memory (KAM) circuit. Clear Continuous Memory Codes. See CLEARING CODES under SELF-DIAGNOSTIC SYSTEM. Wait 5 minutes to allow code to reset. Repeat KOEO SELF-TEST for Continuous Memory Code output. If Continuous Memory Code 15/512 is not displayed, Continuous Memory Code 15/512 testing is complete. Service other codes as necessary. If Continuous Memory Code 15/512 is displayed during retest, go to next step.

Continuous Memory Code 15/512 may be displayed when power to Keep-Alive Memory (KAM) test pin No. 1 at ECA is interrupted. This code may be set when installing a breakout box, and may be displayed the first time self-test is performed and power is restored to ECA. Repeat self-test to ensure correct diagnosis.

2) Inspect Engine Compartment Wire Routing Ensure EEC-IV components and wiring are not close to high-tension secondary voltage wires or ignition components. If EEC-IV wiring is close to high-tension wires, reroute EEC wiring. Clear codes and wait 5 minutes. Repeat KOEO SELF-TEST. If Continuous Memory Code 15/512 is no longer displayed, Continuous Memory Code 15/512 testing is complete; service other codes as necessary. If Continuous Memory Code 15/512 is still displayed, go to next step.

3) Code 15/511: Check KAPWR Circuit Voltage Code 15/511 indicates ECA memory (ROM) failed during KOEO SELF-TEST. Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector and inspect for damaged pins and loose wires. Service as necessary. Install breakout box, leaving ECA disconnected. Set DVOM on 20-volt scale. Connect DVOM positive test lead to test pin No. 1 and negative test lead to pin No. 40 or 60 at breakout box. With KOEO, observe voltage reading while wiggling, bending and shaking small sections of EEC harness from EEC to dash. If reading is less than 10.5 volts, repair open circuit; reconnect ECA and repeat QUICK TEST. If reading is 10.5 volts or more, replace ECA; remove breakout box and repeat QUICK TEST.

Perform this circuit test when directed by other CIRCUIT TESTS. This test is intended to diagnose only the following

1. ECA
2. Throttle plate linkage

1) Check For Codes 23, 53, 63, 121, 122 Or 123 If vehicle is equipped with a speed control, speed control servo must be electrically disconnected. This prevents speed control system from affecting throttle plate movement during Output State Check. Rerun QUICK TEST or Output State Check.

Turn ignition off and wait 10 seconds. Perform KOEO SELF-TEST. If Codes 23, 53, 63, 121, 122 or 123 are displayed, go to appropriate KOEO SELF-TEST CODES chart under SERVICE CODE REFERENCE CHARTS and service code(s) as necessary. If no code is displayed, go to TEST QA, step 1. If Code 11/111 (pass code) is displayed, go to next step.

2) Check Throttle Linkage Check throttle and linkage for sticking or binding. If throttle and linkage are okay, replace TPS and repeat QUICK TEST. If throttle and linkage are binding, repair as necessary and repeat QUICK TEST.

Perform this test only when directed by TEST AA.

This test is intended to diagnose the following components or systems

1. ISC by-pass air system
2. MAP system
3. EGR system
4. MAF system

To prevent replacing good components, be aware that the following non-EEC-IV areas may be at fault

1. Faulty power or ground connections
2. Ignition system (distributor cap, rotor, wires, coil and plugs)
3. Basic mechanical engine components (cam timing, compression, etc.)

1) ISC-BPA Check Attempt to start engine at part throttle. If engine starts and runs smoothly at part throttle, go to TEST KE, step 4. If engine does not function as described, go to step 3.

2) Check For RPM Drop Turn ignition off. Connect a tachometer. Start engine and disconnect ISC solenoid. If RPM drops or engine stalls, reconnect ISC solenoid and go to next step. If RPM does not drop, go to step 4.

3) Power To MAP/BP Sensor If vehicle is not equipped with a MAP/BP sensor, go directly to step 8. Use Ford Motor Co. MAP/BP tester for this test. If Green light is on, VREF circuit voltage is okay. If Red light (or no light) is on, VREF circuit voltage is either too low or too high. Turn ignition off and disconnect MAP/BP sensor from vehicle harness. Connect MAP/BP tester between vehicle harness and MAP/BP sensor. Connect banana plugs of tester into DVOM, and set DVOM on 20-volt scale. With tester connected, turn ignition on. If Green light is on, go to next step. If light is not on, repair open in VREF circuit and remove MAP/BP tester. Reconnect components and retest symptom.

MAP/BP Tester & Circuit. Scheme 63

4) MAP/BP Tester Output Reading Measure several known good MAP/BP sensors to obtain average voltage for specific location and date of testing. With MAP/BP tester and DVOM connected, turn ignition on and measure MAP/BP SIG voltage at MAP sensor. If voltage is in within specification for the specific altitude, go to step 8 (vehicles with MA sensors), or go to next step (all others). See MAP VOLTAGE OUTPUT table. If voltage is not within specification for the specific altitude, replace MAP/BP sensor.

MAP VOLTAGE OUTPUT

5) Check Vacuum Lines Check vacuum lines for correct routing. Refer to VECI decal. Check MAP sensor vacuum line for leaks or blockage. If vacuum lines are okay, go to next step. If vacuum lines are not okay, repair as necessary. Rerun QUICK TEST.

6) Check MAP Sensor Turn ignition off and wait 10 seconds. Disconnect vacuum line from MAP sensor. Install vacuum pump to MAP sensor. Apply 18 in. Hg vacuum to MAP sensor. If MAP sensor holds vacuum, release vacuum and remove vacuum pump. Reconnect vacuum line to MAP sensor and go to next step. If MAP sensor does not hold vacuum, replace MAP sensor. Reconnect vacuum line and rerun QUICK TEST.

7) Check Vacuum Manifold Source Turn ignition off. Disconnect MAP sensor vacuum hose from manifold vacuum "T" fitting, and install vacuum gauge in its place. Start engine and observe vacuum gauge. If manifold vacuum is present, remove vacuum gauge; reconnect MAP sensor vacuum hose and go to next step. If vacuum is not present, remove obstruction; reconnect all components and rerun QUICK TEST.

8) Check EGR Vacuum If vehicle is not equipped with EGR system hardware, go directly to TEST H, step 2. Step 8 and step 9 attempt to determine if EGR system is the cause of driveability symptom or no-start condition. Disconnect and plug vacuum line at EGR valve. Attempt to start engine. If vehicle could not start previously and still does not start, or if vehicle driveability fault is still present, go to next step. If vehicle did not start previously but starts now, or if driveability symptoms are eliminated, go to TEST DN, step 42 (vehicles with EVP), or go to TEST DL, step 21 (all others).

9) Check EGR Valve Inspect EGR valve for leaks. If valve is fully closed, go to TEST H, step 2. If EGR valve is leaking or is not fully seated, replace or repair valve.

Perform this test only when directed by QUICK TEST. This test is intended to diagnose only the following circuits or systems

1. Clutch Engage/Interlock Switch
2. Neutral Drive/Gear Switch
3. ECA
4. Harness Circuits: CES, CIS, NDS, NGS and SIG RTN

TEST PIN WIRE COLOR IDENTIFICATION

1) Code 67/522, 525, 527, 528 Or 634 System Identification Code 67/522, 525, 527, 528 Or 634 is a result of voltage being high at either pin No. 10 (A/C input) or pin No. 30 (neutral drive) while cranking engine or during KOEO SELF-TEST. Possible causes for these faults are as follows

1. A/C circuit shorted to power
2. Clutch engage/interlock circuits open
3. Neutral drive/gear switch open
4. Faulty ECA
5. Starter relay disconnected during self-test

Note. For 1.9L SPFI-MA engines with automatic transmission, go to step 10. For 1.9L SPFI-MA engines with manual transmission, proceed to the next step.

2) Check Neutral Gear/Clutch Input Turn ignition off and wait 10 seconds. Turn A/C off (if equipped). Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires; repair as necessary. Install breakout box, leaving ECA disconnected. Set DVOM to 200-ohm scale. Measure resistance between test pins No. 30 and 46 with transmission in neutral and clutch pedal up. Measure resistance between test pins No. 30 and 46 with transmission in gear and clutch pedal down. If each resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, go to step 5.

Neutral Gear/Clutch Input Circuit. Scheme 64

3) Check Neutral Gear/Clutch Input Integrity Turn ignition off and wait 10 seconds. With breakout box install, ECA disconnected and DVOM set to 200-ohm scale, measure resistance between test pins No. 30 and 46 with transmission in any gear and clutch pedal up. If resistance is less than 5 ohms, go to TEST KM, step 40 (vehicles with A/C), or replace ECA, remove breakout box and rerun QUICK TEST (all others). If resistance is greater than 5 ohms, go to next step.

4) Check For Short To Ground Turn ignition off and wait 10 seconds. Install breakout box, leaving ECA disconnected. Disconnect clutch engage switch. Set DVOM to 200-k/ohm scale. Measure resistance between test pins No. 30 and 46. If resistance is greater than 10 k/ohms, go to TEST KM, step 40 (vehicles with A/C), or replace ECA, remove breakout box and rerun QUICK TEST (all others). If resistance is less than 10 k/ohms, repair short circuit. Remove breakout box, reconnect all components and rerun QUICK TEST.

5) Check Neutral Gear/Clutch Engage Switch Turn ignition off and wait 10 seconds. Install breakout box, leaving ECA disconnected. Set DVOM to 200-ohm scale. Locate neutral gear switch (on transmission) and clutch engage switch (at clutch pedal linkage). Disconnect vehicle harness at both switches and inspect connectors for pushed-back pins. Measure resistance across neutral gear switch terminals with transmission in neutral, and across clutch engage switch with clutch pedal down. If each resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, replace open switch(es). Remove breakout box, reconnect all components and rerun QUICK TEST.

6) Check Neutral Gear/Clutch Harness Turn ignition off and wait 10 seconds. With breakout box installed, ECA disconnected and DVOM set to 200-ohm scale, disconnect neutral gear and clutch switches. Measure resistance between test pin No. 30 and neutral gear switch harness connector, and between test pin No. 30 and clutch engage switch harness connector.

Measure resistance between test pin No. 46 and neutral gear switch harness connector, and between test pin No. 46 and clutch engage switch harness connector. If each resistance is less than 5 ohms, go to TEST KM, step 40 (vehicles with A/C), or replace ECA, remove breakout box and rerun QUICK TEST (all others). If resistance is greater than 5 ohms, repair open circuit. Remove breakout box, reconnect all components and rerun QUICK TEST.

7) Check Clutch Engage Switch Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires; repair as necessary. Install breakout box, leaving ECA disconnected. Set DVOM to 200-ohm scale. Hold clutch pedal down and measure resistance between test pins No. 30 and 40. If resistance is less than 5 ohms, go to TEST KM, step 40 (vehicles with A/C), or replace ECA, remove breakout box and rerun QUICK TEST (all others). If each resistance is greater than 5 ohms, repair open circuit. Remove breakout box, reconnect all components and rerun QUICK TEST.

Checking Clutch Engage Switch. Scheme 65

8) Check Neutral Drive Input Turn ignition off and wait 10 seconds. Ensure heater control is in OFF position (if equipped). Ensure transmission is in NEUTRAL or PARK position. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires; repair as necessary. Install breakout box and connect ECA to breakout box. Set DVOM to 20-volt scale. With KOEO, measure voltage between test pin No. 30 and chassis ground. If voltage is less than one volt, go to TEST KM, step 40 (vehicles with A/C), or replace ECA, remove breakout box and rerun QUICK TEST (all others). If voltage is greater than one volt, go to next step.

Checking Neutral Drive Switch. Scheme 66

9) Check Neutral Drive Switch Turn ignition off and wait 10 seconds. Install breakout box, leaving ECA disconnected. Set DVOM to 200-ohm scale. Disconnect vehicle harness from neutral drive switch and measure resistance across switch. If resistance is less than 5 ohms, repair open circuit in vehicle harness Neutral Drive circuit. Remove breakout box, reconnect all components and rerun QUICK TEST. If resistance is greater than 5 ohms, replace neutral drive switch. Remove breakout box, reconnect all components and rerun QUICK TEST.

10) Check Neutral Drive Input Turn ignition off and wait 10 seconds. Ensure transmission is in NEUTRAL or PARK position. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires; repair as necessary. Install breakout box and connect ECA to breakout box. Set DVOM to 20-volt scale. Disconnect 4EAT module 16-pin connector. With KOEO, measure voltage between test pin No. 30 and chassis ground. If voltage is less than one volt, replace ECA. Remove breakout box, reconnect all components and rerun QUICK TEST. If voltage is greater than one volt, go to next step.

Checking Neutral Drive Input. Scheme 67

11) Check NDS Circuit Continuity Between ECA And 4EAT Module Turn ignition off and wait 10 seconds. Install breakout box and leave ECA disconnected. Disconnect 4EAT 16-pin connector. Set DVOM to 200-ohm scale. Measure resistance between test pin No. 30 and NDS pin at 4EAT module vehicle harness connector. If resistance is less than 5 ohms, diagnose 4EAT system; remove breakout box, reconnect all components and rerun QUICK TEST. If resistance is greater than 5 ohms, repair open circuit; remove breakout box, reconnect all components and rerun QUICK TEST.

Checking NDS Continuity. Scheme 68

12) Check NDS Circuit For Short To Ground Or Closed Neutral Drive Switch Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires; repair as necessary. Install breakout box and leave ECA disconnected. Set DVOM to 200-k/ohm scale. Place transmission in DRIVE position. Measure resistance between test pins No. 30 and 40/60. If resistance is greater than 10 k/ohms, NDS circuit okay. Diagnose other possible causes. If resistance is less than 10 k/ohms, repair closed neutral drive switch or short circuit. Remove breakout box, reconnect all components and rerun QUICK TEST.

See also:
• FUEL PRESSURE SPECIFICATIONS
• CYLINDER BALANCE TEST SERVICE CODES