Engine Controls - Tests W/codes - 5.8L Eec-Iv: Diagnosis Ford Pickup F350

SELF-DIAGNOSTIC SYSTEM

DIAGNOSTIC FORMATS

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

Before starting any CIRCUIT TEST, follow all steps under QUICK TEST to find correct CIRCUIT TEST. If vehicle passes QUICK TEST and no driveability symptoms or intermittent faults exist, EEC-IV system is operating properly at this time.

DIAGNOSTIC TROUBLE CODES (DTC)

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

KOEO & KOER SELF-TEST Codes

PCM outputs codes one digit at a time. These codes indicate current faults in system and should be serviced in order of appearance. Use DIAGNOSTIC TROUBLE CODE REFERENCE CHART to identify correct CIRCUIT TEST.

If using an analog voltmeter or Malfunction Indicator Light (MIL), pay careful attention to length of pauses in order to read codes correctly. Digits in DTC will be displayed by a needle pulse sweep (analog voltmeter) or a flash (MIL).

Diagnostic Trouble Codes (DTCs) are represented by a 3-digit number. For example, the first digit of DTC 312 would be displayed by 3 sweeps/flashes with a 0.4-second pause in-between each sweep/flash. A 2-second pause will occur between first and second digits of DTC. Second digit of DTC 312 will be displayed by one sweep/flash then another 2-second pause. Third digit of DTC 312 will be displayed by 2 sweeps/flashes with a 0.4 pause in-between each sweep/flash. A 4-second pause occurs between each code. see scheme 1 KOEO codes are separated from Continuous Memory codes by a 6 to 9-second delay, a 0.4-second sweep/flash (separator pulse) and then another 6 to 9-second delay. see scheme 2

Scan tester, if used, will count pulses and display them as a digital code. STAR tester cannot be used to read 3-digit codes. Super STAR II or New Generation STAR tester can be used to read 3-digit codes. If using Super STAR II tester, 3-digit codes will only be displayed in fast code mode. If slow code mode is used, display will be blank.

Diagnostic Aids

After each service or repair procedure has been completed, repeat QUICK TEST to ensure all EEC-IV systems work properly and diagnostic trouble codes are no longer present.

KOEO SELF-TEST

Ensure engine is warmed to normal operating temperature. If engine does not start (or stalls after starting), continue KOEO SELF-TEST. DO NOT depress throttle. Turn ignition off. Ensure test equipment is properly attached. Turn ignition on (engine off). Record all KOEO and Continuous Memory Codes.

If a Code 111 (pass code) is not retrieved, service KOEO codes. See DIAGNOSTIC TROUBLE CODE REFERENCE CHART . If PCM will not output codes, go to CIRCUIT TEST QA. If diagnostic trouble codes are retrieved, perform the following

1. If Malfunction Indicator Light (MIL) is on, service diagnostic trouble codes in order retrieved. See «DIAGNOSTIC TROUBLE CODE REFERENCE CHART»(ref-23598-S35260139562001010300000) .
2. If vehicle has a no-start condition, go to CIRCUIT TEST AA.
3. If vehicle displays Code 111 (pass code) and does not have any symptoms described in previous steps, go to KOER SELF-TEST.

DO NOT enter this test sequence until a Code 111 (pass code) has been retrieved in KOEO SELF-TEST . If system has not passed KOEO SELF-TEST, codes 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 engine, and run it for 2 minutes at 2000 RPM to warm Heated Exhaust Gas Oxygen Sensor (HO2S). 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 diagnostic trouble codes displayed. Check following items

1. If Code 998 is displayed, EEC-IV system is operating in Failure Management Effects Mode (FMEM) and vehicle has not passed «KOEO SELF-TEST»(ref-23598-S28031615042001010300000). Vehicle cannot be diagnosed while in FMEM mode.
2. If vehicle is equipped with a Brake On-Off (BOO) switch, brake pedal must be depressed and released after ID code portion of test.
3. If Dynamic Response Code appears, perform a brief Wide Open Throttle (WOT). DO NOT perform WOT unless requested. see scheme 2
4. If KOER codes are present, see «DIAGNOSTIC TROUBLE CODE REFERENCE CHART»(ref-23598-S35260139562001010300000). If system will not output codes, go to CIRCUIT TEST QA.
5. If a Code 111 (pass code) is retrieved during Continuous Memory Code portion of KOEO SELF-TEST and no driveability problem exists, testing complete. If driveability problems still present, go to «TESTS W/O CODES - 5.8L EEC-IV»(ref-23634) article.
6. If a Code 111 (pass code) is retrieved during KOER SELF-TEST and intermittent fault(s) continue, go to «CONTINUOUS MONITOR MODE (WIGGLE TEST)»(ref-23598-S23726050792001010300000).

CONTINUOUS MONITOR MODE (WIGGLE TEST)

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

KOEO Wiggle Test Procedure

Connect test equipment. see scheme 3or see scheme 4. Turn ignition on. Activate self-test using jumper lead or diagnostic tester. Wait 10 seconds, and then deactivate and reactivate self-test. Wiggle test mode is now activated. Tap, move and wiggle suspect sensor and/or harness area. If a fault is detected, a diagnostic trouble code may be stored in memory and may be indicated at diagnostic tester or scan tester. Retrieve code, and perform appropriate test as indicated in the DIAGNOSTIC TROUBLE CODE REFERENCE CHART.

KOER Wiggle Test Procedure

Connect test equipment. see scheme 3or see scheme 4. Start engine. Activate self-test using jumper lead or diagnostic tester. Wait 10 seconds, and then deactivate and reactivate self-test. DO NOT turn engine off. KOER wiggle test mode is now activated. Tap, move and wiggle suspect sensor and/or harness area. If a fault is detected, a diagnostic trouble code may be stored in memory and may be indicated at diagnostic tester or scan tester. Retrieve code, and perform appropriate test. See DIAGNOSTIC TROUBLE CODE REFERENCE CHART.

Output State Diagnostic Test Mode (DTM)

1. Step 1) Output state DTM is used as an aid in servicing output actuators associated with EEC-IV system. It allows technicians to energize and de-energize most system output actuators on command. This mode is entered from «KOEO SELF-TEST»(ref-23598-S28031615042001010300000) after all codes have been retrieved.
2. Step 2) With DVOM on 20-volt scale, connect DVOM negative lead to STO terminal at Diagnostic Link Connector (DLC). Connect positive lead to positive battery terminal. Using jumper wire, connect STI to SIG RTN at Diagnostic Link Connector (DLC).
3. Step 3) Perform «KOEO SELF-TEST»(ref-23598-S28031615042001010300000) until continuous memory test is complete. DVOM will read less than one volt when test is complete. Depress and release throttle. If voltage increases, output state DTM has been entered. If voltage does not increase, depress throttle to WOT and release. If STO voltage still does not increase, see procedures under CIRCUIT TEST QC.

DIAGNOSTIC TROUBLE CODE REFERENCE CHART

DTC REFERENCE CHART

CIRCUIT TEST AA - NO START (DISTRIBUTOR IGNITION SYSTEMS)

Enter this CIRCUIT TEST only when steps in QUICK TEST have been successfully completed but engine still does not start or if directed here from another test or chart.

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

1. Powertrain Control Module (PCM).
2. Spark (PCM-controlled).
3. Wiring harness circuits (PIP, SPOUT, IGN GND and VPWR).

Identifying ICM Circuit & Connector Terminals. Scheme 221

TEST PIN NO. 16 (IGN GND) WIRE COLOR IDENTIFICATION

TEST PIN NO. 36 (SPOUT) WIRE COLOR IDENTIFICATION

TEST PIN NO. 56 (PIP) WIRE COLOR IDENTIFICATION

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

1. Fuel quality and quantity.
2. Ignition (general system condition).
3. Engine mechanical components.
4. Starter and battery circuits.
5. Distributor.
6. Ignition Control Module (ICM).
7. Camshaft Position (CMP) sensor.
8. Ignition coil.

Scheme 222

1. Step 1) Check No-Start Condition Try to start engine. If engine does not start, go to next step. If engine starts, no-start condition is intermittent. Check and repair ignition system as necessary. See procedures in the «SYSTEM/COMPONENT TESTS - 5.8L EEC-IV»(ref-23711) article.
2. Step 2) Attempt To Crank Engine Try to crank engine. If engine does not crank, check vehicle starting and charging systems. If engine cranks, verify inertia switch button is pushed in. If inertia switch button is pushed in, go to next step.
3. Step 3) Check VREF Signal At TP Sensor Turn ignition off. Disconnect Throttle Position (TP) sensor. Turn ignition on (engine off). Measure voltage at TP sensor wiring harness connector between VREF and SIG RTN. (Scheme 222) If voltage is 4-6 volts, reconnect TP sensor and go to next step. If voltage is not 4-6 volts, go to CIRCUIT TEST C. (Scheme 222): TP Sensor Wiring Harness Connector Terminals
4. Step 4) Check For Spark At Plugs Disconnect any spark plug wire. Connect spark tester between spark plug wire and ground. Crank engine and check for spark. If spark is present and consistent, connect spark plug wire and go to step 14). If spark does not exist, connect spark plug wire and go to step next step.
5. Step 5) Check For Spark At Coil Remove coil secondary wire from distributor. Install spark tester. Check for spark while cranking engine. If spark exists, connect coil wire, and service ignition secondary system. If no spark exists, connect coil wire and go to next step.
6. Step 6) Check Ignition Circuit Ground Continuity Turn ignition off. Disconnect and inspect PCM 60-pin connector. Install Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Disconnect Camshaft Position (CMP) sensor connector. Measure resistance between test pin No. 16 at breakout box and IGN GND circuit at CMP sensor connector. If resistance is 5 ohms or more, repair open IGN GND circuit. Remove breakout box, reconnect components and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If resistance is less than 5 ohms, go to next step.
7. Step 7) Isolate SPOUT Circuit Fault Connect CMP sensor connector. Connect PCM to breakout box. Set breakout box timing switch to DIST position. Try to start vehicle. If vehicle starts, go to step 12). If vehicle does not start, go to next step.
8. Step 8) Check SPOUT Signal Turn ignition off. Set DVOM on 20-volt scale. Turn ignition on. Measure voltage between test pin No. 36 at breakout box and negative battery terminal while cranking engine. If voltage is 3-6 volts, EEC-IV system is not at fault. Diagnose ignition system. See IGNITION SYSTEMS in «SYSTEM/COMPONENT TESTS - 5.8L EEC-IV»(ref-23711) article. If voltage is not 3-6 volts, go to next step.
9. Step 9) Check SPOUT & PIP Circuits For Short To Power Turn ignition off. With breakout box installed, move timing switch to COMPUTED position. Disconnect PCM. Disconnect CMP sensor and ICM connectors. Turn ignition on. Measure voltage between test pin No. 36 (SPOUT) and negative battery terminal. Also, measure voltage between test pin No. 56 (PIP) and negative battery terminal. If either reading is more than 10.5 volts, repair short to power. Remove breakout box, reconnect components and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If both readings are 10.5 volts or less, go to next step.
10. Step 10) Check SPOUT & PIP Circuits For Short To Ground Turn ignition off. Measure resistance between test pin No. 36 (SPOUT) and test pins No. 16, 20, 40, 46 and 60 for short to ground. Also, measure resistance between test pin No. 36 and test pin No. 56 for short to PIP. Also, measure resistance between test pin No. 56 (PIP) and test pins No. 16, 20, 40, 46 and 60. If all readings are 10,000 ohms or more, go to next step. If any reading is less than 10,000 ohms, repair short in wiring harness. Remove breakout box, reconnect components and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If engine still does not start, go to next step.
11. Step 11) Isolate Shorts In PCM Turn ignition off. With breakout box installed, reconnect PCM. Disconnect CMP and ICM connectors. Measure resistance between test pin No. 36 (SPOUT) and test pins No. 37, 40, 57 and 60. Also, measure resistance between test pin No. 56 (PIP) and test pins No. 37, 40, 57 and 60. If any reading is less than 500 ohms, replace PCM. Remove breakout box, reconnect components and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If all readings are 500 ohms or more, reconnect components, and go to next step.
12. Step 12) Check PIP Signal Turn ignition off. With breakout box installed and PCM connected, move timing switch to COMPUTED position. While cranking engine, measure voltage between test pin No. 56 (PIP) and test pins No. 40 and 60. If voltage is 3-7 volts, replace PCM. Remove breakout box, reconnect components and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If voltage is not 3-7 volts, go to next step.
13. Step 13) Check Continuity Of PIP Circuit Turn ignition off. Disconnect PCM from breakout box. Disconnect CMP sensor connector. Measure resistance between test pin No. 56 and PIP circuit at CMP sensor. If resistance is 5 ohms or more, repair open PIP circuit. Remove breakout box, reconnect components and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If resistance is less than 5 ohms, remove breakout box and diagnose ignition system. See IGNITION SYSTEM in the «SYSTEM/COMPONENT TESTS - 5.8L EEC-IV»(ref-23711) article.
14. Step 14) Verify SPOUT Signal Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install breakout box, leaving PCM connected. Ensure breakout box timing switch is in COMPUTED position. Set DVOM on 20-volt scale. Measure voltage between test pin No. 36 and test pins No. 40 and 60 while cranking engine. If voltage is 3-6 volts, go to step 21). If voltage is not 3-6 volts, return to step 9). NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 14) to step 21). No test procedures have been omitted. CAUTION: Use safety precautions when working on fuel system. DO NOT allow smoking or open flame. If fuel starts leaking, immediately turn ignition off.
15. Step 21) 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 CIRCUIT TEST S. If pressure does not increase, repair fuel system as necessary. See FUEL SYSTEM in the «BASIC TESTING - 5.8L»(ref-23710) article.

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

This test is only intended to diagnose following

1. Power Control Module (PCM).
2. EEC power relay.
3. Wiring harness circuits (SIG RTN, PWR GND, VPWR, KAPWR and VREF).

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

1. Battery cables and ground straps.
2. Voltage regulator.
3. Alternator.
4. Ignition switch.

Identifying Power Relay Circuits. Scheme 223

1. Step 1) Battery Voltage Check Turn ignition on (engine off). Measure battery voltage. If voltage is less than 10.5 volts, recharge or replace battery. Check charging system. If voltage is 10.5 volts or more, go to next step.
2. Step 2) Check Continuity Of PWR GND Circuit Turn ignition off. Disconnect PCM. Inspect connector pins and repair if necessary. Install Breakout Box (T83L-50-EEC-IV), leaving PCM connected. Measure resistance between test pins No. 40 and 60 at breakout box and negative battery terminal. If resistance is 5 ohms or more, repair open PWR GND circuit, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If both readings are less than 5 ohms, go to next step.
3. Step 3) Check For Open Between SIG RTN & PWR GND Circuits At PCM With breakout box installed and PCM connected, measure resistance between test pin No. 46 and test pins No. 40 and 60 at breakout box. If readings are 5 ohms or more, replace PCM and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If resistance readings are less than 5 ohms, go to next step.
4. Step 4) Check Continuity Of SIG RTN Circuit Ensure ignition is turned off. Measure resistance between test pin No. 46 at breakout box and SIG RTN terminal (Gray/Red wire) at Data Link Connector (DLC). If resistance is 5 ohms or more, repair open SIG RTN circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If resistance is less than 5 ohms, go to next step.
5. Step 5) Check KAPWR Circuit Voltage At EEC Power Relay Turn ignition off. Locate relay block in engine compartment. Disconnect EEC power relay from relay block. Turn ignition on. Measure voltage between KAPWR terminal (Yellow wire) at EEC power relay connector and negative battery terminal. Also, measure voltage between test pin No. 1 at breakout box and negative battery terminal. If either voltage is 10.5 volts or less, repair open KAPWR circuit between EEC power relay and positive battery terminal. If voltage is 10.5 volts or more, go to next step. NOTE: Vehicles equipped with Power Distribution Boxes use a diode to provide electrical surge protection for the ignition switch and Ignition Control Module (ICM). If a no-start/no-code condition exists, ensure diode continuity is present in one direction only before going to step 6).
6. Step 6) Check Ignition Circuit Voltage At EEC Power Relay Ensure PCM is connected to breakout box and EEC power relay is disconnected. Turn ignition on. Measure voltage between negative battery terminal and IGN START/RUN circuit terminal at EEC power relay connector. If voltage is less than 10.5 volts, repair open ignition switch circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If voltage is 10.5 volts or more, go to next step.
7. Step 7) Check PWR GND Circuit Continuity Turn ignition off. With PCM connected to breakout box, measure resistance between negative battery terminal and PWR GND terminal (Black/White wire) at EEC power relay connector. If resistance 10 ohms or more, repair open circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If reading is less than 10 ohms, go to next step.
8. Step 8) Check VPWR Circuit Continuity Turn ignition off. Measure resistance between test pins No. 37 and 57 (VPWR) at breakout box and VPWR terminal (Red wire) at EEC power relay connector. If resistance is 5 ohms or more, repair open VPWR circuit between EEC power relay and PCM. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If reading is less than 5 ohms, go to next step.
9. Step 9) Check VPWR Circuit Voltage Turn ignition off. Install EEC power relay. Turn ignition on. With PCM connected, measure voltage between test pins No. 37 and 57 (VPWR) and test pins No. 40 and 60 (PWR GND) and 46 (SIG RTN) at breakout box. If voltage is 10.5 volts or more, repair circuit between PCM and EEC power relay. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If voltage 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

1. Sensor Input CIRCUIT TEST ADJUSTMENTS
2. Sensor Input CIRCUIT TEST DF
3. Sensor Input CIRCUIT TEST DH
4. Sensor Input CIRCUIT TEST DN
5. Sensor Input CIRCUIT TEST DS

Or if directed by: CIRCUIT TEST AA or CIRCUIT TEST QA.

SIG RTN is a dedicated ground used by most EEC-IV system sensors. VREF is a 5-volt reference voltage that is continuously output by PCM. This consistent voltage signal is used on all 3-wire sensors.

This circuit test is only intended to diagnose SIG RTN, VREF, TP, EVP and MAP circuits.

Reference Voltage Circuits & Connector Terminals. Scheme 224

TEST PIN NO. 26 (VREF) WIRE COLOR IDENTIFICATION

TEST PIN NO. 46 (SIG RTN) WIRE COLOR IDENTIFICATION

1. Step 1) Check Battery Power Circuit Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install Breakout Box (T83L-50-EEC-IV). Connect PCM to breakout box. Turn ignition on. Measure and record voltage between breakout box test pin No. 37 and SIG RTN terminal at Data Link Connector (DLC). Measure and record voltage across battery terminals. If either reading less than 10.5 volts, or if they differ by more than one volt, reconnect sensor (if applicable) and go to CIRCUIT TEST B. If voltage readings are 10.5 volts or more and do not differ from one another by more than one volt, go to next step.
2. Step 2) Check VREF Voltage With breakout box installed and PCM connected, turn ignition on. Measure voltage between test pins No. 26 and 46 at breakout box. If voltage is 4-6 volts, go to next step. If voltage is more than 6 volts, go to step 4). If voltage is less than 4 volts, go to step 5).
3. Step 3) Check VREF & SIG RTN Circuit Continuity Turn ignition off. If directed here by a sensor test, ensure sensor is disconnected. Disconnect PCM from breakout box. Measure resistance between test pin No. 26 and VREF terminal at wiring harness connector of disconnected sensor. Measure resistance between test pin No. 46 and SIG RTN circuit terminal at wiring harness connector of disconnected sensor. If both readings are less than 5 ohms, VREF circuit is okay. If either reading is 5 ohms or more, repair open VREF or SIG RTN circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
4. Step 4) Check For Excess VREF Circuit Voltage Turn ignition off. With breakout box installed, disconnect PCM and scan tester or Star tester (if applicable). Turn ignition on. Measure voltage between test pin No. 26 and battery ground. If voltage is less than 0.5 volt, replace PCM and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If voltage is 0.5 volt or more, repair short to battery power in wiring harness. Remove breakout box and repeat QUICK TEST. Replace PCM if fault still occurs.
5. Step 5) Check For Shorted Throttle Position (TP) Sensor Turn ignition off. Connect PCM to breakout box. Disconnect TP sensor from wiring harness. Turn ignition on. Measure voltage between test pins No. 26 and 46 at breakout box. If voltage is 4 volts or more, replace TP sensor and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If voltage is less than 4 volts, reconnect TP sensor and go to next step.
6. Step 6) Check For Shorted EVP Sensor Turn ignition off. Disconnect EVP sensor. Turn ignition on. Measure voltage between test pins No. 26 and 46. If voltage is 4 volts or more, replace EVP sensor and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If voltage is less than 4 volts, reconnect EVP sensor and go to next step.
7. Step 7) Check For Shorted MAP Sensor Turn ignition off. Disconnect MAP sensor. Turn ignition on. Measure voltage between test pins No. 26 and 46. If voltage is 4 volts or more, replace MAP sensor and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If voltage is less than 4 volts, reconnect MAP sensor and go to next step.
8. Step 8) Check VREF Circuit For Short To Ground Turn ignition off. Disconnect PCM, TP sensor, MAP sensor and EVP sensor. Measure resistance between test pin No. 26 and test pins No. 20, 40, 46 and 60. If any reading is less than 10,000 ohms, repair short to ground. Remove breakout box, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If all readings are 10,000 ohms or more, replace PCM 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 IAT sensor. 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.

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

1. Intake Air Temperature (IAT) sensor.
2. Engine Coolant Temperature (ECT) sensor.
3. Wiring harness circuits (IAT, ECT and SIG RTN).
4. Powertrain Control Module (PCM).

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

1. Coolant level low.
2. Cooling system, water pump or fan.
3. Engine operating temperature.
4. Engine oil level low.
5. Thermostat.
6. Air cleaner duct.
7. Ambient temperature.

Temperature Sensor Circuits & Connector Terminals. Scheme 225

TEST PIN NO. 7 (ECT) WIRE COLOR IDENTIFICATION

TEST PIN NO. 25 (IAT) WIRE COLOR IDENTIFICATION

TEST PIN NO. 46 (SIG RTN) WIRE COLOR IDENTIFICATION

1. Step 1) Code 114 Or 116 Code 114 (IAT) or 116 (ECT) indicates corresponding sensor is out of self-test range. Correct range for measurement is.3-3.7 volts. Check for following possible causes: Low ambient temperature (less than 50°F). Low coolant level. Faulty harness connector. Faulty sensor. If vehicle cannot be started, go to step 3). If vehicle stalls, go to CIRCUIT TEST S. If vehicle starts, run engine for 2 minutes at 2000 RPM. Ensure upper radiator hose hot and pressurized. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If Code 114 or 116 is present, go to next step. If Code 114 or 116 is not present, service other codes as necessary.
2. Step 2) Check VREF Circuit Voltage At TP (TP) Sensor Turn ignition off. Disconnect TP sensor. Turn ignition on. Measure voltage between VREF and SIG RTN circuits at TP sensor harness connector. see scheme 13 If voltage 4-6 volts, reconnect TP sensor, go to next step. If voltage not 4-6 volts, go to CIRCUIT TEST C.
3. Step 3) Check Sensor Resistance With Engine Off Turn ignition off. Disconnect suspect IAT or ECT sensor. Measure resistance between sensor signal circuit and SIG RTN circuit at sensor. If resistance is not within specification, replace suspected sensor. See «ECT & IAT SENSOR SPECIFICATIONS»(ref-23598-S39965049042002011500000) table. Reconnect wiring harness, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If resistance is within specification, perform following step as applicable. For ECT sensor and a no-start condition, DO NOT service Code Step 116 at this time. Go to next step. For vehicles with distributor ignition system, go to CIRCUIT TEST AA. ECT & IAT SENSOR SPECIFICATIONS Temperature °F (°C) (1) Volts (1) Ohms 50 (10) 3.51 58,750 68 (20) 3.07 37,300 86 (30) 2.60 24,270 104 (40) 2.13 16,150 122 (50) 1.70 10,970 140 (60) 1.33 7700 158 (70) 1.02 5370 176 (80) 0.78 3840 194 (90) 0.60 2800 212 (100) 0.46 2070 (1) Values may vary by 15 percent. see scheme 13: TP Sensor Wiring Harness Connector Terminals
4. Step 4) Check Sensor Resistance With Engine Running Warm engine to normal operating temperature. Turn ignition off. Disconnect suspect IAT or ECT sensor. Run engine at 2000 RPM for 2 minutes. Measure resistance between sensor signal circuit and SIG RTN circuit at suspect sensor. If resistance is within specification, replace PCM and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). See «ECT & IAT SENSOR SPECIFICATIONS»(ref-23598-S39965049042002011500000) table. If sensor is not within specification, replace sensor and repeat QUICK TEST. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 4) to step 10). No test procedures have been omitted.
5. Step 10) Code 113 Or 118: Induce Opposite Code (Code 112 Or 117) Code 113 (IAT) or 118 (ECT) indicates corresponding sensor signal is greater than self-test maximum. Maximum signal voltage for ECT sensor and IAT sensor is 4.6 volts. Possible causes for excess voltage signals are: Open circuit in wiring harness (IAT or ECT). Faulty connection. Faulty sensor. Faulty PCM. Turn ignition off. Disconnect suspect IAT or ECT sensor. Connect a jumper wire between sensor signal terminal and SIG RTN terminal at sensor wiring harness connector. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If an error message is displayed, remove jumper wire immediately and go to step 12). If Code 112 or 117 is displayed, remove jumper wire and replace suspect sensor. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If Code 112 or 117 is not displayed, remove jumper wire and go to next step.
6. Step 11) Check Continuity Of Sensor Signal & SIG RTN Circuits Turn ignition off. Ensure suspect IAT or ECT sensor is disconnected. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance of sensor signal circuit between test pin No. 7 (ECT sensor) or test pin No. 25 (IAT sensor) at breakout box and signal terminal at sensor wiring harness connector. Also, measure resistance between test pin No. 46 and SIG RTN circuit at sensor wiring harness connector. If both readings are less than 5 ohms, replace PCM and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If either reading is 5 ohms or more, repair open circuit. Remove breakout box and repeat QUICK TEST.
7. Step 12) Check For Short To VREF In Sensor Signal Circuit Turn ignition off. Ensure suspect IAT or ECT sensor is disconnected. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between test pin No. 26 (VREF) and No. 7 (ECT sensor) or test pin No. 25 (IAT sensor) at breakout box. If resistance is more than 10,000 ohms, replace PCM and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If resistance is less than 10,000 ohms, repair short to VREF. Remove breakout box and repeat QUICK TEST. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 12) to step 20). No test procedures have been omitted.
8. Step 20) Code 112 Or 117: Induce Opposite Code (113 Or 118) Code 112 (IAT) or 117 (ECT) indicates sensor signal is less than self-test minimum. Minimum signal for IAT sensor and ECT sensor is 0.2 volt. Possible causes for this fault are: Circuit grounded in wiring harness (IAT or ECT). Faulty sensor. Faulty PCM. Faulty connection. Turn ignition off. Disconnect wiring harness connector from suspect IAT or ECT sensor. Check for damaged pins, corrosion and loose wires. Repair as necessary. Repeat KOEO SELF-TEST. If Code 113 or 118 is present, replace sensor and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If Code 113 or 118 is not present, go to next step.
9. Step 21) Check VREF Circuit Voltage At TP Sensor Turn ignition off. Ensure wiring harness connector from suspect IAT or ECT sensor is disconnected. Disconnect TP sensor. Turn ignition on. Measure voltage between VREF and SIG RTN at TP sensor harness connector. If voltage is not 4-6 volts, go to CIRCUIT TEST C. If voltage is 4-6 volts, connect TP sensor and go to next step.
10. Step 22) Check Sensor Signal For Short To Ground Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between test pin No. 7 (ECT) or 25 (IAT) and pins No. 40, 46 and 60. If any reading is less than 10,000 ohms, repair short circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If all readings are 10,000 ohms or more, replace PCM and repeat QUICK TEST. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 22) to step 90). No test procedures have been omitted.
11. Step 90) Continuous Memory Code 112, 113, 117 Or 118 A Continuous Memory Code 113 or 118 indicates sensor signal is greater than self-test maximum of 4.6 volts. Code is set during normal driving conditions. Continuous Memory Code 112 or 117 indicates sensor signal is less than self-test minimum of 0.2 volt. Code is set during normal driving conditions. Possible causes for these faults are: Faulty sensor. Open or grounded circuit in harness. Faulty PCM. Enter KOEO wiggle test mode. See «CONTINUOUS MONITOR MODE (WIGGLE TEST)»(ref-23598-S23726050792001010300000) under QUICK TEST. Observe analog voltmeter or scan tester for indication of fault while tapping sensor lightly and wiggling sensor connector. If fault is not indicated, go to next step. 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»(ref-23598-S07232509482001010300000). SENSOR CODES Sensor Continuous Memory Code IAT 112 Or 113 ECT 117 Or 118
12. Step 91) Check EEC-IV Wiring Harness While in «CONTINUOUS MONITOR MODE (WIGGLE TEST)»(ref-23598-S23726050792001010300000), observe analog voltmeter or scan tester while wiggling and bending wiring harness, a small section at a time, working from sensor connector toward instrument panel. Also check harness from instrument panel to PCM. If fault is indicated, isolate fault and repair as necessary. Clear continuous memory, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If no fault is found, go to next step.
13. Step 92) Inspect PCM & Wiring Harness Connectors Turn ignition off. Disconnect PCM 60-pin connector and suspect IAT or ECT sensor connector. Inspect both connectors for damaged pins, corrosion and loose wires. Repair as necessary, repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If connectors/terminals okay, fault cannot be duplicated now, see INTERMITTENTS in the «TESTS W/O CODES - 5.8L EEC-IV»(ref-23634) article. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 92) to step 100). No test procedures have been omitted.
14. Step 100) Continuous Memory Code 338 A Continuous Memory Code 338 indicates cooling system has not reached normal operating temperature. Possible causes for this fault are: Thermostat stuck open. Coolant leaks. Water pump gasket leak. Head gasket leak. Check for coolant leaks and repair cooling system as necessary. Clear continuous memory, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If no coolant leaks are found, check thermostat. Repair as necessary.
15. Step 101) Continuous Memory Code 339 A Continuous Memory Code 339 indicates cooling system has overheated. Possible causes for this fault are: Coolant level low. Thermostat stuck closed. Coolant system clogged. Radiator fins clogged. Water pump damaged or worn. Radiator cap damaged or worn. Cooling fan defective or worn. Check and repair cooling system as necessary. Clear continuous memory, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000).

Perform this test when directed by QUICK TEST or CIRCUIT TEST S. To prevent replacement of good components, be aware the following non-EEC related areas may be cause of problem

1. Unusually high or low atmospheric barometric pressure.
2. Kinked or blocked vacuum lines.
3. Engine mechanical condition (compression, timing, etc.).

This test is intended to diagnose the following

1. MAP sensor.
2. Wiring harness circuits (VREF, MAP SIG and SIG RTN).
3. MAP vacuum line.
4. Powertrain Control Module (PCM).

MAP Sensor Circuits, Connector Terminals & Tester Hookup. Scheme 226

TEST PIN NO. 26 (VREF) WIRE COLOR IDENTIFICATION

TEST PIN NO. 45 (MAP SIG) WIRE COLOR IDENTIFICATION

TEST PIN NO. 46 (SIG RTN) WIRE COLOR IDENTIFICATION

MAP SENSOR SPECIFICATIONS

1. Step 1) Code 126: Check Power To MAP Sensor Code 126 indicates MAP sensor is out of self-test voltage range (1.4-1.6 volts). Following are possible causes of this code: Vacuum trapped at MAP sensor. MAP signal circuit open between sensor and PCM. MAP signal circuit shorted to VREF, SIG RTN or GND. VREF circuit open at sensor. SIG RTN circuit open at sensor. Faulty MAP sensor. Faulty PCM. Turn ignition off. Disconnect MAP sensor from wiring harness. Connect MAP tester between wiring harness and MAP sensor. Connect banana plugs of tester into DVOM. Set DVOM on 20-volt scale. Turn ignition on. If Red light or no light is on, VREF is out of range. Go to next step. If Green light is on, VREF is okay. Go to step 3).
2. Step 2) Check Power At Sensor Wiring Harness Connector Disconnect MAP sensor. Turn ignition on. If Green light on tester is lit, replace MAP sensor and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If Green light is not on, remove MAP tester. Connect MAP sensor, and go to CIRCUIT TEST C.
3. Step 3) Check MAP Sensor Output With MAP 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 tester and go to next step. See «MAP SENSOR VOLTAGE OUTPUT»(ref-23598-S29136172862002011500000) table. If output reading is not within range, remove MAP tester and go to step 5).

If possible, measure output voltage of several known-good MAP sensors on available vehicles. Average voltage reading will be typical for location and time of testing.

MAP SENSOR VOLTAGE OUTPUT

1. Step 4) Check MAP SIG Circuit Continuity Turn ignition off. Disconnect MAP sensor wiring harness connector. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between MAP SIG terminal at sensor wiring harness connector and test pin No. 45. If resistance is less than 5 ohms, replace PCM and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If resistance is 5 ohms or more, repair open MAP SIG circuit and repeat QUICK TEST.
2. Step 5) Check MAP SIG Circuit For Short To VREF, SIG RTN & Ground Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Disconnect wiring harness at MAP sensor. Measure resistance between test pin No. 45 and test pins No. 26, 40, 46 and 60 at breakout box. If any reading is less than 10,000 ohms, repair short circuit. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If all readings are 10,000 ohms or more, replace MAP sensor. Repeat QUICK TEST. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 5) to step 7). No test procedures have been omitted.
3. Step 7) KOER Code 126: Check For EGR-Related Codes Code 126 indicates MAP signal is out of self-test range during «KOER SELF-TEST»(ref-23598-S29311478132001010300000) . Possible causes for this code are: Excess EGR flow. Damaged or mis-routed MAP sensor vacuum hose. Faulty MAP sensor. If Code 326, 327, 328, 332, 334, 336 or 337 is present, perform applicable CIRCUIT TEST. See «DIAGNOSTIC TROUBLE CODE REFERENCE CHART»(ref-23598-S35260139562001010300000) . If codes are not present, go to next step.
4. Step 8) Check MAP Sensor Operation Turn ignition off. Disconnect vacuum hose from MAP sensor. Connect vacuum pump to MAP sensor, and apply 18 in. Hg. If MAP sensor does not hold vacuum, replace sensor and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If MAP sensor holds vacuum, release vacuum and go to next step.
5. Step 9) Attempt To Eliminate Code 126 Plug MAP sensor vacuum supply hose. Start engine, and run it at 1400-1600 RPM. Slowly apply 15 in. Hg to MAP sensor. Perform «KOER SELF-TEST»(ref-23598-S29311478132001010300000) . Check for Code 126. Disregard any other codes at this time. If Code 126 is still present, replace MAP sensor. If Code 126 is not present, inspect MAP sensor vacuum supply hose. 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.
6. Step 10) Code 129: Repeat Dynamic Response Test Code 129 indicates MAP sensor output did not change enough during dynamic response test. Possible causes for this code are: System failed to detect Wide Open Throttle (WOT). Damaged or mis-routed MAP sensor vacuum hose. Faulty MAP sensor. Repeat «KOER SELF-TEST»(ref-23598-S29311478132001010300000) . Ensure complete WOT is performed during dynamic response portion of test. If KOER Code 129 is still present, go to next step. If code is not present, service any other codes as necessary.
7. Step 11) Continuous Memory Code 128 Continuous Memory Code 128 indicates MAP sensor vacuum has not changed more than 2 in. Hg during normal vehicle operation. Possible causes for this code are: MAP sensor vacuum hose is improperly routed, blocked or is leaking. MAP sensor is leaking. Check vacuum lines for correct routing. Refer to Vehicle Emission Control Identification (VECI) decal. Check for loose connections, kinks and blockage. Repair vacuum lines as necessary. If vacuum lines are okay, go to next step.
8. Step 12) Check MAP Sensor Operation Turn ignition off. Disconnect vacuum supply hose from MAP sensor. Attach 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 and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
9. Step 13) Verify Vacuum To MAP Sensor Decreases During Dynamic Response Test Turn ignition off. Use a "T" fitting to install a vacuum gauge in MAP sensor vacuum hose. Perform «KOER SELF-TEST»(ref-23598-S29311478132001010300000) while observing vacuum gauge. If vacuum decreases by more than 10 in. Hg during dynamic response test, replace MAP sensor and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If vacuum does not decrease by more than 10 in. Hg, EEC-IV system is okay. Check for engine mechanical problems affecting engine vacuum. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 13) to step 90). No test procedures have been omitted.
10. Step 90) Continuous Memory Code 126 Code 126 indicates MAP sensor was out of self-test range (1.4-1.6 volts) during normal driving conditions. Possible causes for this code are: Faulty MAP sensor. Faulty wiring harness or connectors. Enter «CONTINUOUS MONITOR MODE (WIGGLE TEST)»(ref-23598-S23726050792001010300000) . Observe test equipment while performing following: Connect a vacuum pump to MAP sensor. Slowly apply 25 in. Hg to sensor. Slowly bleed off vacuum from sensor. Lightly tap on sensor (to simulate road shock). Wiggle sensor connector. If a fault is indicated, disconnect sensor and inspect connectors. Repair if necessary. If connectors are okay, replace MAP sensor. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If a fault is not indicated, go to next step.
11. Step 91) Check EEC-IV Wiring Harness Stay in wiggle test. Observe analog VOM or scan tester for indication of fault while bending or wiggling small sections of harness from sensor connector to firewall, and from firewall to PCM. If fault is indicated, isolate fault in harness and repair as necessary. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If no fault is indicated, go to next step.
12. Step 92) Check PCM & Wiring Harness Connectors Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. If connectors and terminals are okay, fault cannot be duplicated at this time. Testing is complete. Refer to INTERMITTENTS in the «TESTS W/O CODES - 5.8L EEC-IV»(ref-23634) article.

Perform this test only when directed by QUICK TEST . This test is intended to diagnose the following

1. TP sensor.
2. Wiring harness circuits (TP, SIG RTN and VREF).
3. Powertrain Control Module (PCM).

Normal range of throttle angle measurement for TP sensor is 0-85 degrees. To pass QUICK TEST procedure, range of throttle rotation (in degrees) must be within 3 percent of specification. see scheme 16

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

1. Idle speed.
2. Binding throttle shaft or linkage.
3. Choke cam adjustment (if equipped).
4. TP sensor not seated.

TEST PIN NO. 26 (VREF) WIRE COLOR IDENTIFICATION

TEST PIN NO. 46 (SIG RTN) WIRE COLOR IDENTIFICATION

TEST PIN NO. 47 (TP) WIRE COLOR IDENTIFICATION

1. Step 1) KOER Code 121: Check For Other Codes KOER Code 121 indicates TP sensor rotational setting may be out of self-test range. Possible causes for this fault are: Binding throttle linkage. TP sensor not seated correctly. Faulty TP sensor. Faulty Powertrain Control Module (PCM). Perform «KOER SELF-TEST»(ref-23598-S29311478132001010300000). Check for Code 327. If Code 327 is present with Code 121, service Code 327 and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If Code 327 is not present, go to next step.
2. Step 2) KOEO Code 121: Check For Binding Throttle Plate Inspect throttle body for binding. If throttle body is binding, check for binding throttle or cruise control linkage, vacuum line or harness interference, etc. Repair as necessary, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If no mechanical problem is found, go to next step.
3. Step 3) Code 123: Attempt To Generate Code 122 Code 123 indicates TP sensor signal is greater than self-test maximum value. Possible causes for this fault are: TP sensor not seated properly. Faulty TP sensor. Short circuit to power. Faulty PCM. Turn ignition off. Disconnect TP sensor wiring harness connector. Inspect for damaged pins, corrosion and loose wires. Repair as necessary. Repeat «KOEO SELF-TEST»(ref-23598-S28031615042001010300000). Ignore all other codes at this time. If Code 122 is not displayed, go to step 5). If Code 122 is displayed, go to next step.
4. Step 4) Check VREF Circuit Voltage Turn ignition on. Measure voltage between VREF and SIG RTN terminals at TP sensor wiring harness connector. If voltage is 4-6 volts, replace TP sensor and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If voltage is not 4-6 volts, reconnect sensor and go to CIRCUIT TEST C.
5. Step 5) Check TP Circuit For Short To Power Turn ignition off. Leave TP sensor disconnected. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between test pin No. 47 and test pins No. 26 and 57. If either reading is less than 10,000 ohms, repair short circuit in wiring harness and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If both readings are 10,000 ohms or more, replace PCM and repeat QUICK TEST. NOTE: A break in step numbering sequence occurs at this point.Procedure skips from step 5) to step 10). No test procedures have been omitted.
6. Step 10) Code 122: Attempt To Generate Code 121 Or 123 Code 122 indicates TP signal is less than minimum self-test value. see scheme 16 Possible causes for this fault are: TP sensor not installed correctly. Faulty TP sensor. Open circuit in wiring harness. Grounded circuit in wiring harness. Faulty PCM. Turn ignition off. Disconnect TP sensor from harness. Install a jumper wire between VREF and TP terminals at TP sensor wiring harness connector. Perform «KOEO SELF-TEST»(ref-23598-S28031615042001010300000). If no codes are generated, remove jumper wire and go to step 13). If only Code 122 is present, remove jumper wire and go to next step. If Code 121 or 123 is present, replace TP sensor and repeat «QUICK TEST»(ref-23598-S07232509482001010300000).
7. Step 11) Check VREF Circuit Voltage Turn ignition on. Measure voltage between VREF and SIG RTN terminals at TP sensor wiring harness connector. If voltage is not 4-6 volts, reconnect all components and go to CIRCUIT TEST C. If voltage is 4-6 volts, go to next step.
8. Step 12) Check TP Sensor Circuit Continuity Turn ignition off. Leave TP sensor disconnected. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between TP terminal at TP sensor harness connector and test pin No. 47. If resistance is 5 ohms or more, repair open circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If resistance is less than 5 ohms, go to next step.
9. Step 13) Check TP Circuit For Short To Ground Turn ignition off. Leave TP sensor disconnected. With breakout box installed, measure resistance between test pin No. 47 and test pins No. 40, 46 and 60. If any reading is less than 10,000 ohms, repair short circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If all readings are 10,000 ohms or more, replace PCM and repeat QUICK TEST. NOTE: A break in step numbering sequence occurs at this point.Procedure skips from step 13) to step 20). No test procedures have been omitted.
10. Step 20) Code 167: Repeat Dynamic Response Test KOER Code 167 indicates TP sensor did not exceed 25 percent rotation during dynamic response portion of «KOER SELF-TEST»(ref-23598-S29311478132001010300000). A complete Wide Open Throttle (WOT) must be performed during dynamic response portion of test. Perform «KOER SELF-TEST»(ref-23598-S29311478132001010300000). Ensure WOT is completed during dynamic response portion of test. If Code 167 is still present, go to next step. If code is not present, system is unable to duplicate Code 167 at this time. Service any other KOER codes. If no other codes are present, testing is complete.
11. Step 21) Check TP Sensor Movement During Dynamic Response Test Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM connected. Set DVOM on 20-volt scale. Connect DVOM between test pins No. 46 and 47 at breakout box. Perform «KOER SELF-TEST»(ref-23598-S29311478132001010300000) and ensure proper WOT is completed during dynamic response test. If DVOM voltage exceeds 3.5 volts during dynamic response test, replace PCM and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If voltage does not exceed 3.5 volts, ensure TP sensor is correctly installed and adjusted. If TP sensor is correctly installed and adjusted, replace TP sensor. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000). NOTE: A break in step numbering sequence occurs at this point.Procedure skips from step 21) to step 90). No test procedures have been omitted.
12. Step 90) Continuous Memory Code 123 This test monitors TP sensor under simulated road conditions. Enter wiggle test. See «CONTINUOUS MONITOR MODE (WIGGLE TEST)»(ref-23598-S23726050792001010300000) under QUICK TEST. Connect Analog Volt-Ohmmeter (VOM) or diagnostic tester to STO terminal of Data Link Connector (DLC). While slowly opening throttle to WOT, observe VOM or diagnostic tester for indication of fault. Slowly bring throttle to closed position. Lightly tap TP sensor and wiggle harness connector. This test checks for open or shorted TP sensor and wiring harness. If no fault is indicated, go to step 92). If fault is indicated, go to next step.
13. Step 91) Measure TP Circuit Voltage While Exercising TP Sensor Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM connected. Stay in wiggle test (as in previous step). Connect Analog Volt-Ohmmeter (VOM) between test pins No. 47 and 46. Set VOM on 20-volt scale. With ignition on and engine off, observe VOM and repeat step 90). If fault occurs at less than 4.25 volts, inspect TP sensor connectors and terminals. If connectors and terminals are okay, replace TP sensor, clear codes and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If fault does not occur at less than 4.25 volts, TP sensor over-travel may have caused Continuous Memory Code 123. TP sensor is okay; go to next step to check wiring harness.
14. Step 92) Check EEC-IV Wiring Harness While in wiggle test, bend and shake small sections of wiring harness from TP sensor wiring harness connector to firewall and from firewall to PCM while observing analog voltmeter or scan tester. If fault is indicated, isolate fault in wiring and repair as necessary. Clear codes, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If no fault is indicated, go to next step.
15. Step 93) Check PCM & Harness Connectors Turn ignition off. Disconnect PCM 60-pin connector from breakout box, inspect for damaged pins, corrosion and loose wires. Repair as necessary. Clear codes from PCM memory, repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If connectors and terminals are okay, fault cannot be duplicated at this time. Continuous Memory Code 123 testing is complete.
16. Step 94) Continuous Memory Code 122 Enter wiggle test. See «CONTINUOUS MONITOR MODE (WIGGLE TEST)»(ref-23598-S23726050792001010300000) under QUICK TEST. Connect VOM or diagnostic tester to STO terminal of Data Link Connector (DLC). Observe VOM or diagnostic tester for indication of fault while performing the following: Slowly open throttle to WOT. Slowly bring throttle to closed position. Lightly tap TP sensor and wiggle connector. If fault is indicated, disconnect TP sensor. Inspect connectors and terminals. Repair as necessary. If connectors and terminals are okay, replace TP sensor. Clear codes from PCM memory, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If no fault is indicated, go to next step.
17. Step 95) Check EEC-IV Wiring Harness Stay in wiggle test (as in previous step). Bend, wiggle and shake small sections of wiring harness from TP sensor wiring harness connector to firewall and from firewall to PCM while observing analog voltmeter or scan tester. If fault is indicated, isolate fault in wiring and repair as necessary. Clear codes from PCM memory, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If no fault is indicated, go to next step.
18. Step 96) Check PCM & Harness Connectors Turn ignition off. Disconnect PCM 60-pin connector, and check for damaged pins, corrosion and loose wires. Repair as necessary. Clear codes from PCM memory, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If connectors and terminals are okay, fault cannot be duplicated at this time. Continuous Memory Code 122 testing is complete.

EVR solenoid receives variable input from PCM, which allows it to control vacuum level to EGR valve. Vacuum not used by EGR is routed to EVR solenoid and vented to atmosphere.

Perform this test when instructed by QUICK TEST or if directed by other test procedures. To prevent replacement of good components, be aware a damaged EGR valve may be cause of problem. This CIRCUIT TEST is intended to diagnose the following

1. EVP sensor.
2. EVR solenoid.
3. EGR valve assembly.
4. Powertrain Control Module (PCM).
5. EGR and EVR vacuum lines.
6. Wiring harness circuits (VREF, EVP, SIG RTN, EVR and VPWR).

EVP Sensor & EVR Solenoid Connector Terminals. Scheme 227

TEST PIN NO. 26 (VREF) WIRE COLOR IDENTIFICATION

TEST PIN NO. 27 (EVP) WIRE COLOR IDENTIFICATION

TEST PIN NO. 33 (EVR) WIRE COLOR IDENTIFICATION

TEST PIN NO. 46 (SIG RTN) WIRE COLOR IDENTIFICATION

Note. EVR sensor is preloaded when attached to EGR valve. Valve failure causing EVR sensor to lose preload may set Code 327.

1. Step 1) Code 327: Generate Code 337 - Code 327 indicates EVP sensor signal is less than self-test minimum of 0.2 volt. Possible causes for this fault are: Faulty EVP sensor. Faulty EGR valve. Open or grounded harness. Faulty PCM. Turn ignition off. Disconnect EVP sensor connector. Install a jumper wire between VREF terminal and EVP terminal at EVP sensor wiring harness connector. Repeat «KOEO SELF-TEST»(ref-23598-S28031615042001010300000) and KOER SELF-TEST. Check for Code 337. Ignore all other codes at this time. If Code 337 is present, replace EVP sensor and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If Code 337 is not present, remove jumper wire and go to next step. If no codes are present, remove jumper wire and go to step 4).
2. Step 2) Check VREF Circuit Voltage Disconnect EVP sensor. Turn ignition on. Measure voltage between VREF terminal and SIG RTN terminal at EVP sensor wiring harness connector. If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, go to CIRCUIT TEST C.
3. Step 3) Check EVP Circuit Resistance Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between EVP terminal at EVP sensor wiring harness connector and test pin No. 27 at breakout box. If resistance 5 ohms or more, repair open circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If resistance is less than 5 ohms, go to next step.
4. Step 4) Check EVP Circuit For Short To Ground Ensure ignition is off and EVP sensor is disconnected. Measure resistance between test pin No. 27 and test pins No. 40, 46 and 60 at breakout box. If any reading is less than 10,000 ohms, repair short circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If all readings are 10,000 ohms or more, replace PCM and repeat QUICK TEST.
5. Step 5) Code 337: Generate Code 327 Code 337 indicates EVP sensor signal is greater than self-test maximum of 4.81 volts. Possible causes for this fault are: Faulty EVP sensor. Faulty PCM. Short to power in vehicle harness. Open SIG RTN circuit. Turn ignition off. Disconnect EVP sensor. Perform KOEO SELF-TEST and «KOER SELF-TEST»(ref-23598-S29311478132001010300000) . Check for Code 327. Ignore all other codes at this time. If Code 327 is present, go to next step. If Code 327 is not present, go to step 7).
6. Step 6) Check VREF Circuit Voltage Turn ignition on. Measure voltage between VREF terminal and SIG RTN terminal at EVP sensor wiring harness connector. If voltage is 4-6 volts, replace EVP sensor. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If voltage is not 4-6 volts, go to CIRCUIT TEST C.
7. Step 7) Check EVP Circuit For Short To Power Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between test pin No. 27 and test pins No. 26 and 57 at breakout box. If either reading is less than 10,000 ohms, repair short circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If both readings are 10,000 ohms or more, replace PCM and repeat QUICK TEST. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 7) to step 10). No test procedures have been omitted.
8. Step 10) Code 558: Check EVR Solenoid Resistance Code 558 indicates fault in EVR solenoid circuit. Possible causes for this fault are: Faulty EVR solenoid. Faulty PCM. Shorted or open harness. Turn ignition off. Disconnect EVR solenoid connector. Measure resistance across EVR solenoid terminals. If resistance is not 20-70 ohms, replace EVR solenoid assembly and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If resistance is 20-70 ohms, go to next step.
9. Step 11) Check VPWR Circuit Voltage Disconnect EVR solenoid. Turn ignition on. Measure voltage between negative battery terminal and VPWR terminal at EVR solenoid wiring harness connector. If voltage is less than 10.5 volts, repair open VPWR circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If voltage is 10.5 volts or more, go to next step.
10. Step 12) Check EVR Circuit Continuity Turn ignition off. Disconnect EVR solenoid. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between EVR terminal at EVR solenoid wiring harness connector and test pin No. 33. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
11. Step 13) Check EVR Circuit For Short To Power Or Ground Ensure ignition is off. Measure resistance between test pin No. 33 and pins No. 37, 40, 46, 57 and 60 at breakout box. If any reading is less than 10,000 ohms, repair short circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If code is repeated, replace EVR solenoid. If all readings are 10,000 ohms or more, replace PCM. Remove breakout box, and repeat QUICK TEST. NOTE: A break in step numbering sequence occurs at this point.Procedure skips from step 13) to step 20). No test procedures have been omitted.
12. Step 20) Code 334: Check For Code 558 Code 334 indicates EGR valve and/or EVP is not fully seated in closed position. EVP voltage signal, in closed position, is greater than self-test maximum of 0.67 volt. Because of EVP sensor preload, determining whether EGR valve is seated or EVP sensor contacts EGR valve stem is difficult. Possible causes for this fault are: Poor contact in EVP sensor circuit. EGR valve not seated. Faulty EGR valve. Faulty EVP sensor. Faulty EVP solenoid. Faulty PCM. Perform «KOEO SELF-TEST»(ref-23598-S28031615042001010300000) . If Code 558 is present, return to step 10). If Code 558 is not present, go to next step.
13. Step 21) Perform SELF-TEST Without EGR Remove and plug vacuum line to EGR valve. Perform KOEO SELF-TEST and «KOER SELF-TEST»(ref-23598-S29311478132001010300000) . If Code 334 is still present, go to next step. If Code 334 is not present, check EVR solenoid for obstructions. If no obstructions are present, replace EVR solenoid.
14. Step 22) Check EGR Valve & EVP Sensor Operation Turn ignition off. Disconnect EVP sensor. Inspect harness and connector, and service if necessary. Remove and plug vacuum hose to EGR valve. Install vacuum gauge at EGR valve vacuum hose. Operate EGR valve by applying/releasing vacuum. Install vacuum hose to EGR valve and wiring harness connector to EVP sensor. Repeat «KOEO SELF-TEST»(ref-23598-S28031615042001010300000) and «KOER SELF-TEST»(ref-23598-S29311478132001010300000) . If Code 334 is present, go to next step. If Code 334 is not present, original fault was caused by poor continuity at EVP sensor connector or binding/sticking of EGR valve stem.
15. Step 23) Check EVP Signal Voltage Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV). Connect PCM to breakout box. Turn ignition on. Measure voltage between test pins No. 27 and 46 at breakout box. If voltage is 0.67 volt or less, replace PCM and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If voltage is more than 0.67 volt, go to next step.
16. Step 24) EGR Valve/EVP Sensor Fault Isolation Remove EGR valve and EVP sensor. Inspect valve and sensor for binding, carbon deposits, excessive wear and damage. Repair or replace as necessary. Install EGR valve and EVP sensor. Perform «KOEO SELF-TEST»(ref-23598-S28031615042001010300000) and «KOER SELF-TEST»(ref-23598-S29311478132001010300000) . If Code 334 is still present, replace EGR valve. If Code 334 is not present, testing is complete.
17. Step 25) Code 328: Check EVP Sensor & EGR Valve Operation Code 328 indicates EVP sensor is lower than normal (0.24 volt) in closed position. Possible causes for this fault are: Faulty EGR valve. Faulty EVP sensor. Faulty PCM. Poor continuity in EVP sensor circuit. Turn ignition off. Disconnect EVP sensor wiring harness connector. Inspect harness/connector, and service as necessary. Remove EGR valve vacuum hose. Attach vacuum pump to EGR valve. Operate EGR valve by applying/releasing vacuum. Install vacuum hose to EGR valve and wiring harness connector to EVP sensor. Repeat «KOEO SELF-TEST»(ref-23598-S28031615042001010300000) and «KOER SELF-TEST»(ref-23598-S29311478132001010300000) . If Code 328 is not present, original fault was caused by poor continuity at EVP sensor connector or binding/sticking of EGR valve stem. If Code 328 is present, go to next step.
18. Step 26) Check EVP Signal Voltage Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV). Connect PCM to breakout box. Remove and plug EGR valve vacuum hose. Connect vacuum pump to EGR valve vacuum hose. Turn ignition on. Measure voltage between test pins No. 27 and 46 at breakout box while performing following: apply 6 in. Hg to EGR valve and slowly bleed vacuum completely off. If voltage does not drop to less than 0.24 volt, replace PCM and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If voltage drops to less than 0.24 volt, go to next step.
19. Step 27) Substitute EVP Sensor On Original EGR Valve Turn ignition off. Install a known-good EVP sensor on original EGR valve. Ensure all hoses and electrical connectors are attached. Perform «KOEO SELF-TEST»(ref-23598-S28031615042001010300000) and KOER SELF-TEST. If Code 328 is present, check EGR valve for mechanical malfunction. If Code 328 is not present, replace original EVP sensor. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . NOTE: A break in step numbering sequence occurs at this point.Procedure skips from step 27) to step 40). No test procedures have been omitted.
20. Step 40) KOER Code 332: Check Vacuum At EGR KOER Code 332 indicates EVP sensor input did not change after PCM signaled operation of EGR. Possible causes for this fault are: Leaking vacuum hose. Restricted vacuum hose. Restricted EVR solenoid. Faulty EVR solenoid. Faulty EVP sensor. Faulty EGR valve. Turn ignition off. Disconnect vacuum hose from EGR valve. Connect a vacuum gauge at open end of hose. Perform «KOER SELF-TEST»(ref-23598-S29311478132001010300000) while observing vacuum gauge. If vacuum reading is more than one in. Hg, remove vacuum gauge and go to step 43). If reading is one in. Hg or less, go to next step.
21. Step 41) Verify Vacuum Supply To EVR Solenoid Turn ignition off. Disconnect EVR solenoid vacuum hose. Install vacuum gauge at 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 line to EVR solenoid. Repair if necessary. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
22. Step 42) Check Vacuum Between EVR Solenoid & EGR Valve Check vacuum hose for cracks, loose connections, blockage and kinks. Repair or replace vacuum hose if necessary, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If vacuum hose is okay, check EVR solenoid filter for obstructions. Replace if necessary. If filter is okay, replace EVR solenoid. After repairs are made, repeat QUICK TEST.
23. Step 43) Check EVP Sensor & EGR Valve Operation Turn ignition off. Disconnect EVP sensor. Inspect connector and harness for damaged pins, corrosion and loose wires. Repair as necessary. Remove vacuum hose from EGR valve. Connect vacuum pump to EGR valve. Operate EGR valve operation by applying and releasing vacuum. Connect vacuum line to EGR valve. Connect wiring harness connector to EVP sensor. Repeat «KOER SELF-TEST»(ref-23598-S29311478132001010300000) . If Code 332 is still present, go to next step. If Code 332 is not present, original code was set either by poor continuity at EVP sensor connector or sticking EGR valve. Test is complete.
24. Step 44) Verify EGR Valve Vacuum Control Turn ignition off. Install tachometer. Remove Idle Air Control (IAC) wiring harness connector. Remove and plug vacuum hose from EGR valve. Start engine, and allow it to idle with transmission in Neutral. Ensure idle speed is adjusted correctly. Connect vacuum pump to EGR valve. Slowly apply 5-10 in. Hg. If engine idle decreases more than 100 RPM with vacuum applied and returns to correct idle with vacuum released, replace EVP sensor. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If vacuum does not drop more than 100 RPM with vacuum applied, repair or replace EGR valve. Repeat QUICK TEST. NOTE: A break in step numbering sequence occurs at this point.Procedure skips from step 44) to step 90). No test procedures have been omitted.
25. Step 90) Continuous Memory Code 327, 328 Or 337 Continuous Memory Code 327 or 328 indicates EGR valve closed further than normal or EVP circuit failed with intermittent low voltage sometime during engine operation. Code 337 indicates EVP signal to PCM was above maximum self-test limit sometime during engine operation. Possible causes for these faults are: Obstructed vacuum valve. Faulty EVP sensor. Faulty EVP sensor. EGR valve. Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV). Connect PCM to breakout box. Turn ignition on. Connect DVOM between test pins No. 27 and 46 at breakout box. Wiggle wiring harness and lightly tap on EVP sensor. If voltage remains steady at .24-.67 volt, go to next step. If voltage is erratic or not within .24-.67 volt range, remove and inspect EVP sensor wiring harness connector. Repair or replace if necessary. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If sensor connector is okay, replace EVP sensor. Repeat QUICK TEST.
26. Step 91) Check Wiring Harness Turn ignition off. Connect DVOM between test pins No. 27 and 46 at breakout box. Observe DVOM for fault indication while wiggling and bending small sections of wiring harness near sensor, working from sensor toward dash panel. Wiggle and bend wiring harness from firewall to PCM. If fault is indicated, isolate fault and repair wiring harness. Clear codes, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If fault is not found, go to next step.
27. Step 92) Measure EVP Signal Voltage While Exercising EVP Sensor Remove and plug vacuum hose to EGR valve. Install vacuum gauge at EGR valve vacuum hose. Turn ignition on. Measure voltage between test pins No. 27 and 46 at breakout box while performing following: apply 5-10 in. Hg to EGR valve and slowly bleed off vacuum completely. If voltage steadily fluctuates between 0.24-4.81 volts, problem is intermittent and cannot be duplicated at this time. If voltage does not fluctuate between 0.24-4.81 volts, replace EVP sensor and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . NOTE: A break in step numbering sequence occurs at this point.Procedure skips from step 92) to step 110). No test procedures have been omitted.
28. Step 110) Continuous Memory Code 332 Code 332 indicates EGR valve did not open with engine at normal operating temperature and with EVR solenoid signal present sometime during engine operation. Possible causes of this fault are: Fault in vacuum line. Faulty EGR valve. Open or shorted EVR circuit. Turn ignition off. Disconnect vacuum hose at EGR valve. Connect vacuum pump to valve. Apply 10-20 in. Hg to EGR valve. If EGR valve opens and holds vacuum, go to next step. If EGR valve does not open and hold vacuum, service or replace EGR valve as necessary and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
29. Step 111) EVR Solenoid & Wiring Harness Check Turn ignition off. Disconnect and inspect vacuum hose between EVR solenoid and EGR valve. Replace hose as necessary. Connect EGR valve hose to vacuum gauge. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV). Connect PCM to breakout box and go to next step.
30. Step 112) Start engine, and allow it to idle. Connect jumper wire between test pins No. 33 and 40. Tap on EVR sensor and wiggle wiring harness while observing vacuum gauge. If vacuum gauge shows a sudden drop in vacuum, isolate cause and repair as necessary. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If vacuum gauge does not show a drop in vacuum, problem is intermittent and cannot be duplicated at this time. NOTE: A break in step numbering sequence occurs at this point.Procedure skips from step 112) to step 115). No test procedures have been omitted.
31. Step 115) Continuous Memory Code 334 Code 334 indicates EGR valve was open with engine idling at normal operating temperature. Possible causes for this fault are: Faulty EVP sensor. Faulty EVR solenoid. Faulty EGR valve. Turn ignition off. Disconnect vacuum hose from EGR valve. Connect EGR valve hose to vacuum gauge. Start engine, and allow it to idle. Tap EVR sensor and wiggle wiring harness while observing vacuum gauge. If vacuum gauge reading does not remain less than one in. Hg and/or has sudden vacuum increase, service or replace EVR solenoid. If vacuum gauge reading remains less than one in. Hg with no sudden increase, go to next step.
32. Step 116) EVR Solenoid Check Leave engine idling and vacuum gauge connected to EGR valve hose. Observe vacuum gauge while wiggling and bending small sections of wiring harness near EVR sensor, working from sensor toward dash panel. Wiggle and bend wiring harness from firewall to PCM. If vacuum gauge shows an increase in vacuum, isolate cause and repair as necessary. If vacuum gauge does not show an increase in vacuum, go to next step.
33. Step 117) Check EVR Signal At PCM Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV). Connect PCM to breakout box. Start engine, and allow it to idle. Connect DVOM between test pins No. 27 and 46 at breakout box. Wiggle wiring harness and lightly tap EVP sensor. If voltage is 0.67 volt or less, problem is intermittent and cannot be duplicated at this time. If voltage increases to more than 0.67 volt, remove and service EGR valve. If voltage is still more than 0.67 volt, replace EVP sensor. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . Testing is complete.

Perform this test when directed by QUICK TEST . This CIRCUIT TEST is intended to diagnose

1. PSOM output to PCM.
2. PSOM (+) and PSOM (-) wiring harness circuits.
3. PCM.

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

1. Cruise control system.
2. Rear anti-lock brake system.
3. Ring gear inside differential.
4. Instrumentation system.

Programmable Speedometer/Odometer Module (PSOM) Circuit Logic. Scheme 228

Programmable Speedometer/Odometer Module (PSOM) Circuit & Connector Terminals. Scheme 229

TEST PIN NO. 3 (PSOM +) WIRE COLOR IDENTIFICATION

TEST PIN NO. 6 (PSOM -) WIRE COLOR IDENTIFICATION

1. Step 1) Continuous Memory Code 452 Code 452 indicates PCM detected incorrect output from VSS sometime during vehicle operation. Following are possible causes of code: PSOM Output To PCM PSOM (+) And PSOM (-) Wiring Harness Circuits PCM Turn ignition off. Remove PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between test pins No. 3 and 6 at breakout box. If reading is 21,000-55,000 ohms, go to step 4). If resistance is not 21,000-55,000 ohms, go to next step.
2. Step 2) Check PSOM Circuit Continuity Ensure ignition is off. Disconnect PSOM wiring harness connector. Disconnect cruise control module. Measure resistance between test pin No. 3 at breakout box and PSOM (+) circuit at PSOM wiring harness connector. Also, measure resistance between test pin No. 6 at breakout box and PSOM (-) circuit at PSOM wiring harness connector. If any reading is 5 ohms or more, repair open circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If both readings are less than 5 ohms or less, go to next step.
3. Step 3) Check For Short Circuit Ensure ignition is off. Measure resistance between test pin No. 3 and test pins No. 6, 37 and 40 at breakout box. If any reading is 10,000 ohms or less, repair short circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If all readings are more than 10,000 ohms, go to next step.
4. Step 4) Check Rear Anti-Lock Brake Sensor (RABS) Turn ignition off. Disconnect RABS connector. Measure resistance between sensor terminals. If resistance is not 1300-1550 ohms, replace RABS and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If resistance is 1300-1550 ohms, go to next step.
5. Step 5) Check PSOM Output Voltage Turn ignition off. Connect PCM to breakout box. Connect wiring harness connector to PSOM. Set DVOM on 20-volt AC scale. Start engine, and warm it to normal operating temperature. Using an assistant, measure voltage between test pins No. 3 and 6 while gradually increasing vehicle speed to 50 MPH. If maximum voltage is 4 volts or less, fault is in instrument cluster. If maximum voltage is more than 4 volts, replace PCM.

Perform this test when directed by QUICK TEST . This test is intended to diagnose a faulty BOO switch circuit or PCM. To prevent replacement of good components, be aware following non-EEC related areas may be at fault

1. Brakelight bulb.
2. Brakelight switch or brakelight fuse.

BOO Switch Circuit. Scheme 230

TEST PIN NO. 2 (BOO) WIRE COLOR IDENTIFICATION

1. Step 1) Code 536: Verify Brake Pedal Was Depressed Code 536 indicates that when brake pedal is applied during «KOER SELF-TEST»(ref-23598-S29311478132001010300000) , BOO signal did not cycle high and low. Possible causes for this fault are: Brake pedal not applied during self-test. Brake pedal applied during entire self-test. Open brakelight circuit. Short to ground or power. Faulty Powertrain Control Module (PCM). If brake was not applied during «KOER SELF-TEST»(ref-23598-S29311478132001010300000) , repeat test. Depress and release brake pedal only once during test. If pedal was depressed, go to next step. NOTE: On some models it is necessary to depress and release brake pedal after the dynamic response code, but before the brief Wide Open Throttle (WOT).
2. Step 2) Check Brakelight Operation With ignition on, check operation of brakelights. If brakelights operate normally, go to next step. If brakelights do not operate, go to step 4). If brakelights are always on, go to step 5).
3. Step 3) Check For BOO Switch Circuit Cycling Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure voltage between test pin No. 2 and test pin No. 40 while applying and releasing brake. If voltage cycles, replace PCM and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If voltage does not cycle, repair open BOO switch circuit between PCM and BOO switch connection to brakelight circuit. Repeat QUICK TEST.
4. Step 4) Check For Power To Brakelight Switch Ensure related fuses and brakelight bulbs are in good condition. Turn ignition off. Disconnect brakelight switch (located on brake pedal). Measure voltage between B+ input to brakelight switch and ground. If voltage is more than 10 volts, check condition of brakelight switch. If brakelight switch is okay, repair open circuit between brakelight switch and brakelight ground. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If voltage is 10 volts or less, repair open B+ circuit to brakelight switch and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
5. Step 5) Verify Brakelight Switch Is Not Always Closed Turn ignition off. Disconnect brakelight switch (located on brake pedal). Turn ignition on. If brakelights are still on, go to next step. If brakelights are not on, verify correct installation of brakelight switch. If installation is okay, replace brakelight switch and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
6. Step 6) Check For Short To Power In PCM Turn ignition off. Disconnect PCM. Turn ignition on. Check brakelights. If brakelights are on, go to next step. If brakelights are not on, replace PCM and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
7. Step 7) Check For Short To Power In Shift Lock Actuator Turn ignition off. Ensure PCM and brakelight switch are disconnected. Disconnect shift lock actuator, cruise control module and ABS module (if equipped). Turn ignition on. If brakelights are still on, repair short to power in BOO or STOPLAMP circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If brakelights are not on, repair short circuit in shift lock actuator circuit, cruise control system circuit or ABS circuit. Repeat QUICK TEST. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 7) to step 90). No test procedures have been omitted.
8. Step 90) Continuous Memory Code 536: Check For Proper Brakelight Switch Installation Code 536 indicates a BOO circuit failure. Possible causes for this fault are: Brakelight switch installed improperly. Open brakelight circuit. Short to ground or power. Faulty brakelight switch. Faulty brakelight switch ground connection. Check brakelight switch for proper installation (alignment with brake pedal, corrosion or frayed wires). If brakelight switch is okay, go to next step. If brakelight switch is not okay, repair as necessary. Clear codes and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
9. Step 91) Check Brakelight Switch Ground Check brakelight switch ground connection. Also, check brakelight connector wires for corrosion or damage. Repair as necessary. Clear codes and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If connector and wires are okay, go to next step.
10. Step 92) Check Brakelight BOO Circuits For Short To Power Turn ignition on. Observe brakelights. With brake pedal released, wiggle brakelight BOO circuit wires and connectors. If brakelights flash, isolate short to power and repair as necessary. Clear codes and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If brakelights do not flash, go to next step.
11. Step 93) Check Brakelight Circuit Continuity Turn ignition off. Depress and hold-down brake pedal. Observe brakelights and wiggle brakelight circuit wires and connectors. Also, lightly tap on brakelight switch (to simulate road shock). If brakelights flash or go off, isolate open in brakelight circuit and repair as necessary. Clear codes and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If brakelights stay on (normal operation), go to next step.
12. Step 94) Check BOO Circuit Continuity Turn ignition off. Release brake pedal. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Connect DVOM between BOO test pin No. 2 at breakout box and BOO terminal at brakelight switch. Observe DVOM and wiggle BOO circuit wires and connectors. If resistance is more than 5 ohms at anytime, isolate open in BOO circuit and repair as necessary. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If resistance is 5 ohms or less at all time, fault is intermittent and cannot be duplicated at this time. Testing is complete.

CIRCUIT TEST H - FUEL CONTROL

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

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

Fuel-contaminated engine oil may affect Codes 136, 137, 139, 144, 171, 172, 173, 175, 176 and 177. If fuel-contaminated engine oil is suspected, remove PCV valve from valve cover and repeat QUICK TEST . If problem is corrected, change engine oil and filter.

Only use this test to diagnose

1. HO2S and sensor connection.
2. Vacuum systems.
3. Fuel injector and/or fuel injector circuitry.
4. Powertrain Control Module (PCM).
5. Electrical circuits (HO2S, HO2S GND, INJ 1-8, VPWR and SIG RTN).

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

1. Ignition system.
2. Faulty evaporative emission system.
3. EGR and/or PCV system.
4. Air intake system.
5. Engine oil contamination.
6. Fuel system.
7. Intake manifold leaks.
8. Exhaust system leaks or restriction.
9. Electrical system.
10. Secondary air injection system.
11. Engine cooling system.

Identifying Fuel Injector & HO2S Connector Terminals. Scheme 231

INDIVIDUAL INJECTOR RESISTANCE (1)

INJECTOR BANK RESISTANCE

TEST PIN NO. 29 (HO2S) WIRE COLOR IDENTIFICATION

TEST PINS NO. 49 & 46 (HO2S-GROUND) WIRE COLOR IDENTIFICATION

FUEL INJECTOR TEST PIN NO. IDENTIFICATION

1. Step 1) Check For Contaminated Engine Oil Turn ignition off. Remove PCV valve from valve cover. Inspect PCV system for damage. Inspect valve for blockage and movement of valve plunger. Repair as necessary. Perform «KOEO SELF-TEST»(ref-23598-S28031615042001010300000) and «KOER SELF-TEST»(ref-23598-S29311478132001010300000) . Service ignition continuous memory code (if present) before KOER codes. If vehicle has a no-start condition, KOER Code 136, 137, 172, 173 or Continuous Memory Code 139, 144, 171, 175, 176, or 177 is set, install PCV valve and go to next step. If no codes are set, change engine oil and filter. Install PCV valve, and drive vehicle for 5 miles at 55 MPH. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
2. Step 2) Check Fuel Pressure Turn ignition off. Release fuel pressure. 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. Check fuel pressure. For fuel pressure specifications, see «FUEL PRESSURE SPECIFICATIONS»(ref-123322) article. If fuel pressure is within specification, go to next step. If pressure is not within specification, go to FUEL SYSTEM in the «SYSTEM/COMPONENT TESTS - 5.8L EEC-IV»(ref-23711) article.
3. Step 3) Check System Ability To Hold Fuel Pressure Cycle ignition on and off several times. Turn ignition on. Check fuel system for leaks. Repair or replace as necessary. If fuel system does not leak and pressure remains at specification for 60 seconds, go to next step for no-start condition or step 5) for other codes or symptoms.
4. Step 4) Fuel Delivery Test Release fuel system pressure. With fuel pressure gauge installed, pressurize fuel system as in step 2). Disconnect Inertia Fuel Shutoff (IFS) switch. See «INERTIA FUEL SHUTOFF SWITCH LOCATION»(ref-23598-S09704128162002011500000) table. Crank engine for 5 seconds. If fuel pressure drop is more than 5 psi after 5 seconds of cranking, EEC-IV system is not causing no-start condition. Check additional no-start tests in the «TESTS W/O CODES - 5.8L EEC-IV»(ref-23634) article. If fuel pressure drop is less than 5 psi, remove fuel pressure gauge. Connect inertia switch and go to step 6). INERTIA FUEL SHUTOFF SWITCH LOCATION Application Location Pickup Behind Right Kick Panel
5. Step 5) Cylinder Balance Test Connect tachometer to engine. Start and run engine at idle. Disconnect and reconnect injectors individually, noting RPM drop as each injector is disconnected. IAC motor will attempt to re-establish RPM. If each injector does not produce a momentary drop in RPM, go to next step. If each injector produces a momentary drop in RPM, go to step 11) for Code 136, 172 or 176, or step 21) for Code 137, 173 or 177. Go to step 12) for all others.
6. Step 6) Check Injector & Harness Resistance Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance of injector bank No. 1 between test pins No. 37 and 58 at breakout box. Measure resistance of injector bank No. 2 between test pins No. 37 and 59 at breakout box. Record resistances. If all readings are as specified, go to step 10). See «INJECTOR BANK RESISTANCE»(ref-23598-S25018309162001010300000) table. If any reading is not as specified, repair open VPWR circuit for no-start condition, or go to next step for all other conditions.
7. Step 7) Check Continuity Of Fuel Injector Harness Turn ignition off. Disconnect injector wiring harness connector at suspect injector. Measure resistance between test pins No. 37 or 57 at breakout box and VPWR terminal at suspect injector wiring harness connector. Also, measure resistance between injector test pin(s) at breakout box and same injector circuit terminal at each injector wiring harness connector. If each reading is less than 5 ohms, go to next step. If any reading is 5 ohms or more, repair open circuit. Remove breakout box, reconnect all components and drive vehicle for 5 miles at 55 MPH. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
8. Step 8) Check Injector Harness Circuit For Short To Power Or Ground Turn ignition off. With breakout box installed and PCM disconnected, disconnect suspect fuel injector wiring harness connector. Measure resistance between injector test pin(s) and test pins No. 37, 40, 46, 57 and 60 at breakout box. Also, measure resistance between injector test pin(s) at breakout box and chassis ground. If all readings are more than 10,000 ohms, go to next step. If any reading is 10,000 ohms or less, repair short circuit. Remove breakout box, reconnect all components and drive vehicle for 5 miles at 55 MPH. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
9. Step 9) Isolate Faulty Injector Circuit Turn ignition off. Install breakout box, and disconnect PCM. Disconnect all injectors on suspect bank. With DVOM set on 200 ohm scale, connect one injector and measure resistance between test pin No. 37 and test pin No. 58 (injector bank No. 1) or No. 59 (injector bank No. 2). Disconnect injector, and repeat process for all other injectors. See «INDIVIDUAL INJECTOR RESISTANCE»(ref-23598-S11238383002001010300000) table. If all injectors are within specification, go to next step. If any injector resistance is not as specified, replace injector. Remove breakout box, and reconnect components. Drive vehicle for 5 miles at 55 MPH. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
10. Step 10) Check Injector Drive Signal With ignition off and breakout box installed, connect PCM to breakout box. Connect a non-powered 12-volt test light between test pins No. 37 and 58 at breakout box. Connect another test light between test pins No. 37 and 59 at breakout box. Crank or start engine. If test lights glow dimly, system is operating correctly. Clean injectors, and drive vehicle for 5 miles at 55 MPH. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) and CYLINDER BALANCE TEST (step 5). If either test light does not glow dimly (no light/bright light), replace PCM. Reconnect all components. Drive vehicle for 5 miles at 55 MPH. Repeat QUICK TEST.
11. Step 11) Check Secondary Air Injection Operation A HO2S which is always lean could be caused by secondary air being diverted upstream from HO2S. Turn ignition off. Disconnect secondary air hose(s) from pump and vent to atmosphere. Perform «KOER SELF-TEST»(ref-23598-S29311478132001010300000) . If Code 136, 172 or 176 is present, reconnect air hose(s) and go next step. If Continuous Memory Code 139, 144, 171, 176 or 177 is present, go to step 90). If Code 311, 312 or 313 is present, go to CIRCUIT TEST KC. If code(s) is not present, check and repair air injection system as necessary. See EMISSION SYSTEMS & SUB-SYSTEMS in the «SYSTEM/COMPONENT TESTS - 5.8L EEC-IV»(ref-23711) article.
12. Step 12) Check HO2S Integrity An HO2S which is always lean, slow to switch or does not switch could be caused by: Moisture inside HO2S connector causing a short to ground. HO2S coated with contaminants. HO2S circuit open. HO2S circuit shorted to ground. Turn ignition off. Inspect HO2S wiring harness for damage. Inspect HO2S and connector for signs of fluid entry. Repair or replace as necessary. Start engine, and run it at 2000 RPM for 2 minutes. Turn ignition off. Run «KOER SELF-TEST»(ref-23598-S29311478132001010300000) . If fault codes are present, go to next step. If no code is present, go to step 18).
13. Step 13) Check HO2S Vacuum or air leaks in non-EEC-IV areas could cause Code 136, 172 or 176. Check following possibilities before continuing: Leaking vacuum actuated motor. Leaking intake gasket. EGR system. PCV system. Lead-contaminated HO2S. Turn ignition off. Ensure MAP sensor output voltage is correct. See CIRCUIT TEST DF, step 3). Disconnect HO2S from wiring harness connector. Connect DVOM to HO2S signal terminal and HO2S GND terminal at sensor wiring harness connector. Disconnect and plug vacuum line at MAP sensor. Start engine, and apply 10-14 in. Hg to MAP sensor. Run engine at 2000 RPM for 2 minutes. If voltage is more than 0.5 volt, go to next step. If voltage is 0.5 volt or less, replace HO2S and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
14. Step 14) Check Continuity Of HO2S Ground Circuits Turn ignition off. Install breakout box, leaving PCM disconnected. Disconnect HO2S wiring harness connector. Inspect connector for damage, moisture and corrosion. Repair as necessary. Measure resistance between HO2S test pin at breakout box and HO2S signal terminal at sensor wiring harness connector. Also, measure resistance between test pin No. 46 at breakout box and HO2S GND terminal at HO2S wiring harness connector. If each resistance is less than 5 ohms, go to next step. If any resistance is 5 ohms or more, repair open circuit. Remove breakout box, and reconnect all components. Drive vehicle for 5 minutes at 55 MPH. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
15. Step 15) Check HO2S Circuit For Short To Ground Turn ignition off. Leave breakout box installed and PCM disconnected. Disconnect HO2S. Measure resistance between HO2S circuit test pin and test pins No. 40, 46 or 49 at breakout box. If any reading is 10,000 ohms or less, repair short to ground. Drive vehicle at 55 MPH for 5 minutes and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If all readings are more than 10,000 ohms, go to next step.
16. Step 16) Check HO2S For Short To Ground Ensure ignition is off and PCM is disconnected. With HO2S disconnected, measure resistance between PWR GND and HO2S signal terminal at HO2S connector. Also, measure resistance between HO2S signal terminal and HO2S GND terminal at HO2S wiring harness connector. If any reading is 10,000 ohms or less, replace HO2S. Drive vehicle for 5 miles at 55 MPH and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If both readings are more than 10,000 ohms, go to next step.
17. Step 17) Check Resistance Of HO2S Heating Element Turn ignition off. Disconnect HO2S. Inspect both ends of connector for damage, moisture and corrosion. Repair as necessary. Measure resistance between VPWR terminal and PWR GND circuit at HO2S connector. Hot to warm engine resistance should be 5-30 ohms. Cold engine temperature resistance is 2-5 ohms. If resistance is within specification, go to next step. If resistance is not as specified, replace HO2S and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
18. Step 18) Check For Power At HO2S Harness Connector Disconnect HO2S. Turn ignition on. Measure voltage between negative battery terminal and VPWR terminal at HO2S wiring harness connector. If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, repair open VPWR circuit. Reconnect HO2S and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
19. Step 19) Check Continuity Of Power Ground Circuit Turn ignition off. Measure resistance between PWR GND circuit at HO2S wiring harness connector and negative battery terminal. If resistance is 5 ohms or more, repair open PWR GND circuit. Reconnect HO2S and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If resistance is less than 5 ohms, go to step 90) for Codes, 139, 144, 171, 174, 175 and 178, or go to next step for Codes 136, 172 or 176.
20. Step 20) Attempt To Eliminate Code 136, 172 Or 176 Turn ignition off. Connect PCM to breakout box. Connect HO2S. Disconnect and plug MAP sensor vacuum hose. Start engine and apply 10-14 in. Hg to MAP sensor. Increase engine speed to 2000 RPM for 2 minutes. Allow engine to return to idle. Perform «KOER SELF-TEST»(ref-23598-S29311478132001010300000) . If diagnosing continuous memory codes, drive vehicle 5 miles at 55 MPH. If Code 136, 172 or 176 is still present, remove breakout box. Connect all components. If engine does not run rough, replace PCM, drive vehicle 5 miles at 55 MPH, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If engine runs rough, go to CIRCUIT TEST S, step 2). If code is not present, remove breakout box and connect all components. HO2S input circuit and fuel delivery are okay; fault is in area common to all cylinders (vacuum leak, fuel contamination, EGR, ignition system, etc.). See the «TESTS W/O CODES - 5.8L EEC-IV»(ref-23634) article.
21. Step 21) Diagnostic Test Code 137, 173 Or 177: Check HO2S SIGNAL For Short To Power HO2S continuously rich could be caused by: Moisture inside wiring harness causing short to power. HO2S shorted to power. Turn ignition off. Disconnect HO2S. Inspect connector for damage and repair as necessary. Turn ignition on. Measure voltage between HO2S and PWR GND terminals at HO2S wiring harness connector. If voltage is less than 0.5 volt, go to step 23). If voltage is 0.5 volt or more, go to next step.
22. Step 22) Check For Short To Power Turn ignition off. Disconnect HO2S. Inspect wiring harness for damage and repair as necessary. Disconnect PCM 60-pin connector. Install Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between VPWR test pin No. 37 or 57 and HO2S test pin at breakout box. If resistance is more than 10,000 ohms, replace PCM. Remove breakout box, and reconnect all components. Drive vehicle 5 miles at 55 MPH. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If resistance is 10,000 ohms or less, repair short to power. Remove breakout box, and reconnect all components. Drive vehicle 5 miles at 55 MPH. Repeat QUICK TEST.
23. Step 23) Check HO2S For Short To VPWR Circuit Turn ignition off. Disconnect HO2S. Measure resistance between VPWR terminal and HO2S terminal at HO2S connector. If resistance is 10,000 ohms or less, replace HO2S. Drive vehicle for 5 miles at 55 MPH, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If resistance is more than 10,000 ohms, go to next step for Codes 137, 173 or 177, or go to step 25) for Codes 171, 174, 175 and 178.
24. Step 24) Attempt To Generate Code 136, 172 Or 176 Turn ignition off. Disconnect HO2S connector. Connect a jumper wire between negative battery terminal and HO2S terminal at HO2S wiring harness connector. Repeat «KOER SELF-TEST»(ref-23598-S29311478132001010300000) . If Code 136, 172 or 176 is present, remove jumper wire and go to next step. If Code 136, 172 or 176 is not present, remove jumper wire. Disconnect PCM connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. If connector is okay, replace PCM. Drive vehicle for 5 miles at 55 MPH. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .

Because MAP sensor greatly influences fuel control, MAP sensor may malfunction without setting Code 126. Next 2 steps test MAP vacuum circuit.

1. Step 25) Check MAP Sensor For Vacuum Leaks Turn ignition off. Disconnect vacuum hose from MAP sensor. Inspect hose for damage and repair as necessary. Connect vacuum pump to sensor. Apply 18 in. Hg to MAP sensor. If sensor does not hold vacuum, replace MAP sensor. Drive vehicle for 5 miles at 55 MPH. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If sensor holds vacuum, release vacuum and go to next step.
2. Step 26) Check For Loss Of Vacuum To MAP Sensor Using vacuum "T", connect vacuum gauge in MAP sensor vacuum circuit. Start engine. Note vacuum reading after idle stabilizes. Turn ignition off. Remove "T" and vacuum gauge. Reconnect hose to MAP sensor. Connect vacuum gauge at a different manifold vacuum location. Start engine, and note vacuum reading. If readings do not differ by more than one in. Hg, go to next step. If readings differ by more than one in. Hg, inspect vacuum hoses for leaks, kinks and blockage. Repair as necessary. Connect all components, and drive vehicle for 5 miles at 55 MPH. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
3. Step 27) HO2S Check Turn ignition off. Disconnect HO2S. Connect DVOM to HO2S terminal and HO2S GND terminal at HO2S connector. Create a vacuum leak to force HO2S to go lean. Start engine. Raise engine speed to about 2000 RPM. DVOM should indicate less than 0.4 volt within 30 seconds. If voltage is not as specified, replace HO2S. Reconnect vacuum hoses, and drive vehicle for 5 miles at 55 MPH. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If voltage is as specified, go to step 90). NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 27) to step 90). No test procedures have been omitted.
4. Step 90) Check Continuous Monitor Mode Start engine, and warm it to normal operating temperature. Raise engine speed to 2000 RPM for 2 minutes and then return to idle. Enter KOER wiggle test. See «CONTINUOUS MONITOR MODE (WIGGLE TEST)»(ref-23598-S23726050792001010300000) under QUICK TEST. While observing VOM or scan tester, shake or bend small sections of wiring harness from HO2S to PCM. Wiggle, shake or bend small sections of wiring harness from HO2S GND to PCM. 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. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
5. Step 91) Continuous Monitor Test Drive Check While still in KOER wiggle test, test drive vehicle for 5 miles at 55 MPH over smooth roads. Drive an additional 5 miles at 55 MPH over rough roads. If possible, drive vehicle through a pool of water to wet HO2S and connector. If fault is indicated, isolate fault and repair as necessary. Clear codes, and remove breakout box. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If no fault is indicated, exit KOER wiggle test and go to next step.
6. Step 92) Check HO2S Switching Turn ignition off. Inspect wiring harness for proper routing and insulation. Check for burnt, chaffed or open wires. Repair as necessary. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install breakout box. Connect PCM to breakout box. Connect analog voltmeter to HO2S test pin and HO2S GND at breakout box. Test drive vehicle for 5 miles at 55 MPH while observing voltmeter. HO2S should switch from .3 volt to .9 volt within 3 seconds. If HO2S does not switch as described, replace HO2S. Connect all components, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If HO2S switches as described, fault cannot be identified or duplicated at this time. See INTERMITTENTS in the «TESTS W/O CODES - 5.8L EEC-IV»(ref-23634) article.

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

Perform this test when directed by QUICK TEST . PCM uses adaptive fuel logic to compensate for normal variances in fuel system components. If fuel system appears to be too rich or too lean, adaptive fuel will make appropriate shift in fuel delivery calculations to compensate. For fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS article.

If possible, measure several known-good MAP sensors. Average voltage reading will be typical for location and day of testing.

MAP SENSOR VOLTAGE OUTPUT

1. Step 1) Continuous Memory Codes 181, 183, 189 & 192 These codes identify a lean fuel condition resulting in adaptive fuel strategy enriching fuel system to compensate.

When ignition switch is in the ON or START position, the PCM connects FUEL PUMP circuit (PCM terminal No. 22) to ground. The fuel pump relay is energized and electrical current flows to the fuel pump. If PCM does not receive ignition PIP signal within 2 seconds, FUEL PUMP circuit is opened and fuel pump operation is terminated. Perform this test when instructed by QUICK TEST or CIRCUIT TEST AA. This test is only intended to diagnose

1. Fuel pump relay.
2. Inertia Fuel Shutoff (IFS) switch.
3. Wiring harness circuits (B+, VPWR, FP, GND, FPM and POWER-TO -PUMP).
4. Faulty Powertrain Control Module (PCM).

Fuel Pump Monitor Schematic Diagram. Scheme 232

Fuel Pump Monitor Circuit Diagram. Scheme 233

Scheme 234

1. Step 1) Code 556: Check VPWR To Fuel Pump Relay Code 556 indicates a fuel pump primary circuit failure. Possible causes for this fault are: IFS switch not reset or circuit open. Open or shorted circuit. Faulty fuel pump relay. Faulty PCM. Disconnect fuel pump relay. Turn ignition on. Measure voltage between chassis ground and VPWR circuit at fuel pump relay wiring harness connector. If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, verify IFS switch is in ON position. If switch is okay, repair open VPWR circuit between EEC power relay and fuel pump relay. Connect fuel pump relay and repeat «QUICK TEST»(ref-23598-S07232509482001010300000).
2. Step 2) Check Fuel Pump Relay Turn ignition off. Disconnect fuel pump relay. Measure resistance between terminals No. 85 and 86. (Scheme 234) Resistance should be 40-120 ohms. Set DVOM to 10-k/ohm scale. Measure resistance between terminal No. 85 and terminals No. 30 and 87. All resistances should be more than 10,000 ohms. If resistances are as specified, go to next step. If resistances are not as specified, replace fuel pump relay and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). (Scheme 234): Identifying Fuel Pump Relay Connector Terminals
3. Step 3) Check For Short To Power Turn ignition off. Disconnect fuel pump relay. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Turn ignition on. Measure voltage between test pin No. 22 and negative battery terminal. If voltage is less than one volt, go to next step. If voltage is one volt or more, repair short circuit. Reconnect PCM, and attempt to start vehicle. If vehicle fails to start, replace PCM. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000).
4. Step 4) Check For Short To Ground Turn ignition off. Leave fuel pump relay and PCM disconnected. Measure resistance between test pin No. 22 and test pins No. 40 and 60. If resistance is 10,000 ohms or less, repair short circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If resistance is more than 10,000 ohms, go to next step.
5. Step 5) Check Fuel Pump Circuit Continuity Turn ignition off. Leave fuel pump relay and PCM disconnected. Measure resistance between FUEL PUMP circuit (Light Blue/Orange wire) at fuel pump relay wiring harness connector and test pin No. 22 at breakout box. If resistance is less than 5 ohms, replace PCM and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If resistance is 5 ohms or more, repair open circuit and repeat QUICK TEST. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 5) to step 10). No test procedures have been omitted.
6. Step 10) Code 542 A KOEO Code 542 indicates one of the following conditions

On models with dual fuel tanks, perform KOEO SELF-TEST twice, once with front tank selected and once with rear tank selected. If KOEO Code 542 is present in only one test, check for an open circuit between fuel tank select switch and suspect pump circuit ground. Repair as necessary and repeat QUICK TEST . If KOEO Code 111 and Continuous Code 542 are present both times, proceed with testing. Start engine. Check for engine miss or intermittent fuel pump deactivation while performing following

1. Shake and bend POWER-TO-PUMP circuit wiring harness connector between fuel pump relay and fuel pump.
2. Shake and bend fuel pump ground circuit between fuel pump and ground.
3. Lightly tap fuel pump to simulate road shock.
4. Lightly tap IFS switch to simulate road shock.

Turn ignition off. Check harness connectors for corrosion and damage. Isolate and repair any faults. Clear continuous memory, and repeat QUICK TEST . If no faults are found, go to next step.

1. Step 91) Check FPM Circuit Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Connect test light between test pin No. 8 and test pin No. 37 at breakout box. With test light lit, perform wiggle test on FPM circuit between fuel pump and PCM. Light will go out if fault is found, indicating an open circuit. If a fault is found, repair as necessary and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If no fault is found, go to next step.
2. Step 92) Check For Short To Power Connect a test light between breakout box test pins No. 8 and 40. Test light should be off. Observe test light while bending and shaking FPM circuit and POWER-TO-PUMP circuit. Lightly tap fuel pump relay to simulate road shock. Fault is indicated if test light comes on. Isolate and repair fault as necessary, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If no fault is found, go to step 99).
3. Step 93) Continuous Memory Code 543: Check For Continuous Memory Code 556 If Code 556 is also present, go to step 95). If Code 556 is not displayed, go to next step.
4. Step 94) Check EEC-IV Harness A Continuous Memory Code 543, without an accompanying Continuous Memory Code 556, indicates one of the following conditions has occurred during vehicle operation: Open B+ circuit between B+ and fuel pump relay. Fuel pump relay contacts open. Open POWER-TO-PUMP circuit between fuel pump relay to FPM splice (if applicable). Start engine. Check for engine miss or intermittent fuel pump deactivation while performing the following: Shake and bend B+ circuit wiring harness between power source and fuel pump relay. Shake and bend POWER-TO-PUMP circuit wiring harness connector between fuel pump relay and FPM splice (if applicable). Lightly tap fuel pump relay to simulate road shock. Turn ignition off. Inspect all fuel pump relay and B+ connectors for damage and corrosion. If fault is found, repair as necessary and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If no fault is found, Continuous Memory Code 543 may have been set without Continuous Memory Code 556 even though a fault has occurred in fuel pump primary circuit. Go to next step for fuel pump primary circuit check.
5. Step 95) Continuous Memory Code 556: Check EEC-IV Harness A Continuous Memory Code 556 indicates primary fuel pump circuit has failed during vehicle operation. Possible causes for this fault are: Open VPWR circuit between EEC power relay and fuel pump relay. Open coil in fuel pump relay. Open fuel pump circuit (pin No. 22). Faulty IFS switch. Start engine. Check for engine miss or intermittent fuel pump deactivation while performing the following: Shake and bend VPWR circuit wiring harness between EEC and fuel pump relay. Shake and bend FP circuit wiring harness connector between fuel pump relay and PCM. Lightly tap fuel pump relay to simulate road shock. Lightly tap IFS switch to simulate road shock. Turn ignition off. Disconnect fuel pump relay connector and PCM 60-pin connector. Inspect terminals. If fault is found, isolate and repair as necessary. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If no faults are found, go to next step. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 95) to step 99). No test procedures have been omitted. CAUTION: Following road test is an optional procedure. Follow all applicable safety procedures and traffic laws. This road test requires a driver and an assistant. Assistant should make measurements, observe changes and record notes. If this test not performed, go to «TESTS W/O CODES - 5.8L EEC-IV»(ref-23634) article for other possible causes.
6. Step 99) Road Test Vehicle Purpose of this test is to identify faults by monitoring certain controlled parameters while trying to recreate a drive-ability or MIL symptom. To prepare for road test: Install fuel pressure gauge and MAP tester (if available). Disconnect PCM 60-pin connector, install breakout box, and reconnect PCM to breakout box. Connect "T" vacuum gauge into manifold vacuum line. Have DVOM, writing materials and appropriate schematics and pin voltage charts available. With ignition on and negative lead of DVOM connected to negative battery terminal, ensure following signals are correct: POWER: KAPWR (pin No. 1) is greater than 10.5 volts, VPWR (pins No. 37 and 57) is greater than 10.5 volts, and VREF (pin No. 26) is 4-6 volts. GROUND: PWR GND (pins No. 40 and 60), SIG RTN (pin No. 46) and IGN GND (pin No. 16) are 0.0-0.5 volt. OPTIONAL GROUNDS: HO2S GND (pin No. 49) and CSE GND (pin No. Step 20) are 0.0-0.5 volt.

Test lights and DVOM are useful during diagnosis. For example: with Continuous Memory Code 556 (fuel pump primary circuit failure) and a surge or stall symptom, connect a test light to fuel pump relay between VPWR and ground. Connect DVOM between FP circuit at fuel pump relay and breakout box test pin No. 1. Under normal driving conditions, test light will be on and DVOM will read battery voltage. If vehicle stalls, PCM will open FP circuit and DVOM voltage will be low. If fault is in fuel pump circuit, test light and DVOM status will change as fault occurs. If test light at VPWR circuit goes out, fault is in VPWR circuit to fuel pump relay.

If test light and DVOM status do not change and Continuous Memory Code 556 is set again, replace fuel pump relay. If only FP voltage goes low, fault is in FP circuit or PCM. To diagnose FP circuit and PCM, connect DVOM between breakout box test pins No. 1 and 22. If voltage goes low as symptom occurs, replace PCM. If voltage stays high as symptom occurs, fault is in FP circuit. For fuel pump secondary circuit Codes 542 and 543, circuits B+, POWER-TO-PUMP and FPM can be diagnosed using same procedure. Drive vehicle and attempt to induce symptom. Information provided by vehicle operator may help when trying to recreate symptom. When symptom occurs, assistant should observe and record changes in voltage signals.

Information about symptom and operating condition value of voltage signal and any other information available should be recorded for analysis. If unable to duplicate symptom during road test, verify EEC-IV values are within acceptable range. After test is completed, analyze results to locate and repair fault causing symptom. If problem cannot be identified, go to TESTS W/O CODES - 5.8L EEC-IV article for other possible causes of symptom.

PCM uses secondary air injection solenoids to control Air Injection Bypass (AIRB) and Air Injection Diverter (AIRD) valves. AIRB and AIRD are used to direct air to either engine or exhaust system.

Perform this test when instructed by QUICK TEST or if directed by other test procedures. This test is only intended to diagnose

1. AIRB/AIRD solenoid valve assembly.
2. Wiring harness circuits (AIRB, AIRD and VPWR).
3. Vacuum supply.
4. Powertrain Control Module (PCM).

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

1. Secondary air injection system (belt, pump, valve or reservoir).
2. Blocked or restricted secondary air passages in engine.

Secondary Air System Electrical Circuits & Wiring Harness Connector Terminals. Scheme 235

Note. Vehicle is equipped with a AIRD solenoid.

AIRD WIRE COLOR & TEST PIN IDENTIFICATION

VREF WIRE COLOR & TEST PIN IDENTIFICATION

1. Step 1) Codes 311, 312, 313 & 314 Code 311 or 314 indicates that secondary air injection system is inoperative. Code 312 indicates that secondary air is incorrectly routed. Code 313 indicates that secondary air is not by-passed when directed. Possible causes for these faults are: Vacuum hoses leaking, blocked or kinked. AIRB/AIRD valve inoperative. Defective AIRB/AIRD solenoid. Defective air pump. Check for correct vacuum hose routing to AIRB/AIRD solenoid and bypass diverter valve. See Vehicle Emission Control Information (VECI) label. Check for kinked or blocked vacuum hoses. Check for kinked or blocked air hoses. Check for disconnected vacuum hoses. Also, check for loose or broken air pump belt. If faults are detected, repair as necessary and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If no faults are detected, go to next step.
2. Step 2) Check Vacuum Hoses Carefully check the following vacuum hoses: Hose from AIRB solenoid to AIRB valve. Hose from AIRD solenoid to AIRD valve. Hose from manifold vacuum tee to AIRB/AIRD solenoid. Check for obstructions, cracks, kinks and leaks. Replace vacuum hoses as necessary and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If vacuum hoses are okay, and Code 311 or 314 is present, go to step 5). If Code 313 is present, go to step 4). If Code 312 is present, go to next step.
3. Step 3) Attempt To Eliminate Code 312 Disconnect and plug vacuum hose at AIRD valve. Repeat «KOER SELF-TEST»(ref-23598-S29311478132001010300000) . If Code 312 is present, EEC-IV system is okay. Inspect AIRD valve and check valve for faults. If Code 312 is not present, go to step 5).
4. Step 4) Attempt To Eliminate Code 313 Disconnect and plug vacuum hose at AIRB valve. Repeat «KOER SELF-TEST»(ref-23598-S29311478132001010300000) . If Code 313 is present, EEC-IV system is okay. Check AIRB valve for problem. If Code 313 is not present, go to next step.
5. Step 5) Check AIRD & AIRB Solenoids Enter output state Diagnostic Test Mode (DTM). See OUTPUT STATE DIAGNOSTIC TEST MODE (DTM) under «ADDITIONAL SYSTEM FUNCTIONS»(ref-23598-S09111925882001010300000) . After output state DTM has been entered, disconnect AIRB solenoid. Set DVOM to 20-volt scale. Connect DVOM positive lead to VPWR terminal (Red wire) and negative lead to AIRB terminal at AIRB solenoid wiring harness connector. While observing DVOM, depress and release throttle several times to cycle voltage output on and off. Repeat test for AIRD solenoid. Connect DVOM positive lead to VPWR terminal (Red wire) and negative test lead to AIRD terminal on AIRD solenoid wiring harness connector. Cycle AIRD solenoid on and off. If either solenoid does not cycle more than 0.5 volt, remove jumper and go to step 9). If both solenoids cycle more than 0.5 volt, stay in output state DTM. Reconnect solenoids and go to next step.
6. Step 6) Check AIRB & AIRD For Internal Vacuum Leaks Reconnect AIRB and AIRD connectors. Connect a vacuum pump to AIRB solenoid supply port. Connect a vacuum gauge to solenoid output port. Apply 15 in. Hg and observe vacuum gauge. Repeat procedure for AIRD solenoid. If both solenoids hold vacuum, stay in output state DTM and go to next step. If either solenoid does not hold vacuum, replace solenoid and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
7. Step 7) Check Solenoids For Vacuum Cycling Connect vacuum pump to solenoid vacuum supply port. Connect vacuum gauge to output port. Maintain 15 in. Hg at vacuum source while depressing and releasing throttle to cycle output on and off. Observe vacuum gauge. Repeat for other solenoid. If either output does not cycle on and off, replace solenoid assembly and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If both outputs cycle on and off, fault is in secondary air injection system (belt, pump, valve or reservoir).
8. Step 8) Codes 552 & 553 Codes 552 and 553 indicate voltage output for secondary air injection solenoid did not change when activated. Possible causes for this fault are: AIRB/AIRD circuit(s) shorted or open. Fault in solenoid or PCM. Disconnect both solenoid connectors. Turn ignition on. Measure voltage between VPWR terminal of wiring harness connector and negative battery terminal for both solenoids. If any reading less than 10.5 volts, repair wiring harness open circuit, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If both readings are 10.5 volts or more, go to next step.
9. Step 9) Measure Solenoid Resistance Turn ignition off. Leave solenoid connectors disconnected. Measure resistance of both solenoids. If either reading is not 50-100 ohms, replace solenoid assembly and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If both readings are 50-100 ohms, go to next step.
10. Step 10) Check Circuit Continuity Leave ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between AIRB test pin at breakout box and AIRB terminal at vehicle wiring harness connector. Also, measure resistance between AIRD test pin at breakout box and AIRD terminal at vehicle wiring harness connector. If any reading is 5 ohms or more, repair open circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If both readings are less than 5 ohms, go to next step.
11. Step 11) Check For Short To Ground Leave ignition off and solenoids disconnected. Measure resistance between AIRB test pin at breakout box and test pins No. 40, 46 and 60. Also, measure resistance between AIRD test pin at breakout box and test pins No. 40, 46 and 60. If any reading is less than 10,000 ohms, repair short to ground. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If all readings are 10,000 ohms or more, go to next step.
12. Step 12) Check For Short To Power Circuit Turn ignition off. Measure resistance between AIRB test pin at breakout box and test pins No. 37 and 57. Also, measure resistance between AIRD test pin at breakout box and test pins No. 37 and 57. If any resistance is less than 10,000 ohms, repair short to power. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If code is repeated, replace PCM. If each resistance is 10,000 ohms or more, replace PCM. Remove breakout box, reconnect all components, and repeat QUICK TEST.

Perform this test when instructed by QUICK TEST or if directed by other test procedures. This test is only intended to diagnose

1. CANP solenoid.
2. Harness circuits (CANP and VPWR).
3. Powertrain Control Module (PCM).

Canister Purge (CANP) Circuit. Scheme 236

CANP WIRE COLOR & TEST PIN IDENTIFICATION

TEST PINS NO. 37 & 57 (VPWR) WIRE COLOR IDENTIFICATION

1. Step 1) Check System Function Turn ignition off. Enter output state Diagnostic Test Mode (DTM). See OUTPUT STATE DIAGNOSTIC TEST MODE (DTM) under «ADDITIONAL SYSTEM FUNCTIONS»(ref-23598-S09111925882001010300000) . After output state DTM has been entered, disconnect CANP solenoid. Connect DVOM positive lead to VPWR circuit terminal (Red wire) and negative lead to CANP circuit terminal (Gray/Yellow wire) at CANP vehicle wiring harness connector. Set DVOM to 20-volt scale. Observe DVOM, and depress and release throttle several times to cycle voltage output. If voltage output change is 0.2 volt or more, remain in output state DTM. Go to next step. If voltage output change is less than 0.2 volt, go to step 6).
2. Step 2) Measure CANP Valve Resistance Leave ignition off and CANP solenoid connector disconnected. Measure resistance between CANP solenoid terminals. If resistance is not 30-90 ohms, replace CANP valve and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If resistance is 30-90 ohms, go to next step.
3. Step 3) Check Solenoid For Vacuum Leaks Turn ignition on. Leave CANP solenoid disconnected. Disconnect vacuum hose at CANP solenoid from manifold vacuum side of solenoid. Apply 16 in. Hg vacuum to manifold vacuum side of CANP solenoid. If CANP solenoid does not hold vacuum for 20 seconds, replace solenoid and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If fault is still present, service fuel evaporation canister or hoses. If CANP holds vacuum for 20 seconds, remain in output state DTM, leave vacuum pump attached and go to next step.
4. Step 4) Check CANP Valve Electrical/Mechanical Operation Reconnect CANP valve connector. Ensure 16 in. Hg is applied to input port. Fully apply and release throttle. If vacuum is not released, replace CANP valve and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If vacuum is released, remove jumper wire between SIG RTN and STI terminals of DLC. Go to next step.
5. Step 5) Check Vacuum Supply To CANP Solenoid Disconnect vacuum hose from CANP solenoid on manifold vacuum side. Start engine. If vacuum is present at vacuum hose, engine control system is okay. Check evaporative canister. If vacuum is not present at hose, check vacuum hose for improper routing, kinks and blockage. If hose is okay, check engine for mechanical cause of low vacuum.
6. Step 6) Code 565 Or 569: Check VPWR To CANP Solenoid Code 565 or 569 indicates fault in CANP solenoid circuit. Possible causes for this fault are: Faulty CANP solenoid. Open or short circuit in wiring harness. Faulty PCM. Turn ignition off. Disconnect CANP solenoid connector. Measure voltage between negative battery terminal and VPWR circuit terminal at CANP solenoid vehicle wiring harness connector. If voltage more than 10.5 volts, go to next step. If voltage 10.5 volts or less, repair open VPWR circuit. Reconnect components and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
7. Step 7) Check CANP Resistance Turn ignition off. Measure resistance between CANP solenoid terminals. If resistance is 30-90 ohms, go to next step. If resistance is not 30-90 ohms, replace CANP solenoid and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
8. Step 8) Check Continuity Of CANP Circuit Turn ignition off. Disconnect CANP solenoid. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between CANP test pin No. 31 at breakout box and CANP circuit terminal (Gray/Yellow wire) at CANP vehicle wiring harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open circuit. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
9. Step 9) Check CANP Circuit For Short To Ground Turn ignition off. Disconnect scan tester from DLC, if applicable. With CANP solenoid disconnected, measure resistance between breakout box CANP test pin No. 31 and test pins No. 40, 46 and 60. If all readings are more than 10,000 ohms, go to next step. If any reading is 10,000 ohms or less, repair short to ground. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
10. Step 10) Check CANP Circuit For Short To Power Turn ignition off. With CANP solenoid and PCM disconnected, measure resistance between breakout box CANP test pin No. 31 and test pins No. 37 and 57. If all readings more than 10,000 ohms, replace PCM. Remove breakout box, reconnect all components, repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If any reading is 10,000 ohms or less, repair short to power. Remove breakout box, reconnect all components, and repeat QUICK TEST.

The IAC solenoid controls engine idle speed and dashpot functions by regulating volume of air by-passing throttle plate. IAC solenoid positioning is determined by signals sent from PCM.

Perform this test when instructed by QUICK TEST or if directed by other test procedures. This test is intended to diagnose

1. RPM during SELF-TEST mode.
2. IAC solenoid.
3. Wiring harness circuits (IAC and VPWR).
4. Powertrain Control Module (PCM).

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

1. Engine temperature outside correct operating range.
2. A/C input (electrical problem).
3. Incorrect throttle stop adjustment.
4. Faulty throttle or cruise control linkage.

Idle Air Control Circuit. Scheme 237

TEST PIN NO. 21 (ISC) WIRE COLOR IDENTIFICATION

TEST PINS NO. 37 & 57 (VPWR) WIRE COLOR IDENTIFICATION

Scheme 238

Scheme 239

1. Step 1) Code 412 Code 412 indicates engine RPM could not be controlled within upper RPM limit during «KOER SELF-TEST»(ref-23598-S29311478132001010300000). Possible causes for this fault are: Open or shorted circuit. Sticking or binding throttle linkage. Incorrect idle airflow setting. Throttle body or IAC solenoid contaminated. Faulty IAC solenoid. Faulty PCM. Mechanical faults unrelated to EEC-IV which could affect RPM. Turn ignition off. Connect tachometer to engine. Start engine. Disconnect Idle Air Control (IAC) harness. If RPM drops or engine stalls, go to next step. If RPM does not drop and engine does not stall, go to step 3).
2. Step 2) Check For EGR Codes If EGR service Code 213, 327, 328, 332 or 334 is displayed, reconnect IAC solenoid. Go to appropriate CIRCUIT TEST. See the «DIAGNOSTIC TROUBLE CODE REFERENCE CHART»(ref-23598-S35260139562001010300000). If these codes are not displayed, go to next step.
3. Step 3) Check For Other Diagnostic Test Codes If Code 126, 136, 137, 172 or 173 is displayed, reconnect IAC solenoid. Go to appropriate CIRCUIT TEST. See «DIAGNOSTIC TROUBLE CODE REFERENCE CHART»(ref-23598-S35260139562001010300000). If these codes are not displayed, go to next step.
4. Step 4) Measure IAC Solenoid Resistance Turn ignition off. Disconnect IAC solenoid. Connect DVOM positive lead to VPWR terminal and negative lead to IAC terminal. (Scheme 238) Measure resistance of IAC solenoid. If resistance is not 6-13 ohms, replace IAC solenoid and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If resistance is 6-13 ohms, go to next step. (Scheme 238): IAC Solenoid Connector
5. Step 5) Check For Internal Short To IAC Solenoid Case Turn ignition off. With IAC solenoid disconnected, measure resistance from either IAC terminal pin to IAC solenoid housing. If reading is more than 10,000 ohms, go to next step. If reading is 10,000 ohms or less, replace IAC solenoid. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000).
6. Step 6) Check VPWR Circuit Voltage Leave IAC harness disconnected. Turn ignition on. Measure voltage between VPWR terminal at IAC harness connector and battery ground terminal. If voltage is 10.5 volts or more, go to next step. If voltage less than 10.5 volts, repair open circuit, repeat «QUICK TEST»(ref-23598-S07232509482001010300000).
7. Step 7) Check IAC Circuit Continuity Turn ignition off. Leave IAC solenoid disconnected. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between test pin No. 21 and IAC terminal at IAC wiring harness connector. If resistance is 5 ohms or less, go to next step. If resistance is more than 5 ohms, repair open circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000).
8. Step 8) Check IAC Circuit For Short To Ground Turn ignition off. Leave IAC solenoid and PCM disconnected. Measure resistance between test pin No. 21 and test pins No. 40, 46 and 60. If any reading is less than 10,000 ohms, repair short to ground and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If all readings are 10,000 ohms or more, go to next step.
9. Step 9) Check IAC Circuit For Short To Power Leave IAC solenoid and PCM disconnected. Turn ignition on. Measure voltage between breakout box test pin No. 21 and chassis ground. If voltage is more than one volt, repair short circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If code or symptom is still present, replace PCM. If voltage is one volt or less, go to next step.
10. Step 10) Check IAC Signal From PCM Turn ignition off. Reconnect IAC solenoid. Connect PCM to breakout box. Connect DVOM between test pins No. 21 and 40 at breakout box. Start engine. Observe DVOM while slowly increasing engine speed to 3000 RPM. If DVOM voltage reading is 3.0-11.5 volts, go to next step. If DVOM voltage reading is not 3.0-11.5 volts, remove IAC solenoid to confirm that it is not stuck open. Repair or replace if necessary. If IAC is okay, replace PCM and repeat «QUICK TEST»(ref-23598-S07232509482001010300000).
11. Step 11) Check Base Idle Verify base idle speed is correct. See «ADJUSTMENTS - 5.8L»(ref-23633) article. If base idle speed is within specification, remove IAC solenoid and inspect for contamination. Repair or replace if necessary. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If code or symptom is still present, replace IAC solenoid. If base idle speed is not correct, reset idle speed to specification. Repeat QUICK TEST. If unable to set idle to specification, go to next step.
12. Step 12) Check For Faults Affecting Idle Speed Check following mechanical items for faults: Throttle linkage and/or cruise control linkage (sticking or binding). Throttle body (contamination). Vacuum hoses. Check Vehicle Emission Control Information (VECI) label. Check for leaks around IAC solenoid (gaskets, etc.). If any of these items are faulty, service as necessary, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If all of these items are okay, remove IAC solenoid and inspect for contamination. Repair or replace as necessary. Repeat QUICK TEST. If code or symptom is still present, replace IAC solenoid. Repeat QUICK TEST. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 12) to step 15). No test procedures have been omitted.
13. Step 15) Code 411 Code 411 indicates engine RPM could not be controlled within lower RPM limit during «KOER SELF-TEST»(ref-23598-S29311478132001010300000). Possible causes for this fault are: Incorrect idle airflow setting. Vacuum leaks. Sticking or binding throttle linkage. Throttle plates open. Incorrect ignition timing. Throttle body or IAC solenoid contamination. IAC circuit shorted to ground. Faulty IAC solenoid. If listed items are okay and idle is set to specification, remove IAC solenoid and inspect for contamination. Repair or replace as necessary. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If code or symptom is still present, replace IAC solenoid. If idle speed is not within specification, adjust as necessary and repeat QUICK TEST. If idle speed cannot be set to specification, go to next step.
14. Step 16) Check For Conditions Affecting Idle Speed Check following mechanical components: Vacuum hoses. Check Vehicle Emission Control Information (VECI). Throttle linkage and/or cruise control linkage (sticking or binding). Ensure throttle plates are fully closed. Induction system (vacuum leaks). Throttle body (contamination). Ensure CANP solenoid is not stuck open. Ensure base ignition timing is to specification. See the «ADJUSTMENTS - 5.8L»(ref-23633) article. If everything checks okay, go to next step. If fault is found, service as necessary and repeat «QUICK TEST»(ref-23598-S07232509482001010300000).
15. Step 17) Check For Internal Short To IAC Solenoid Case Turn ignition off. Disconnect IAC solenoid wiring harness connector. Measure resistance from either IAC terminal pin to IAC solenoid housing. (Scheme 239) If reading is more than 10,000 ohms, go to next step. If reading is 10,000 ohms or less, replace IAC solenoid. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000). (Scheme 239): IAC Solenoid Schematic
16. Step 18) Check IAC Circuit For Short To Ground Turn ignition off. Leave IAC solenoid disconnected. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between test pin No. 21 and test pins No. 40, 46 and 60. If any reading is less than 10,000 ohms, repair short to ground. Reconnect components, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If all readings are 10,000 ohms or more, go to next step.
17. Step 19) Check IAC Signal From PCM Turn ignition off. Connect PCM to breakout box. Reconnect IAC solenoid. Set DVOM on 20-volt scale. Connect DVOM between test pins No. 21 and 40. Start engine. Observe DVOM while slowly increasing and decreasing engine RPM. If voltage is 3.0-11.5 volts, remove IAC solenoid and inspect for contamination. Repair or replace as necessary, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If voltage is not 3.0-11.5 volts, replace PCM and repeat QUICK TEST.

Perform this test when instructed by QUICK TEST or id directed by other test procedures. This test is only intended to diagnose

1. Wiring harness circuits (ACCS).
2. Faulty Powertrain Control Module (PCM).

A/C Demand Switch Circuits. Scheme 240

TEST PIN NO. 10 (ACCS) WIRE COLOR IDENTIFICATION

Note. Before continuing with this test, ensure A/C is off and shift selector is in Park position (E4OD transmissions). If A/C was on or shift selector not in Park, repeat QUICK TEST . If Code 539 is still present, continue with this test.

1. Step 1) Code 539: Check A/C Input Circuit Code 539 indicates Air Conditioning Cycling Switch (ACCS) voltage input to PCM was high during SELF-TEST. Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install breakout box, leaving PCM disconnected. Turn ignition on. Measure voltage between test pin No. 10 at breakout box and chassis ground. If voltage is one volt or more, check operation of A/C demand switch. If switch is okay, repair short to power in A/C circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If voltage is less than one volt, replace PCM and repeat QUICK TEST. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 1) to step 10). No test procedures have been omitted.
2. Step 10) Low Idle With A/C On: Check A/C Input Turn A/C on. Perform KOEO SELF-TEST. If Code 539 is not present, turn A/C off and go to next step. If Code 539 present, PCM receiving/recognizing A/C input. See «TESTS W/O CODES - 5.8L EEC-IV»(ref-23634) article for other possible causes of low idle.
3. Step 11) Check A/C Input Circuit Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Turn ignition and A/C on. Measure voltage between test pins No. 10 and 40 at breakout box. If voltage is more than 10.5 volts, replace PCM. Reconnect components and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If voltage is 10.5 volts or less, repair open in A/C circuit. Reconnect components and repeat QUICK TEST.

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

1. Technician did not perform brief Wide Open Throttle (WOT) after Dynamic Response Code.
2. Engine did not go over 2000 RPM during WOT.

This test is only intended to diagnose

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

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

Code 538: System Failed To Recognize WOT Test

Repeat KOER SELF-TEST as follows

1. Activate SELF-TEST.
2. Start engine.
3. Observe ID Code start of test.
4. Observe Dynamic Response Code 1 (Code 0 with Star tester).
5. Perform brief WOT.
6. Testing is complete; Diagnostic Test Code (DTC) output begins.

Ensure vehicle speed reached 2000 RPM during WOT. If Code 538 is present, replace PCM. If Code 538 is not present, vehicle has passed dynamic response test. Service other codes if necessary.

The MIL is turned on when PCM detects a fault in EEC circuit(s). The light will remain on as long as fault remains in system.

Perform this test only when instructed by QUICK TEST or if directed by CIRCUIT TEST QA. This test does not include procedure for models with electronic instrument panel. To prevent replacing good components, be aware that fuse, bulb or bulb socket may be cause of problem. This test is only intended to diagnose

1. STO/MIL circuit.
2. Faulty PCM.

Identifying Data Link Connector (DLC) Terminals. Scheme 241

TEST PIN NO. 17 (STO/MIL) WIRE COLOR IDENTIFICATION

DATA (+) TEST PIN & WIRE COLOR IDENTIFICATION

DATA (-) TEST PIN & WIRE COLOR IDENTIFICATION

1. Step 1) Malfunction Indicator Light (MIL) Always On If vehicle will not start, go to CIRCUIT TEST AA. If vehicle starts, service all KOEO and continuous memory codes before proceeding with this test. Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between test pins No. 17 and 40 at breakout box. If resistance is more than 5 ohms, replace PCM and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If resistance is 5 ohms or less, repair short between test pin No. 17 and Data Link Connector (DLC) terminal No. 17 or MIL. Reconnect all components, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
2. Step 2) Malfunction Indicator Light (MIL) Does Not Light If vehicle will not start, go to CIRCUIT TEST AA. If vehicle starts, turn ignition on. Measure voltage between negative battery terminal and ground side of MIL fuse. If voltage is more than 10.5 volts, go to step 4). If voltage is 10.5 volts or less, go to next step.
3. Step 3) Check For Voltage At Fuse Turn ignition on. Measure voltage from negative battery terminal to power side of MIL fuse. If voltage is more than 10.5 volts, replace fuse. Verify repair by turning ignition on. If voltage is 10.5 volts or less, repair open MIL/B+ circuit. Verify repair by turning ignition on.
4. Step 4) Check B+ Circuit Voltage Turn ignition on. Measure voltage between B+ side of MIL bulb socket and negative battery terminal. If voltage is 10.5 volts or less, repair open MIL circuit between fuse and bulb. Verify repair by turning ignition on. If voltage is more than 10.5 volts, go to next step.
5. Step 5) Check MIL Bulb Response To Grounding Turn ignition off. Attach jumper wire between ground side of MIL bulb socket and chassis ground. Turn ignition on. If MIL comes on, remove jumper wire, and go to next step. If MIL does not come on, remove jumper wire. Replace MIL bulb socket. Turn ignition on to verify correct MIL operation.
6. Step 6) Check Continuity Of MIL Circuit Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between test pin No. 17 at breakout box and MIL wiring harness connector terminal. If resistance is less than 5 ohms, replace PCM. Turn ignition on to verify correct MIL operation. If resistance is 5 ohms or more, repair open ground side of MIL circuit. Turn ignition on to verify correct MIL operation. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 6) to step 10). No test procedures have been omitted.
7. Step 10) MIL On Intermittently, Check For Intermittent Short From STO To Ground If vehicle will not start, go to CIRCUIT TEST AA. If vehicle starts, service all fault codes before proceeding. If no codes are output, proceed with this test. Enter KOEO wiggle test. See «CONTINUOUS MONITOR MODE (WIGGLE TEST)»(ref-23598-S23726050792001010300000) under QUICK TEST. Check DVOM for indication of fault while performing wiggle test on harness in the following areas: From Data Link Connector (DLC) to dash panel. Dash panel to PCM. Dash panel to Malfunction Indicator Light (MIL). If a fault is indicated, repair short to ground and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If a fault is not indicated, fault cannot be duplicated at this time. Testing is complete. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 10) to step 15). No test procedures have been omitted.
8. Step 15) MIL Flashes With Erratic Idle Symptoms indicate STI is grounded and PCM is performing self-test without tester installed. Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between STI connector and engine ground. If resistance is less than 10,000 ohms, repair short circuit. Reconnect PCM, and turn ignition on to verify correct MIL operation. If resistance is 10,000 ohms or more, MIL circuit is okay. Verify symptom, and test for other rough idle symptoms. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 15) to step 20). No test procedures have been omitted.
9. Step 20) CHECK ENGINE Message Displayed If vehicle will not start, go to CIRCUIT TEST AA. If vehicle starts, perform «KOEO SELF-TEST»(ref-23598-S28031615042001010300000) . If result is Code 111-10-111 (pass code), fault is in instrument cluster. If pass code is not displayed, service codes as necessary. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 20) to step 25). No test procedures have been omitted.
10. Step 25) Continuous Memory Code 529 Or 533: CHECK ENGINE Or CHECK DCL Message Displayed Codes 529 and 533 indicate circuit fault has occurred on Data Communications Link (DCL). These codes can occur alone or with another code. Fault will occur under following conditions: Code 529 indicates PCM or DCL circuit failure. Code 533 indicates DCL to electronic instrument cluster circuit failure. If vehicle will not start, go to CIRCUIT TEST AA. If vehicle starts, clear continuous memory codes. Wait 5 minutes, and repeat «KOEO SELF-TEST»(ref-23598-S28031615042001010300000) . If result is pass code (Code 111-10-111), fault is in instrument cluster. If pass code is not displayed, service codes as necessary.

The IDM is an input signal to the PCM that verifies spark plug fire based on ignition coil primary discharge. IDM signal consists of a single pulse for each engine RPM. No IDM pulse indicates secondary ignition misfire.

Perform this test when directed by QUICK TEST . This test is only intended to diagnose EEC-IV portion of ignition system. For additional information on ignition system and component testing, see the SYSTEM/COMPONENT TESTS - 5.8L EEC-IV article. To prevent replacing good components, be aware the following non-EEC related areas may be cause of problem

1. Ignition Control Module (ICM).
2. Ignition coil.
3. Spark plugs and/or wires.
4. Distributor.
5. Secondary ignition short to ground.

This test is intended to diagnose

1. IDM circuit.
2. Faulty Powertrain Control Module (PCM).

IDM Circuit Schematic. Scheme 242

TEST PIN NO. 4 (IDM) WIRE COLOR IDENTIFICATION

TEST PIN NO. 56 (PIP) WIRE COLOR IDENTIFICATION

1. Step 1) Continuous Memory Code 211 Code 211 indicates 2 successive erratic Profile Ignition Pick-Up (PIP) pulses occurred, resulting in a possible engine miss or stall. Check for the following possible causes of fault: Loose wires or connectors. Secondary ignition short to ground. On-board transmitter equipment (2-way radio). Repair if necessary and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If problem is not found, go to next step. If vehicle doesn't start, check ignition. See IGNITION SYSTEMS in the «SYSTEM/COMPONENT TESTS - 5.8L EEC-IV»(ref-23711) article.
2. Step 2) Continuous Memory Code 212: Check IDM Circuit Continuity Continuous Memory Code 212 indicates loss of IDM input to PCM. Possible causes for this fault are: Open or shorted circuit in wiring harness. Faulty ICM. Faulty PCM. If vehicle does not start, check ignition system. See IGNITION SYSTEMS in «SYSTEM/COMPONENT TESTS - 5.8L EEC-IV»(ref-23711) article. If vehicle starts, go to next step.
3. Step 3) Check IDM Circuit Continuity Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Disconnect ICM. Measure resistance between test pin No. 4 at breakout box and IDM terminal at ICM wiring harness connector. If resistance is 5 ohms or less, go to step 5). If resistance is more than 5 ohms, repair open circuit, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 3) to step 5). No test procedures have been omitted.
4. Step 5) Check IDM Circuit For Short To Power (Except VREF) Turn ignition off. Leave ICM and PCM disconnected. Measure voltage between breakout box test pin No. 4 and negative battery terminal. Turn ignition on. Measure voltage between test pin No. 4 and test pins No. 40 and 60 at breakout box. If voltage is more than 10.5 volts, repair short circuit. Clear codes, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If voltage is 10.5 volts or less, go to next step.
5. Step 6) Check IDM Circuit For Short To PIP & VREF Turn ignition off. Leave PCM and ICM disconnected. Disconnect ignition coil wiring harness connector (non-CCD). Remove scan tester (if applicable). For short to PIP, measure resistance between test pins No. 4 and 56 at breakout box. For short to VREF, measure resistance between test pins No. 4 and 26 at breakout box. If any resistance is 10,000 ohms or less, repair short circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If each resistance is more than 10,000 ohms, go to next step.
6. Step 7) Check IDM Circuit For Short To Ground Turn ignition off. Remove scan tester (if applicable). Leave ignition coil, ICM and PCM disconnected. Measure resistance between test pin No. 4 and test pins No. 20, 40, 46 and 60 at breakout box. If each resistance is more than 10,000 ohms, reconnect scan tester and go to next step. If any resistance is 10,000 ohms or less, repair short to ground in IDM circuit. Clear codes, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
7. Step 8) Check Ignition Control Module (ICM) Turn ignition off. Connect PCM to breakout box. Reconnect ICM and ignition coil to wiring harness connectors. Connect DVOM between test pins No. 4 and 16 at breakout box. Start engine. Observe DVOM for voltage surge while lightly tapping on ICM to simulate road shock. Wiggle all ICM wiring and harness connector. If fault (voltage surge) is indicated, disconnect and inspect wiring harness connectors and terminals for damage. If fault is not indicated, go to next step.
8. Step 9) Check PCM & Harness Connectors Ensure engine is still running and DVOM is still connected between test pins No. 4 and 16 at breakout box. While observing DVOM, wiggle and bend wiring harness, a small section at a time, from ICM to instrument panel. Also, check harness from instrument panel to PCM. If fault is indicated, isolate fault and repair as necessary. Remove breakout box, reconnect all components, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If no fault is found, go to next step.
9. Step 10) Check PCM & Harness Connectors Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Clear codes, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If connector is okay, go to next step.
10. Step 11) Check PCM For Short To Power Turn ignition off. Connect PCM to breakout box. Measure voltage between test pin No. 4 at breakout box and chassis ground. Turn ignition on. Measure voltage between test pin No. 4 and test pins No. 40 and 60 at breakout box. If either voltage reading is more than 10.5 volts, replace PCM and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If both voltage readings are 10.5 volts or less, go to next step.
11. Step 12) Check PCM For Short To Ground Turn ign off. Leave PCM connected to breakout box. Measure resistance between test pin No. 4 and test pins No. 40, 46 and 60 at breakout box. If resistance more than 10,000 ohms, check ignition. See IGNITION SYSTEMS in «SYSTEM/COMPONENT TESTS - 5.8L EEC-IV»(ref-23711) article. If resistance is 10,000 ohms or less, replace PCM and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .

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

1. SPOUT wiring harness circuit.
2. Base timing.
3. Powertrain Control Module (PCM).

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

1. Basic engine condition (compression, valve timing, etc.).
2. Distributor.
3. Ignition Control Module (ICM).

Identifying ICM Connector Terminals. Scheme 243

TEST PIN NO. 36 (SPOUT) WIRE COLOR IDENTIFICATION

1. Step 1) Check For Power To PCM Before proceeding with this step, ensure base timing is correct. See the «ADJUSTMENTS - 5.8L»(ref-23633) article. If timing is okay, turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Turn ignition on. Measure voltage between test pins No. 37 and 40, and between test pins No. 57 and 60 at breakout box. If either voltage reading is less than 10.5 volts, go to CIRCUIT TEST B. If both voltage readings are 10.5 volts or more, go to next step.
2. Step 2) Check SPOUT Circuit For Continuity Turn ignition off. Disconnect ICM wiring harness connector. Measure resistance between test pin No. 36 at breakout box and SPOUT terminal at ICM wiring harness connector. If resistance is more than 5 ohms, repair open circuit. Reconnect all components, and check ignition timing. If resistance is 5 ohms or less, go to next step.
3. Step 3) Check SPOUT Circuit For Short To B+ Turn ignition off. Leave PCM and ICM disconnected. Turn ignition on. Measure voltage between test pin No. 36 and test pin No. 40 or 60. If voltage is more than 10.5 volts, repair short circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If voltage is 10.5 volts or less, go to next step.
4. Step 4) Check SPOUT Circuit For Short To PIP, VREF & Ground Turn ignition off. Leave PCM and ICM disconnected. To check for short to VREF, use DVOM to measure resistance between test pins No. 26 and 36 at breakout box. To test for short to PIP, measure resistance between test pins No. 36 and 56 at breakout box. To test for short to ground, measure resistance between test pin No. 36 and test pins No. 16, 20, 40, 46 or 60. If any resistance 10,000 ohms or less, repair short circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If each resistance is more than 10,000 ohms, EEC system is okay. Check ignition. See IGNITION SYSTEMS in «SYSTEM/COMPONENT TESTS - 5.8L EEC-IV»(ref-23711) article.

Aftermarket 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 state and repeat QUICK TEST .

Perform this test when directed by QUICK TEST or other test procedures. This test is intended to diagnose

1. Powertrain Control Module (PCM).
2. EEC power relay.
3. Wiring harness circuits (HO2S, SIG RTN, STO, STI, VPWR and VREF).

No Codes/Codes Not Listed Circuits. Scheme 244

TEST PIN NO. 17 (STO/MIL) WIRE COLOR IDENTIFICATION

TEST PINS NO. 37 & 57 (VPWR) WIRE COLOR IDENTIFICATION

TEST PIN NO. 46 (SIG RTN) WIRE COLOR IDENTIFICATION

TEST PIN NO. 48 (STI) WIRE COLOR IDENTIFICATION

1. Step 1) Check VREF Voltage At Data Link Connector (DLC) Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV). Connect PCM to breakout box. Turn ignition on. Measure voltage between test pin No. 26 at breakout box and SIG RTN terminal at DLC. If voltage is 4-6 volts, go to step 3). If voltage is not 4-6 volts, go to next step.
2. Step 2) Check SIG RTN Circuit Continuity Turn ignition off. Disconnect PCM from breakout box. Measure resistance between test pin No. 46 at breakout box and SIG RTN terminal at DLC. If resistance less than 5 ohms, go to CIRCUIT TEST C. If resistance is 5 ohms or more, repair open circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
3. Step 3) Check STI Circuit Continuity Turn ignition off. Disconnect PCM from breakout box. Measure resistance between test pin No. 48 at breakout box and Self-Test Input (STI) terminal at pigtail connector. If resistance is 5 ohms or more, repair open circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If resistance is less than 5 ohms, go to next step.
4. Step 4) Check STO Circuit Continuity Leave ignition off and PCM disconnected. Measure resistance between test pin No. 17 at breakout box and STO terminal at DLC. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .

Diagnostic Aid

A HO2S short to power could prevent EEC system from entering self-diagnostics.

1. Step 5) Check HO2S Signal For Short To Power Leave PCM disconnected. Turn ignition on. Measure voltage between test pin No. 40 or 60 and HO2S SIGNAL test pin No. 29 at breakout box. If voltage is 2 volts or less, go to step 7). If voltage is more than 2 volts, go to next step.
2. Step 6) Isolate Short To Harness Or HO2S Sensor Turn ignition off. Leave PCM disconnected. Disconnect HO2S sensor connector. Turn ignition on. Measure voltage between HO2S SIGNAL test pin No. 29 and test pins No. 40 and 60 at breakout box. If any measurement is 2 volts or more, repair short to power in HO2S SIGNAL circuit, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If voltage is less than 2 volts, replace HO2S sensor and repeat QUICK TEST.
3. Step 7) Check STO Circuit For Short To Ground Turn ignition off. Leave PCM disconnected. Measure resistance between STO at DLC and engine ground. If resistance is more than 5 ohms, go to next step. If resistance is 5 ohms or less, repair STO or MIL circuit for short to ground and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .
4. Step 8) Check If Power Relay Is Always On Leave ignition off and PCM disconnected. Connect DVOM between test pin No. 37 or 57 and pin No. 40 or 60 at breakout box. Turn ignition on and then off. Wait 10 seconds. If voltage changes from 10.5 volts (or more) to less than one volt, go to step 10). If voltage does not change from 10.5 volts (or more) to less than one volt, go to next step.
5. Step 9) Check VPWR Circuit For Short To Power Turn ignition off. Leave PCM disconnected. Disconnect EEC power relay. Connect DVOM to test pin No. 37 or 57 and test pin No. 40 or 60 at breakout box. If voltage is more than one volt, repair VPWR circuit short to power and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If voltage is one volt or less, replace EEC power relay and repeat QUICK TEST.
6. Step 10) Check Malfunction Indicator Light (MIL) Function If MIL is always on, go to CIRCUIT TEST ML, step 1). If MIL is always off, go to CIRCUIT TEST ML, step 2). If MIL is flashing off and on, go to CIRCUIT TEST ML, step 15). If MIL is working normally, replace PCM and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .

Perform this test when directed by QUICK TEST . This test is intended to diagnose

1. Faulty Powertrain Control Module (PCM).
2. KAPWR wiring harness circuits.

KAPWR Circuit Schematic. Scheme 245

TEST PIN NO. 1 (KAPWR) WIRE COLOR IDENTIFICATION

Continuous Memory Code 512 may be displayed when power to PCM is interrupted. This code may be set when a breakout box is installed or battery is disconnected.

1. Step 1) Continuous Memory Code 512: Check KAPWR Circuit Voltage Code 512 indicates PCM power interruption in Keep-Alive Memory (KAM). Clear codes and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If Code 512 is repeated, turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure voltage between test pin No. 1 and test pins No. 40 or 60 at breakout box. Observe voltage reading while wiggling small sections of EEC wiring harness from PCM to dash. If reading is less than 10.5 volts, repair open circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If reading is 10.5 volts or more, go to next step.
2. Step 2) Inspect Wiring Harness Routing Ensure EEC wiring is not routed close to ignition components and secondary ignition wires. If necessary, reroute EEC wiring. Clear codes, and wait 5 minutes. Repeat «KOEO SELF-TEST»(ref-23598-S28031615042001010300000) . If Continuous Memory Code 512 is not repeated, testing is complete. If Continuous Memory Code 512 is still present, replace PCM and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) .

Perform this circuit test when directed by other CIRCUIT TESTS. This test is only intended to diagnose

1. Faulty Powertrain Control Module (PCM).
2. Throttle plate linkage.

1. Step 1) Check For Codes 121, 122 & 123 Disconnect cruise control servo wiring harness connector (if equipped). Perform «KOEO SELF-TEST»(ref-23598-S28031615042001010300000) . If Code 121, 122 or 123 is present, go to appropriate CIRCUIT TEST. See «DIAGNOSTIC TROUBLE CODE REFERENCE CHART»(ref-23598-S35260139562001010300000) . If Code 111 (pass code) is displayed, go to next step. If no code is displayed, go to CIRCUIT TEST QA.
2. Step 2) Check Throttle Linkage Check throttle and linkage for sticking and binding. If throttle and linkage are okay, replace Throttle Position (TP) sensor and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If throttle and linkage are binding, repair as necessary and repeat QUICK TEST.

Perform this test only when directed by QUICK TEST . This test is intended to diagnose

1. Battery voltage.
2. Powertrain Control Module (PCM).

Perform this test only when directed by CIRCUIT TEST AA. This test is intended to diagnose

1. IAC system.
2. MAP system.
3. EGR system.

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

1. Faulty power or ground connections.
2. Secondary ignition (distributor cap, rotor, wires, coil and plugs).
3. Engine mechanical components (compression, timing, valves, etc.).

1. Step 1) IAC Check Try to start engine at part throttle. If engine starts and runs smoothly at part throttle, go to CIRCUIT TEST KE, step 4). If engine does not run as described, go to step 3). If engine starts and idles smoothly, go to next step.
2. Step 2) Check For RPM Drop Turn ignition off. Connect a tachometer to engine. Start engine. Disconnect IAC solenoid. If RPM drops or engine stalls, reconnect IAC solenoid and go to next step. If RPM does not drop, CIRCUIT TEST KE, step 4).
3. Step 3) Power To MAP Sensor Turn ignition off. Disconnect MAP sensor. Connect MAP tester between wiring harness and MAP sensor. see scheme 36 Connect banana plugs of tester into DVOM. Turn ignition on. If Green light is on, go to next step. If Green light is off, repair open VREF circuit and check system operation. see scheme 36: MAP Tester & Circuit
4. Step 4) MAP Tester Output Reading If possible, measure several known-good MAP sensors to obtain average voltage for location and day of testing. With MAP tester and DVOM connected, turn ignition on. Measure MAP voltage at MAP sensor. If voltage is not within specification for specific altitude, replace MAP sensor. See MAP VOLTAGE OUTPUT table. If voltage is in within specification for specific altitude, go to next step. MAP VOLTAGE OUTPUT Approximate Elevation (Ft.) Voltage Output (Volts) 0 1.55-1.63 1000 1.52-1.60 2000 1.49-1.57 3000 1.46-1.54 4000 1.43-1.51 5000 1.40-1.48 6000 1.37-1.45 7000 1.35-1.43
5. Step 5) Check Vacuum Lines Check vacuum hoses for correct routing. Refer to VECI decal. Check MAP sensor vacuum hose for leaks and blockage. If vacuum hoses are okay, go to next step. If vacuum hoses are not okay, repair as necessary. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000).
6. Step 6) Check MAP Sensor Turn ignition off. Disconnect vacuum hose from manifold vacuum source. Connect vacuum pump to MAP sensor hose. Apply 18 in. Hg vacuum to MAP sensor. If MAP sensor holds vacuum, go to next step. If MAP sensor does not hold vacuum, replace MAP sensor or hose and repeat «QUICK TEST»(ref-23598-S07232509482001010300000).
7. Step 7) Check Vacuum Manifold Source Install vacuum gauge at manifold vacuum source. 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 and repeat «QUICK TEST»(ref-23598-S07232509482001010300000).
8. Step 8) Check EGR Vacuum If vehicle is not equipped with EGR system, go to CIRCUIT TEST H, step 2). Disconnect and plug vacuum line at EGR valve. Attempt to start engine. If vehicle did not start previously but starts now or if driveabilitymptoms are eliminated, go to CIRCUIT TEST DN, step 42). If vehicle could not start previously and still does not start or if vehicle driveability fault is still present, go to next step.
9. Step 9) Check EGR Valve Inspect EGR valve for leaks. If valve is fully closed, go to CIRCUIT TEST H, step 2). If EGR valve is leaking or is not fully seated, repair or replace valve as necessary.

Perform this test only when directed by QUICK TEST . This test is intended to diagnose

1. Clutch Pedal Position (CPP) switch.
2. Park/Neutral Position (PNP) switch.
3. Powertrain Control Module (PCM).
4. Wiring harness circuits (CPP, PNP and SIG RTN).

CPP Switch Circuit Schematic (With C6 Transmission). Scheme 246

CPP Switch Circuit Schematic (With M/T). Scheme 247

TEST PIN NO. 30 (CPP/PNP) WIRE COLOR IDENTIFICATION

TEST PIN NO. 46 (SIG RTN) WIRE COLOR IDENTIFICATION

1. Step 1) Code 522, 525 Or 528 Code 522, 525 or 528 is a result of voltage being high at No. 30 (CPP/PNP input) while cranking engine or during «KOEO SELF-TEST»(ref-23598-S28031615042001010300000) . Possible causes for these faults are: CPP or PNP circuit open. Faulty Powertrain Control Module (PCM). Starter relay disconnected during self-test. On all A/T models, go to step 3). On all M/T models, go to next step.
2. Step 2) Check CPP Input Turn ignition off. Turn A/C off (if equipped). Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Depress clutch pedal. Measure resistance between test pin No. 30 and Red/Light Blue wire at starter relay. If resistance less than 5 ohms, replace PCM. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If resistance is 5 ohms or more, repair open circuit and repeat QUICK TEST.
3. Step 3) Check PNP Switch Input Turn ignition and A/C off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV). Connect PCM to breakout box. Turn ignition on. Measure voltage between chassis ground and test pin No. 30 at breakout box. If voltage is less than one volt, replace PCM and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If voltage is one volt or more, go to next step.
4. Step 4) Check PNP Switch Resistance Turn ignition off. Disconnect PCM from breakout box. Disconnect PNP wiring harness connector. Measure resistance across switch terminals. If resistance is less than 5 ohms, repair open PNP circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If resistance is 5 ohms or more, replace PNP switch and repeat QUICK TEST.

Perform this test only when directed by QUICK TEST . To prevent replacing good components, be aware the following non-EEC areas may be at fault

1. Engine base condition (compression, valve timing, etc.).
2. Brakes.
3. Transmission fluid, friction elements and cooling.
4. Transfer case linkage or internal condition.

This test is only intended to diagnose

1. Harness circuits (4x4 LOW, TCIL and TCS).
2. Faulty PCM.

4x4 Low Switch Circuit (Touch Drive Option). Scheme 248

Transmission Control Switch Circuit. Scheme 249

4x4 Low Switch Circuit (Touch Drive Option). Scheme 250

Scheme 251

1. Step 1) Codes 633 & 691 Code 633 indicates 4x4 low selector lever is not in 4x2 or 4x4 HIGH position during «KOEO SELF-TEST»(ref-23598-S28031615042001010300000). Code 691 indicates 4x4 selector fault is set when KAM value for engine speed/vehicle speed disagrees with PCM logic regarding engine speed/vehicle speed verses TCS position. Possible causes for these faults are: Faulty 4x4 Low switch or 4x4 selector lever position. Transfer case damaged internally. Wiring harness circuit open or grounded. Faulty PCM. If 4x4 low selector lever was in 4x2 or 4x4 HIGH position during «KOEO SELF-TEST»(ref-23598-S28031615042001010300000), go to step 4). If 4x4 low selector was not in 4x2 or 4x4 HIGH position, repeat KOEO SELF-TEST with lever in 4x2 or 4x4 HIGH position.
2. Step 2) Codes 632 & 653 Codes 632 and 653 indicate TCS is not cycled between engine ID code and WOT check during «KOER SELF-TEST»(ref-23598-S29311478132001010300000). Possible causes for these faults are: Faulty TCS or switch not cycled. Wiring harness circuit open or grounded. Faulty PCM. Ensure TCS is cycled between engine ID code and WOT check during «KOER SELF-TEST»(ref-23598-S29311478132001010300000), and go to step 4).
3. Step 3) Codes 631 & 623 Codes 631 and 623 indicate TCS light circuit fault during «KOEO SELF-TEST»(ref-23598-S28031615042001010300000). Possible causes for these faults are: TCS bulb burned out. Wiring harness circuit open or grounded. Ensure TCS is cycled during «KOEO SELF-TEST»(ref-23598-S28031615042001010300000), go to step 5).
4. Step 4) Cycle 4x4 Or Overdrive Cancel Switch Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Turn ignition on. To check 4x4 LOW circuit, measure voltage between test pin No. 12 and test pins No. 40 and 60 at breakout box while cycling switch in and out of 4x4 low position. To check TCS circuit, measure voltage between test pin No. 41 and test pins No. 40 and 60 at breakout box while cycling overdrive cancel switch. On all models, if voltage cycles, replace PCM and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If voltage does not cycle, go to next step if diagnosing a trouble code or step 7) if diagnosing driveabilitymptom only.
5. Step 5) Check Circuits For Short To Ground Turn ignition off. Leave PCM disconnected from breakout box. Disconnect switch connector. Inspect for damage and repair as necessary. To check 4x4 LOW circuit, measure resistance between test pin No. 12 and test pins No. 40 and 60 at breakout box. To check TCS circuit, measure resistance between test pin No. Step 41 and pins No. 40 and 60 at breakout box. Also, measure resistance between test pin No. 32 and pins No. 40 and 60 at breakout box. If all readings are more than 10,000 ohms, go to next step for Code 631 or 623, or step 8) for Code 632, 633, 653 or 691. If any reading 10,000 ohms or less, repair short circuit. Repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If code is still present, go to step 7).
6. Step 6) Check Power Through TCIL Circuit Turn ignition off. Leave PCM disconnected from breakout box. Measure voltage between test pin No. 32 and test pins No. 40 and 60 at breakout box. If voltage is more than 10.5 volts, replace PCM and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If voltage is 10.5 volts or less, go to next step.
7. Step 7) Check Output Driver Voltage Signal Leave PCM disconnected from breakout box. Turn ignition on. To check 4x4 LOW circuit, disconnect switch. Connect DVOM positive lead to test pin No. 12 and negative lead to PWR GND terminal of breakout box. To check TCIL circuit, connect DVOM positive lead to test pin No. 32 and negative lead to PWR GND terminal of breakout box. On all models, if either voltage reading is less than 2 volts, check bulb and fuse. If bulb and fuse are okay, repair open circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If all voltage readings are 2 volts or more, go to next step. (Scheme 251): Identifying KEY POWER Terminal In Fuse Panel
8. Step 8) Check Circuit Continuity Turn ignition off. Leave PCM disconnected from breakout box. Leave switch disconnected. To check 4x4 LOW circuit, measure resistance between test pin No. 12 at breakout box and 4x4 LOW LED circuit at switch wiring harness connector. To check TCS/TCIL circuit, connect DVOM positive lead on KEY POWER terminal of fuse panel and negative lead on power side of TCS wiring harness connector. Also, connect DVOM positive lead on test pin No. 41 at breakout box and negative lead on power side of TCS wiring harness connector. On all models, if any resistance reading is 5 ohms or more, repair open circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If all resistance readings are less than 5 ohms, go to next step.
9. Step 9) Check Circuits For Short To Power Turn ignition off. Leave PCM disconnected from breakout box. Leave switch disconnected. To check 4x4 LOW circuit, measure resistance between test pin No. 12 and test pins No. 37 and 57 at breakout box. To check TCS circuit, measure resistance between test pin No. Step 32 and test pins No. 37 and 57 at breakout box. Also, measure resistance between test pin No. 41 and test pins No. 37 and Step 57 at breakout box. On all models, if each resistance is more than 10,000 ohms, replace switch and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If any resistance is 10,000 ohms or less, repair short circuit and repeat QUICK TEST.

Perform this test only when directed by QUICK TEST . To prevent replacing good components, be aware the following non-EEC areas may be at fault

1. Engine condition (compression, cam timing, valves, etc.).
2. Chargingstem or battery.
3. Transmission linkage, internal components or cooling.

This test is not intended to diagnose transmission. This test is intended to diagnose

1. Wiring harness circuits (TCC, CCS, EPC, SS3/4, SS1, SS2, SS3, SIG RTN, EPC PWR and VPWR).
2. Faulty Powertrain Control Module (PCM).

CIRCUIT TEST TC ACRONYMS

Identifying E4OD Solenoid Circuits. Scheme 252

TEST PINS NO. 37 & 57 WIRE COLOR IDENTIFICATION

E4OD DTC IDENTIFICATION

1. Step 1) OUTPUT STATE CHECK Code 621, 622, 626 or 629 indicates shift solenoid did not respond to PCM command. Possible causes for these faults are: Faulty solenoid assembly. Circuit open or grounded. Faulty Powertrain Control Module (PCM). To enter output state Diagnostic Test Mode (DTM), use only VOM or DVOM. DO NOT use scan tester. Turn ignition off. Disconnect cruise control servo wiring harness connector. Connect DVOM negative lead to STO terminal at Data Link Connector (DLC). Connect positive lead to positive battery terminal. Install a jumper wire between SIG RTN terminal and STI terminal at DLC. (Scheme 244) Perform «KOEO SELF-TEST»(ref-23598-S28031615042001010300000) until continuous memory test is complete. DVOM will read less than one volt when test is complete to indicate PCM has entered output state DTM. Depress and release throttle. If voltage increases, remain in output state DTM and go to next step. If voltage does not increase, depress throttle to WOT and release. If STO voltage goes high, go to next step. If STO voltage does not go high, leave test equipment connected and go to CIRCUIT TEST QC.
2. Step 2) Check Solenoid Electrical Condition Turn ignition off. Disconnect transmission wiring harness connector. Inspect terminals and repair if damaged. Connect VOM or DVOM positive test lead to solenoid wiring harness connector VPWR terminal. Connect negative test lead to appropriate shift solenoid terminal at transmission wiring harness connector. Turn ignition on. Cycle solenoid output on and off by depressing and releasing throttle 3-5 times. If voltage output changes by 0.5 volt or more, fault is in transmission. If voltage output does not change by 0.5 volt or more, go to next step.
3. Step 3) Check Solenoid & VPWR Circuit Continuity Turn ignition off. Leave transmission wiring harness disconnected. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between suspect transmission wiring harness connector terminal and corresponding test terminal at breakout box. See the «E4OD DTC IDENTIFICATION»(ref-23598-S25349574492001010300000) table at beginning of this circuit test. Also, measure resistance between breakout box test pins No. 37 and 57 and VPWR terminal at transmission wiring harness connector. If each resistance is less than 5 ohms, go to next step. If any resistance is 5 ohms or more, repair open circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000).
4. Step 4) Check Solenoid Circuit For Short To Power Or Ground Leave ignition off and PCM disconnected. Leave transmission wiring harness disconnected. Measure resistance between suspect PCM output signal test pin and test pins No. 37 and 57 at breakout box. Measure resistance between suspect PCM output signal test pin and pins No. 40, 46 and 60 at breakout box. If any resistance is less than 10,000 ohms, repair short circuit and repeat QUICK TEST. If each resistance is 10,000 ohms or more, check solenoids. If solenoids are okay, replace PCM and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 4) to step 10). No test procedures have been omitted.
5. Step 10) Code 624 Or 625: Check VPWR To Solenoid Code 624 indicates failure of EPC circuit. Code 625 indicates EPC driver failure. Possible causes for these faults are: Faulty solenoid. Circuit open or grounded. Turn ignition off. Disconnect transmission wiring harness connector. Turn ignition on. Measure resistance between VPWR and EPC PWR terminal at transmission wiring harness connector and chassis ground. If voltage is less than 10.5 volts, repair open circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If voltage is 10.5 volts or more, go to next step.
6. Step 11) Check Solenoid Signal & VPWR Circuit Continuity Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between VPWR/EPC PWR terminal at transmission wiring harness connector breakout box test pins No. 37 and 57. Also, measure resistance between test pin No. 38 at breakout box and EPC terminal at transmission wiring harness connector. If resistance 5 ohms or more, repair open circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If resistance is less than 5 ohms, go to next step.
7. Step 12) Check Circuit For Short To Power Or Ground Leave ignition off and PCM disconnected. Leave transmission wiring harness connector disconnected. Measure resistance between test pins No. 37 and 57 and suspect solenoid test pin at breakout box. Also, measure resistance between test pins No. 40, 46 and 60 and suspect solenoid test pin at breakout box. If any resistance is less than 10,000 ohms, repair short circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If each resistance is 10,000 ohms or more, check solenoids. If solenoids are okay, replace PCM and repeat QUICK TEST.

Perform this test only when directed by QUICK TEST . To prevent replacing good components, be aware the following non-EEC areas may be at fault

1. Transmission linkage and internal components.
2. Electrical (alternator, battery, add-on devices, etc.).

This test is not intended to diagnose transmission. This test is intended to diagnose

1. Wiring harness circuits (TR and SIG RTN).
2. Powertrain Control Module (PCM).

TR Sensor Connector Terminals (4R70W Transmission). Scheme 253

TR Sensor Connector Terminals (E4OD Transmission). Scheme 254

1. Step 1) Codes 634, 654, 667 & 668 Code 634 indicates TR sensor is out of self-test range (3770-4607 ohms) when gear selector is in Park. Code 654 indicates gear selector was not in gear during SELF-TEST. Code 667 indicates a short to ground in TR circuit. Code 668 indicates an open circuit in TR circuit. Possible causes for these faults are: Linkage not adjusted correctly. Transmission not in Park during SELF-TEST. Faulty TR sensor. Circuit open or grounded. Faulty Powertrain Control Module (PCM). Turn ignition off. Apply parking brake. Place transmission gear selector in Neutral. Place TR Sensor Gauge (T92P-70010-AH) in sensor slot. If gauge does not fit, loosen TR sensor mounting bolts and adjust sensor as necessary. If gauge fits, remove gauge and go to next step.
2. Step 2) Check TR Sensor Circuit Continuity Turn ignition off. Disconnect TR sensor wiring harness connector. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between TR terminal at TR sensor wiring harness connector and test pin No. 30 at breakout box. Also, measure resistance between SIG RTN terminal at TR sensor wiring harness connector and test pin No. 46 at breakout box. If either resistance is more than 5 ohms, repair open circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If each resistance is 5 ohms or less, go to next step.
3. Step 3) Check TR Sensor For Short To Power & Ground Turn ignition off. Leave PCM and TR sensor disconnected. Measure resistance between test pin No. 30 and test pins No. 37, 40, 46, 57 and 60 at breakout box. Also, measure resistance between test pin No. 30 and chassis ground. If any resistance is less than 10,000 ohms, repair short circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If each resistance is 10,000 ohms or more, go to next step.
4. Step 4) Check TR Sensor Resistance Turn ignition off. Connect TR sensor. Leave PCM disconnected. Unlock steering column. Measure resistance between test pins No. 30 and 46 at breakout box while cycling gear selector. See «TR SENSOR RESISTANCE»(ref-23598-S32451059892002011500000) table. If resistance is within specification, replace PCM and repeat «QUICK TEST»(ref-23598-S07232509482001010300000) . If resistance is not within specification, replace TR sensor and repeat QUICK TEST. TR SENSOR RESISTANCE Gear Selected Ohms Park 3770-4607 Reverse 1304-1593 Neutral 660-807 Overdrive 361-442 Drive 190-232 First 190-232

Perform this test only when directed by QUICK TEST . To prevent replacing good components, be aware the following non-EEC areas may be at fault

1. Engine and/or transmission fluid level.
2. Engine and/or transmission fluid temperature.
3. Ambient temperature.

This test is intended to diagnose

1. TFT sensor.
2. Wiring harness circuits (TFT and SIG RTN).
3. Faulty Powertrain Control Module (PCM).

TFT Sensor Circuit At E4OD Transmission. Scheme 255

TFT SENSOR SPECIFICATIONS

1. Step 1) Code 636 KOEO Code 636 indicates TFT sensor is out of self-test range. Possible causes for these faults are: Transmission fluid level incorrect. Transmission fluid temperature incorrect. Sensor resistance out of specification. Faulty Powertrain Control Module (PCM). Ensure transmission fluid temperature is more than 50°F (10°C). Repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If Code 636 is present, go to next step. If Code 636 is not present, no problem is indicated at this time. Test is complete.
2. Step 2) Check VREF At Throttle Position (TP) Sensor Turn ignition off. Disconnect TP sensor wiring harness connector. Turn ignition on. Measure voltage between VREF and SIG RTN terminals at TP sensor wiring harness connector. see scheme 47 If voltage is 4-6 volts, go to next step. If voltage is not 4-6 volts, go to CIRCUIT TEST C.
3. Step 3) Check TFT Sensor Resistance Turn ignition off. Disconnect PCM from breakout box. Allow transmission to cool. Measure and record resistance between test pin No. 46 and TFT test pin at breakout box. Reconnect PCM connector. Drive vehicle until transmission fluid is at normal operating temperature. Disconnect PCM from breakout box. Again, measure resistance between test pin No. 46 and TFT test pin at breakout box. If cold resistance measurement different than warm resistance measurement, and warm resistance within specs, replace PCM and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). See «TFT SENSOR SPECIFICATIONS»(ref-23598-S03784630052002011500000) table. If resistance is not as specified, replace TFT sensor. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 3) to step 10). No test procedures have been omitted.
4. Step 10) KOEO Code 637 KOEO Code 637 indicates TFT sensor output exceeds self-test maximum voltage (4.8 volts). Possible causes for these faults are: Transmission fluid level incorrect. Open wiring harness circuit. Faulty TFT sensor. Faulty PCM. Turn ignition off. Disconnect TFT wiring harness connector. Inspect terminals, and repair if damaged. Connect jumper wire between TFT and SIG RTN terminals. Perform «KOEO SELF-TEST»(ref-23598-S28031615042001010300000). If Code 638 is present, go to step 25). If Code 638 is not present, remove jumper wire and go to next step. If no codes are present, go to step 12).
5. Step 11) Check TFT & SIG RTN Circuit Continuity Turn ignition off. Leave TFT sensor disconnected. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving PCM disconnected. Measure resistance between TFT circuit at TFT wiring harness connector and TFT test pin at breakout box. Also, measure resistance between SIG RTN circuit at TFT wiring harness connector and test pin No. 46 at breakout box. If either resistance more than 5 ohms, repair open circuit, repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If each resistance is 5 ohms or less, go to next step.
6. Step 12) Check TFT Sensor For Short To VPWR Turn ignition off. Leave PCM and TFT sensor disconnected. Measure resistance between TFT test pin and test pins No. 37 and 57 at breakout box. If resistance is more than 10,000 ohms, replace PCM and repeat QUICK TEST. If resistance is 10,000 ohms or less, repair short circuit and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 12) to step 20). No test procedures have been omitted.
7. Step 20) KOEO Code 638 KOEO Code 638 indicates TFT sensor output is lower than self-test minimum voltage. Possible causes for these faults are: Incorrect fluid level. Damaged TFT sensor. Shorted wiring harness circuit. Faulty PCM. Turn ignition off. Disconnect transmission harness connector. Inspect terminals, repair if damaged. Perform «KOEO SELF-TEST»(ref-23598-S28031615042001010300000). If Code 637 is present, go to step 25). If Code 637 is not present, go to next step.
8. Step 21) Check VREF At Throttle Position (TP) Sensor Turn ignition off. Disconnect TP sensor wiring harness connector. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV). Connect PCM to breakout box. Turn ignition on. Measure voltage between VREF and SIG RTN terminals at TP sensor wiring harness connector. see scheme 47 If voltage is 4-6 volts, reconnect TP sensor and go to next step. If voltage is not 4-6 volts, go to CIRCUIT TEST C. see scheme 47: Throttle Position (TP) Sensor Connector Terminals
9. Step 22) Check TFT Circuit For Short To Ground Turn ignition off. Disconnect PCM from breakout box. Measure resistance between TFT test pin at breakout box and test pins No. 40, 46 and 60. If resistance is more than 10,000 ohms, replace PCM and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If resistance is 10,000 ohms or less, repair short circuit and repeat QUICK TEST. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 22) to step 25). No test procedures have been omitted.
10. Step 25) Check Transmission Wiring Harness Turn ignition off. Check transmission internal and external wiring and connectors for damage and corrosion. Repair or replace if necessary. If wiring okay, replace TFT sensor and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 25) to step 90). No test procedures have been omitted.
11. Step 90) Continuous Memory Code 637 Or 638 Continuous Memory Code 637 or 638 indicates a fault has been detected in TFT circuit during previous 80 warm-up cycles. Possible causes for these faults are: Incorrect fluid level. Intermittent fault in TFT sensor. Intermittent short or open in wiring harness. Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV). Connect PCM to breakout box. Connect DVOM between test pins No. 2 and 46 at breakout box. Turn ignition on. Shake and bend TFT and SIG RTN wires between transmission and PCM. Voltage should remain stable or change gradually. If voltage drops to zero, a short to ground is indicated. If voltage increases up to 5 volts, an open circuit is indicated. If voltage increases to more than 5 volts, a short to power is indicated. If fault is indicated, isolate and repair as necessary. If no faults are found, problem is intermittent and cannot be located at this time. NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 90) to step 100). No test procedures have been omitted.
12. Step 100) Continuous Memory Code 657 Continuous Memory Code 657 indicates excessive transmission temperatures. Possible causes for these faults are: Damage in transmission coolingstem. Pulling overweight trailer. Incorrect fluid level. Damaged clutch. Fault in TFT sensor. Intermittent short or open in wiring harness. Turn ignition off. Disconnect transmission wiring harness connector. Inspect terminals and repair if damaged. Perform «KOEO SELF-TEST»(ref-23598-S28031615042001010300000). If no codes are present, fault is in transmission. If Code 657 is present, check for fault causing transmission to overheat. If any other code(s) present, service as necessary, repeat «QUICK TEST»(ref-23598-S07232509482001010300000).

Perform this test only when directed by QUICK TEST . This test is intended to diagnose

1. Wiring harness circuits (CCS, SS1, SS2, SS3, EPC, TCC, TFT, and TR).
2. Powertrain Control Module (PCM).

E4OD Transmission Circuit & Wiring Connector Terminals. Scheme 256

4R70W Transmission Circuit & Wiring Connector Terminals. Scheme 257

Note. Procedure begins with step 90). No test procedures have been omitted.

1. Step 90) Drive Cycle Test (4R70W & E4OD) Ensure all components are connected. Ensure transmission fluid level is correct. Warm engine to normal operating temperature. Perform «KOEO SELF-TEST»(ref-23598-S28031615042001010300000), and record all continuous memory codes. Clear all codes. With transmission gear selector in Drive, press Transmission Control Switch (TCS). Transmission Control Indicator Light (TCIL) should come on. Moderately accelerate vehicle to 40 MPH for at least 15 seconds (30 seconds above 4000 feet elevation). Transmission should be in 3rd gear. While holding speed steady, press TCS. TCIL should go off. Accelerate from 40 MPH to 50 MPH. Transmission should shift from 3rd gear to 4th gear. Hold speed steady for 15 seconds. While holding speed steady, lightly apply and release brakes to turn brakelights on. Maintain 50 MPH for about 5 seconds. Stop and park vehicle for a minimum of 20 seconds with transmission gear selector in Drive. Repeat procedure 5 times. After completing DRIVE CYCLE TEST, perform «KOEO SELF-TEST»(ref-23598-S28031615042001010300000), and record all continuous memory codes. If Code 111 is present, fault cannot be duplicated at this time. Fault may be internal transmission damage. If Code 624 is present, go to next step. If Code 452 is present, go to CIRCUIT TEST DS. If any other code(s) is present, go to step 92). see scheme 50: TR Sensor Circuit & Wiring Connector Terminals (4R70W) see scheme 51: TR Sensor Circuit & Wiring Connector Terminals (E4OD)
2. Step 91) Code 624 Code 624 indicates Electronic Pressure Control (EPC) failure. Possible causes for these faults are: Faulty EPC solenoid. Faulty TR sensor. Circuit open or grounded. Damaged PCM connector pins. Turn ignition off. Disconnect PCM 60-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install EEC-IV Breakout Box (T83L-50-EEC-IV). Connect PCM to breakout box. To test EPC solenoid, connect DVOM to EPC test pin and EPC VPWR test pin at breakout box. Turn ignition on. Voltage should be less than 10 volts. Shake and bend EPC wiring harness. Lightly tap on components to simulate road shock. Voltage should remain stable. If voltage changes or exceeds specification, fault in circuit is indicated. If fault is indicated, isolate and repair as necessary. Clear continuous memory codes, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If no faults are found, problem cannot be located at this time.
3. Step 92) Check Circuit Harness & Connectors Enter CONTINUOUS MONITOR MODE. Shake and bend EEC wiring harness while observing analog VOM or scan tool. Lightly tap on components to simulate road shock. If VOM indicator has erratic movement or scan tool beep, fault is indicated. If fault is indicated, isolate and repair as necessary. Clear continuous memory codes, and repeat «QUICK TEST»(ref-23598-S07232509482001010300000). If no faults are found, problem cannot be located at this time. CIRCUIT TEST KOEO CONTINUOUS MEMORY CODES Code Fault 617 Improper 1-2 Shift 618 Improper 2-3 Shift 619 Improper 3-4 Shift 628 Excessive Converter Clutch Slippage 637 Excessive TFT Circuit Voltage 638 Inadequate TFT Circuit Voltage 645 Inadequate 1st Gear Command Response 646 Inadequate 2nd Gear Command Response 647 Inadequate 3rd Gear Command Response 648 Inadequate 4th Gear Command Response 656 Continuous Slippage Detected

5.8L PCM Wiring Diagram (EEC-IV - 1 Of 2). Scheme 258

5.8L PCM Wiring Diagram (EEC-IV - 2 Of 2). Scheme 259