Engine Controls - System & Component Testing: Other Infiniti G20 II

Power & Ground Circuits (G20)

1. Start engine. If engine starts, go to next step. If engine does not start, turn ignition off and on. Measure voltage between ground and ECM terminal No. 43 by backprobing. (Scheme 48)and (Scheme 49). If battery voltage exists, go to step 8. If battery voltage does not exist, go to next step.
2. Turn ignition off. Measure voltage between ground and ECM terminal No. 67 by backprobing. (Scheme 48)and (Scheme 49). If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit and retest system. See appropriate wiring diagram in WIRING DIAGRAMS article.
3. Measure voltage between ground and ECM terminals No. 110 and 112 by backprobing. While observing voltmeter, turn ignition on and off. Battery voltage should exist for a few seconds after turning ignition off. After a few seconds, voltage should drop to about zero volts. If voltage is as specified, go to step 8. If battery voltage does not exist, go to next step. If battery voltage exists for more than a few seconds after ignition is turned off, go to step 7.
4. Disconnect ECM and ECM relay harness connectors. (Scheme 48)and (Scheme 50). Check continuity of White wire between ECM relay harness connector terminal No. 3 and ECM harness connector terminals No. 110 and 112. Also check circuit for short to ground and short to voltage. Repair as necessary and retest system. If circuit is okay, go to next step.
5. Measure voltage between ground and ECM relay harness connector terminals No. 1 and 5 (White/Blue wires). If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit and retest system. See appropriate wiring diagram in WIRING DIAGRAMS article.
6. Check continuity of White/Green wire between ECM relay harness connector terminal No. 2 and ECM harness connector terminal No. 31. Also check circuit for short to ground and short to voltage. Repair as necessary and retest system. If circuit is okay, go to next step.
7. Check ECM relay. See «RELAYS & SOLENOIDS»(ref-3089-S41157121132000041700000). Replace, if necessary and retest system. If ECM relay is okay, go next step.
8. Turn ignition off. Disconnect ECM harness connector. Check continuity between engine ground and ECM harness connector terminals No. 48, 57, 106 and 108. Also check circuits for short to voltage. Repair as necessary and retest system. If ground circuits are okay, go to next step.
9. No problem is indicated at this time. Problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.

Scheme 48

Scheme 49

Scheme 50

Power & Ground Circuits (Q45)

1. Start engine. If engine starts, go to step 3. If engine does not start, crank engine for at least 5 seconds, then check for DTCs. DTC P1320 is present, perform diagnosis for DTC P1320. See SELF-DIAGNOSTICS - Q45 article. If DTC P1320 is not present, go to next step.
2. Turn ignition on. Measure voltage between ground and ECM terminal No. 78 by backprobing. (Scheme 51)and (Scheme 52). If battery voltage exists, go to step 9. If battery voltage does not exist, repair open or short circuit and retest system. See appropriate wiring diagram in WIRING DIAGRAMS article.
3. Turn ignition off. Measure voltage between ground and ECM terminals No. 56 and 123 by backprobing. (Scheme 51)and (Scheme 52). If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit and retest system. See appropriate wiring diagram in WIRING DIAGRAMS article.
4. Measure voltage between ground and ECM terminals No. 130 and 131 by backprobing. While observing voltmeter, turn ignition on and off. Battery voltage should exist for a few seconds after turning ignition off. After a few seconds, voltage should drop to about zero volts. If voltage is as specified, or if battery voltage exists for more than a few seconds, go to step 8. If battery voltage does not exist, go to next step.
5. Disconnect ECM and ECCS relay harness connectors. (Scheme 53) Check continuity of Red/Green wire between ECCS relay harness connector terminal No. 3 and ECM harness connector terminals No. 130 and 131. Also check circuit for short to ground and short to voltage. Repair as necessary and retest system. If circuit is okay, go to next step.
6. Measure voltage between ground and ECCS relay harness connector terminals No. 2 and 5 (White/Blue wires). If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit and retest system. See appropriate wiring diagram in WIRING DIAGRAMS article.
7. Check continuity of White/Black wire between ECCS relay harness connector terminal No. 1 and ECM harness connector terminal No. 124. Also check circuit for short to ground and short to voltage. Repair as necessary and retest system. If circuit is okay, go to next step.
8. Check ECCS relay. See «RELAYS & SOLENOIDS»(ref-3089-S41157121132000041700000). Replace if necessary. If ECCS relay is okay, go to next step.
9. Turn ignition off. Loosen and retighten engine ground bolts. (Scheme 54) Disconnect ECM harness connector. (Scheme 51) Check continuity between engine ground and ECM harness connector terminals No. 121, 122, 125, 126, 127 and 128. Also check circuits for short to voltage. Repair as necessary and retest system. If ground circuits are okay, go to next step.
10. No problem is indicated at this time. Problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.

Scheme 51

Scheme 52

Scheme 53

Scheme 54

ENGINE SENSORS & SWITCHES

Note. Sensor resistance and/or voltage values (when available) can be found in SENSOR OPERATING RANGE CHARTS article.

Note. For system testing of sensors and switches, see appropriate SELF-DIAGNOSTICS article.

ABSOLUTE PRESSURE (AP) SENSOR

See DTC P0105: ABSOLUTE PRESSURE (AP) SENSOR under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.

CRANKSHAFT POSITION (CKP) SENSOR

See DTC P0335 OR P1336: CRANKSHAFT POSITION (CKP) SENSOR under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.

CAMSHAFT POSITION (CMP) SENSOR

See DTC P0340: CAMSHAFT POSITION (CMP) SENSOR under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.

ENGINE COOLANT TEMPERATURE (ECT) SENSOR

DTC P0115 OR P0125: ENGINE COOLANT TEMPERATURE (ECT) SENSOR under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.

EGR TEMPERATURE SENSOR

See EMISSION SYSTEMS & SUB-SYSTEMS .

FUEL LEVEL SENSOR (G20)

See DTC P0460: FUEL LEVEL SENSOR FUNCTION (SLOSH) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - G20 article.

FUEL TANK TEMPERATURE SENSOR

See DTC P0180: FUEL TANK TEMPERATURE SENSOR under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.

IGNITION SWITCH (START SIGNAL)

On G20, measure voltage between ground and ECM harness connector terminal No. 41 by backprobing. (Scheme 49) On Q45, measure voltage between ground and ECM harness connector terminal No. 80 by backprobing. (Scheme 52) On all models, battery voltage should exist when ignition switch is in START position. If voltage is not as specified, repair ignition switch or circuit. See appropriate wiring diagram in WIRING DIAGRAMS article.

INTAKE AIR TEMPERATURE (IAT) SENSOR

See DTC P0110: INTAKE AIR TEMPERATURE (IAT) SENSOR under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.

FRONT HEATED OXYGEN SENSOR (HO2S)

See appropriate DTC for FRONT HEATED OXYGEN SENSOR (HO2S) under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article. Refer to appropriate DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION table in SELF-DIAGNOSTICS - INTRODUCTION article.

REAR HEATED OXYGEN SENSOR (HO2S)

See appropriate DTC for REAR HEATED OXYGEN SENSOR (HO2S) under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article. Refer to appropriate DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION table in SELF-DIAGNOSTICS - INTRODUCTION article.

KNOCK SENSOR (KS)

See DTC P0325: KNOCK SENSOR (KS) under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.

MASS AIRFLOW (MAF) SENSOR

See DTC P0100: MASS AIRFLOW (MAF) SENSOR under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.

POWER STEERING PRESSURE SWITCH

Turn ignition off. Disconnect power steering pressure switch harness connector, located on high-pressure hose. Start engine. Check continuity between switch terminals. Continuity should exist when steering wheel is being turned. Continuity should not exist when steering wheel is not being turned. Replace switch if continuity is not as specified.

G20

1. Start engine. Measure voltage between ground and ECM terminal No. 46 by backprobing. (Scheme 48)and (Scheme 49). When steering wheel is turned quickly, voltage should be about zero volts. When steering wheel is not being turned, voltage should be about 5 volts. If voltage is as specified, system is okay. If voltage is not as specified, go to next step.
2. Turn ignition off. Disconnect power steering pressure switch harness connector located on high-pressure hose. Check continuity between engine ground and power steering pressure switch harness connector terminal No. 2 (Black wire). Also check circuit for short to voltage. Repair as necessary and retest system. If ground circuit is okay, go to next step.
3. Disconnect ECM harness connector. Check continuity of Light Blue wire between power steering pressure switch harness connector terminal No. 1 and ECM harness connector terminal No. 46. Also check circuit for short to ground and short to voltage. Repair as necessary and retest system. If circuit is okay, go to next step.
4. Check power steering pressure switch. See «POWER STEERING PRESSURE SWITCH»(ref-3089-S28502254792000041700000). Replace if necessary. If power steering pressure switch is okay, go to next step.
5. No problem is indicated at this time. Problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.

Q45

1. Start engine. Measure voltage between ground and ECM terminal No. 100 by backprobing. (Scheme 51)and (Scheme 52). Voltage should be about zero volts when steering wheel is being turned quickly. Battery voltage should exist when steering wheel is not being turned.
2. If voltage is as specified, system is okay. If voltage is not as specified, turn ignition off. Disconnect Idle Air Control Valve-Fast Idle Control Device (IACV-FICD) harness connector. (Scheme 55) Turn ignition on. Measure voltage between ground and IACV-FICD harness connector terminal No. 1 (Green/Yellow wire). If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit and retest system. See in appropriate wiring diagram in WIRING DIAGRAMS article.
3. Turn ignition off. Reconnect IACV-FICD harness connector. Disconnect power steering pressure switch harness connector, located on high-pressure hose. Measure voltage between ground and power steering pressure switch harness connector terminal No. 1 (Green wire). If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit between IACV-FICD, ECM and power steering pressure switch. Retest system.
4. Turn ignition off. Check continuity between ground and power steering pressure switch harness connector terminal No. 2 (Black wire). Also check circuit for short to voltage. Repair as necessary and retest system. If ground circuit is okay, go to next step.
5. Disconnect ECM harness connector. Check continuity of Green wire between power steering pressure switch harness connector terminal No. 1 and ECM harness connector terminal No. 100. Also check circuit for short to ground and short to voltage. Repair as necessary and retest system. If circuit is okay, go to next step.
6. Check power steering pressure switch. See «POWER STEERING PRESSURE SWITCH»(ref-3089-S28502254792000041700000). Check IACV-FICD. See «RELAYS & SOLENOIDS»(ref-3089-S41157121132000041700000). Replace components if necessary. If components are okay, go to next step.
7. No problem is indicated at this time. Problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.

Scheme 55

THROTTLE POSITION (TP) SENSOR

See DTC P0120: THROTTLE POSITION (TP) SENSOR under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.

VEHICLE SPEED SENSOR (VSS)

See DTC P0500: VEHICLE SPEED SENSOR (VSS) under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.

A/C Clutch Relay

See MISCELLANEOUS CONTROLS .

ECCS, ECM & Fuel Pump Relays

1. Two types of relays are used; 4-terminal and 6-terminal. For relay location (Scheme 50)or (Scheme 53). Remove appropriate relay. Apply battery voltage and ground to terminals No. 1 and 2. (Scheme 56)or (Scheme 57).
2. Continuity should exist between terminals No. 3 and 5. On 6-terminal relays, continuity should also exist between terminals No. 6 and 7. On all relays, when battery voltage is removed, continuity should not exist. Replace relay if test values are not as specified.

Scheme 56

Scheme 57

SOLENOIDS

Note. For EGR and EVAP system components, see EMISSION SYSTEMS & SUB-SYSTEMS .

FUEL PRESSURE RELEASE

Remove fuel pump fuse. Start engine and allow to run until engine stalls due to lack of fuel. Crank engine 2-3 more times to verify all pressure has dissipated.

FUEL DELIVERY

For basic fuel pressure procedures and specifications, see FUEL PRESSURE under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article.

Fuel Pump Control System (G20)

1. Turn ignition on. Pinch fuel hose (at filter outlet) with fingers. For 5 seconds after ignition is turned on, pulsation should be felt on fuel hose. If pulsation is felt, system is okay. If pulsation is not felt, go to next step.
2. Turn ignition off. Disconnect fuel pump relay No. 1 harness connector. (Scheme 50) Turn ignition on. Measure voltage between ground and fuel pump relay No. 1 harness connector terminal No. 1 (Black/White wire). If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit and retest system. See appropriate wiring diagram in WIRING DIAGRAMS article.
3. Measure voltage between ground and fuel pump relay No. 1 harness connector terminal No. 3 (Black/Red wire). If battery voltage exists, go to step 8. If battery voltage does not exist, go to next step.
4. Turn ignition off. Disconnect fuel pump relay No. 2 harness connector. (Scheme 58) Turn ignition on. Measure voltage between ground and fuel pump relay No. 2 harness connector terminals No. 1 (Black/White wire) and No. 3 (Black/Orange wire). If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit and retest system. See appropriate wiring diagram in WIRING DIAGRAMS article.
5. Turn ignition off. Check continuity of Black/Red wire between fuel pump relay No. 2 harness connector terminal No. 5 and fuel pump relay No. 1 harness connector terminal No. 3. Also check circuit for short to ground and short to voltage. Repair as necessary and retest system. If circuit is okay, go to next step.
6. Check continuity between body ground and fuel pump relay No. 2 harness connector terminal No. 2 (Black wire). Also check circuit for short to voltage. Repair as necessary and retest system. If ground circuit is okay, go to next step.
7. Check fuel pump relay No. 2. See «RELAYS & SOLENOIDS»(ref-3089-S41157121132000041700000). Replace, if necessary and retest system. If relay is okay, go to next step.
8. Turn ignition off. Disconnect fuel pump harness connector located behind access cover, under rear seat. Check continuity of Black/Yellow wire between fuel pump harness connector terminal No. 1 and fuel pump relay No. 1 harness connector terminal No. 5. Also check circuit for short to ground and short to voltage. Repair as necessary and retest system. If circuit is okay, go to next step.
9. Check continuity between body ground and fuel pump harness connector terminal No. 2 (Black wire). Also check circuit for short to voltage. Repair as necessary and retest system. If ground circuit is okay, go to next step.
10. Disconnect ECM harness connector. (Scheme 48) Check continuity of Black/Pink wire between ECM harness connector terminal No. 21 and fuel pump relay No. 1 harness connector terminal No. 2. (Scheme 49) Also check circuit for short to ground and short to voltage. Repair as necessary and retest system. If circuit is okay, go to next step.
11. Check fuel pump relay No. 1. See «RELAYS & SOLENOIDS»(ref-3089-S41157121132000041700000). Replace, if necessary and retest system. If relay is okay, go to next step.
12. Measure resistance between fuel pump terminals. Resistance should be 0.2-5.0 ohms at 77°F (25°C). If resistance is as specified, go to next step. If resistance is not as specified, replace fuel pump and retest system.
13. No problem is indicated at this time. Problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.

Scheme 58

Fuel Pump Control System (Q45)

1. Turn ignition on. Pinch fuel hose (before fuel damper) with fingers. For 5 seconds after ignition is turned on, pulsation should be felt on fuel hose. If pulsation is felt, system is okay. If pulsation is not felt, go to next step.
2. Turn ignition off. Disconnect fuel pump relay. (Scheme 53) Turn ignition on. Measure voltage between ground and fuel pump relay harness connector terminals No. 1 (White wire) and No. 3 (Black/White wire). If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit and retest system. See appropriate wiring diagram in WIRING DIAGRAMS article.
3. Turn ignition off. Disconnect fuel pump, Fuel Pump Control Module (FPCM) and dropping resistor harness connectors. (Scheme 60)and (Scheme 61). Fuel pump harness connector is located in bottom of trunk. Check continuity of Black/Yellow wire between fuel pump relay harness connector terminal No. 5, FPCM harness connector terminal No. 3 and fuel pump harness connector terminal No. 1. Also check circuit for short to ground and short to voltage. Repair as necessary and retest system. If circuit is okay, go to next step.
4. Check continuity between body ground and dropping resistor harness connector terminal No. 2 (Black wire). Also check circuit for short to voltage. Repair as necessary and retest system. If ground circuit is okay, go to next step.
5. Disconnect ECM harness connector. (Scheme 51) Check continuity of Black/Pink wire between fuel pump relay harness connector terminal No. 2 and ECM harness connector terminal No. 42. (Scheme 52) Also check circuit for short to ground and short to voltage. Repair as necessary and retest system. If circuit is okay, go to next step.
6. Check fuel pump relay. See «RELAYS & SOLENOIDS»(ref-3089-S41157121132000041700000). Replace, if necessary and retest system. If fuel pump relay is okay, go to next step.
7. Measure resistance between fuel pump terminals No. 1 and 3. (Scheme 59) Resistance should be 0.2-5.0 ohms at 77°F (25°C). If resistance is as specified, go to next step. If resistance is not as specified, replace fuel pump and retest system.
8. No problem is indicated at this time. Problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.

Scheme 59

Scheme 60

Scheme 61

Fuel Pump Control Module (FPCM) - Q45

See DTC P1220: FUEL PUMP CONTROL MODULE (FPCM) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - Q45 article.

Fuel Pump Relay

See RELAYS under RELAYS & SOLENOIDS.

Fuel Injector

Turn ignition off. Disconnect fuel injector harness connector. Measure resistance between injector terminals. Resistance should be 10-14 ohms at 77°F (25°C). Replace injector if resistance is not as specified.

Fuel Injector Circuits (G20)

1. With engine idling, listen to each injector for operating sound. Each injector should click. If each injector clicks, test is complete. If any injector does not click, go to next step.
2. Turn ignition off. Disconnect inoperative injector harness connectors. Turn ignition on. Measure voltage between ground and injector harness connector terminal No. 1 (Black/Red wire). If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit and retest system. See appropriate wiring diagram in WIRING DIAGRAMS article.
3. Turn ignition off. Disconnect ECM harness connector. (Scheme 48) Check continuity of the following: Red/Black wire between injector No. 1 harness connector terminal No. 2 and ECM harness connector terminal No. 101. Yellow/Black wire between injector No. 2 harness connector terminal No. 2 and ECM harness connector terminal No. 103. Green/Black wire between injector No. 3 harness connector terminal No. 2 and ECM harness connector terminal No. 105. Blue/Black wire between injector No. 4 harness connector terminal No. 2 and ECM harness connector terminal No. 107. (Scheme 49) Also check circuit for short to ground and short to voltage. Repair as necessary and retest system. If circuit is okay, go to next step.
4. Check fuel injector. See «FUEL INJECTOR»(ref-3089-S06892987212000041700000). Replace, if necessary and retest system. If fuel injector is okay, go to next step.
5. No problem is indicated at this time. Problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.

Fuel Injector Circuits (Q45)

1. With engine idling, listen to each injector for operating sound. Each injector should click. If each injector clicks, test is complete. If any injector does not click, go to next step.
2. Turn ignition off. Disconnect injector sub-harness connectors. (Scheme 62)and (Scheme 63). Turn ignition on. Measure voltage between ground and right bank injector sub-harness connector terminal No. 4 (White wire). Measure voltage between ground and left bank injector sub-harness connector terminal No. 5 (White wire). If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit and retest system. See appropriate wiring diagram in WIRING DIAGRAMS article.
3. Turn ignition off. Reconnect right bank injector sub-harness connector. Disconnect all right bank injectors and ECM harness connectors. (Scheme 51) Check continuity of the following: Between injector No. 2 harness connector terminal No. 1 (Red/Black wire) and ECM harness connector terminal No. 7 (Light Green wire). Between injector No. 4 harness connector terminal No. 1 (Red/White wire) and ECM harness connector terminal No. 6 (Gray/Blue wire). Between injector No. 6 harness connector terminal No. 1 (Red/Green wire) and ECM harness connector terminal No. 4 (White/Red wire). Between injector No. 8 harness connector terminal No. 1 (Red/Blue wire) and ECM harness connector terminal No. 2 (Red/White wire). Red/Black wire between left bank injector sub-harness connector terminal No. 3 and ECM harness connector terminal No. 1. Red/Blue wire between left bank injector sub-harness connector terminal No. 2 and ECM harness connector terminal No. 14. Purple/Red wire between left bank injector sub-harness connector terminal No. 1 and ECM harness connector terminal No. 5. Red/Yellow wire between left bank injector sub-harness connector terminal No. 6 and ECM harness connector terminal No. 3. (Scheme 52) Also check circuit for short to ground and short to voltage. Repair as necessary and retest system. If circuit is okay, go to next step.
4. Remove intake manifold collector. See 4.1L - Q45 article in ENGINES. Disconnect all left bank injector harness connectors. Check continuity between the following: Red/Black wire between left bank injector sub-harness connector terminal No. 3 and injector No. 1 harness connector terminal No. 1. Red/White wire between left bank injector sub-harness connector terminal No. 2 and injector No. 3 harness connector terminal No. 1. Red/Green wire between left bank injector sub-harness connector terminal No. 1 and injector No. 5 harness connector terminal No. 1. Red/Blue wire between left bank injector sub-harness connector terminal No. 6 and injector No. 7 harness connector terminal No. 1. Also check circuit for short to ground and short to voltage. Repair as necessary and retest system. If circuit is okay, go to next step.
5. Check fuel injector. See «FUEL INJECTOR»(ref-3089-S06892987212000041700000). Replace if necessary. If fuel injector is okay, go to next step.
6. No problem is indicated at this time. Problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.

Scheme 62

Scheme 63

IDLE AIR CONTROL VALVE-AUXILIARY AIR CONTROL (IACV-AAC) VALVE

See DTC P0505: IDLE AIR CONTROL VALVE-AUXILIARY AIR CONTROL (IACV-AAC) VALVE under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.

Remove IACV-FICD. (Scheme 55) Using jumper wires, apply battery voltage to IACV-FICD terminals. IACV-FICD should click when jumper wires are connected and disconnected. Inspect IACV-FICD plunger for sticking. Also check for broken spring.

IGNITION SYSTEM

Faults in ignition signal should set a DTC P1320. For testing procedure, see DTC P1320: IGNITION SIGNAL in appropriate SELF-DIAGNOSTICS article.

Ignition Coil

See IGNITION SYSTEMS in BASIC DIAGNOSTIC PROCEDURES article.

Power Transistor

Faults in power transistor should set a DTC P1320. For testing procedure, refer to DTC P1320: IGNITION SIGNAL under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.

See DTC P0340: CAMSHAFT POSITION (CMP) SENSOR under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.

Timing Advance System

ECM controls ignition timing advance based upon sensor input signals that reflect ignition timing needs. If timing problems are experienced, inspect input signals listed below for proper operation. To check input signals, see ENGINE SENSORS & SWITCHES or ECM pin voltage charts in PIN VOLTAGE CHARTS article.

1. Battery Voltage
2. Camshaft Position (CMP) Sensor
3. Mass Airflow Sensor
4. Engine Coolant Temperature
5. Ignition (START) Signal
6. Knock Sensor
7. Park/Neutral Switch
8. Power Steering Pressure Switch
9. Throttle Position Sensor
10. Vehicle Speed Sensor
11. Secondary Throttle Position Sensor (Q45 only)

PCV VALVE

With engine idling, remove PCV valve, leaving vacuum hose connected. A hissing noise should be heard as air passes through valve. A strong vacuum should be felt immediately when a finger is placed over valve inlet. If operation is not as specified, replace PCV valve.

EGR System Check

See DTC P0400: EGR FUNCTION or DTC P1402: EGR FUNCTION under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.

EGR Backpressure Transducer (Q45)

See DTC P0402: EGR BACKPRESSURE TRANSDUCER (EGR-BPT) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - Q45 article.

EGRC Solenoid (Q45)

DTC 1400: EGR CONTROL (EGRC) SOLENOID under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - Q45 article.

See DTC P1401: EGR TEMPERATURE SENSOR under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.

EGR Valve (G20 & Q45)

See DTC P0400: EGR FUNCTION or DTC P1402: EGR FUNCTION under DIAGNOSTIC TESTS in appropriate SELF-DIAGNOSTICS article.

EGR Volume Control Valve (EGR-VCV) - G20

See DTC P0403: EGR VOLUME CONTROL VALVE (EGR-VCV) under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - G20 article.

ON BOARD REFUELING VAPOR RECOVERY (ORVR) SYSTEM

For system description (Scheme 64)

Scheme 64

Strong Fuel Odor From EVAP Canister (G20)

1. Remove EVAP canister with EVAP Canister Vent Control Valve (EVAP-CVCV) attached. see scheme 17 Weigh EVAP canister with EVAP-CVCV attached. If weight is less than 4.0 lbs. (1.8 kg), go to next step. If weight is more than 4.0 lbs. (1.8 kg), go to step 3.
2. Invert EVAP canister. If water drains from EVAP canister, go to next step. If water does not drain from EVAP canister, go to step 5.
3. Replace EVAP canister. Remove water separator. see scheme 17 Inspect water separator and hose for cracks or blockage. Repair as necessary. If no problems are found, go to next step. CAUTION: DO NOT disassemble water separator.
4. With water separator port "A" plugged, blow air into port "B". (Scheme 65) Air should flow out of port "C". With port "C" plugged, blow air into port "B". Air should flow out of port "A". If operation is as specified, go to next step. If operation is not as specified, replace water separator.
5. Check refueling EVAP vapor cut valve. See «REFUELING EVAP VAPOR CUT VALVE»(ref-3089-S17039384202000060700000). If refueling EVAP vapor cut valve is okay, go to next step. If refueling EVAP vapor cut valve is not okay, replace fuel tank.
6. Check refueling control valve. See «REFUELING CONTROL VALVE»(ref-3089-S07999657592000060700000). If refueling control valve is okay, test is complete. If refueling control valve is not okay, replace fuel tank.

Scheme 65

Strong Fuel Odor From EVAP Canister (Q45)

1. Remove EVAP canister with EVAP Canister Vent Control Valve (EVAP-CVCV) attached. see scheme 18 Weigh EVAP canister with EVAP-CVCV attached. If weight is more than 4.0 lbs. (1.8 kg), replace EVAP canister. If weight is less than 4.0 lbs. (1.8 kg), invert EVAP canister. If water drains from EVAP canister, replace EVAP canister. If water does not drain from EVAP canister, go to next step.
2. Check refueling EVAP vapor cut valve. See «REFUELING EVAP VAPOR CUT VALVE»(ref-3089-S17039384202000060700000). If refueling EVAP vapor cut valve is okay, go to next step. If refueling EVAP vapor cut valve is not okay, replace fuel tank.
3. Check refueling control valve. See «REFUELING CONTROL VALVE»(ref-3089-S07999657592000060700000). If refueling control valve is okay, test is complete. If refueling control valve is not okay, replace fuel tank.

Cannot Refuel/Fuel Odor From Fuel Filler While Refueling (G20)

1. Remove EVAP canister with EVAP Canister Vent Control Valve (EVAP-CVCV) attached. see scheme 17 Weigh EVAP canister with EVAP-CVCV attached. If weight is less than 4.0 lbs. (1.8 kg), go to next step. If weight is more than 4.0 lbs. (1.8 kg), go to step 3.
2. Invert EVAP canister. If water drains from EVAP canister, go to next step. If water does not drain from EVAP canister, go to step 5.
3. Replace EVAP canister. Remove water separator. see scheme 17 Inspect water separator and hose for cracks or blockage. Repair as necessary. If no problems are found, go to next step. CAUTION: DO NOT disassemble water separator.
4. With water separator port "A" plugged, blow air into port "B". (Scheme 65) Air should flow out of port "C". With port "C" plugged, blow air into port "B". Air should flow out of port "A". If operation is as specified, go to next step. If operation is not as specified, replace water separator.
5. Check hoses between EVAP canister and refueling control valve for blockage, leak or improper connection. (Scheme 64)and see scheme 21. Also check signal line and recirculation line for blockage or leak. Repair as necessary. If no problems are found, go to next step.
6. Check refueling control valve. See «REFUELING CONTROL VALVE»(ref-3089-S07999657592000060700000). If refueling control valve is okay, test is complete. If refueling control valve is not okay, replace fuel tank.
7. Check refueling EVAP vapor cut valve. See «REFUELING EVAP VAPOR CUT VALVE»(ref-3089-S17039384202000060700000). If refueling EVAP vapor cut valve is okay, go to next step. If refueling EVAP vapor cut valve is not okay, replace fuel tank.
8. Check fuel filler tube and hose for blockage or leak. Replace fuel filler tube, if necessary. If fuel filler tube is okay, go to next step.
9. Check one-way fuel valve for blockage. Repair as necessary. If no blockage exists, ensue fuel tank is empty. Insert a suitable dowel through one-way fuel valve. One-way fuel valve should open. Remove dowel. One-way fuel valve should close. If operation is as specified, test is complete. If operation is not as specified, replace fuel tank.

Cannot Refuel/Fuel Odor From Fuel Filler While Refueling (Q45)

1. Remove water separator. see scheme 18 With water separator port "A" plugged, blow air into port "B". (Scheme 65) Air should flow out of port "C". With port "C" plugged, blow air into port "B". Air should flow out of port "A". If operation is as specified, go to next step. If operation is not as specified, replace water separator.
2. Remove EVAP canister with EVAP Canister Vent Control Valve (EVAP-CVCV) attached. see scheme 18 Weigh EVAP canister with EVAP-CVCV attached. If weight is more than 4.0 lbs. (1.8 kg), replace EVAP canister. If weight is less than 4.0 lbs. (1.8 kg), invert EVAP canister. If water drains from EVAP canister, replace EVAP canister. If water does not drain from EVAP canister, go to next step.
3. Check hoses between EVAP canister and refueling control valve for blockage, leak or improper connection. (Scheme 64)and see scheme 22. Also check signal line and recirculation line for blockage or leak. Repair as necessary. If no problems are found, go to next step.
4. Check refueling control valve. See «REFUELING CONTROL VALVE»(ref-3089-S07999657592000060700000). If refueling control valve is okay, test is complete. If refueling control valve is not okay, replace fuel tank.
5. Check refueling EVAP vapor cut valve. See «REFUELING EVAP VAPOR CUT VALVE»(ref-3089-S17039384202000060700000). If refueling EVAP vapor cut valve is okay, go to next step. If refueling EVAP vapor cut valve is not okay, replace fuel tank.
6. Check fuel filler tube and hose for blockage or leak. Replace fuel filler tube, if necessary. If fuel filler tube is okay, go to next step.
7. Check one-way fuel valve for blockage. Repair as necessary. If no blockage exists, ensue fuel tank is empty. Remove fuel filler tube and hose. Push one-way fuel valve with finger. One-way fuel valve should open. Remove finger. One-way fuel valve should close. If operation is as specified, test is complete. If operation is not as specified, replace fuel tank.

POSITIVE CRANKCASE VENTILATION (PCV)

Run engine at idle. Remove ventilation hose from PCV valve; hissing noise should be heard and a strong vacuum should be felt immediately when finger is placed over valve inlet. If vacuum is not felt, check PCV valve for clogging. Service or replace as necessary.

MISCELLANEOUS CONTROLS

Note. Although some of the controlled devices listed here are not technically engine performance components, they can affect driveability if they malfunction.

1. A/C clutch relay is controlled by ECM. Under normal conditions, ECM will engage clutch relay by providing a ground circuit for relay windings. If ECM receives a wide open throttle signal from throttle position sensor while it is also receiving an A/C on signal from A/C auto amplifier, ECM will disengage relay.
2. Remove A/C relay. On G20, A/C clutch relay is located in relay box on right side of engine compartment. On Q45, relay is located on right inner fender panel, rear of strut tower.
3. Apply battery voltage to terminals No. 1 and 2. (Scheme 56) Continuity should exist between terminals No. 3 and 5. When battery voltage is removed, continuity should not exist. Replace relay if continuity is not as specified.

1. Turn ignition on. Measure voltage between ground and ECM terminal No. 50 by backprobing. (Scheme 48)and (Scheme 49). With rear window defogger switch in ON position, battery voltage should exist. With rear window defogger switch in OFF position, zero volts should exist. If voltage is as specified, go to next step. If voltage is not as specified, go to step 3.
2. While monitoring voltage, turn headlight switch to ON position. Battery voltage should exist. Turn headlight switch to OFF position. Zero volts should exist. If voltage is as specified, system is okay. If voltage is not as specified, go to step 6.
3. Start engine. Turn rear window defogger on. If rear window heats up, go to next step. If rear window does not heat up, repair rear window defogger system. See REAR WINDOW DEFOGGERS article in ACCESSORIES & EQUIPMENT.
4. Turn ignition off. Disconnect ECM harness connector. Disconnect rear window defogger relay harness connector located in engine compartment relay box. Connect negative ohmmeter lead to rear window defogger relay harness connector terminal No. 5 (Blue/Red wire). Connect positive ohmmeter lead to ECM harness connector terminal No. 50 (Red wire). Continuity should exist. Reverse ohmmeter leads. Continuity should not exist. If continuity is as specified, go to step 9. If continuity is not as specified, go to next step.
5. Check for open or short in the following wires: Blue/Red wire between rear window defogger relay harness connector terminal No. 5 and connector M-93 terminal No. 3. White wire between connector M-93 terminal No. 4 and connector M-94 terminal No. 3. Red wire between ECM harness connector terminal No. 50 and connector M-94 terminal No. 4. Connectors M-93 and M-94 are located behind top of instrument panel, near center of vehicle, taped to main wiring harness. See appropriate wiring diagram in REAR WINDOW DEFOGGERS article in ACCESSORIES & EQUIPMENT. Also check diodes located at connectors M-93 and M-94. Repair as necessary and retest system. If circuits and diodes are okay, go to step 9.
6. Start engine. Turn headlights on. If headlights operate, go to next step. If headlights do not operate, repair headlights and retest system. See appropriate wiring diagram in HEADLIGHT SYSTEMS article in ACCESSORIES & EQUIPMENT.
7. Turn ignition off. Disconnect ECM harness connector. Disconnect headlight switch harness connector. Connect positive ohmmeter lead to ECM harness connector terminal No. 50. Connect negative ohmmeter lead to headlight switch harness connector terminal No. 9 (Red/Black wire), then terminal No. 10 (Red/Yellow wire). Continuity should exist. Reverse ohmmeter leads. Continuity should not exist. If continuity is as specified, go to step 9. If continuity is not as specified, go to next step.
8. Check for open or short in the following wires: Red/Yellow wire between headlight switch harness connector terminal No. 10 and connector M-94 terminal No. 1. Red/Black wire between headlight switch harness connector terminal No. 9 and connector M-94 terminal No. 6. Red wire between ECM harness connector terminal No. 50 and connector M-94 terminal No. 4. Connector M-94 is located behind top of instrument panel, near center of vehicle, taped to main wiring harness. See appropriate wiring diagram in HEADLIGHT SYSTEMS article in ACCESSORIES & EQUIPMENT. Also check diodes located at connector M-94. Repair as necessary and retest system. If circuits and diodes are okay, go to next step.
9. No problem is indicated at this time. Problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.

1. Turn ignition off. Disconnect ECM harness connector. (Scheme 51) Turn ignition on. Measure voltage between ground and ECM harness connector terminal No. 79. (Scheme 52) Turn rear window defogger on. Battery voltage should exist. Turn rear window defogger off. Zero volts should exist. If voltage is as specified, go to next step. If voltage is not as specified, go to step 3.
2. Measure voltage between ground and ECM harness connector terminal No. 72. Turn headlights on. Battery voltage should exist. Turn headlights off. Zero volts should exist. If voltage is as specified, test is complete. If voltage is not as specified, go to step 5.
3. Check rear window defogger operation. If rear window defogger operates properly, go to next step. If rear window defogger does not operate properly, repair rear window defogger system. See REAR WINDOW DEFOGGERS article in ACCESSORIES & EQUIPMENT.
4. Turn ignition off. Disconnect rear window defogger relay, located behind left kick panel. Check continuity of Blue/Red wire between rear window defogger relay harness connector terminal No. 5 and ECM harness connector terminal No. 79. Also check circuit for short to ground and short to voltage. Repair as necessary and retest system. If circuit is okay, go to step 8.
5. Check operation of headlights. If headlights operate properly, go to next step. If headlights do not operate properly, repair headlight system. See appropriate wiring diagram in HEADLIGHT SYSTEMS article in ACCESSORIES & EQUIPMENT.
6. Remove headlight relay, located in relay box on right side of engine compartment. Check continuity between ECM harness connector terminal No. 72 (Red/Yellow wire) and headlight relay harness connector terminal No. 6 (Blue/White wire). Also check circuit for short to ground and short to voltage. Repair as necessary and retest system. If circuit is okay, go to next step.
7. If vehicle is not equipped with xenon headlights, go to next step. If vehicle is equipped with xenon headlights, remove High Intensity Discharge (HID) relay, located next to headlight relay. Check continuity of Red/Yellow wire between ECM harness connector terminal No. 72 and HID relay harness connector terminal No. 7. Also check circuit for short to ground and short to voltage. Repair as necessary and retest system. If circuit is okay, go to next step.
8. No problem is indicated at this time. Problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.