Engine Controls - System & Component Testing: Other Nissan Quest II

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.

A/C HIGH PRESSURE SWITCH (QUEST)

See appropriate AIR CONDITIONING & HEATING article.

CAMSHAFT POSITION (CMP) SENSOR

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

CRANKSHAFT POSITION (CKP) SENSOR

See DTC P0335: CRANKSHAFT POSITION (CKP) SENSOR in appropriate SELF-DIAGNOSTICS article.

EGR TEMPERATURE SENSOR

See EMISSION SYSTEMS & SUB-SYSTEMS .

ENGINE COOLANT TEMPERATURE (ECT) SENSOR

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

FRONT HEATED OXYGEN SENSOR (HO2S)

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

FUEL LEVEL SENSOR

See DTC 0460: FUEL LEVEL SENSOR in appropriate SELF-DIAGNOSTICS article.

FUEL TANK TEMPERATURE SENSOR (FTTS)

See DTC P0180: FUEL TANK TEMPERATURE SENSOR (FTTS) in appropriate SELF-DIAGNOSTICS article.

Except Maxima, Pathfinder & Sentra

1. Measure voltage between ground and PCM harness connector terminal No. 20 by backprobing. see scheme 2and see scheme 4. Turn ignition switch to START position. Battery voltage should exist. With ignition switch in any other position, about zero volts should exist. If voltage is not as specified, replace 10-amp (7.5-amp on Frontier, Quest and Xterra) fuse. If fuse is okay, for Quest go to next step. For all other models, go to step 3.
2. On Quest, turn ignition off, then turn to START position. If starter motor operates, go to next step. If starter motor does not operate, repair starter circuit. See appropriate article in STARTING & CHARGING SYSTEMS.
3. On all models, turn ignition off. Disconnect PCM harness connector. Remove 10-amp (7.5-amp on Frontier, Quest and Xterra) fuse from fuse block. Check continuity between PCM harness connector terminal No. 20 and fuse block cavity No. 26 (cavity No. 7 on Frontier and Xterra, cavity No. 12 on Quest). If continuity does not exist, repair short or ground in power circuit. If continuity exists, no problem is indicated at this time. Problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article. If continuity does not exist, repair open or short circuit.

Maxima

1. Measure voltage between ground and PCM harness connector terminal No. 42 (Brown/White wire) by backprobing. see scheme 7 Turn ignition switch to START position. Battery voltage should exist. With ignition switch in any other position, about zero volts should exist. If voltage is as specified, go to step 4. If voltage is not as specified, go to next step.
2. Turn ignition off, then turn to START position. If starter motor operates, go to next step. If starter motor does not operate, repair starter circuit. See appropriate article in STARTING & CHARGING SYSTEMS.
3. Turn ignition off. Remove 10-amp fuse from fuse block. Replace fuse as necessary. With good fuse in place, disconnect PCM and ignition switch harness connectors. Check continuity between PCM harness connector terminal No. 42 (Brown/White wire) and fuse block cavity, and between ignition switch and fuse block cavity. If continuity exists, go to next step. If continuity does not exist, repair open or short circuit.
4. No problem is indicated at this time. Problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article. If continuity does not exist, repair open or short circuit.

Pathfinder

1. Measure voltage between ground and PCM harness connector terminal No. 20 (Black/Yellow wire) by backprobing. see scheme 4 Turn ignition switch to START position. Battery voltage should exist. With ignition switch in any other position, about zero volts should exist. If voltage is as specified, go to step 5. If voltage is not as specified, go to next step.
2. Turn ignition off, then turn to START position. If starter motor operates, go to next step. If starter motor does not operate, repair starter circuit. See appropriate article in STARTING & CHARGING SYSTEMS.
3. Turn ignition off. Remove 7.5-amp fuse from fuse block. Replace fuse as necessary. With good fuse in place, measure voltage between fuse block cavity No. 26 and ground. With ignition in START position, battery voltage should exist. If voltage is as specified, go to next step. If voltage is not as specified, repair short or open between fuse block and ignition switch.
4. Turn ignition off. Disconnect PCM harness connector. Remove ECCS relay from fuse block. see scheme 9 Check continuity of Black/Yellow wire between PCM harness connector terminal No. 20 and fuse block cavity. If continuity exists, go to next step. If continuity does not exist, repair open or short circuit.
5. No problem is indicated at this time. Problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article. If continuity does not exist, repair open or short circuit.

Sentra

1. Measure voltage between ground and PCM harness connector terminal No. 41 (Black/Yellow wire) by backprobing. see scheme 7 Turn ignition switch to START position. Battery voltage should exist. With ignition switch in any other position, about zero volts should exist. If voltage is not as specified, replace 10-amp fuse. If fuse is okay, go to next step.
2. Turn ignition off. Disconnect PCM harness connector. Remove 10-amp fuse from fuse block. Check continuity between PCM harness connector terminal No. 41 (Black/Yellow wire) and fuse block cavity No. 21. If continuity does not exist, repair short or ground in power circuit. If continuity exists, no problem is indicated at this time. Problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article. If continuity does not exist, repair open or short circuit.

INTAKE AIR TEMPERATURE (IAT) SENSOR

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

KNOCK SENSOR (KS)

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

MASS AIRFLOW (MAF) SENSOR

See DTC P0100: MASS AIRFLOW (MAF) SENSOR 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. If switch has only one terminal, check continuity between ground and switch terminal. 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.

Altima

1. Start engine. Measure voltage between ground and PCM harness connector terminal No. 25 (Light Green/Black wire) by backprobing. see scheme 2 When steering wheel is being 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, go to step 4. If voltage is not as specified, go to next step.
2. Turn ignition off. Disconnect PCM harness connector. Check continuity between power steering pressure switch harness connector and PCM harness connector terminal No. 25 (Light Green/Black wire). If continuity exists, go to next step. If continuity does not exist, repair open circuit.
3. Check power steering pressure switch. See «POWER STEERING PRESSURE SWITCH»(ref-3193-S37077702572000041900000). Replace, if necessary. If power steering pressure switch is okay, go to next step.
4. No problem is indicated at this time. Problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.

Frontier, Pathfinder, Quest & Xterra

1. Start engine. Measure voltage between ground and PCM harness connector terminal No. 39 (Gray/Red on Frontier and Xterra, Red/Black on Pathfinder, or Pink on Quest) by backprobing. see scheme 4 With steering wheel fully turned, voltage should be about zero volts. When steering wheel is not being turned, voltage should be about 5 volts. If voltage is as specified, go to step 5. If voltage is not as specified, go to next step.
2. Turn ignition off. On V6 models, turn ignition off. Disconnect power steering pressure switch harness connector located on high-pressure hose. On all but Quest, check continuity between ground and power steering pressure switch harness connector (Black wire on Pathfinder, or Black/Red wire on Frontier V6 and Xterra V6). If continuity exists, go to next step. If continuity does not exist, repair open ground circuit.
3. On all models, disconnect PCM harness connector. Check continuity between power steering pressure switch harness connector (Gray/Red wire on Frontier and Xterra, Red/Black wire on Pathfinder, or Pink wire on Quest) and PCM harness connector terminal No. 39. If continuity exists, go to next step. If continuity does not exist, repair open circuit.
4. Check power steering pressure switch. See «POWER STEERING PRESSURE SWITCH»(ref-3193-S37077702572000041900000). 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.

Scheme 24

1. Start engine. Measure voltage between ground and PCM harness connector terminal No. 47 (Green wire) by backprobing. see scheme 7 With steering wheel fully turned, voltage should be about zero volts. When steering wheel is not being turned, voltage should be about 5 volts. If voltage is as specified, go to step 5. If voltage is not as specified, go to next step.
2. Turn ignition off. Disconnect power steering pressure switch harness connector located near right shock tower. (Scheme 24) Check continuity between ground and power steering pressure switch harness connector terminal No. 1 (Black wire). If continuity exists, go to next step. If continuity does not exist, repair open ground circuit. See appropriate wiring diagram in WIRING DIAGRAMS article.
3. Turn ignition off. Disconnect PCM harness connector. Check continuity of Green wire between power steering pressure switch harness connector terminal No. 2 and PCM terminal No. 47. If continuity exists, go to next step. If continuity does not exist, repair open in Green wire.
4. Check power steering pressure switch. See «POWER STEERING PRESSURE SWITCH»(ref-3193-S37077702572000041900000). Replace components, if necessary. If components are 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.

1. Start engine. Measure voltage between ground and PCM harness connector terminal No. 46 (Purple/White wire) by backprobing. see scheme 7 With steering wheel fully turned, voltage should be about zero volts. When steering wheel is not being turned, voltage should be about 5 volts. If voltage is as specified, go to step 5. 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 ground and power steering pressure switch harness connector Black wire. If continuity exists, go to next step. If continuity does not exist, repair open in Black wire
3. Turn ignition off. Disconnect PCM harness connector. Check continuity of Purple/White wire between power steering pressure switch harness connector and PCM harness connector terminal No. 46. If continuity exists, go to next step. If continuity does not exist, repair open circuit.
4. Check power steering pressure switch. See «POWER STEERING PRESSURE SWITCH»(ref-3193-S37077702572000041900000). Replace components, if necessary. If components are 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.

REAR HEATED OXYGEN SENSOR (HO2S)

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

REFRIGERANT PRESSURE SENSOR - MAXIMA & SENTRA

See appropriate AIR CONDITIONING & HEATING article.

THROTTLE POSITION (TP) SENSOR

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

VEHICLE SPEED SENSOR (VSS)

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

A/C Clutch Relay

See MISCELLANEOUS CONTROLS .

Scheme 25

ECCS, PCM & Fuel Pump Relays

1. Two types of relays are used: 4-terminal and 6-terminal. For relay location, see «ECCS, PCM & FUEL PUMP RELAY LOCATIONS»(ref-3193-S01025880742000041900000) table. Remove appropriate relay. Apply battery voltage and ground to terminals No. 1 and 2. (Scheme 26), (Scheme 27) and (Scheme 28).
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.

ECCS, PCM & FUEL PUMP RELAY LOCATIONS

Scheme 26

Scheme 27

Scheme 28

SOLENOIDS

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

Relieving Fuel Pressure

Remove fuel pump fuse. Start engine and allow engine to run until it stalls. Crank engine an additional 2-3 times to ensure all pressure has dissipated.

Fuel Pressure

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

Fuel Pressure Regulator

1. Relieve fuel pressure from system. See «RELIEVING FUEL PRESSURE»(ref-3193-S36545925462000041900000) . Connect fuel pressure gauge in line between fuel filter and fuel rail. Remove vacuum hose from fuel pressure regulator, and plug hose. Connect hand-held vacuum pump to pressure regulator. Start engine and let idle.
2. Gradually apply vacuum to regulator. Fuel pressure should decrease as vacuum increases. Compare values to FUEL PRESSURE table in BASIC DIAGNOSTIC PROCEDURES article. If results are not as specified, replace fuel pressure regulator.

Fuel Pump

Disconnect fuel pump harness connector. For location, see FUEL PUMP HARNESS CONNECTOR LOCATIONS table. On Frontier and Xterra 4-cylinder models, measure resistance between fuel pump connector terminals P1 and P2. (Scheme 29) On Maxima and Sentra, measure resistance between fuel pump connector terminals No. 1 and 3. (Scheme 30) On Quest, measure resistance between fuel pump connector terminals No. 2 and 3. (Scheme 31) On all models except Frontier and Xterra 4-cylinder models, Maxima, Quest and Sentra, measure resistance between fuel pump 2-pin connector terminals. On all models, resistance should be 0.2-5.0 ohms at 77°F (25°C). Replace fuel pump, if resistance is not as specified.

FUEL PUMP HARNESS CONNECTOR LOCATIONS

Scheme 29

Scheme 30

Scheme 31

Scheme 32

Scheme 33

Scheme 34

1. On Quest, check inertia fuel shutoff switch located behind left kick panel. If switch has been triggered, push reset button. If switch has not been triggered, go to next step.
2. On all models, turn ignition on. Pinch fuel hose with fingers. Pulsation should be felt on fuel hose for 5 seconds after ignition is turned on (one second on Maxima). If pulsation is felt, system is okay. If pulsation is not felt, go to next step.
3. Turn ignition off. Disconnect fuel pump relay harness connector. For location, see «ECCS, PCM & FUEL PUMP RELAY LOCATIONS»(ref-3193-S01025880742000041900000) table under RELAYS & SOLENOIDS. Turn ignition on. Measure voltage between ground and fuel pump relay harness connector power supply terminals. See «FUEL PUMP RELAY CIRCUIT IDENTIFICATION»(ref-3193-S33559402452000041900000) table. If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit. See appropriate wiring diagram in WIRING DIAGRAMS article.
4. Turn ignition off. Disconnect fuel pump harness connector. For location, see «FUEL PUMP HARNESS CONNECTOR LOCATIONS»(ref-3193-S38817069042000041900000) table under FUEL PUMP. On Maxima, disconnect dropping resistor harness connector located in trunk. (Scheme 33) On Quest, disconnect fuel pump and fuel temperature sensor harness connector located behind fuel tank. (Scheme 34) On all models, check continuity of fuel pump ground circuit. See «FUEL PUMP CIRCUIT IDENTIFICATION»(ref-3193-S14404563262000041900000) table. If continuity exists, go to next step. If continuity does not exist, repair open ground circuit.
5. On Maxima, check continuity of fuel pump power supply wires between fuel pump harness connector terminal No. 2 and body ground, and between fuel pump harness connector terminal No. 1 and fuel pump relay harness connector terminal No. 3. On all other models, check continuity of fuel pump power supply wires between fuel pump harness connector and fuel pump relay harness connector. See «FUEL PUMP RELAY CIRCUIT IDENTIFICATION»(ref-3193-S33559402452000041900000) and «FUEL PUMP CIRCUIT IDENTIFICATION»(ref-3193-S14404563262000041900000) tables. If continuity exists, go to next step. If continuity does not exist, repair open in appropriate wire.
6. Disconnect PCM harness connector. Check continuity of specified wire between fuel pump relay harness connector and PCM harness connector terminal No. 6 (Altima), No. 11 (Frontier, Pathfinder, Quest and Xterra), No. 28 (Maxima), No. 20 (Sentra without engine immobilizer system) or No. 21 (Sentra with engine immobilizer system). See «FUEL PUMP RELAY CIRCUIT IDENTIFICATION»(ref-3193-S33559402452000041900000) table. see scheme 2, see scheme 4, see scheme 7, (Scheme 26), (Scheme 27) and (Scheme 28). If continuity exists, go to next step. If continuity does not exist, repair open in appropriate wire.
7. Check fuel pump relay. See «RELAYS»(ref-3193-S33815262082000041900000) under RELAYS & SOLENOIDS. Replace, if necessary. If fuel pump relay is okay, check fuel pump. See «FUEL PUMP»(ref-3193-S18905704542000041900000). Replace, if necessary. If fuel pump 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.

FUEL PUMP RELAY CIRCUIT IDENTIFICATION

FUEL PUMP CIRCUIT IDENTIFICATION

Fuel Pump Control Module (Maxima)

See DTC P1220: FUEL PUMP CONTROL MODULE (FPCM) in SELF-DIAGNOSTICS - MAXIMA 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 13.5-17.5 ohms at 68°F (20°C) on Sentra and 10-14 ohms at 77°F (25°C) on all other models. Replace injector if resistance is not as specified.

Fuel Injector Circuits (Altima, Frontier, Sentra & Xterra)

1. Start engine. Listen to each fuel injector. If every injector clicks, system is okay. If any injector does not click, go to next step.
2. Turn ignition off. Disconnect inoperative injector harness connector. Turn ignition on. Measure voltage between ground and injector harness connector Black/Red wire. If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit. See appropriate wiring diagram in WIRING DIAGRAMS article.
3. Turn ignition off. Disconnect PCM harness connector. Check continuity of specified wire between PCM harness connector and appropriate injector harness connector. See appropriate FUEL INJECTOR CIRCUIT IDENTIFICATION table. see scheme 2, see scheme 4 and see scheme 7. If continuity exists, go to next step. If continuity does not exist, repair open in appropriate wire.
4. Check fuel injector. See «FUEL INJECTOR»(ref-3193-S14992666172000041900000). Replace, if necessary. If injector is okay, 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 CIRCUIT IDENTIFICATION (ALTIMA)

FUEL INJECTOR CIRCUIT IDENTIFICATION (FRONTIER & XTERRA 4-CYLINDER MODELS)

FUEL INJECTOR CIRCUIT IDENTIFICATION (FRONTIER & XTERRA V6 MODELS)

FUEL INJECTOR CIRCUIT IDENTIFICATION (SENTRA)

Scheme 35

1. Start engine. With engine idling, listen to each fuel injector. If every injector clicks, system is okay. If any injector does not click, go to next step.
2. Turn ignition off. For injectors on left bank, disconnect inoperative injector harness connector. Turn ignition on. Measure voltage between ground and injector harness connector Red wire. For injectors on right bank, disconnect right bank injector circuit harness connector. (Scheme 35) Turn ignition on. Measure voltage between ground and right bank injector circuit harness connector terminal No. 5 (Red wire). (Scheme 36) If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit. See appropriate wiring diagram in WIRING DIAGRAMS article.
3. Turn ignition off. Disconnect PCM harness connector. Check continuity of specified wire between PCM harness connector and appropriate injector harness connector (on left bank), or right bank injector circuit harness connector (on right bank). See «FUEL INJECTOR CIRCUIT IDENTIFICATION (MAXIMA)»(ref-3193-S40018625932000041900000) table. see scheme 7and (Scheme 36). If continuity exists, go to next step. If continuity does not exist, repair open circuit.
4. If inoperative injector is on left bank, go to next step. If inoperative injector is on right bank, check continuity of appropriate wire between right bank injector circuit harness connector and PCM harness connector. See «FUEL INJECTOR CIRCUIT IDENTIFICATION (MAXIMA)»(ref-3193-S40018625932000041900000) table. If continuity exists, go to next step. If continuity does not exist, repair open circuit.
5. Check fuel injector. See «FUEL INJECTOR»(ref-3193-S14992666172000041900000). Replace, if necessary. If injector is okay, 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 CIRCUIT IDENTIFICATION (MAXIMA)

Scheme 36

Fuel Injector Circuits (Pathfinder)

1. Start engine. If engine does not start, go to step 5. If engine starts, listen to each injector. If every injector clicks, system is okay. If any injector does not click, go to next step.
2. Turn ignition off. Disconnect inoperative injector harness connector. Turn ignition on. Measure voltage between ground and injector harness connector White/Red wire. If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit. See appropriate wiring diagram in WIRING DIAGRAMS article.
3. Turn ignition off. Disconnect PCM harness connector. Check continuity of specified wire between PCM harness connector and appropriate injector harness connector. See «FUEL INJECTOR CIRCUIT IDENTIFICATION (PATHFINDER)»(ref-3193-S16612770732000041900000) table. see scheme 4 If continuity exists, go to next step. If continuity does not exist, repair open in appropriate wire.
4. Check fuel injector. See «FUEL INJECTOR»(ref-3193-S14992666172000041900000). Replace, if necessary. If injector is okay, no problem is indicated at this time. Problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.
5. Turn ignition off. Disconnect Black 8-pin injector sub-harness connector located near oil filler cap. Turn ignition on. Measure voltage between ground and injector sub-harness connector terminal No. 1 (White/Red wire). (Scheme 36) If battery voltage exists, reconnect injector sub-harness connector and go to step 2. If battery voltage does not exist, go to next step.
6. Turn ignition off. Remover ECCS relay from underhood relay box. Measure voltage between ground and ECCS relay harness connector terminals No. 1 (White/Red wire) and No. 5 (Red/White wire). (Scheme 28) If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit. See appropriate wiring diagram in WIRING DIAGRAMS article.
7. Check continuity of White/Red wire between ECCS relay harness connector terminal No. 3 and injector sub-harness connector terminal No. 1. (Scheme 28)and (Scheme 36). If continuity exists, go to next step. If continuity does not exist, repair open in White/Red wire.
8. Disconnect PCM harness connector. see scheme 1 Check continuity of Blue/Black wire between ECCS relay harness connector terminal No. 2 and PCM harness connector terminal No. 4. see scheme 4and (Scheme 28). If continuity exists, go to next step. If continuity does not exist, repair open in Blue/Black wire.
9. Check ECCS relay. See «RELAYS»(ref-3193-S33815262082000041900000) under RELAYS & SOLENOIDS. Replace, if necessary. If ECCS relay is okay, check PCM power supply. See «POWERTRAIN CONTROL MODULE (PCM)»(ref-3193-S31269617542000041900000) under COMPUTERIZED ENGINE CONTROLS.

FUEL INJECTOR CIRCUIT IDENTIFICATION (PATHFINDER)

Fuel Injector Circuits (Quest)

1. Start engine. If engine does not start, go to next step. If engine starts, listen to each injector. If every injector clicks, system is okay. If any injector does not click, go to next step.
2. Turn ignition off. Disconnect inoperative injector harness connector. Turn ignition on. Measure voltage between ground and appropriate injector harness connector Yellow wire. If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit. See appropriate wiring diagram in WIRING DIAGRAMS article.
3. Turn ignition off. Disconnect PCM harness connector. Check continuity of specified wire between PCM harness connector and appropriate injector harness connector. See «FUEL INJECTOR CIRCUIT IDENTIFICATION (QUEST)»(ref-3193-S10935905392000041900000) table. see scheme 4 If continuity exists, go to next step. If continuity does not exist, repair open in appropriate wire.
4. Check fuel injector. See «FUEL INJECTOR»(ref-3193-S14992666172000041900000). Replace, if necessary. If injector is okay, 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 CIRCUIT IDENTIFICATION (QUEST)

IDLE AIR CONTROL (IAC) VALVE

See DTC P0505: IDLE AIR CONTROL (IAC) in appropriate SELF-DIAGNOSTICS article.

Except Maxima & Sentra

Remove IACV-FICD solenoid. See COMPONENT LOCATIONS. Using jumper wires, apply battery voltage to IACV-FICD solenoid terminals. On Quest (Scheme 37) On all models, IACV-FICD solenoid should click. Inspect IACV-FICD solenoid plunger for sticking. Also check for broken spring. Replace IACV-FICD solenoid, if operation is not as specified.

Scheme 37

IGNITION SYSTEM

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

Ignition Coil

See IGNITION CHECKS in BASIC DIAGNOSTIC PROCEDURES article.

Power Transistor

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

Crankshaft Position Sensor

PCM depends upon crankshaft position sensor for RPM signals. PCM uses signals to determine triggering of power transistors and fuel injectors. See DTC P0335 OR P1336: CRANKSHAFT POSITION (CKP) SENSOR in appropriate SELF-DIAGNOSTICS article.

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

Timing Advance System

PCM 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 PCM pin voltage charts in PIN VOLTAGE CHARTS article.

1. A/C Clutch Signal
2. Closed Throttle Position Switch
3. Crankshaft Position Sensor
4. Engine Coolant Temperature
5. Ignition (START) Signal
6. Mass Airflow Sensor
7. Park/Neutral Switch
8. Power Steering Pressure Switch
9. Throttle Position Sensor
10. Vehicle Speed Sensor

EXHAUST GAS RECIRCULATION (EGR)

PCM controls EGR system based on engine operating conditions. On Maxima and Sentra, PCM controls ground circuits for EGR Volume Control Valve (EGR-VCV). On all models except Maxima and Sentra, PCM controls ground circuit for EGR Control (EGRC) solenoid. (Scheme 38)and (Scheme 39). EGR-VCV or EGRC solenoid remains closed under certain conditions including the following

1. Engine stopped.
2. Engine starting.
3. Engine idling.
4. Low engine coolant temperature.
5. Excessively high engine coolant temperature.
6. High engine speed.
7. Mass airflow sensor malfunction.

Scheme 38

Scheme 39

EGR System Check

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

EGR Backpressure Transducer (Except Maxima & Sentra)

See DTC P0402: EGR BACKPRESSURE TRANSDUCER (EGR-BPT) in appropriate SELF-DIAGNOSTICS article.

EGRC Solenoid (Except Maxima & Sentra)

See DTC 1400: EGR CONTROL (EGRC) SOLENOID in appropriate SELF-DIAGNOSTICS article.

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

EGR Valve (Except Maxima & Sentra)

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

EGR Volume Control Valve (Maxima & Sentra)

See DTC P0403: EGR VOLUME CONTROL VALVE (EGR-VCV) in SELF-DIAGNOSTICS - MAXIMA article.

EVAP Canister

Remove EVAP canister. Plug vent hose and blow air into port "A". Air should flow freely out of port "B". (Scheme 40) Replace EVAP canister, if operation is not as specified.

Scheme 40

ON BOARD REFUELING VAPOR RECOVERY (ORVR) SYSTEM (ALTIMA, MAXIMA & SENTRA)

Note. Refueling control valve is not replaceable. If defective, fuel tank must be replaced.

Cannot Refuel/Strong Fuel Odor From Fuel Filler While Refueling (Altima & Maxima)

1. Remove water separator. With water separator port "A" plugged, blow air into port "B". see scheme 43 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. 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 and tubes between EVAP canister and refueling control valve for blockage, leak or improper connection. Also check signal line and recirculation line for blockage, cracks or leaks. Repair as necessary. If no problems are found, go to next step.
4. Check refueling control valve. See appropriate REFUELING CONTROL VALVE TEST. 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 appropriate REFUELING EVAP VAPOR CUT VALVE TEST. 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, check one-way fuel valve for blockage. If valve operation is as specified, test is complete. If operation is not as specified, replace fuel tank.

Cannot Refuel/Strong Fuel Odor From Fuel Filler While Refueling (Sentra)

1. Remove EVAP canister with EVAP Canister Vent Control Valve (EVAP-CVCV) attached. 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 step 3.
2. Remove water separator. With water separator port "A" plugged, blow air into port "B". see scheme 43 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.
3. Check hoses and tubes between EVAP canister and refueling control valve for blockage, leak or improper connection. Also check signal line and recirculation line for blockage, cracks or leaks. Repair as necessary. If no problems are found, go to next step.
4. Check refueling control valve. See appropriate REFUELING CONTROL VALVE TEST. 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 appropriate REFUELING EVAP VAPOR CUT VALVE TEST. 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, check one-way fuel valve for blockage. See «REFUELING ONE-WAY FUEL VALVE TEST - ALTIMA, MAXIMA & SENTRA»(ref-3193-S33615976642000070500000). If valve operation is as specified, test is complete. If operation is not as specified, replace fuel tank.

POSITIVE CRANKCASE VENTILATION (PCV)

With engine idling, remove vent hose from PCV valve. A hissing noise should be heard. Strong vacuum should be felt immediately when a finger is placed over valve inlet. Clean or replace PCV valve, if it does not operate as specified.

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 PCM. Under normal conditions, PCM will engage clutch relay by providing a ground circuit for relay windings. If PCM 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, PCM will disengage relay.
2. Remove A/C relay located in underhood relay box. Apply battery voltage to terminals No. 1 and 2. (Scheme 26), (Scheme 27) and (Scheme 28). 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 off. Disconnect PCM harness connector. Turn ignition on. Measure voltage between ground and PCM harness connector terminal No. 55 (Blue/Red wire). see scheme 2 With rear window defogger on, battery voltage should exist. With 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 4.
2. Measure voltage between ground and PCM harness connector terminal No. 60 (Brown wire). With headlights or daytime running lights on, battery voltage should exist. With headlights and daytime running lights off, zero volts should exist. If voltage is as specified, go to next step. If voltage is not as specified, go to step 6.
3. Turn ignition off. Check continuity between ground and PCM harness connector terminal No. 59 (Light Green/Red wire). With blower fan turned on, continuity should exist. With blower fan turned off, continuity should not exist. If continuity is not as specified, go to step 8. If continuity is as specified, go to step 10.
4. Turn ignition off. Disconnect rear window defogger relay, located above passenger compartment fuse block. Check continuity of Blue/Red wire between PCM harness connector terminal No. 55 and rear window defogger relay harness connector terminal No. 5. see scheme 2, (Scheme 26), (Scheme 27) and (Scheme 28). If continuity exists, go to next step. If continuity does not exist, repair open in Blue/Red wire.
5. Disconnect rear window defogger timer and smart entrance control unit harness connectors, located behind center of instrument panel. Check continuity of Green/Red wire between rear window defogger relay harness connector terminal No. 2, rear window defogger timer harness connector terminal No. 2 and smart entrance control unit harness connector terminal No. 36. If continuity does not exist, repair open in Green/Red wire. If continuity exists, check rear window defogger system. See REAR WINDOW DEFOGGERS article in ACCESSORIES & EQUIPMENT. Repair as necessary.
6. Turn ignition off. Disconnect Light Blue 6-pin diode harness connector located behind left kick panel. Check continuity of Brown wire between PCM harness connector terminal No. 60 and diode harness connector terminal No. 4. If continuity exists, go to next step. If continuity does not exist, repair open in Brown wire.
7. Check continuity of Red/Yellow wire between diode harness connector terminal No. 6 and combination switch harness connector terminal No. 10. Also check continuity of Red/Black wire between diode harness connector terminal No. 1 and combination switch harness connector terminal No. 9. If continuity does not exist, repair open circuit. If continuity exists, check diode. Replace, if necessary. If diode is okay, test is complete.
8. Check continuity of Light Green/Red wire between PCM harness connector terminal No. 59, blower fan switch harness connector terminal No. 5 and push control unit harness connector terminal No. 19. If continuity exists, go to next step. If continuity does not exist, repair open in Light Green/Red wire.
9. Check continuity of Black wire between ground and blower fan switch harness connector terminal No. 6. If continuity does not exist, repair open in Black wire. If continuity exists, 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.

1. Turn ignition on. Measure voltage between ground and PCM harness connector terminal No. 52 (White/Green wire). see scheme 7 With rear window defogger on, battery voltage should exist. With rear window defogger off, zero volts should exist. If voltage is not as specified, go to step 3. If voltage is as specified, go to next step.
2. Again, measure voltage between ground and PCM harness connector terminal No. 52 (White/Green wire). With headlights on, battery voltage should exist. With headlights off, zero volts should exist. If voltage is not as specified, go to step 5. If voltage is as specified, go to step 7.
3. Check rear window defogger for correct operation. See appropriate REAR WINDOW DEFOGGERS article in ACCESSORIES & EQUIPMENT. If rear window defogger operates normally, go to next step. If rear window defogger does not operate normally, repair as necessary.
4. Disconnect rear window defogger relay, located in underhood relay box. With PCM harness connector disconnected, check continuity between PCM terminal No. 52 (White/Green wire) and rear window defogger relay harness connector terminals No. 5 and 7 (Green wires). see scheme 7, (Scheme 26), (Scheme 27) and (Scheme 28). If continuity does not exist, repair open circuit. If continuity exists, go to step 7.
5. Start engine and check headlight high beam operation. See HEADLIGHT SYSTEMS article in ACCESSORIES & EQUIPMENT. If headlights operate normally, go to next step. If headlights do not operate normally, repair as necessary.
6. Disconnect headlamp relay, located in underhood relay box. With PCM harness connector disconnected, check continuity between PCM terminal No. 52 (White/Green wire) and headlamp relay harness connector terminal No. 3 (Orange/Black wire). see scheme 7, (Scheme 26), (Scheme 27) and (Scheme 28). If continuity does not exist, repair open circuit. If continuity exists, 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.

Sentra 1.8L

1. Turn ignition on. Measure voltage by backprobing between ground and PCM harness connector terminal No. 50 (Red/White wire). see scheme 7 With rear window defogger on, battery voltage should exist. With 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 4.
2. Measure voltage by backprobing between ground and PCM harness connector terminal No. 50 (Red/White wire). With headlights on, battery voltage should exist. With headlights off, zero volts should exist. If voltage is as specified, go to next step. If voltage is not as specified, go to step 6.
3. Measure voltage by backprobing between ground and PCM harness connector terminal No. 51 (Light Green/Black wire). With blower fan on, battery voltage should exist. With blower fan off, zero volts should exist. If voltage is as specified, go to step 10. If voltage is not as specified, go to step 8.
4. Start engine. Turn rear window defogger on. If rear window warms up, go to next step. If rear window does not warm up, repair rear window defogger. See appropriate REAR WINDOW DEFOGGERS article in ACCESSORIES & EQUIPMENT. CAUTION: Blue/Red wire from rear window defogger relay changes to Red/White wire at diode No. 3, terminal No. 2 located near fuel pump relay at left kick panel. (Scheme 32) Wire is Red/White at PCM connector terminal No. 50.
5. Stop engine. Disconnect rear window defogger relay, located next to fuel pump relay behind left kick panel. Disconnect PCM harness connector. Check continuity of Blue/Red wire between PCM harness connector terminal No. 50 and rear window defogger relay harness connector terminals No. 5 and 7. see scheme 7and (Scheme 28). If continuity exists, go to step 10. If continuity does not exist, repair open in Blue/Red wire.
6. Start engine. Turn headlights on. If headlights illuminate, go to next step. If headlights do not illuminate, repair lighting system. See HEADLIGHT SYSTEMS article in ACCESSORIES & EQUIPMENT. CAUTION: Red/Yellow wire from headlight switch changes to Red/White wire at diode No. 3, terminal No. 2 located near fuel pump relay at left kick panel. Wire is Red/White at PCM connector terminal No. 50.
7. Stop engine. Turn ignition off. Disconnect headlight switch harness and PCM harness connectors. Check continuity of Red/Yellow wire between headlight switch harness connector terminal No. 10 and PCM harness connector terminal No. 50. If continuity does not exist, repair open in Red/Yellow wire. If continuity exists, go to step 10.
8. Start engine. Turn heater fan on. If fan motor operates, go to next step. If fan motor does not operate, repair blower motor. See appropriate MANUAL OR AUTOMATIC A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING.
9. Stop engine. Disconnect heater fan control switch harness and PCM harness connectors. Check continuity of Light Green/Black wire between heater fan control switch harness connector terminal No. 6 and PCM harness connector terminal No. 51. Also check continuity of Black wire between ground and heater fan control switch harness connector terminal No. 5. If continuity exists, go to next step. If continuity does not exist, repair open in appropriate wire. See appropriate wiring diagram in WIRING DIAGRAMS article.
10. No problem is indicated at this time. Problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article.

Sentra 2.0L

1. Turn ignition on. Measure voltage by backprobing between ground and PCM harness connector terminal No. 50 (Red/White wire). see scheme 7 With rear window defogger on, battery voltage should exist. With 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 5.
2. Measure voltage by backprobing between ground and PCM harness connector terminal No. 50 (Red/White wire). With headlights on low beam, battery voltage should exist. With headlights off, zero volts should exist. If voltage is as specified, go to next step. If voltage is not as specified, go to step 7.
3. Measure voltage by backprobing between ground and PCM harness connector terminal No. 50 (Red/White wire). With headlights on high beam, battery voltage should exist. With headlights off, zero volts should exist. If voltage is as specified, go to next step. If voltage is not as specified, go to step 9.
4. Measure voltage by backprobing between ground and PCM harness connector terminal No. 51 (Light Green/Black wire). With heater fan on, battery voltage should exist. With heater fan off, zero volts should exist. If voltage is as specified, go to step 13. If voltage is not as specified, go to step 11.
5. Start engine. Turn rear window defogger on. If rear window warms up, go to next step. If rear window does not warm up, repair rear window defogger. See appropriate REAR WINDOW DEFOGGERS article in ACCESSORIES & EQUIPMENT. CAUTION: Blue/Red wire from rear window defogger relay changes to Red/White wire at diode No. 3, terminal No. 2 located near relay at left kick panel. (Scheme 32) Wire is Red/White at PCM connector terminal No. 50.
6. Stop engine. Disconnect rear window defogger relay, located next to fuel pump relay behind left kick panel. Disconnect PCM connector. Check continuity of Blue/Red wire between PCM harness connector terminal No. 50 and rear window defogger relay harness connector terminals No. 5 and 7. see scheme 7and (Scheme 28). If continuity exists, go to step 13. If continuity does not exist, repair open in Blue/Red wire.
7. Start engine. Turn headlights on low beam. If low beam headlights illuminate, go to next step. If low beam headlights do not illuminate, repair lighting system. See HEADLIGHT SYSTEMS article in ACCESSORIES & EQUIPMENT. CAUTION: Red/Yellow wire from headlight switch changes to Red/White wire at diode No. 3, terminal No. 2 located near relay at left kick panel. Wire is Red/White at PCM connector terminal No. 50.
8. Stop engine. Turn ignition off. Disconnect headlight switch harness and PCM harness connectors. Check continuity of Red/Yellow wire between headlight switch harness connector terminal No. 10 and PCM harness connector terminal No. 50. If continuity does not exist, repair open in Red/Yellow wire. If continuity exists, go to step 13.
9. Start engine. Turn headlights on high beam. If high beam headlights illuminate, go to next step. If high beam headlights do not illuminate, repair lighting system. See HEADLIGHT SYSTEMS article in ACCESSORIES & EQUIPMENT. CAUTION: Red/Black wire from headlight switch changes to Red/White wire at diode No. 3, terminal No. 2 located near relay at left kick panel. Wire is Red/White at PCM connector terminal No. 50.
10. Stop engine. Turn ignition off. Disconnect headlight switch harness and PCM harness connectors. Check continuity of Red/Black wire between headlight switch harness connector terminal No. 9 and PCM harness connector terminal No. 50. If continuity does not exist, repair open in Red/Black wire. If continuity exists, go to step 13.
11. Start engine. Turn heater fan on. If fan motor operates, go to next step. If fan motor does not operate, repair blower motor. See appropriate MANUAL OR AUTOMATIC A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING.
12. Stop engine. Turn ignition off. Disconnect heater fan control switch harness and PCM harness connectors. Check continuity of Light Green/Black wire between heater fan control switch harness connector terminal No. 6 and PCM harness connector terminal No. 51. Also check continuity of Black wire between ground and heater fan control switch harness connector terminal No. 5. If continuity exists, go to next step. If continuity does not exist, repair open in appropriate wire. See appropriate wiring diagram in WIRING DIAGRAMS article.
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 41

1. Start engine and warm to normal operating temperature. Set parking brake and let engine idle. While depressing brake pedal, shift transmission into Drive. Observe amount of body vibration. Increase engine speed to more than 1000 RPM. Disconnect front or rear engine mount harness connector. (Scheme 41)
2. Allow engine to idle. Observe amount of body vibration. If amount of body vibration does not increase to more than amount observed in previous step, go to next step. If amount of body vibration increased to more than amount observed in previous step, system is okay. Test is complete.
3. Turn ignition off. Measure voltage between ground and front or rear engine mount harness connector White/Blue wire. If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit. See appropriate wiring diagram in WIRING DIAGRAMS article.
4. Disconnect PCM harness connector. Check continuity of White wire between front or rear engine mount harness connector and PCM harness connector terminal No. 49. see scheme 7 Also check continuity of White/Red wire between front or rear engine mount harness connector and PCM harness connector terminal No. 50. If continuity exists, go to next step. If continuity does not exist, repair open circuit.
5. No problem is indicated at this time. Problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article. Visually inspect front engine mount. Replace, if damaged.

Scheme 42

1. Start engine and warm to normal operating temperature. Set parking brake and increase engine speed to more than 5000 RPM. If power valve actuator moves, system is operating properly. If power valve does not move, go to next step.
2. Stop engine and turn ignition off. Disconnect VIAS control solenoid valve harness connector. (Scheme 42) Turn ignition on. Measure voltage between ground and VIAS control solenoid valve harness connector Red/Yellow wire. If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short circuit. See appropriate wiring diagram in WIRING DIAGRAMS article.
3. Turn ignition off. Disconnect PCM harness connector. With VIAS control solenoid valve harness connector disconnected, measure continuity of Yellow/Green wire between PCM harness connector terminal No. 16 and VIAS control solenoid valve harness connector. If continuity exists, go to next step. If continuity does not exist, repair open or short circuit. See appropriate wiring diagram in WIRING DIAGRAMS article.
4. Reconnect all connectors and repeat step 1). If power valve actuator operates as specified, system is operating properly. If power valve actuator does not operate as specified, problem may be intermittent. See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article. Visually inspect VIAS control solenoid valve. Replace, if damaged.