diagram INFINITI QX4 2001 Factory Service Manual

Diagnostic Procedure=NBEC0631
1 CHECK FUEL LEVEL SENSOR POWER SUPPLY CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect fuel level sensor unit harness connector.
3. Turn ignition switch ªONº.
4. Check voltage between fuel level sensor unit terminal 3 and ground, ECM terminal 83 and ground with CONSULT-II or
tester.
SEF374Z
OK or NG
OK©GO TO 3.
NG©GO TO 2.
2 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors M2, B1 and M94, F27
IHarness for open or short between combination meter and fuel level sensor unit
©Repair or replace harness or connectors.
3 CHECK FUEL LEVEL SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Check harness continuity between fuel level sensor unit terminal 2 and body ground. Refer to Wiring Diagram.
Continuity should exist.
3. Also check harness for short to power.
OK or NG
OK©GO TO 4.
NG©Repair open circuit or short to power in harness or connectors.
4 CHECK FUEL LEVEL SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal 59 and fuel level sensor terminal 2. Refer to Wiring Diagram.
Continuity should exist.
3. Also check harness for short to power.
OK or NG
OK©GO TO 6.
NG©GO TO 5.
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DTC P0464 FUEL LEVEL SENSOR CIRCUIT
Diagnostic Procedure
EC-415

Wiring DiagramNBEC0247
MEC965C
DTC P0500 VEHICLE SPEED SENSOR (VSS)
Wiring Diagram
EC-420

Diagnostic ProcedureNBEC0248
1 CHECK VEHICLE SPEED SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector and combination meter harness connector.
3. Check harness continuity between ECM terminal 86 and combination meter terminal 13.
Refer to Wiring Diagram.
Continuity should exist.
4. Also check harness for short to power.
OK or NG
OK©GO TO 3.
NG©GO TO 2.
2 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors M32, F23
IHarness for open or short between ECM and combination meter
©Repair open circuit or short to ground or short to power in harness or connectors.
3 CHECK SPEEDOMETER FUNCTION
Make sure that speedometer functions properly.
OK or NG
OK©GO TO 5.
NG©GO TO 4.
4 CHECK SPEEDOMETER CIRCUIT FOR OPEN AND SHORT
Check the following.
IHarness connectors M70, B50
IHarness for open or short between combination meter and vehicle speed sensor
IHarness for open or short between vehicle speed sensor and ECM
OK or NG
OK©Check combination meter and vehicle speed sensor. Refer to EL section.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
5 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-140.
©INSPECTION END
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DTC P0500 VEHICLE SPEED SENSOR (VSS)
Diagnostic Procedure
EC-421

Wiring DiagramNBEC0254
MEC966C
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DTC P0505 IDLE AIR CONTROL VALVE (IACV) Ð AUXILIARY AIR CONTROL
(AAC) VALVE
Wiring Diagram
EC-425

3 CHECK IACV-AAC VALVE OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminals and IACV-AAC valve terminals as follows.
Refer to Wiring Diagram.
MTBL0354
Continuity should exist.
4. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 5.
NG©GO TO 4.
4 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors F101, F6
IHarness for open or short between IACV-AAC valve and ECM
©Repair harness connectors.
5 CHECK AIR CONTROL VALVE (POWER STEERING) OPERATION-I
1. Reconnect ECM harness connector and IACV-AAC valve harness connector.
2. Disconnect vacuum hose connected to air control valve (Power steering) at intake air duct.
3. Start engine and let it idle.
4. Check vacuum hose for vacuum existence.
SEF995Y
Vacuum slightly exists or does not exist.
OK or NG
OK©GO TO 6.
NG©Replace air control valve (Power steering).
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DTC P0505 IDLE AIR CONTROL VALVE (IACV) Ð AUXILIARY AIR CONTROL
(AAC) VALVE
Diagnostic Procedure (Cont'd)
EC-427

Wiring Diagram=NBEC0262
MEC967C
DTC P0510 CLOSED THROTTLE POSITION SWITCH
Wiring Diagram
EC-434

Diagnostic ProcedureNBEC0263
1 CHECK CLOSED THROTTLE POSITION SWITCH POWER SUPPLY CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect throttle position switch harness connector.
SEF944Y
3. Turn ignition switch ªONº.
4. Check voltage between throttle position switch terminal 5 and engine ground with CONSULT-II or tester.
SEF346X
OK or NG
OK©GO TO 3.
NG©GO TO 2.
2 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors M32, F23
IHarness for open or short between throttle position switch and ECM
©Repair harness or connectors.
3 CHECK CLOSED THROTTLE POSITION SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminal 56 and throttle position switch terminal 6.
Refer to Wiring Diagram.
Continuity should exist.
4. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 4.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
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DTC P0510 CLOSED THROTTLE POSITION SWITCH
Diagnostic Procedure
EC-435

Wiring DiagramNBEC0269
MEC968C
DTC P0600 A/T COMMUNICATION LINE
Wiring Diagram
EC-442

Diagnostic ProcedureNBEC0270
1 CHECK A/T CONTROL INPUT SIGNAL CIRCUIT FOR OPEN
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector and TCM (Transmission Control Module) harness connector.
SEF955Y
SEF001Z
3. Check harness continuity between ECM terminal 114 and TCM terminal 33.
Refer to Wiring Diagram.
Continuity should exist.
OK or NG
OK©GO TO 3.
NG©GO TO 2.
2 DETECT MALFUNCTION PART
Check the following.
IHarness connectors M94, F27
IHarness for open or short between ECM and TCM (Transmission control module)
©Repair harness or connectors.
3 CHECK A/T CONTROL INPUT SIGNAL CIRCUIT FOR SHORT
1. Check harness continuity between ECM terminal 114 and ground.
Refer to Wiring Diagram.
Continuity should not exist.
2. Also check harness for short to power.
OK or NG
OK©GO TO 4.
NG©Repair short to ground or short to power in harness or connectos.
4 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-140.
©INSPECTION END
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DTC P0600 A/T COMMUNICATION LINE
Diagnostic Procedure
EC-443

Wiring DiagramNBEC0703RIGHT BANKNBEC0703S01
MEC989C
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D T C P 1111(RIGHT, -B1), P1136 (LEFT, -B2) INTAKE VALVE TIMING CONTROL
SOLENOID VALVE (CIRCUIT)
Wiring Diagram
EC-453