diagram INFINITI QX4 2001 Factory Manual PDF

4 CHECK MAFS POWER SUPPLY CIRCUIT
1. Disconnect mass air flow sensor (MAFS) harness connector.
SEF960Y
2. Turn ignition switch ªONº.
3. Check voltage between MAFS terminals 2, 4 and ground with CONSULT-II or tester.
SEF297X
OK or NG
OK©GO TO 6.
NG©GO TO 5.
5 DETECT MALFUNCTIONING PART
Check the following.
IHarness for open or short between ECM relay and mass air flow sensor
IHarness for open or short between mass air flow sensor and ECM
©Repair harness or connectors.
6 CHECK MAFS GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector.
3. Check harness continuity between MAFS terminal 3 and ECM terminal 73.
Refer to Wiring Diagram.
Continuity should exist.
4. Also check harness for short to power.
OK or NG
OK©GO TO 7.
NG©Repair open circuit or short to power in harness or connectors.
DTC P0100 MASS AIR FLOW SENSOR (MAFS)
Diagnostic Procedure (Cont'd)
EC-156

7 CHECK MAFS INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between MAFS terminal 1 and ECM terminal 61.
Refer to Wiring Diagram.
Continuity should exist.
2. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 8.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
8 CHECK MASS AIR FLOW SENSOR
1. Reconnect harness connectors disconnected.
2. Start engine and warm it up to normal operating temperature.
3. Check voltage between ECM terminal 61 (Mass air flow sensor signal) and ground.
SEF298X
4. If the voltage is out of specification, disconnect MAFS harness connector and connect it again.
Then repeat above check.
OK or NG
OK©GO TO 9.
NG©Replace mass air flow sensor.
9 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-140.
©INSPECTION END
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0100 MASS AIR FLOW SENSOR (MAFS)
Diagnostic Procedure (Cont'd)
EC-157

Wiring Diagram=NBEC0730
MEC943C
DTC P0105 ABSOLUTE PRESSURE SENSOR
Wiring Diagram
EC-160

3 CHECK ABSOLUTE PRESSURE SENSOR POWER SUPPLY CIRCUIT
1. Turn ignition switch ªONº.
2. Check voltage between absolute pressure sensor terminal 1 and ground with CONSULT-II or tester.
SEF299X
OK or NG
OK©GO TO 4.
NG©Repair harness or connectors.
4 CHECK ABSOLUTE PRESSURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Check harness continuity between absolute pressure sensor terminal 3 and engine ground.
Refer to Wiring Diagram.
Continuity should exist.
3. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 6.
NG©GO TO 5.
5 DETECT MALFUNCTIONING PART
Check the following.
IHarness for open or short between ECM and absolute pressure sensor
IHarness for open or short between TCM (Transmission Control Module) and absolute pressure sensor
©Repair open circuit or short to ground or short to power in harness or connectors.
6 CHECK ABSOLUTE PRESSURE SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal 80 and absolute pressure sensor terminal 2.
Continuity should exist.
3. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 7.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
DTC P0105 ABSOLUTE PRESSURE SENSOR
Diagnostic Procedure (Cont'd)
EC-162

Wiring DiagramNBEC0067
MEC944C
DTC P0110 INTAKE AIR TEMPERATURE SENSOR
Wiring Diagram
EC-166

Diagnostic ProcedureNBEC0068
1 CHECK INTAKE AIR TEMPERATURE SENSOR POWER SUPPLY CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect intake air temperature sensor harness connector.
SEF962Y
3. Turn ignition switch ªONº.
4. Check voltage between terminal 1 and ground.
SEF301X
OK or NG
OK©GO TO 3.
NG©GO TO 2.
2 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors E1, M1
IHarness connectors M33, F22
IHarness for open or short between ECM and intake air temperature sensor
©Repair harness or connectors.
3 CHECK INTAKE AIR TEMPERATURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Check harness continuity between sensor terminal 2 and engine ground.
Refer to Wiring Diagram.
Continuity should exist.
3. Also check harness for short to power.
OK or NG
OK©GO TO 5.
NG©GO TO 4.
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0110 INTAKE AIR TEMPERATURE SENSOR
Diagnostic Procedure
EC-167

Wiring DiagramNBEC0072
MEC945C
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0115 ENGINE COOLANT TEMPERATURE SENSOR (ECTS) (CIRCUIT)
Wiring Diagram
EC-171

Diagnostic ProcedureNBEC0073
1 CHECK ECTS POWER SUPPLY CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect engine coolant temperature sensor (ECTS) harness connector F112, F28.
SEF370Z
3. Turn ignition switch ªONº.
4. Check voltage between ECTS harness connector F28 terminal 3 and ground with CONSULT-II or tester.
SEF371Z
OK or NG
OK©GO TO 3.
NG©GO TO 2.
2 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors F112, F28
IHarness for open or short between ECM and engine coolant temperature sensor
©Repair harness or connectors.
3 CHECK ECTS GROUND CIRCUIT FOR OPEN AND CIRCUIT
1. Turn ignition switch ªOFFº.
2. Check harness continuity between ECTS terminal 2 and engine ground.
Refer to Wiring Diagram.
Continuity should exist.
3. Also check harness for short to power.
OK or NG
OK©GO TO 5.
NG©GO TO 4.
DTC P0115 ENGINE COOLANT TEMPERATURE SENSOR (ECTS) (CIRCUIT)
Diagnostic Procedure
EC-172

Wiring DiagramNBEC0079
MEC946C
DTC P0120 THROTTLE POSITION SENSOR
Wiring Diagram
EC-180

5 CHECK THROTTLE POSITION SENSOR POWER SUPPLY CIRCUIT
1. Disconnect throttle position sensor harness connector.
SEF944Y
2. Turn ignition switch ªONº.
3. Check voltage between throttle position sensor terminal 1 and ground with CONSULT-II or tester.
SEF964Y
OK or NG
OK©GO TO 6.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
6 CHECK THROTTLE POSITION SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Check harness continuity between sensor terminal 3 and engine ground.
Refer to Wiring Diagram.
Continuity should exist.
3. Also check harness for short to power.
OK or NG
OK©GO TO 8.
NG©GO TO 7.
7 DETECT MALFUNCTIONING PART
Check the following.
IHarness for open or short between ECM and throttle position sensor
IHarness for open or short between TCM (Transmission Control Module) and throttle position sensor
©Repair open circuit or short to power in harness or connectors.
DTC P0120 THROTTLE POSITION SENSOR
Diagnostic Procedure (Cont'd)
EC-182