2001 INFINITI QX4 ignition

4 CHECK IGNITION TIMING AND ENGINE IDLE SPEED
Check the following items. Refer to ªBasic Inspectionº, EC-101.
MTBL0656
Models with CONSULT-II©GO TO 6.
Models without CON-
SULT-II©GO TO 6.
5 CHECK THROTTLE POSITION SWITCH
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch ªOFFº.
3. Remove vacuum hose connected to throttle opener.
4. Connect suitable vacuum hose to vacuum pump and the throttle opener.
5. Apply vacuum [more than þ40.0 kPa (þ300 mmHg, þ11.81 inHg)] until the throttle drum becomes free from the rod of
the throttle opener.
SEF793W
6. Turn ignition switch ªONº.
7. Select ªDATA MONITORº mode with CONSULT-II.
8. Check indication of ªCLSD THL/P SWº under the following conditions.
Measurement must be made with throttle position switch installed in vehicle.
MTBL0355
OK or NG
OK (With CONSULT-II)©GO TO 8.
OK (Without CONSULT-
II)©GO TO 9.
NG©GO TO 7.
DTC P0510 CLOSED THROTTLE POSITION SWITCH
Diagnostic Procedure (Cont'd)
EC-436

6 CHECK THROTTLE POSITION SWITCH
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch ªOFFº.
3. Remove vacuum hose connected to throttle opener.
4. Connect suitable vacuum hose to vacuum pump and the throttle opener.
5. Apply vacuum [more than þ40.0 kPa (þ300 mmHg, þ11.81 inHg)] until the throttle drum becomes free from the rod of
the throttle opener.
SEF793W
6. Disconnect closed throttle position switch harness connector.
7. Check continuity between closed throttle position switch terminals 6 and 5 under the following conditions.
Resistance measurement must be made with throttle position switch installed in vehicle.
SEF998Y
OK or NG
OK (With CONSULT-II)©GO TO 8.
OK (Without CONSULT-
II)©GO TO 9.
NG©GO TO 7.
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DTC P0510 CLOSED THROTTLE POSITION SWITCH
Diagnostic Procedure (Cont'd)
EC-437

7 ADJUST THROTTLE POSITION SWITCH
Check the following items. Refer to ªBasic Inspectionº, EC-101.
MTBL0655
Is it possible to adjust closed throttle position switch?
YesorNo
Yes (With CONSULT-II)©GO TO 9.
Yes (Without CONSULT-
II)©GO TO 9.
No©Replace throttle position switch.
8 CHECK THROTTLE POSITION SENSOR
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Stop engine (ignition switch OFF).
3. Remove the vacuum hose connected to the throttle opener.
4. Connect suitable vacuum hose to the vacuum pump and the opener.
5. Apply vacuum [more than þ40.0 kPa (þ300 mmHg, þ11.81 inHg)] until the throttle drum becomes free from the rod of
the throttle opener.
SEF793W
6. Turn ignition switch ON.
7. Select ªDATA MONITORº mode with CONSULT-II.
8. Check voltage of ªTHRTL POS SENº under the following conditins.
Voltage measurement must be made with throttle position sensor installed in vehicle.
MTBL0230
OK or NG
OK©GO TO 10.
NG©Replace throttle position sensor.
DTC P0510 CLOSED THROTTLE POSITION SWITCH
Diagnostic Procedure (Cont'd)
EC-438

9 CHECK THROTTLE POSITION SENSOR
1. Start engine and warm it up to normal operating temperature.
2. Stop engine (ignition switch OFF).
3. Remove the vacuum hose connected to the throttle opener.
4. Connect suitable vacuum hose to the vacuum pump and the opener.
5. Apply vacuum [more than þ40.0 kPa (þ300 mmHg, þ11.81 inHg)] until the throttle drum becomes free from the rod of
the throttle opener.
SEF793W
6. Turn ignition switch ON.
7. Check voltage between ECM terminal 91 (Throttle position sensor signal) and ground.
Voltage measurement must be made with throttle position sensor installed in vehicle.
SEF348X
OK or NG
OK©GO TO 10.
NG©Replace throttle position sensor.
10 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-140.
©INSPECTION END
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DTC P0510 CLOSED THROTTLE POSITION SWITCH
Diagnostic Procedure (Cont'd)
EC-439

System DescriptionNBEC0264This circuit line (LAN) is used to control the smooth shifting up and down of A/T during the hard acceleration/
deceleration.
Pulse signals are exchanged between ECM and TCM (Transmission Control Module).
Be sure to erase the malfunction information such as DTC not only in TCM but also ECM after the A/T
related repair.
ECM Terminals and Reference ValueNBEC0672Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
114 G/RCommunication line
(LAN)[Engine is running]
IIdle speedApproximately 2V
On Board Diagnosis LogicNBEC0266Malfunction is detected when ECM receives incorrect voltage from
TCM (Transmission Control Module) continuously.
Possible CauseNBEC0517IHarness or connectors
[The communication line circuit between ECM and TCM
(Transmission Control Module) is open or shorted.]
ITCM
IDead (Weak) battery
SEF058Y
DTC Confirmation ProcedureNBEC0267NOTE:
If ªDTC Confirmation Procedureº has been previously conducted,
always turn ignition switch ªOFFº and wait at least 10 seconds
before conducting the next test.
TESTING CONDITION:
Before performing the following procedure, confirm that bat-
tery voltage is more than 10.5V at idle.
WITH CONSULT-IINBEC0267S011) Turn ignition switch ªONº.
DTC P0600 A/T COMMUNICATION LINE
System Description
EC-440

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

SEC220B
Component DescriptionNBEC0271The ECM consists of a microcomputer and connectors for signal
input and output and for power supply. The unit controls the engine.
On Board Diagnosis LogicNBEC0272Malfunction is detected when ECM calculation function is
malfunctioning.
Possible CauseNBEC0518IECM
DTC Confirmation ProcedureNBEC0273NOTE:
If ªDTC Confirmation Procedureº has been previously conducted,
always turn ignition switch ªOFFº and wait at least 10 seconds
before conducting the next test.
SEF058Y
WITH CONSULT-IINBEC0273S011) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Start engine.
4) Run engine for at least 30 seconds at idle speed.
5) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-445.
WITH GSTNBEC0273S02Follow the procedure ªWITH CONSULT-IIº above.
DTC P0605 ECM
Component Description
EC-444

Diagnostic ProcedureNBEC0274
1 INSPECTION START
With CONSULT-II
1. Turn ignition switch ªONº.
2. Select ªSELF DIAG RESULTSº mode with CONSULT-II.
3. Touch ªERASEº.
4.Perform ªDTC Confirmation Procedureº.
See EC-444.
5. Is the 1st trip DTC P0605 displayed again?
With GST
1. Turn ignition switch ªONº.
2. Select MODE 4 with GST.
3. Touch ªERASEº.
4.Perform ªDTC Confirmation Procedureº.
See EC-444.
5. Is the 1st trip DTC P0605 displayed again?
YesorNo
Ye s©GO TO 2.
No©INSPECTION END
2 REPLACE ECM
1. Replace ECM.
2. Perform initialization of NVIS (NATS) system and registration of all NVIS (NATS) ignition key IDs. Refer to ªNVIS (NIS-
SAN VEHICLE IMMOBILIZER SYSTEM Ð NATS)º, EC-74.
3. Perform ªIdle Air Volume Learningº, EC-57,
Is the result CMPLT or INCMP?
CMPLT or INCMP
CMPLT©INSPECTION END
INCMP©Follow the construction of ªIdle Air Volume Learningº.
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DTC P0605 ECM
Diagnostic Procedure
EC-445