ignition INFINITI QX4 2005 Factory Service Manual

DTC P1124, P1126 THROTTLE CONTROL MOTOR RELAY
EC-405
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Revision: October 20052005 QX56
DTC P1124, P1126 THROTTLE CONTROL MOTOR RELAYPFP:16119
Component DescriptionUBS00H7P
Power supply for the throttle control motor is provided to the ECM via throttle control motor relay. The throttle
control motor relay is ON/OFF controlled by the ECM. When the ignition switch is turned ON, the ECM sends
an ON signal to throttle control motor relay and battery voltage is provided to the ECM. When the ignition
switch is turned OFF, the ECM sends an OFF signal to throttle control motor relay and battery voltage is not
provided to the ECM.
CONSULT-II Reference Value in Data Monitor ModeUBS00H7Q
Specification data are reference values.
On Board Diagnosis LogicUBS00H7R
These self-diagnoses have the one trip detection logic.
FAIL-SAFE MODE
When the malfunction is detected, ECM enters fail-safe mode and the MlL lights up.
DTC Confirmation ProcedureUBS00H7S
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
PROCEDURE FOR DTC P1124
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 8V.
With CONSULT-II
1. Turn ignition switch ON and wait at least 1 second.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. If DTC is detected, go to EC-408, "
Diagnostic Procedure" .
With GST
Follow the procedure “With CONSULT-II” above.
MONITOR ITEM CONDITION SPECIFICATION
THRTL RELAY

Ignition switch: ON ON
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1124
11 2 4Throttle control motor
relay circuit shortECM detect the throttle control motor
relay is stuck ON.

Harness or connectors
(Throttle control motor relay circuit is shorted)

Throttle control motor relay
P1126
11 2 6Throttle control motor
relay circuit openECM detects a voltage of power source
for throttle control motor is excessively
low.

Harness or connectors
(Throttle control motor relay circuit is open)

Throttle control motor relay
Engine operating condition in fail-safe mode
ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return
spring.
SEF 0 58 Y

EC-406Revision: October 2005
DTC P1124, P1126 THROTTLE CONTROL MOTOR RELAY
2005 QX56
PROCEDURE FOR DTC P1126
With CONSULT-II
1. Turn ignition switch ON and wait at least 2 seconds.
2. Select “DATA MONITOR””mode with CONSULT-II.
3. Start engine and let it idle for 5 seconds.
4. If DTC is detected, go to EC-408, "
Diagnostic Procedure" .
With GST
Follow the procedure “With CONSULT-II” above.
SEF 0 58 Y

EC-408Revision: October 2005
DTC P1124, P1126 THROTTLE CONTROL MOTOR RELAY
2005 QX56
Specification 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.
Diagnostic ProcedureUBS00H7U
1. CHECK THROTTLE CONTROL MOTOR RELAY POWER SUPPLY CIRCUIT-I
1. Turn ignition switch OFF.
2. Check voltage between ECM terminal 104 and ground with
CONSULT-II or tester.
OK or NG
OK >> GO TO 4.
NG >> GO TO 2.
2. CHECK THROTTLE CONTROL MOTOR RELAY POWER SUPPLY CIRCUIT-II
1. Disconnect ECM harness connector.
2. Disconnect IPDM E/R harness connector E122.
3. Check continuity between ECM terminal 104 and IPDM E/R terminal 47.
Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 3.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
3. CHECK FUSE
1. Disconnect 20A fuse.
2. Check 20A fuse for blown.
OK or NG
OK >> GO TO 7.
NG >> Replace 20A fuse.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
3LThrottle control motor relay
power supply[Ignition switch: ON]BATTERY VOLTAGE
(11 - 14V)
104 O Throttle control motor relay[Ignition switch: OFF]BATTERY VOLTAGE
(11 - 14V)
[Ignition switch: ON]0 - 1.0V
Voltage: Battery voltage
PBIB11 71 E
Continuity should exist.

DTC P1124, P1126 THROTTLE CONTROL MOTOR RELAY
EC-409
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Revision: October 20052005 QX56
4. CHECK THROTTLE CONTROL MOTOR RELAY INPUT SIGNAL CIRCUIT-I
1. Check voltage between ECM terminal 3 and ground under the
following conditions with CONSULT-II or tester.
OK or NG
OK >> GO TO 7.
NG >> GO TO 5.
5. CHECK THROTTLE CONTROL MOTOR RELAY INPUT SIGNAL CIRCUIT-II
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Disconnect IPDM E/R harness connector E119.
4. Check continuity between ECM terminal 3 and IPDM E/R terminal 6.
Refer to Wiring Diagram.
5. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 7.
NG >> GO TO 6.
6. DETECT MALFUNCTIONING PART
Check the following.

Harness connectors E2, F32

Harness for open or short between ECM and IPDM E/R
>> Repair open circuit or short to ground or short to power in harness or connectors.
7. CHECK INTERMITTENT INCIDENT
Refer to EC-156, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
OK or NG
OK >> Replace IPDM E/R. Refer to PG-17, "IPDM E/R (INTELLIGENT POWER DISTRIBUTION MOD-
ULE ENGINE ROOM)" .
NG >> Repair or replace harness or connectors.
Ignition switch Voltage
OFF Approximately 0V
ONBattery voltage
(11 - 14V)
MBIB0028E
Continuity should exist.

EC-410Revision: October 2005
DTC P1128 THROTTLE CONTROL MOTOR
2005 QX56
DTC P1128 THROTTLE CONTROL MOTORPFP:16119
Component DescriptionUBS00H7V
The throttle control motor is operated by the ECM and it opens and closes the throttle valve.
The current opening angle of the throttle valve is detected by the throttle position sensor and it provides feed-
back to the ECM to control the throttle control motor to make the throttle valve opening angle properly in
response to driving condition.
On Board Diagnosis LogicUBS00H7W
This self-diagnosis has the one trip detection logic.
FAIL -S AFE M OD E
When the malfunction is detected, the ECM enters fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureUBS00H7X
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
WITH CONSULT-II
1. Turn ignition switch ON and wait at least 2 seconds.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Start engine and let it idle for 5 seconds.
4. If DTC is detected, go to EC-412, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-II” above.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1128
11 2 8Throttle control motor
circuit shortECM detects short in both circuits between
ECM and throttle control motor.

Harness or connectors
(Throttle control motor circuit is shorted.)

Electric throttle control actuator
(Throttle control motor)
Engine operating condition in fail-safe mode
ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return
spring.
SEF 0 58 Y

EC-412Revision: October 2005
DTC P1128 THROTTLE CONTROL MOTOR
2005 QX56
Specification data are reference values and are measured between each terminal and ground.
Pulse signal is measured by CONSULT-II.
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.
: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)
Diagnostic ProcedureUBS00H7Z
1. CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
Refer to EC-162, "
Ground Inspection" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
4L/WThrottle control motor
(Close)[Ignition switch: ON]

Engine: Stopped

Selector lever: D

Accelerator pedal: Fully released0 - 14V
5L/BThrottle control motor
(Open)[Ignition switch: ON]

Engine: Stopped

Selector lever: D

Accelerator pedal: Fully depressed0 - 14V
PBIB1104E
PBIB1105E
BBIA0354E

EC-416Revision: October 2005
DTC P1146, P1166 HO2S2
2005 QX56
DTC Confirmation ProcedureUBS00H85
NOTE:
If DTC confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
WITH CONSULT-II
TESTING CONDITION:
For better results, perform “DTC WORK SUPPORT” at a temperature of 0 to 30 °C (32 to 86 °F).
1. Turn ignition switch ON and select “DATA MONITOR” mode with
CONSULT-II.
2. Start engine and warm it up to the normal operating tempera-
ture.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Start engine and keep the engine speed between 3,500 and
4,000 rpm for at least 1 minute under no load.
5. Let engine idle for 1 minute.
6. Make sure that “COOLAN TEMP/S” indicates more than 70°C
(158°F).
If not, warm up engine and go to next step when “COOLAN
TEMP/S” indication reaches to 70°C (158°F).
7. Open engine hood.
8. Select “HO2S2 (B1) P1146” or “HO2S2 (B2) P1166” of “HO2S2” in “DTC WORK SUPPORT” mode with
CONSULT-II.
9. Start engine and following the instruction of CONSULT-II.
NOTE:
It will take at most 10 minutes until “COMPLETED” is displayed.
10. Make sure that “OK” is displayed after touching “SELF-DIAG RESULTS”.
If “NG” is displayed, refer to EC-421, "
Diagnostic Procedure" .
If “CAN NOT BE DIAGNOSED” is displayed, perform the following.
a. Turn ignition switch OFF and leave the vehicle in a cool place (soak the vehicle).
b. Return to step 1.
Overall Function CheckUBS00H86
Use this procedure to check the overall function of the heated oxygen sensor 2 circuit. During this check, a 1st
trip DTC might not be confirmed.
WITH GST
1. Start engine and warm it up to the normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
4. Let engine idle for 1 minute.
5. Set voltmeter probes between ECM terminal 55 [HO2S2 (B1) signal] or 74 [HO2S2 (B2) signal] and
ground.
SEF 1 74 Y
PBIB2372E

DTC P1146, P1166 HO2S2
EC-421
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Revision: October 20052005 QX56
Specification 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.
Diagnostic ProcedureUBS00H88
1. CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
Refer to EC-162, "
Ground Inspection" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
74 LHeated oxygen sensor 2
(bank 2)[Engine is running]

Warm-up condition

Revving engine from idle to 3,000 rpm
quickly after the following conditions are met
–After keeping the engine speed between
3,500 and 4,000 rpm for 1 minute and at idle
for 1 minute under no load0 - Approximately 1.0V
78 B/WSensor ground
(Heated oxygen sensor 2) [Engine is running]

Warm-up condition

Idle speed Approximately 0V
BBIA0354E

EC-422Revision: October 2005
DTC P1146, P1166 HO2S2
2005 QX56
2. CLEAR THE SELF-LEARNING DATA
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Select “SELF-LEARNING CONT” in “WORK SUPPORT” mode
with CONSULT-II.
3. Clear the self-learning control coefficient by touching “CLEAR”.
4. Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0172 or P0175 detected?
Is it difficult to start engine?
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF.
3. Disconnect mass air flow sensor harness connector, and restart
and run engine for at least 5 seconds at idle speed.
4. Stop engine and reconnect mass air flow sensor harness con-
nector.
5. Make sure DTC P0102 is displayed.
6. Erase the DTC memory. Refer to EC-62, "
HOW TO ERASE
EMISSION-RELATED DIAGNOSTIC INFORMATION" .
7. Make sure DTC P0000 is displayed.
8. Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0172 or P0175 detected?
Is it difficult to start engine?
Ye s o r N o
Yes >> Perform trouble diagnosis for DTC P0172 or P0175. Refer to EC-245, "DTC P0172, P0175 FUEL
INJECTION SYSTEM FUNCTION" .
No >> GO TO 3.
SEF 9 68 Y
BBIA0368E

DTC P1146, P1166 HO2S2
EC-423
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Revision: October 20052005 QX56
3. CHECK HO2S2 GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect heated oxygen sensor 2 harness connector.
3. Disconnect ECM harness connector.
4. Check harness continuity between ECM terminal 78 and HO2S2 terminal 4.
Refer to Wiring Diagram.
5. 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.
4. CHECK HO2S2 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between ECM terminal and HO2S2 terminal as follows.
Refer to Wiring Diagram.
2. Check harness continuity between the following terminals and ground.
Refer to Wiring Diagram.
3. Also check harness for short to power.
OK or NG
OK >> GO TO 5.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.Continuity should exist.
BBIA0435E
DTCTe r m i n a l s
Bank
ECM Sensor
P1146 55 1 1
P1166 74 1 2
Continuity should exist.
DTCTe r m i n a l s
Bank
ECM Sensor
P1146 55 1 1
P1166 74 1 2
Continuity should not exist.