engine INFINITI QX56 2007 Factory Service Manual

EC-516
< SERVICE INFORMATION >
DTC P1564 ASCD STEERING SWITCH
Diagnosis Procedure
INFOID:0000000003532051
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
Refer to EC-143, "
Ground Inspection".
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2.CHECK ASCD STEERING SWITCH CIRCUIT
With CONSULT-II
1. Turn ignition switch ON.
2. Select “MAIN SW”, “CANCEL SW”, RESUME/ACC SW” and “SET SW” in “DATA MONITOR” mode with
CONSULT-II.
3. Check each item indication under the following conditions.
TER-
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NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
67 B Sensor ground[Engine is running]
•Warm-up condition
• Idle speedApproximately 0V
99 G/Y ASCD steering switch[Ignition switch: ON]
• ASCD steering switch: OFFApproximately 4V
[Ignition switch: ON]
• MAIN switch: ONApproximately 0V
[Ignition switch: ON]
• CANCEL switch: ONApproximately 1V
[Ignition switch: ON]
• RESUME/ACCELERATTTE switch: ONApproximately 3V
[Ignition switch: ON]
• SET/COAST switch: ONApproximately 2V
BBIA0354E
Switch Monitor item Condition Indication
MAIN switch MAIN SWPressed ON
Released OFF
CANCEL switch CANCEL SWPressed ON
Released OFF
RESUME/ACCELERATE
switchRESUME/ACC SWPressed ON
Released OFF
SET/COAST switch SET SWPressed ON
Released OFF
SEC006D

DTC P1572 ICC BRAKE SWITCH
EC-521
< SERVICE INFORMATION >
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• Procedure for malfunction B is not described here. It takes extremely long time to complete procedure for
malfunction B. By performing procedure for malfunction A, the incident that causes malfunction B can be
detected.
TESTING CONDITION:
Steps 4 and 5 may be conducted with the drive wheels lifted in the shop or by driving the vehicle. If a
road test is expected to be easier, it is unnecessary to lift the vehicle.
WITH CONSULT-II
1. Start engine (VDC switch OFF).
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Press MAIN switch and make sure that CRUISE lamp lights up.
4. Drive the vehicle for at least 5 consecutive seconds under the
following conditions.
If 1st trip DTC is detected, go to EC-523, "
Diagnosis Procedure".
If 1st trip DTC is not detected, go to the following step.
5. Drive the vehicle for at least 5 consecutive seconds under the following conditions.
6. If 1st trip DTC is detected, go to EC-523, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-II” above.
VHCL SPEED SE More than 30 km/h (19 MPH)
Selector lever Suitable position
PBIB2386E
VHCL SPEED SE More than 30 km/h (19 MPH)
Selector lever Suitable position
Driving locationDepress the brake pedal for more than
five seconds so as not to come off from
the above-mentioned vehicle speed.

DTC P1572 ASCD BRAKE SWITCH
EC-529
< SERVICE INFORMATION >
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TESTING CONDITION:
Steps 4 and 5 may be conducted with the drive wheels lifted in the shop or by driving the vehicle. If a
road test is expected to be easier, it is unnecessary to lift the vehicle.
WITH CONSULT-II
1. Start engine (VDC switch OFF).
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Press MAIN switch and make sure that CRUISE indicator lights
up.
4. Drive the vehicle for at least 5 consecutive seconds under the
following condition.
If DTC is detected, go to EC-531, "
Diagnosis Procedure".
If DTC is not detected, go to the following step.
5. Drive the vehicle for at least 5 consecutive seconds under the following condition.
6. If DTC is detected, go to EC-531, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-II” above.
VHCL SPEED SE More than 30 km/h (19 MPH)
Selector lever Suitable position
VHCL SPEED SE More than 30 km/h (19 MPH)
Selector lever Suitable position
Driving locationDepress the brake pedal for more than
five seconds so as not to come off from
the above-mentioned condition.
PBIB2386E

DTC P1574 ICC VEHICLE SPEED SENSOR
EC-535
< SERVICE INFORMATION >
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DTC P1574 ICC VEHICLE SPEED SENSOR
Component DescriptionINFOID:0000000003532070
The ECM receives two vehicle speed signals via CAN communication line. One is sent from “unified meter and
A/C amp.”, and the other is from TCM (Transmission control module). The ECM uses these signals for ICC
control. Refer to ACS-6
for ICC functions.
On Board Diagnosis LogicINFOID:0000000003532071
•This self-diagnosis has the one trip detection logic.
•The MIL will not light up for this self-diagnosis.
NOTE:
•If DTC P1574 is displayed with DTC U1000, U1001, first perform the trouble diagnosis for DTC U1000,
U1001. Refer to EC-145
.
•If DTC P1574 is displayed with DTC U1010, first perform the trouble diagnosis for DTC U1010. Refer
to EC-147
.
•If DTC P1574 is displayed with DTC P0500, first perform the trouble diagnosis for DTC P0500. Refer
to EC-429
.
•If DTC P1574 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605. Refer
to EC-444
.
DTC Confirmation ProcedureINFOID:0000000003532072
CAUTION:
Always drive vehicle at a safe speed.
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.
TESTING CONDITION:
Step 3 may be conducted with the drive wheels lifted in the shop or by driving the vehicle. If a road test
is expected to be easier, it is unnecessary to lift the vehicle.
WITH CONSULT-II
1. Start engine.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Drive the vehicle at more than 40 km/h (25MPH).
4. If DTC is detected, go to EC-536, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-II” above.
DTC No. Trouble Diagnosis Name DTC Detecting Condition Possible Cause
P1574
1574ICC vehicle speed sensorECM detects a difference between two vehicle
speed signals is out of the specified range.• Harness or connectors
(The CAN communication line is open or
shorted.)
• Combination meter
• ABS actuator and electric unit (control unit)
• Wheel sensor
•TCM
•ECM
SEF058Y

DTC P1574 ASCD VEHICLE SPEED SENSOR
EC-537
< SERVICE INFORMATION >
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DTC P1574 ASCD VEHICLE SPEED SENSOR
Component DescriptionINFOID:0000000003532074
The ECM receives two vehicle speed sensor signals via CAN communication line. One is sent from combina-
tion meter and the other is from TCM (Transmission control module). The ECM uses these signals for ASCD
control. Refer to EC-30
for ASCD functions.
On Board Diagnosis LogicINFOID:0000000003532075
•This self-diagnosis has the one trip detection logic.
•The MIL will not light up for this self-diagnosis.
NOTE:
•If DTC P1574 is displayed with DTC U1000, U1001, first perform the trouble diagnosis for DTC U1000,
U1001. Refer to EC-145
.
•If DTC P1574 is displayed with DTC U1010, first perform the trouble diagnosis for DTC U1010. Refer
to EC-147
.
•If DTC P1574 is displayed with DTC P0500, first perform the trouble diagnosis for DTC P0500. Refer
to EC-429
.
•If DTC P1574 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605. Refer
to EC-444
.
DTC Confirmation ProcedureINFOID:0000000003532076
CAUTION:
Always drive vehicle at a safe speed.
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.
TESTING CONDITION:
Step 3 may be conducted with the drive wheels lifted in the shop or by driving the vehicle. If a road test
is expected to be easier, it is unnecessary to lift the vehicle.
WITH CONSULT-II
1. Start engine (VDC switch OFF).
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Drive the vehicle at more than 40 km/h (25 MPH).
4. If DTC is detected, go to EC-538, "
Diagnosis Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-II” above.
DTC No.Trouble Diagnosis
NameDTC Detecting Condition Possible Cause
P1574
1574ASCD vehicle speed
sensorECM detects a difference between two vehicle
speed signals is out of the specified range.• Harness or connectors
(The CAN communication line is open or
shorted.)
• Combination meter
• ABS actuator and electric unit (control unit)
• Wheel sensor
•TCM
•ECM
SEF058Y

DTC P1805 BRAKE SWITCH
EC-539
< SERVICE INFORMATION >
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DTC P1805 BRAKE SWITCH
DescriptionINFOID:0000000003532078
Brake switch signal is applied to the ECM through the stop lamp switch when the brake pedal is depressed.
This signal is used mainly to decrease the engine speed when the vehicle is driving.
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000003532079
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000003532080
The MIL will not light up for this self-diagnosis.
FA I L - S A F E M O D E
When the malfunction is detected, the ECM enters fail-safe mode.
DTC Confirmation ProcedureINFOID:0000000003532081
WITH CONSULT-II
1. Turn ignition switch ON.
2. Fully depress the brake pedal for at least 5 seconds.
3. Erase the DTC with CONSULT-II.
4. Select “DATA MONITOR” mode with CONSULT-II.
5. If 1st trip DTC is detected, go to EC-541, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-II” above.
MONITOR ITEM CONDITION SPECIFICATION
BRAKE SW • Ignition switch: ONBrake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1805
1805Brake switchA brake switch signal is not sent to ECM for ex-
tremely long time while the vehicle is driving.• Harness or connectors
(Stop lamp switch circuit is open or short-
ed.)
• Stop lamp switch
Engine operating condition in fail-safe mode
ECM controls the electric throttle control actuator by regulating the throttle opening to a small range.
Therefore, acceleration will be poor.
Vehicle condition Driving condition
When engine is idling Normal
When accelerating Poor acceleration
SEF058Y

DTC P2100, P2103 THROTTLE CONTROL MOTOR RELAY
EC-543
< SERVICE INFORMATION >
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DTC P2100, P2103 THROTTLE CONTROL MOTOR RELAY
Component DescriptionINFOID:0000000003532085
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 ModeINFOID:0000000003532086
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000003532087
These self-diagnoses have the one trip detection logic.
FA I L - S A F E M O D E
When the malfunction is detected, ECM enters fail-safe mode and the MlL lights up.
DTC Confirmation ProcedureINFOID:0000000003532088
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 P2100
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-546, "
Diagnosis Procedure" .
MONITOR ITEM CONDITION SPECIFICATION
THRTL RELAY • Ignition switch: ON ON
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P2100
2100Throttle 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
P2103
2103Throttle 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
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.
SEF058Y

EC-546
< SERVICE INFORMATION >
DTC P2100, P2103 THROTTLE CONTROL MOTOR RELAY
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.)
Diagnosis ProcedureINFOID:0000000003532090
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.
TER-
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COLORITEM CONDITION DATA (DC Voltage)
3LThrottle control motor relay
power supply[Ignition switch: ON]BATTERY VOLTAGE
(11 - 14V)
4L/WThrottle control motor
(Close)[Ignition switch: ON]
• Engine: Stopped
• Selector lever: D
• Accelerator pedal: Released0 - 14V
5L/BThrottle control motor
(Open)[Ignition switch: ON]
• Engine: Stopped
• Selector lever: D
• Accelerator pedal: Fully depressed0 - 14V
104 O Throttle control motor relay[Ignition switch: OFF]BATTERY VOLTAGE
(11 - 14V)
[Ignition switch: ON]0 - 1.0V
PBIB1104E
PBIB1105E
Voltage: Battery voltage
PBIB1171E
Continuity should exist.

EC-548
< SERVICE INFORMATION >
DTC P2101 ELECTRIC THROTTLE CONTROL FUNCTION
DTC P2101 ELECTRIC THROTTLE CONTROL FUNCTION
DescriptionINFOID:0000000003532091
NOTE:
If DTC P2101 is displayed with DTC P2100 or 2119, first perform the trouble diagnosis for DTC P2100
or P2119. Refer to EC-543
or EC-559 .
Electric throttle control actuator consists of throttle control motor, throttle position sensor, etc.
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 LogicINFOID:0000000003532092
This self-diagnosis has the one trip detection logic.
FA I L - S A F E M O D E
When the malfunction is detected, ECM enters fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureINFOID:0000000003532093
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.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 11V when engine
is running.
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-550, "
Diagnosis Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-II” above.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P2101
2101Electric throttle control
performanceElectric throttle control function does not oper-
ate properly.• Harness or connectors
(Throttle control motor circuit is open or
shorted)
• Electric throttle control actuator
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.
SEF058Y

EC-550
< SERVICE INFORMATION >
DTC P2101 ELECTRIC THROTTLE CONTROL FUNCTION
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.)
Diagnosis ProcedureINFOID:0000000003532095
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
Refer to EC-143, "
Ground Inspection" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2.CHECK THROTTLE CONTROL MOTOR RELAY INPUT SIGNAL CIRCUIT-I
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COLORITEM CONDITION DATA (DC Voltage)
3LThrottle control motor relay
power supply[Ignition switch: ON]BATTERY VOLTAGE
(11 - 14V)
4L/WThrottle control motor
(Close)[Ignition switch: ON]
• Engine: Stopped
• Selector lever: D
• Accelerator pedal: Released0 - 14V
5L/BThrottle control motor
(Open)[Ignition switch: ON]
• Engine: Stopped
• Selector lever: D
• Accelerator pedal: Fully depressed0 - 14V
104 O Throttle control motor relay[Ignition switch: OFF]BATTERY VOLTAGE
(11 - 14V)
[Ignition switch: ON]0 - 1.0V
PBIB1104E
PBIB1105E
BBIA0354E