light INFINITI QX56 2006 Factory Service Manual

EC-512Revision: November 2009
DTC P1572 ASCD BRAKE SWITCH
2006 QX56
DTC confirmation ProcedureUBS00L16
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.

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 indicator lights up.
4. Drive the vehicle for at least 5 consecutive seconds under the following condition.
If DTC is detected, go to EC-514, "
Diagnostic 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-514, "
Diagnostic 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 location Depress the brake pedal for more than
five seconds so as not to come off from
the above-mentioned condition.
PBIB2386E

EC-514Revision: November 2009
DTC P1572 ASCD BRAKE SWITCH
2006 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 ProcedureUBS00L18
1. CHECK OVERALL FUNCTION-I
With CONSULT-II
1. Turn ignition switch ON.
2. Select “BRAKE SW1 ” in “DATA MONITOR ” mode with CONSULT-II.
3. Check “BRAKE SW1 ” indication under the following conditions.
Without CONSULT-II
1. Turn ignition switch ON.
2. Check voltage between ECM terminal 108 and ground under the following conditions.
OK or NG
OK >> GO TO 2.
NG >> GO TO 3.
TER-
MINAL NO. WIRE
COLOR ITEM
CONDITION DATA (DC Voltage)
101 R/W Stop lamp switch [Ignition switch: OFF]

Brake pedal: Fully released
Approximately 0V
[Ignition switch: OFF]

Brake pedal: Slightly depressed BATTERY VOLTAGE
(11 - 14V)
108 BR/W ASCD brake switch [Ignition switch: ON]

Brake pedal: Fully released
BATTERY VOLTAGE
(11 - 14V)
[Ignition switch: ON]

Brake pedal: Slightly depressed Approximately 0V
CONDITION
INDICATION
Brake pedal: Slightly depressed OFF
Brake pedal: Fully released ON
SEC011D
CONDITIONVOLTAGE
Brake pedal: Slightly depressed Approximately 0V
Brake pedal: Fully released Battery voltage
MBIB0061E

DTC P1572 ASCD BRAKE SWITCHEC-515
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EC
Revision: November 2009 2006 QX56
2. CHECK OVERALL FUNCTION-II
With CONSULT-II
Check “BRAKE SW2 ” indication in “DATA MONITOR ” mode.
Without CONSULT-II
Check voltage between ECM terminal 101 and ground under the following conditions.
OK or NG
OK >> GO TO 11.
NG >> GO TO 7.
CONDITION INDICATION
Brake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
SEC013D
CONDITIONVOLTAGE
Brake pedal: Fully released Approximately 0V
Brake pedal: Slightly depressed Battery voltage
PBIB1537E

EC-518Revision: November 2009
DTC P1572 ASCD BRAKE SWITCH
2006 QX56
11 . CHECK INTERMITTENT INCIDENT
Refer to EC-144, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>> INSPECTION END
Component InspectionUBS00L19
ASCD BRAKE SWITCH
1. Turn ignition switch OFF.
2. Disconnect ASCD brake switch harness connector.
3. Check harness continuity between ASCD brake switch terminals
1 and 2 under the following conditions.
If NG, adjust ASCD brake switch installation, refer to BR-6,
"BRAKE PEDAL" , and perform step 3 again.
STOP LAMP SWITCH
1. Turn ignition switch OFF.
2. Disconnect stop lamp switch harness connector.
3. Check harness continuity between stop lamp switch terminals 1and 2 under the following conditions.
If NG, adjust stop lamp switch installation, refer to BR-6,
"BRAKE PEDAL" , and perform step 3 again.
ConditionContinuity
Brake pedal: Fully released Should exist.
Brake pedal: Slightly depressed Should not exist.
SEC023D
ConditionContinuity
Brake pedal: Fully released Should not exist.
Brake pedal: Slightly depressed Should exist.
PBIB2103E

DTC P1574 ICC VEHICLE SPEED SENSOREC-519
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Revision: November 2009 2006 QX56
DTC P1574 ICC VEHICLE SPEED SENSORPFP:31036
Component DescriptionUBS00HZ6
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, "
DESCRIPTION" for ICC functions.
On Board Diagnosis LogicUBS00HZ7

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-151, "
DTC U1000, U1001 CAN COMMUNICATION LINE" .

If DTC P1574 is displayed with DTC U1010, first perform the trouble diagnosis for DTC U1010.
Refer to EC-154, "
DTC U1010 CAN COMMUNICATION" .

If DTC P1574 is displayed with DTC P0500, first perform the trouble diagnosis for DTC P0500.
Refer to EC-442, "
DTC P0500 VSS" .

If DTC P1574 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605.
Refer to EC-457, "
DTC P0605 ECM" .
DTC Confirmation ProcedureUBS00HZ8
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-520, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-II” above.
DTC No. Trouble Diagnosis Name DTC Detecting Condition Possible Cause
P1574
1574 ICC vehicle speed sensor ECM 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 SENSOREC-521
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Revision: November 2009 2006 QX56
DTC P1574 ASCD VEHICLE SPEED SENSORPFP:31036
Component DescriptionUBS00HBM
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-29, "
AUTOMATIC SPEED CONTROL DEVICE (ASCD)" for ASCD functions.
On Board Diagnosis LogicUBS00HBN
This self-diagnosis has the one trip detection logic.
The MIL will not light up for this diagnosis.
NOTE:

If DTC P1574 is displayed with DTC U1000, U1001, first perform the trouble diagnosis for DTC
U1000, U1001. Refer to EC-151, "
DTC U1000, U1001 CAN COMMUNICATION LINE" .

If DTC P1574 is displayed with DTC U1010, first perform the trouble diagnosis for DTC U1010.
Refer to EC-154, "
DTC U1010 CAN COMMUNICATION" .

If DTC P1574 is displayed with DTC P0500, first perform the trouble diagnosis for DTC P0500.
Refer to EC-442, "
DTC P0500 VSS".

If DTC P1574 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605.
Refer to EC-457, "
DTC P0605 ECM".
DTC Confirmation ProcedureUBS00HBO
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-522, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-II” above.
DTC No.Trouble Diagnosis
Name DTC Detecting Condition
Possible Cause
P1574
1574 ASCD vehicle speed
sensor ECM 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 SWITCHEC-523
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Revision: November 2009 2006 QX56
DTC P1805 BRAKE SWITCHPFP:25320
DescriptionUBS00HBX
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 ModeUBS00HBY
Specification data are reference values.
On Board Diagnosis LogicUBS00HBZ
The MIL will not light up for this diagnosis.
FAIL-SAFE MODE
When the malfunction is detected, the ECM enters fail-safe mode.
DTC Confirmation ProcedureUBS00HC0
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-525, "
Diagnostic Procedure"
.
WITH GST
Follow the procedure “WITH CONSULT-II” above.
MONITOR ITEM CONDITION SPECIFICATION
BRAKE SW

Ignition switch: ON Brake pedal: Fully released
OFF
Brake pedal: Slightly depressed ON
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1805
1805 Brake switch A brake switch signal is not sent to ECM for
extremely long time while the vehicle is driving.

Harness or connectors
(Stop lamp switch circuit is open or
shorted.)

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 P1805 BRAKE SWITCHEC-525
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Revision: November 2009 2006 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 ProcedureUBS00HC2
1. CHECK STOP LAMP SWITCH CIRCUIT
1. Turn ignition switch OFF.
2. Check the stop lamp when depressing and releasing the brake pedal.
OK or NG
OK >> GO TO 4.
NG >> GO TO 2.
2. CHECK STOP LAMP SWITCH POWER SUPPLY CIRCUIT
1. Disconnect stop lamp switch harness connector.
2. Check voltage between stop lamp switch terminal 3 and ground with CONSULT-II or tester.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
TER-
MINAL NO. WIRE
COLOR ITEM
CONDITION DATA (DC Voltage)
101 R/W Stop lamp switch [Ignition switch: OFF]

Brake pedal: Fully released
Approximately 0V
[Ignition switch: OFF]

Brake pedal: Slightly depressed BATTERY VOLTAGE
(11 - 14V)
Brake pedal
Stop lamp
Fully released Not illuminated
Slightly depressed Illuminated
BBIA0373E
Voltage: Battery voltage
PBIB2102E

DTC P1805 BRAKE SWITCHEC-527
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Revision: November 2009 2006 QX56
Component InspectionUBS00HC3
STOP LAMP SWITCH
1. Disconnect stop lamp switch harness connector.
2. Check continuity between stop lamp switch terminals 3 and 4
under the following conditions.
3. If NG, adjust stop lamp switch installation, refer to BR-6,
"BRAKE PEDAL" , and perform step 2 again.
BBIA0373E
ConditionsContinuity
Brake pedal: Fully released Should not exist.
Brake pedal: Slightly depressed Should exist.
PBIB2103E

EC-528Revision: November 2009
DTC P2100, P2103 THROTTLE CONTROL MOTOR RELAY
2006 QX56
DTC P2100, P2103 THROTTLE CONTROL MOTOR RELAYPFP:16119
Component DescriptionUBS00N77
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 ModeUBS00N78
Specification data are reference values.
On Board Diagnosis LogicUBS00N79
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 ProcedureUBS00N7A
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-531, "
Diagnostic Procedure" .
With GST
Follow the procedure “With CONSULT-II” above.
MONITOR ITEM CONDITIONSPECIFICATION
THRTL RELAY

Ignition switch: ON ON
DTC No. Trouble diagnosis nameDTC detecting condition Possible cause
P2100
2100 Throttle control motor
relay circuit open ECM 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
2103 Throttle control motor
relay circuit short ECM 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) b y the return
spring.
SEF058Y