2006 INFINITI QX56 relay

EC-502Revision: November 2009
DTC P1572 ICC BRAKE SWITCH
2006 QX56
DTC P1572 ICC BRAKE SWITCHPFP:25320
Component DescriptionUBS00L1W
When the brake pedal is depressed, ICC brake switch is turned OFF
and stop lamp switch is turned ON. ECM detects the state of the
brake pedal by this input of two kinds (ON/OFF signal).
Refer to ACS-6, "
DESCRIPTION" for the ICC function.
CONSULT-II Reference Value in Data Monitor ModeUBS00L1X
Specification data are reference values.
On Board Diagnosis LogicUBS00L1Y
This diagnosis has the one trip detection logic.
The MIL will not light up for this diagnosis.
NOTE:

If DTC P1572 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605.
Refer to EC-457, "
DTC P0605 ECM" .

This self-diagnosis has the one trip detection logic. When malfunction A is detected, DTC is not
stored in ECM memory. And in that case, 1st trip DTC and 1st trip freeze frame data are displayed.
1st trip DTC is erased when ignition switch OFF. And even when malfunction A is detected in two
consecutive trips, DTC is not stored in ECM memory.
BBIA0470E
MONITOR ITEM CONDITIONSPECIFICATION
BRAKE SW1
(ICC brake switch)

Ignition switch: ON Brake pedal: Fully released
ON
Brake pedal: Slightly depressed OFF
BRAKE SW2
(stop lamp switch)

Ignition switch: ON Brake pedal: Fully released
OFF
Brake pedal: Slightly depressed ON
DTC No.Trouble diagnosis
name DTC detecting condition
Possible cause
P1572
1572 ICC brake switch A)
When vehicle speed is above 30 km/h (19
MPH), ON signals from the stop lamp
switch and the ICC brake switch are sent
to ECM at the same time.

Harness or connectors
(The stop lamp switch circuit is shorted.)

Harness or connectors
(The ICC brake switch circuit is shorted.)

Stop lamp switch

ICC brake switch

ICC brake hold relay

Incorrect stop lamp switch installation

Incorrect ICC brake switch installation

ECM
B)
ICC brake switch signal is not sent to ECM
for extremely long time while the vehicle is
driving

DTC P1572 ICC BRAKE SWITCHEC-507
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EC
Revision: November 2009 2006 QX56
4. CHECK ICC BRAKE HOLD RELAY POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ICC brake hold relay.
3. Turn ignition switch ON.
4. Check voltage between ICC brake hold relay terminal 4 and ground with CONSULT-II or tester.
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5. DETECT MALFUNCTIONING PART
Check the following.

Harness connectors M31, E152

Fuse block (J/B) connector M4

10A fuse

Harness for open or short between ICC brake hold relay and fuse
>> Repair open circuit or short to ground or short to power in harness or connectors.
6. CHECK ICC BRAKE SWITCH POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ICC brake switch harness connector.
3. Check harness continuity between ICC brake hold relay terminal 3 and ICC brake switch terminal 1.
Refer to Wiring Diagram.
4. 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.
BBIA0471E
Voltage: Battery voltage
MBIB0059E
Continuity should exist.
BBIA0470E

EC-508Revision: November 2009
DTC P1572 ICC BRAKE SWITCH
2006 QX56
7. CHECK ICC BRAKE SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between ICC brake switch terminal 2 and ECM terminal 108. Refer Wiring Diagram.
3. 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 ICC BRAKE HOLD RELAY
Refer to EC-509, "
Component Inspection" .
OK >> GO TO 9.
NG >> Replace ICC brake hold relay.
9. CHECK ICC BRAKE SWITCH
Refer to EC-509, "
Component Inspection" .
OK or NG
OK >> GO TO 14.
NG >> Replace ICC brake switch.
10. CHECK STOP LAMP SWITCH POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect stop lamp switch harness connector.
3. Check voltage between stop lamp switch terminal 3 and ground with CONSULT -II or tester.
OK or NG
OK >> GO TO 12.
NG >> GO TO 11. Continuity should exist.
BBIA0470E
Voltage: Battery voltage
PBIB2102E

EC-510Revision: November 2009
DTC P1572 ICC BRAKE SWITCH
2006 QX56
STOP LAMP SWITCH
1. Turn ignition switch OFF.
2. Disconnect stop lamp switch harness connector.
3. Check continuity between stop lamp switch terminals 3 and 4under the following conditions.
If NG, adjust stop lamp switch installation, refer to BR-6,
"BRAKE PEDAL" , and perform step 3 again.
ICC BRAKE HOLD RELAY
1. Apply 12V direct current between ICC brake hold relay terminals 1 and 2.
2. Check continuity between relay terminals 3 and 4, 6 and 7 under
the following conditions.
3. If NG, replace ICC brake hold relay.
Condition Continuity
Brake pedal: Fully released. Should not exist.
Brake pedal: Slightly depressed. Should exist.
PBIB2103E
ConditionBetween terminals Continuity
12V direct current supply
between terminals 1 and 2 3 and 4
Should not exist
6 and 7 Should exist
No current supply 3 and 4
Should exist
6 and 7 Should not exist
MBIB0063E

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

DTC P2100, P2103 THROTTLE CONTROL MOTOR RELAYEC-529
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EC
Revision: November 2009 2006 QX56
PROCEDURE FOR DTC P2103
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-531, "
Diagnostic Procedure" .
With GST
Follow the procedure “With CONSULT-II” above.
SEF058Y

EC-530Revision: November 2009
DTC P2100, P2103 THROTTLE CONTROL MOTOR RELAY
2006 QX56
Wiring DiagramUBS00N7B
BBWA2100E

DTC P2100, P2103 THROTTLE CONTROL MOTOR RELAYEC-531
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Revision: November 2009 2006 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 ProcedureUBS00N7C
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.
TER-
MINAL NO. WIRE
COLOR ITEM
CONDITION DATA (DC Voltage)
3L Throttle control motor relay
power supply [Ignition switch: ON] BATTERY VOLTAGE
(11 - 14V)
4L/W Throttle control motor
(Close) [Ignition switch: ON]

Engine: Stopped

Selector lever: D

Accelerator pedal: Released 0 - 14V
5L/B Throttle control motor
(Open) [Ignition switch: ON]

Engine: Stopped

Selector lever: D

Accelerator pedal: Fully depressed 0 - 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