DTC INFINITI QX56 2007 Factory Service Manual

EC-520
< SERVICE INFORMATION >
DTC P1572 ICC BRAKE SWITCH
DTC P1572 ICC BRAKE SWITCH
Component DescriptionINFOID:0000000003532056
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
for the ICC function.
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000003532057
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000003532058
•This diagnosis has the one trip detection logic.
•The MIL will not light up for this self-diagnosis.
NOTE:
•If DTC P1572 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605. Refer
to EC-444
.
•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.
DTC Confirmation ProcedureINFOID:0000000003532059
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.
BBIA0470E
MONITOR ITEM CONDITION SPECIFICATION
BRAKE SW1
(ICC brake switch)• Ignition switch: ONBrake pedal: Fully released ON
Brake pedal: Slightly depressed OFF
BRAKE SW2
(stop lamp switch)• Ignition switch: ONBrake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
DTC No.Trouble diagnosis
nameDTC detecting condition Possible cause
P1572
1572ICC brake switchA)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 SWITCH
EC-521
< SERVICE INFORMATION >
C
D
E
F
G
H
I
J
K
L
MA
EC
N
P O
• 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.

EC-522
< SERVICE INFORMATION >
DTC P1572 ICC BRAKE SWITCH
Wiring Diagram
INFOID:0000000003532060
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.
BBWA2129E

DTC P1572 ICC BRAKE SWITCH
EC-523
< SERVICE INFORMATION >
C
D
E
F
G
H
I
J
K
L
MA
EC
N
P O
Diagnosis ProcedureINFOID:0000000003532061
1.CHECK OVERALL FUNCTION-I
With CONSULT-II
1. Turn ignition switch ON.
2. Select “BRAKE SW1” in “DATA MONITOR” mode with CON-
SULT-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.
2.CHECK OVERALL FUNCTION-II
With CONSULT-II
Check “BRAKE SW2” indication in “DATA MONITOR” mode.
TER-
MI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
101 R/W Stop lamp switch[Ignition switch: OFF]
• Brake pedal: Fully releasedApproximately 0V
[Ignition switch: OFF]
• Brake pedal: Slightly depressedBATTERY VOLTAGE
(11 - 14V)
108 BR/W ICC brake switch[Ignition switch: ON]
• Brake pedal: Slightly depressedApproximately 0V
[Ignition switch: ON]
• Brake pedal: Fully releasedBATTERY VOLTAGE
(11 - 14V)
CONDITION INDICATION
Brake pedal: Slightly depressed OFF
Brake pedal: Fully released ON
SEC011D
CONDITION VOLTAGE
Brake pedal: Slightly depressed Approximately 0V
Brake pedal: Fully released Battery voltage
MBIB0061E
CONDITION INDICATION
Brake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
SEC013D

EC-524
< SERVICE INFORMATION >
DTC P1572 ICC BRAKE SWITCH
Without CONSULT-II
Check voltage between ECM terminal 101 and ground under the fol-
lowing conditions.
OK or NG
OK >> GO TO 14.
NG >> GO TO 10.
3.CHECK DTC WITH ICC UNIT
Refer to ACS-34
.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace.
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.
CONDITION VOLTAGE
Brake pedal: Fully released Approximately 0V
Brake pedal: Slightly depressed Battery voltage
PBIB1537E
BBIA0471E
Voltage: Battery voltage
MBIB0059E

DTC P1572 ICC BRAKE SWITCH
EC-525
< SERVICE INFORMATION >
C
D
E
F
G
H
I
J
K
L
MA
EC
N
P O
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.
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-526, "
Component Inspection".
OK >> GO TO 9.
NG >> Replace ICC brake hold relay.
9.CHECK ICC BRAKE SWITCH
Refer to EC-526, "
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.Continuity should exist.
BBIA0470E
Continuity should exist.
BBIA0470E

EC-526
< SERVICE INFORMATION >
DTC P1572 ICC BRAKE SWITCH
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.
11 .DETECT MALFUNCTIONING PART
Check the following.
• Harness connectors M31, E152
• Fuse block (J/B) No. 1 connector M60
• 10A fuse
• Harness for open or short between stop lamp switch and battery
>> Repair open circuit or short to ground or short to power in harness or connectors.
12.CHECK STOP LAMP SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal 101 and stop lamp switch terminal 4.
Refer to Wiring Diagram.
3. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 13.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
13.CHECK STOP LAMP SWITCH
Refer to EC-526, "
Component Inspection".
OK or NG
OK >> GO TO 14.
NG >> Replace stop lamp switch.
14.CHECK INTERMITTENT INCIDENT
Refer to EC-138
.
>>INSPECTION END
Component InspectionINFOID:0000000003532062
ICC BRAKE SWITCH
1. Turn ignition switch OFF.
2. Disconnect ICC brake switch harness connector.Voltage: Battery voltage
PBIB2102E
Continuity should exist.

DTC P1572 ICC BRAKE SWITCH
EC-527
< SERVICE INFORMATION >
C
D
E
F
G
H
I
J
K
L
MA
EC
N
P O
3. Check continuity between ICC brake switch terminals 1 and 2
under the following conditions.
If NG, adjust ICC brake switch installation, refer to BR-5
, and
perform step 3 again.
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 4
under the following conditions.
If NG, adjust stop lamp switch installation, refer to BR-5
, 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 exist.
Brake pedal: Slightly depressed. Should not exist.
PBIB1536E
Condition Continuity
Brake pedal: Fully released. Should not exist.
Brake pedal: Slightly depressed. Should exist.
PBIB2103E
Condition Between terminals Continuity
12V direct current supply
between terminals 1 and 23 and 4 Should not exist
6 and 7 Should exist
No current supply3 and 4 Should exist
6 and 7 Should not exist
MBIB0063E

EC-528
< SERVICE INFORMATION >
DTC P1572 ASCD BRAKE SWITCH
DTC P1572 ASCD BRAKE SWITCH
Component DescriptionINFOID:0000000003532063
When the brake pedal is depressed, ASCD 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 EC-30
for the ASCD function.
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000003532064
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000003532065
•This self-diagnosis has the one trip detection logic.
•The MIL will not light up for this self-diagnosis.
NOTE:
•If DTC P 1572 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605. Refer
to EC-444
.
•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.
DTC Confirmation ProcedureINFOID:0000000003532066
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.
BBIA0373E
MONITOR ITEM CONDITION SPECIFICATION
BRAKE SW 1
(ASCD brake switch)• Ignition switch: ONBrake pedal: Fully released ON
Brake pedal: Slightly depressed OFF
BRAKE SW 2
(Stop lamp switch)• Ignition switch: ONBrake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
DTC No.Trouble Diagnosis
NameDTC Detecting Condition Possible Cause
P1572
1572ASCD brake switchA)When the vehicle speed is above 30km/h (19
MPH), ON signals from the stop lamp switch
and the ASCD brake switch are sent to ECM
at the same time.• Harness or connectors
(The stop lamp switch circuit is shorted.)
• Harness or connectors
(The ASCD brake switch circuit is shorted.)
• Stop lamp switch
• ASCD brake switch
• Incorrect stop lamp switch installation
• Incorrect ASCD brake switch installation
•ECM B)ASCD brake switch signal is not sent to ECM
for extremely long time while the vehicle is
driving

DTC P1572 ASCD BRAKE SWITCH
EC-529
< SERVICE INFORMATION >
C
D
E
F
G
H
I
J
K
L
MA
EC
N
P O
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