2005 INFINITI FX35 brake light

EC-596
[VQ35DE]
DTC P1572 ICC BRAKE SWITCH
Revision: 2005 July 2005 FX
16. CHECK STOP LAMP SWITCH
Refer to EC-596, "
Component Inspection"
OK or NG
OK >> GO TO 17.
NG >> Replace stop lamp switch.
17. CHECK INTERMITTENT INCIDENT
Refer to EC-163, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>> INSPECTION END
Component InspectionABS007ZC
ICC BRAKE SWITCH
1. Turn ignition switch OFF.
2. Disconnect ICC brake switch harness connector.
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-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 continuity between stop lamp switch terminals 1 and 2 under 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 exist.
Brake pedal: Slightly depressed. Should not exist.
SEC023D
Condition Continuity
Brake pedal: Fully released. Should not exist.
Brake pedal: Slightly depressed. Should exist.
PBIB1185E
Condition Between 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

DTC P1572 ASCD BRAKE SWITCH EC-597
[VQ35DE]
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Revision: 2005 July 2005 FX
DTC P1572 ASCD BRAKE SWITCHPFP:25320
Component DescriptionABS006WJ
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-36, "
AUTOMATIC SPEED CONTROL DEVICE (ASCD)"
for the ASCD function.
CONSULT-II Reference Value in Data Monitor ModeABS006WK
Specification data are reference values.
On Board Diagnosis LogicABS006WL
This self-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-402, "
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.
PBIB1605E
MONITOR ITEM CONDITION SPECIFICATION
BRAKE SW1
(ASCD 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 ASCD brake switch A)
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 vehi-
cle is driving

EC-598
[VQ35DE]
DTC P1572 ASCD BRAKE SWITCH
Revision: 2005 July 2005 FX
DTC Confirmation ProcedureABS006WM
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.
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 1st trip DTC is detected, go to EC-600, "
Diagnostic 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 condition.
6. If 1st trip DTC is detected, go to EC-600, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-II” above.
VHCL SPEED SE More than 30 km/h (19 MPH)
Shift lever Suitable position
VHCL SPEED SE More than 30 km/h (19 MPH)
Shift lever Suitable position
Driving location Depress the brake pedal for more than
five seconds so as not to come off from
the above-mentioned vehicle speed.
PBIB2386E

EC-600
[VQ35DE]
DTC P1572 ASCD BRAKE SWITCH
Revision: 2005 July 2005 FX
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 ProcedureABS006WO
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 P/L Stop lamp switch [Ignition switch: OFF]

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

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

Brake pedal: Slightly depressed
Approximately 0V
[Ignition switch: ON]

Brake pedal: Fully released BATTERY 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

DTC P1572 ASCD BRAKE SWITCH EC-601
[VQ35DE]
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Revision: 2005 July 2005 FX
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 13.
NG >> GO TO 8.
CONDITION INDICATION
Brake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
SEC013D
CONDITION VOLTAGE
Brake pedal: Fully released Approximately 0V
Brake pedal: Slightly depressed Battery voltage
MBIB0060E

EC-604
[VQ35DE]
DTC P1572 ASCD BRAKE SWITCH
Revision: 2005 July 2005 FX
11 . DETECT MALFUNCTIONING PART
Check the following.

Harness connectors E211, M41

Harness for open or short between ECM and stop lamp switch
>> Repair open circuit or short to ground or short to power in harness or connectors.
12. CHECK STOP LAMP SWITCH
Refer to EC-604, "
Component Inspection"
OK or NG
OK >> GO TO 13.
NG >> Replace stop lamp switch.
13. CHECK INTERMITTENT INCIDENT
Refer to EC-163, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>> INSPECTION END
Component InspectionABS007ZI
ASCD BRAKE SWITCH
1. Turn ignition switch OFF.
2. Disconnect ASCD brake switch harness connector.
3. Check 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 continuity between stop lamp switch terminals 1 and 2 under the following conditions.
If NG, adjust stop lamp switch installation, refer to BR-6,
"BRAKE PEDAL" , and perform step 3 again.
Condition Continuity
Brake pedal: Fully released. Should exist.
Brake pedal: Slightly depressed. Should not exist.
SEC023D
Condition Continuity
Brake pedal: Fully released. Should not exist.
Brake pedal: Slightly depressed. Should exist.
PBIB1185E

EC-614
[VQ35DE]
DTC P1805 BRAKE SWITCH
Revision: 2005 July 2005 FX
DTC P1805 BRAKE SWITCHPFP:25320
DescriptionABS006X1
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 ModeABS006X2
Specification data are reference values.
On Board Diagnosis LogicABS006X3
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 ProcedureABS006X4
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.
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-616, "
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

EC-616
[VQ35DE]
DTC P1805 BRAKE SWITCH
Revision: 2005 July 2005 FX
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 ProcedureABS006X6
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 1 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 P/L 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
PBIB1605E
Voltage: Battery voltage
PBIB1184E