Infiniti G35 (V35). Manual - part 417

DTC P1572 ASCD BRAKE SWITCH

EC-549

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EC

DTC P1572 ASCD BRAKE SWITCH

PFP:25320

Component Description

NBS000ZX

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-29, "AUTOMATIC SPEED CONTROL DEVICE (ASCD)"

for the ASCD function.

CONSULT-II Reference Value in Data Monitor Mode

NBS000ZY

Specification data are reference values.

On Board Diagnosis Logic

NBS000ZZ

●

This self-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-496, "DTC P0605 ECM"

●

If DTC P1572 is displayed with DTC U1010, first perform the trouble diagnosis for DTC U1010.
Refer to 

EC-164, "DTC U1010 CAN COMMUNICATION"

 .

●

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.

PBIB1005E

MONITOR ITEM

CONDITION

SPECIFICATION

BRAKE SW 1
(ASCD brake switch)

●

Ignition switch: ON

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Brake pedal: Fully released (A/T)

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Brake pedal and clutch pedal: Fully 
released (M/T)

ON

●

Brake pedal: Slightly depressed (A/T)

●

Brake pedal and/or clutch pedal: 
Slightly depressed (M/T)

OFF

BRAKE SW 2
(Stop lamp switch)

●

Ignition switch: ON

Brake pedal: Fully released

OFF

Brake pedal: Slightly depressed

ON

EC-550

DTC P1572 ASCD BRAKE SWITCH

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.)

●

Harness connectors
(The ASCD clutch switch circuit is shorted.)
(M/T models)

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Stop lamp switch

●

ASCD brake switch

●

ASCD clutch switch (M/T models)

●

Incorrect stop lamp switch installation

●

Incorrect ASCD brake switch installation

●

Incorrect ASCD clutch switch installation 
(M/T models)

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ECM

B)

ASCD brake switch signal is not sent to 
ECM for extremely long time while the vehi-
cle is driving

DTC P1572 ASCD BRAKE SWITCH

EC-551

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DTC Confirmation Procedure

NBS00100

CAUTION:

Always drive vehicle at a safe speed.
NOTE:

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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 1st trip DTC is detected, go to 

EC-554, "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-554, "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-552

DTC P1572 ASCD BRAKE SWITCH

Wiring Diagram 

NBS00101

TBWM0826E