Infiniti FX35 / FX45. Manual - part 577

DTC P1572 ASCD BRAKE SWITCH

EC-1069

< SERVICE INFORMATION >

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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-III

1.

Start engine (VDC switch OFF).

2.

Select “DATA MONITOR” mode with CONSULT-III.

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.

5.

Check 1st trip DTC.

6.

If 1st trip DTC is detected, go to 

EC-1071, "Diagnosis Procedure"

.

If 1st trip DTC is not detected, go to the following step.

7.

Drive the vehicle for at least 5 consecutive seconds under the following conditions.

8.

Check 1st trip DTC.

9.

If 1st trip DTC is detected, go to 

EC-1071, "Diagnosis Procedure"

.

 WITH GST

Follow the procedure “WITH CONSULT-III” 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 vehicle speed.

EC-1070

< SERVICE INFORMATION >

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DTC P1572 ASCD BRAKE SWITCH

Wiring Diagram

INFOID:0000000001326946

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.

TBWM1352E

DTC P1572 ASCD BRAKE SWITCH

EC-1071

< SERVICE INFORMATION >

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Diagnosis Procedure

INFOID:0000000001326947

1.

CHECK OVERALL FUNCTION-I

 With CONSULT-III

1.

Turn ignition switch ON.

2.

Select “BRAKE SW1” in “DATA MONITOR” mode with CONSULT-III.

3.

Check “BRAKE SW1” indication under the following conditions.

 Without CONSULT-III

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-III

Check “BRAKE SW2” indication in “DATA MONITOR” mode. 

 Without CONSULT-III

Check voltage between ECM terminal 101 and ground under the following conditions.

TER-

MI-

NAL 

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

When brake pedal: Slightly depressed

OFF

When brake pedal: Fully released

ON

CONDITION

VOLTAGE

When brake pedal: Slightly depressed

Approximately 0V

When brake pedal: Fully released

Battery voltage

MBIB0061E

CONDITION

INDICATION

When brake pedal: Fully released

OFF

When brake pedal: Slightly depressed

ON

EC-1072

< SERVICE INFORMATION >

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DTC P1572 ASCD BRAKE SWITCH

OK or NG

OK

>> GO TO 13.

NG

>> GO TO 8.

3.

CHECK ASCD BRAKE SWITCH POWER SUPPLY CIRCUIT

1.

Turn ignition switch OFF.

2.

Disconnect ASCD brake switch harness connector.

3.

Turn ignition switch ON.

4.

Check voltage between ASCD brake switch terminal 1 and
ground with CONSULT-III or tester.

OK or NG

OK

>> GO TO 5.

NG

>> GO TO 4.

4.

DETECT MALFUNCTIONING PART

Check the following.
• Fuse block (J/B) connector E201
• 10A fuse
• Harness for open or short between ASCD brake switch and fuse

>> Repair open circuit or short to ground or short to power in harness or connectors.

5.

CHECK ASCD BRAKE SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check harness continuity between ECM terminal 108 and ASCD brake switch terminal 2.
Refer to Wiring Diagram.

4.

Also check harness for short to ground and short to power.

OK or NG

OK

>> GO TO 7.

NG

>> GO TO 6.

CONDITION

VOLTAGE

When brake pedal: Fully released

Approximately 0V

When brake pedal: Slightly depressed

Battery voltage

PBIB1537E

PBIB2558E

Voltage: Battery voltage

PBIB0857E

Continuity should exist.