Infiniti Q45. Manual - part 492

DTC P1572 ASCD BRAKE SWITCH

EC-607

C

D

E

F

G

H

I

J

K

L

M

A

EC

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 Procedure

NBS0024O

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

R/W

Stop lamp switch

[Ignition switch: OFF]

●

Brake pedal: Fully released

Approximately 0V

[Ignition switch: OFF]

●

Brake pedal: Slightly depressed

BATTERY VOLTAGE
(11 - 14V)

108

Y/PU

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

SEC011D

CONDITION

VOLTAGE

When brake pedal: Slightly depressed

Approximately 0V

When brake pedal: Fully released

Battery voltage

MBIB0061E

EC-608

DTC P1572 ASCD BRAKE SWITCH

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.

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-II or tester.

OK or NG

OK

>> GO TO 5.

NG

>> GO TO 4.

CONDITION

INDICATION

When brake pedal: Fully released

OFF

When brake pedal: Slightly depressed

ON

SEC013D

CONDITION

VOLTAGE

When brake pedal: Fully released

Approximately 0V

When brake pedal: Slightly depressed

Battery voltage

PBIB1537E

PBIB2433E

Voltage: Battery voltage

PBIB0857E

DTC P1572 ASCD BRAKE SWITCH

EC-609

C

D

E

F

G

H

I

J

K

L

M

A

EC

4. 

DETECT MALFUNCTIONING PART

Check the following.

●

Fuse block (J/B) No. 1 connector M1

●

10A fuse

●

Harness connectors M61, M401

●

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.

6. 

DETECT MALFUNCTIONING PART

Check the following.

●

Harness connectors M401, M61

●

Harness connectors M135, F105

●

Harness for open or short between ECM and ASCD brake switch

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

7. 

CHECK ASCD BRAKE SWITCH

Refer to 

EC-611, "Component Inspection"

  

OK or NG

OK

>> GO TO 13.

NG

>> Replace ASCD brake switch.

Continuity should exist.

EC-610

DTC P1572 ASCD BRAKE SWITCH

8. 

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 10.

NG

>> GO TO 9.

9. 

DETECT MALFUNCTIONING PART

Check the following.

●

Fuse block (J/B) No. 1 connector M1

●

10A fuse

●

Harness connectors M61, M401

●

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.

10. 

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 12.

NG

>> GO TO 11.

PBIB2433E

Voltage: Battery voltage

PBIB2102E

Continuity should exist.