Infiniti G37 Coupe. Manual - part 563

P1572 ASCD BRAKE SWITCH

EC-433

< COMPONENT DIAGNOSIS >

[VQ37VHR]

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18.

CHECK STOP LAMP SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1.

Disconnect ECM harness connector.

2.

Check the continuity between stop lamp switch harness connector and ECM harness connector.

3.

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

Is the inspection result normal?

YES

>> GO TO 20.

NO

>> GO TO 19.

19.

DETECT MALFUNCTIONING PART

Check the following.
• Fuse block (J/B) connectors E103, M2
• 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.

20.

CHECK STOP LAMP SWITCH

Refer to 

EC-434, "Component Inspection (Stop Lamp Switch)"

Is the inspection result normal?

YES

>> GO TO 21.

NO

>> Replace stop lamp switch.

21.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-38, "Intermittent Incident"

.

>> INSPECTION END

Component Inspection (ASCD Brake Switch)

INFOID:0000000001734256

1.

CHECK ASCD BRAKE SWITCH-I

1.

Turn ignition switch OFF.

2.

Disconnect ASCD brake switch harness connector.

3.

Check the continuity between ASCD brake switch terminals under the following conditions.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> GO TO 2.

2.

CHECK ASCD BRAKE SWITCH-II

1.

Adjust ASCD brake switch installation. Refer to 

BR-7, "Inspection and Adjustment"

.

2.

Check the continuity between ASCD brake switch terminals under the following conditions.

Is the inspection result normal?

Stop lamp switch

ECM

Continuity

Connector

Terminal

Connector

Terminal

E110

2

M107

122

Existed

Terminals

Condition

Continuity

1 and 2

Brake pedal

Fully released

Existed

Slightly depressed

Not existed

Terminals

Condition

Continuity

1 and 2

Brake pedal

Fully released

Existed

Slightly depressed

Not existed

EC-434

< COMPONENT DIAGNOSIS >

[VQ37VHR]

P1572 ASCD BRAKE SWITCH

YES

>> INSPECTION END

NO

>> Replace ASCD brake switch.

Component Inspection (ASCD Clutch Switch)

INFOID:0000000001734257

1.

CHECK ASCD CLUTCH SWITCH-I

1.

Turn ignition switch OFF.

2.

Disconnect ASCD clutch switch harness connector.

3.

Check the continuity between ASCD clutch switch terminals under the following conditions.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> GO TO 2.

2.

CHECK ASCD CLUTCH SWITCH-II

1.

Adjust ASCD clutch switch installation. Refer to 

CL-5, "Inspection and Adjustment"

.

2.

Check the continuity between ASCD clutch switch terminals under the following conditions.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace ASCD clutch switch.

Component Inspection (Stop Lamp Switch)

INFOID:0000000001734258

1.

CHECK STOP LAMP SWITCH-I

1.

Turn ignition switch OFF.

2.

Disconnect stop lamp switch harness connector.

3.

Check the continuity between stop lamp switch terminals under the following conditions.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> GO TO 2.

2.

CHECK STOP LAMP SWITCH-II

1.

Adjust stop lamp switch installation. Refer to 

BR-7, "Inspection and Adjustment"

.

2.

Check the continuity between stop lamp switch terminals under the following conditions.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace stop lamp switch.

Terminals

Condition

Continuity

1 and 2

Clutch pedal

Fully released

Existed

Slightly depressed

Not existed

Terminals

Condition

Continuity

1 and 2

Clutch pedal

Fully released

Existed

Slightly depressed

Not existed

Terminals

Condition

Continuity

1 and 2

Brake pedal

Fully released

Not existed

Slightly depressed

Existed

Terminals

Condition

Continuity

1 and 2

Brake pedal

Fully released

Not existed

Slightly depressed

Existed

P1572 ICC BRAKE SWITCH

EC-435

< COMPONENT DIAGNOSIS >

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P1572 ICC BRAKE SWITCH

Description

INFOID:0000000001734259

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 

CCS-15, "System Description"

 for the ICC function.

DTC Logic

INFOID:0000000001734260

DTC DETECTION LOGIC

NOTE:
• If DTC P1572 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605. Refer

to 

EC-356, "DTC Logic"

.

• 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 PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following before conduct-
ing the next test. 
1.

Turn ignition switch OFF and wait at least 10 seconds.

2.

Turn ignition switch ON.

3.

Turn ignition switch OFF and wait at least 10 seconds.

NOTE:
Procedure for malfunction B is not described here. It takes extremely long time to complete procedure for mal-
function B. By performing procedure for malfunction A, the incident that causes malfunction B can be
detected.

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE

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.

CAUTION:

Always drive vehicle at a safe speed.
NOTE:
This procedure 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.

DTC No.

Trouble diagnosis 

name

DTC detecting condition

Possible cause

P1572

ICC brake switch

A)

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

EC-436

< COMPONENT DIAGNOSIS >

[VQ37VHR]

P1572 ICC BRAKE SWITCH

5.

Check 1st trip DTC.

With GST

Follow the procedure “With CONSULT-III” above.
Is 1st trip DTC detected?

YES

>> Go to 

EC-436, "Diagnosis Procedure"

.

NO

>> GO TO 3.

3.

PERFORM DTC CONFIRMATION PROCEDURE

With CONSULT-III

1.

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

CAUTION:

Always drive vehicle at a safe speed.
NOTE:
This procedure 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.

2.

Check 1st trip DTC.

With GST

Follow the procedure “With CONSULT-III” above.

Is 1st trip DTC detected?

YES

>> Go to 

EC-436, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000001734261

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 the voltage between ECM harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 2.

NO-1

>> A/T models: GO TO 3.

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.

Monitor item

Condition

Indication

BRAKE SW1

Brake pedal (A/T)
Brake pedal and clutch pedal (M/T)

Slightly depressed

OFF

Fully released

ON

ECM

Ground

Condition

Voltage

Connector

Terminal

M107

126

(ICC brake switch signal)

Ground

Brake pedal (A/T)
Brake pedal and clutch pedal (M/T)

Slightly depressed

Approx. 0V

Fully released

Battery voltage