Nissan Frontier. Manual — part 680

P1572 ASCD BRAKE SWITCH

EC-1291

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR MEXICO]

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P1572 ASCD BRAKE SWITCH

Component Description

INFOID:0000000009481957

When the brake pedal is depressed, brake pedal position switch (1)

is turned OFF and stop lamp switch (2) is turned ON. ECM detects

the state of the brake pedal by those two types of input (ON/OFF sig-

nal).

Refer to

EC-984, "System Description"

for the ASCD function.

On Board Diagnosis Logic

INFOID:0000000009481958

This self-diagnosis has the one trip detection logic.

The MIL will not illuminate for this diagnosis.

NOTE:

• If DTC P 1572 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605. Refer

to

EC-1251

.

• 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 is turn OFF. And even when malfunction A is detected in

two consecutive trips, DTC is not stored in ECM memory.

DTC Confirmation Procedure

INFOID:0000000009481959

CAUTION:

Always drive vehicle at a safe speed.

NOTE:

• The procedure for malfunction B is not described. It takes an extremely long time to complete the procedure

for malfunction B. By performing the procedure for malfunction A, the condition that causes malfunction B

can be detected.

• If DTC Confirmation Procedure has been previously conducted, always perform the following before con-

ducting the next step.

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.

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

1. Start engine (VDC switch OFF).

MBIB1214E

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 brake pedal position switch are sent
to ECM at the same time.

• Harness or connectors

(The stop lamp switch circuit is shorted.)

• Harness or connectors

(The brake pedal position switch circuit is
shorted.)

• Stop lamp switch
• Brake pedal position switch
• Incorrect stop lamp switch installation
• Incorrect brake pedal position switch instal-

lation

• ECM

B)

Brake pedal position switch signal is not sent
to ECM for extremely long time while the ve-
hicle is being driven

EC-1292

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR MEXICO]

P1572 ASCD BRAKE SWITCH

2. Select “DATA MONITOR” mode with CONSULT.
3. Press MAIN switch and make sure that CRUISE indicator illuminates.
4. Drive the vehicle for at least 5 consecutive seconds under the following condition.

5. Check 1st trip DTC.

If DTC is detected, go to

EC-1292, "Diagnosis Procedure"

.

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

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

7. Check 1st trip DTC.
8. If DTC is detected, go to

EC-1292, "Diagnosis Procedure"

.

WITH GST

Follow the procedure “WITH CONSULT” above.

Diagnosis Procedure

INFOID:0000000009481960

1.

CHECK OVERALL FUNCTION-I

With CONSULT

1. Turn ignition switch ON.

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

3. Check “BRAKE SW1” indication under the following conditions.

Without CONSULT

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

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

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.

CONDITION

INDICATION

Brake pedal: Slightly depressed

OFF

Brake pedal: Fully released

ON

CONDITION

VOLTAGE

Brake pedal: Slightly depressed

Approximately 0V

Brake pedal: Fully released

Battery voltage

MBIB0061E

CONDITION

INDICATION

Brake pedal: Fully released

OFF

Brake pedal: Slightly depressed

ON

P1572 ASCD BRAKE SWITCH

EC-1293

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR MEXICO]

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Without CONSULT

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

OK or NG

OK

>> GO TO 11.

NG

>> GO TO 7.

3.

CHECK BRAKE PEDAL POSITION SWITCH POWER SUPPLY CIRCUIT

1. Turn ignition switch OFF.

2. Disconnect brake pedal position switch (1) harness connector.

-

Stop lamp switch (2)

3. Turn ignition switch ON.

4. Check voltage between brake pedal position switch terminal 1

and ground with CONSULT 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 F160

• 10A fuse

• Harness for open or short between brake pedal position switch and fuse

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

5.

CHECK BRAKE PEDAL POSITION 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 brake pedal position 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 6.

CONDITION

VOLTAGE

Brake pedal: Fully released

Approximately 0V

Brake pedal: Slightly depressed

Battery voltage

MBIB0060E

MBIB1214E

Voltage: Battery voltage

PBIB0857E

Continuity should exist.

EC-1294

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR MEXICO]

P1572 ASCD BRAKE SWITCH

NG

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

6.

CHECK BRAKE PEDAL POSITION SWITCH

Refer to

EC-1295, "Component Inspection"

.

OK or NG

OK

>> GO TO 11.

NG

>> Replace brake pedal position switch. Refer to

BR-20, "Exploded View"

.

7.

CHECK STOP LAMP SWITCH POWER SUPPLY CIRCUIT

1. Turn ignition switch OFF.

2. Disconnect stop lamp switch (2) harness connector.

-

Brake pedal position switch (1)

3. Check voltage between stop lamp switch terminal 1 and ground

with CONSULT or tester.

OK or NG

OK

>> GO TO 9.

NG

>> GO TO 8.

8.

DETECT MALFUNCTIONING PART

Check the following.

• Fuse block (J/B) connector F160

• 10 A fuse (No.20)

• 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.

9.

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 2.

Refer to Wiring Diagram.

3. Also check harness for short to ground and short to power.
OK or NG

OK

>> GO TO 10.

NG

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

10.

CHECK STOP LAMP SWITCH

Refer to

EC-1295, "Component Inspection"

.

OK or NG

OK

>> GO TO 11.

MBIB1214E

Voltage: Battery voltage

PBIB1184E

Continuity should exist.