Nissan Frontier. Manual - part 574

P1572 ASCD BRAKE SWITCH

EC-867

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR USA AND CANADA]

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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 6.

NG

>> GO TO 5.

5.

DETECT MALFUNCTIONING PART

Check the following.

• Fuse block (J/B) connector E160

• 10 A fuse (No.12)

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

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

6.

CHECK BRAKE PEDAL POSITION SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1. Turn ignition switch OFF.

2. Check harness continuity between brake pedal position switch terminal 2 and clutch pedal position switch

terminal 1.

Refer to Wiring Diagram.

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

OK

>> GO TO 7.

NG

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

7.

CHECK BRAKE PEDAL POSITION SWITCH

Refer to 

EC-868, "Component Inspection"

.

OK or NG

OK

>> GO TO 14.

NG

>> Replace brake pedal position switch. Refer to 

BR-20, "Exploded View"

.

8.

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 126 and clutch 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 9.

NG

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

MBIB1214E

Voltage: Battery voltage

Continuity should exist.

Continuity should exist.

EC-868

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR USA AND CANADA]

P1572 ASCD BRAKE SWITCH

9.

CHECK CLUTCH PEDAL POSITION SWITCH

Refer to 

EC-868, "Component Inspection"

.

OK or NG

OK

>> GO TO 14.

NG

>> Replace clutch pedal position switch. Refer to 

CL-9, "Exploded View"

.

10.

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 1 and ground with CONSULT or tester.

OK or NG

OK

>> GO TO 12.

NG

>> GO TO 11.

11.

DETECT MALFUNCTIONING PART

Check the following.

• Fuse block (J/B) connector E160

• 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.

12.

CHECK STOP LAMP SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1. Disconnect ECM harness connector.

2. Check harness continuity between ECM terminal 122 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 13.

NG

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

13.

CHECK STOP LAMP SWITCH

Refer to 

EC-868, "Component Inspection"

.

OK or NG

OK

>> GO TO 14.

NG

>> Replace stop lamp switch. Refer to 

BR-20, "Exploded View"

.

14.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-42, "Intermittent Incident"

.

>> INSPECTION END

Component Inspection

INFOID:0000000009481562

BRAKE PEDAL POSITION SWITCH

1. Turn ignition switch OFF.
2. Disconnect brake pedal position switch harness connector.
3. Check harness continuity between brake pedal position switch terminals 1 and 2 under the following con-

ditions.

Voltage: Battery voltage

Continuity should exist.

P1572 ASCD BRAKE SWITCH

EC-869

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR USA AND CANADA]

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If NG, adjust brake pedal position switch installation, refer to 

BR-16, "Inspection and Adjustment"

, and per-

form step 3 again.

CLUTCH PEDAL POSITION SWITCH

1. Turn ignition switch OFF.
2. Disconnect clutch pedal position switch harness connector.
3. Check harness continuity between clutch pedal position switch terminals 1 and 2 under the following con-

ditions.

If NG, adjust clutch pedal position switch installation, refer to 

CL-7, "On-Vehicle Inspection and Adjust-

ment"

, and perform step 3 again.

STOP LAMP SWITCH

1. Turn ignition switch OFF.
2. Disconnect stop lamp switch harness connector.
3. Check harness continuity between stop lamp switch terminals 1 and 2 under the following conditions.

If NG, adjust stop lamp switch installation, refer to 

BR-16, "Inspection and Adjustment"

, and perform step

3 again.

Condition

Continuity

When brake pedal: Fully released.

Should exist.

When brake pedal: Slightly depressed.

Should not exist.

Condition

Continuity

Clutch pedal: Fully released

Should exist

Clutch pedal: Slightly depressed

Should not exist

Condition

Continuity

When brake pedal: Fully released.

Should not exist.

When brake pedal: Slightly depressed.

Should exist.

EC-870

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR USA AND CANADA]

P1574 ASCD VEHICLE SPEED SENSOR

P1574 ASCD VEHICLE SPEED SENSOR

Component Description

INFOID:0000000009481563

The ECM receives two vehicle speed sensor signals via CAN communication line. One is sent from combina-

tion meter, and the other is from TCM (Transmission control module). The ECM uses these signals for ASCD

control. Refer to 

EC-493, "System Description"

 for ASCD functions.

On Board Diagnosis Logic

INFOID:0000000009481564

This self-diagnosis has the one trip detection logic.

The MIL will not illuminate for this diagnosis.

NOTE:

• If DTC P1574 is displayed with DTC UXXXX, first perform the trouble diagnosis for DTC UXXXX.

• If DTC P1574 is displayed with DTC P0607, first perform the trouble diagnosis for DTC P0607. Refer

to 

EC-829, "On Board Diagnosis Logic"

.

• If DTC P1574 is displayed with DTC P0500, first perform the trouble diagnosis for DTC P0500. Refer

to 

EC-814, "On Board Diagnosis Logic"

.

• If DTC P1574 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605. Refer

to 

EC-827, "On Board Diagnosis Logic"

.

DTC Confirmation Procedure

INFOID:0000000009481565

CAUTION:

Always drive vehicle at a safe speed.

NOTE:

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

ing 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:

Step 3 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.
1. Start engine.
2. Drive the vehicle at more than 40 km/h (25 MPH).
3. Check DTC.
4. If DTC is detected, go to 

EC-870, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000009481566

1.

CHECK DTC WITH TCM

Check DTC with TCM. Refer to 

TM-155, "OBD-II Diagnostic Trouble Code (DTC)"

.

OK or NG

OK

>> GO TO 2.

NG

>> Perform trouble shooting relevant to DTC indicated.

2.

CHECK DTC WITH “ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT)”

Refer to 

BRC-8, "Work Flow"

 (TYPE 1), 

BRC-120, "Work Flow"

 (TYPE 2).

DTC No.

Trouble Diagnosis 

Name

DTC Detecting Condition

Possible Cause

P1574
1574

ASCD vehicle speed 
sensor

The difference between the two vehicle speed 
signals is out of the specified range.

• Harness or connectors

(The CAN communication line is open or 
shorted.)

• Combination meter
• ABS actuator and electric unit (control unit)
• Wheel sensor
• TCM
• ECM