Nissan Altima L32. Manual - part 446

P1572 ASCD BRAKE SWITCH

EC-905

< COMPONENT DIAGNOSIS >

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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-13, "Inspection and Adjustment"

.

2. Check the continuity between ASCD brake switch terminals

under the following conditions.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace ASCD brake switch.

Component Inspection (ASCD Clutch Switch)

INFOID:0000000004349880

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 

BR-13, "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.

Terminals

Condition

Continuity

1 and 2

Brake pedal

Fully released

Existed

Slightly depressed Not existed

SEC023D

Terminals

Condition

Continuity

1 and 2

Brake pedal

Fully released

Existed

Slightly depressed Not existed

SEC023D

Terminals

Condition

Continuity

1 and 2

Clutch pedal

Fully released

Existed

Slightly depressed Not existed

SEC023D

Terminals

Condition

Continuity

1 and 2

Clutch pedal

Fully released

Existed

Slightly depressed Not existed

SEC023D

EC-906

< COMPONENT DIAGNOSIS >

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P1572 ASCD BRAKE SWITCH

Component Inspection (Stop Lamp Switch)

INFOID:0000000004349881

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-13, "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

Brake pedal

Fully released

Not existed

Slightly depressed

Existed

PBIB3444E

Terminals

Condition

Continuity

1 and 2

Brake pedal

Fully released

Not existed

Slightly depressed

Existed

PBIB3444E

P1574 ASCD VEHICLE SPEED SENSOR

EC-907

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P1574 ASCD VEHICLE SPEED SENSOR

Description

INFOID:0000000004349882

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

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

trol. Refer to 

EC-603, "System Description"

 for ASCD functions.

DTC Logic

INFOID:0000000004349883

DTC DETECTION LOGIC

NOTE:

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

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

to 

EC-853, "DTC Logic"

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

to 

EC-864, "DTC Logic"

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

to 

EC-866, "DTC Logic"

.

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at

least 10 seconds before conducting the next test.

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE

1. Start engine.

2. Drive the vehicle at more than 40 km/h (25 MPH).

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.

3. Check DTC.
Is DTC detected?

YES

>> Go to 

EC-907, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000004349884

1.

CHECK DTC WITH TCM

Check DTC with TCM. Refer to 

TM-296, "Diagnosis Description"

.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Perform trouble shooting relevant to DTC indicated.

DTC No.

Trouble diagnosis 

name

DTC detecting condition

Possible cause

P1574

ASCD vehicle speed 
sensor

ECM detects a difference between two vehicle 
speed signals is out of the specified range.

• Harness or connectors

(The CAN communication line is open or 
shorted.)
(Combination meter circuit is open or shorted.)

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

EC-908

< COMPONENT DIAGNOSIS >

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P1574 ASCD VEHICLE SPEED SENSOR

2.

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

Refer to 

BRC-12, "CONSULT-III Function (ABS)"

.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Repair or replace.

3.

CHECK COMBINATION METER

Check combination meter function.

Refer to 

MWI-38, "CONSULT-III Function (METER/M&A)"

.

>> INSPECTION END