Infiniti FX35, FX50 (S51). Manual - part 723

P1572 ICC BRAKE SWITCH

EC-433

< DTC/CIRCUIT DIAGNOSIS >

[VQ35HR]

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17.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-36, "Intermittent Incident"

.

>> INSPECTION END

Component Inspection (ICC Brake Switch)

INFOID:0000000005237038

1.

CHECK ICC BRAKE SWITCH-I

1.

Turn ignition switch OFF.

2.

Disconnect ICC brake switch harness connector.

3.

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

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> GO TO 2.

2.

CHECK ICC BRAKE SWITCH-II

1.

Adjust ICC brake switch installation. Refer to 

BR-19, "Inspection and Adjustment"

.

2.

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

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace ICC brake switch.

Component Inspection (Stop Lamp Switch)

INFOID:0000000005237039

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-19, "Inspection and Adjustment"

.

2.

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

Is the inspection result normal?

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

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

EC-434

< DTC/CIRCUIT DIAGNOSIS >

[VQ35HR]

P1572 ICC BRAKE SWITCH

YES

>> INSPECTION END

NO

>> Replace stop lamp switch.

Component Inspection (ICC Brake Hold Relay)

INFOID:0000000005237040

1.

CHECK ICC BRAKE HOLD RELAY

1.

Turn ignition switch OFF.

2.

Remove ICC brake hold relay.

3.

Check the continuity between ICC brake hold relay terminals
under the following conditions.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace ICC brake hold relay

Terminals

Condition

Continuity

3 and 4

12 V direct current supply between terminals 1 and 2

Not existed

No current supply

Existed

6 and 7

12 V direct current supply between terminals 1 and 2

Existed

No current supply

Not existed

MBIB0063E

P1574 ASCD VEHICLE SPEED SENSOR

EC-435

< DTC/CIRCUIT DIAGNOSIS >

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P1574 ASCD VEHICLE SPEED SENSOR

Description

INFOID:0000000005237041

The ECM receives two vehicle speed signals via CAN communication line. One is sent from “unified meter and
A/C amp.”, and the other is from TCM (Transmission control module). The ECM uses these signals for ASCD
control. Refer to 

EC-66, "System Description"

 for ASCD functions.

DTC Logic

INFOID:0000000005237042

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-345, "DTC Logic"

.

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

to 

EC-356, "DTC Logic"

.

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

to 

EC-358, "DTC Logic"

.

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following procedure
before conducting 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.

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE

1.

Start engine (VDC switch OFF).

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-435, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000005237043

1.

CHECK DTC WITH TCM

Check DTC with TCM. Refer to 

TM-61, "Diagnosis Description"

.

Is the inspection result normal?

DTC No.

Trouble diagnosis 

name

DTC detecting condition

Possible cause

P1574

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.)

• Unified meter and A/C amp.
• ABS actuator and electric unit (control unit)
• Wheel sensor
• TCM
• ECM

EC-436

< DTC/CIRCUIT DIAGNOSIS >

[VQ35HR]

P1574 ASCD VEHICLE SPEED SENSOR

YES

>> GO TO 2.

NO

>> Perform troubleshooting relevant to DTC indicated.

2.

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

Refer to 

BRC-44, "CONSULT-III Function"

.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Repair or replace malfunctioning part.

3.

CHECK DTC WITH “UNIFIED METER AND A/C AMP.”

Refer to 

MWI-45, "CONSULT-III Function (METER/M&A)"

.

>> INSPECTION END