Infiniti FX35, FX50 (S51). Manual - part 879

P1572 ICC BRAKE SWITCH

EC-1057

< DTC/CIRCUIT DIAGNOSIS >

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YES

>> GO TO 13.

NO

>> GO TO 12.

12.

DETECT MALFUNCTIONING PART

Check the following.
• Fuse block (J/B) connector E103
• 10 A fuse (No. 7)
• Harness for open or short between battery and stop lamp switch
• Harness for open or short between battery and ICC brake hold relay

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

13.

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.

Check the continuity between ICC brake hold relay harness connector and ECM harness connector.

4.

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

Is the inspection result normal?

YES

>> GO TO 15.

NO

>> GO TO 14.

14.

DETECT MALFUNCTIONING PART

Check the following.
• Fuse block (J/B) connector E103, M2
• Harness for open or short between ECM and stop lamp switch
• Harness for open or short between ECM and ICC brake hold relay

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

15.

CHECK STOP LAMP SWITCH

Refer to 

EC-1058, "Component Inspection (Stop Lamp Switch)"

.

Is the inspection result normal?

YES

>> GO TO 16.

NO

>> Replace stop lamp switch.

16.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-36, "Intermittent Incident"

.

>> INSPECTION END

Component Inspection (ICC Brake Switch)

INFOID:0000000005237550

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.

Stop lamp switch

ECM

Continuity

Connector

Terminal

Connector

Terminal

E110

4

M160

110

Existed

ICC brake hold relay

ECM

Continuity

Connector

Terminal

Connector

Terminal

E91

6

M160

110

Existed

EC-1058

< DTC/CIRCUIT DIAGNOSIS >

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P1572 ICC BRAKE SWITCH

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-7, "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:0000000005237551

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

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

3 and 4

Brake pedal

Fully released

Not existed

Slightly depressed

Existed

Terminals

Condition

Continuity

3 and 4

Brake pedal

Fully released

Not existed

Slightly depressed

Existed

P1574 ASCD VEHICLE SPEED SENSOR

EC-1059

< DTC/CIRCUIT DIAGNOSIS >

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P1574 ASCD VEHICLE SPEED SENSOR

Description

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The ECM receives two vehicle speed signals by the 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-631, "System Description"

 for ASCD functions.

DTC Logic

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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-948, "DTC Logic"

.

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

to 

EC-962, "DTC Logic"

.

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

to 

EC-964, "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-1059, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

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1.

CHECK DTC WITH TCM

Check DTC with TCM. Refer to 

CCS-44, "Diagnosis Description"

.

Is the inspection result normal?

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.)

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

EC-1060

< DTC/CIRCUIT DIAGNOSIS >

[VK50VE]

P1574 ASCD VEHICLE SPEED SENSOR

YES

>> GO TO 2.

NO

>> Perform Diagnosis Procedure corresponding to the 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

>> Perform Diagnosis Procedure corresponding to the DTC indicated.

3.

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

Refer to 

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

.

>> INSPECTION END