Infiniti QX56 (JA60). Manual - part 421

EC-336

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P1568 ICC FUNCTION

P1568 ICC FUNCTION

On Board Diagnosis Logic

INFOID:0000000005149396

• This self-diagnosis has the one trip detection logic. 

• The MIL will not light up for this self-diagnosis. 

NOTE:

• If DTC P1568 is displayed with DTC UXXXX, first perform the trouble diagnosis for DTC UXXXX.

• If DTC P1568 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605. Refer

to 

EC-286, "On Board Diagnosis Logic"

.

• If DTC P1568 is displayed with DTC P0607, first perform the trouble diagnosis for DTC P0607. Refer

to 

EC-288, "On Board Diagnosis Logic"

.

DTC Confirmation Procedure

INFOID:0000000005149397

CAUTION:

Always drive vehicle at a safe speed.

NOTE:

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

before conducting 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 4 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. Turn ignition switch ON.

2. Press MAIN switch on ICC steering switch.

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

4. Press SET/COAST switch.

5. Check DTC.

6. If DTC is detected, go to 

EC-336, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000005149398

1.

REPLACE ICC UNIT

1. Replace ICC unit.

2. Perform 

CCS-8

.

3. Check DTC of ICC unit. Refer to 

CCS-18

.

>> INSPECTION END

DTC No.

Trouble Diagnosis 

Name

DTC Detecting Condition

Possible Cause

P1568
1568

ICC function

ECM detects a difference between signals 
from ICC unit is out of specified range.

• Harness or connectors

(The CAN communication line is open or 
shorted.)

• ICC unit
• ECM

P1572 ICC BRAKE SWITCH

EC-337

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P1572 ICC BRAKE SWITCH

Component Description

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When the brake pedal is depressed, ICC brake switch is turned OFF

and stop lamp switch is turned ON. ECM detects the state of the

brake pedal by this input of two kinds (ON/OFF signal).

Refer to 

CCS-13

 for the ICC function.

On Board Diagnosis Logic

INFOID:0000000005149400

• This diagnosis has the one trip detection logic.

• The MIL will not light up for this self-diagnosis.

NOTE:

• If DTC P1572 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605. Refer

to 

EC-286, "On Board Diagnosis Logic"

.

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

consecutive trips, DTC is not stored in ECM memory.

DTC Confirmation Procedure

INFOID:0000000005149401

CAUTION:

Always drive vehicle at a safe speed.

NOTE:

• Procedure for malfunction B is not described here. It takes extremely long time to complete procedure for

malfunction B. By performing procedure for malfunction A, the incident that causes malfunction B can be

detected. 

• If DTC Confirmation Procedure has been previously conducted, always perform the following procedure

before conducting 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 3 and 6 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 (VDC switch OFF).

2. Press MAIN switch and make sure that CRUISE lamp lights up.

3. Drive the vehicle for at least 5 consecutive seconds under the following conditions.

BBIA0470E

DTC No.

Trouble diagnosis 

name

DTC detecting condition

Possible cause

P1572
1572

ICC brake switch

A)

When vehicle speed is above 30 km/h (19 
MPH), ON signals from the stop lamp 
switch and the ICC brake switch are sent to 
ECM at the same time.

• Harness or connectors

(The stop lamp switch circuit is shorted.)

• Harness or connectors

(The ICC brake switch circuit is shorted.)

• Stop  lamp  switch
• ICC brake switch
• ICC brake hold relay
• Incorrect stop lamp switch installation
• Incorrect ICC brake switch installation
• ECM

B)

ICC brake switch signal is not sent to ECM 
for extremely long time while the vehicle is 
driving

EC-338

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P1572 ICC BRAKE SWITCH

4. Check 1st trip DTC.

5. If 1st trip DTC is detected, go to 

EC-338, "Diagnosis Procedure"

.

If 1st trip DTC is not detected, go to the following step.

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

7. Check 1st trip DTC.

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

EC-338, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000005149402

1.

CHECK OVERALL FUNCTION-I

 With CONSULT-III

1. Turn ignition switch ON.

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

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

 Without CONSULT-III

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-III

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

 Without CONSULT-III

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 ICC BRAKE SWITCH

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Check voltage between ECM terminal 101 and ground under the fol-

lowing conditions.

OK or NG

OK

>> GO TO 15.

NG

>> GO TO 9.

3.

CHECK ICC BRAKE SWITCH POWER SUPPLY CIRCUIT-I

1. Turn ignition switch OFF.

2. Disconnect ICC brake switch harness connector.

3. Turn ignition switch ON.

4. Check voltage between ICC brake switch terminal 1 and ground

with CONSULT-III or tester.

OK or NG

OK

>> GO TO 7.

NG

>> GO TO 4.

4.

CHECK ICC BRAKE SWITCH POWER SUPPLY CIRCUIT-II

1. Turn ignition switch OFF.

2. Disconnect ICC brake hold relay.

3. Check harness continuity between ICC brake switch terminal 1 and ICC brake hold relay terminal 3

Refer to Wiring Diagram.

CONDITION

VOLTAGE

Brake pedal: Fully released

Approximately 0V

Brake pedal: Slightly depressed

Battery voltage

PBIB1537E

BBIA0470E

Voltage: Battery voltage

PBIB0857E

BBIA0471E