Infiniti QX56 (Z62). Manual - part 599

EC-374

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

P0603 ECM POWER SUPPLY

P0603 ECM POWER SUPPLY

DTC Logic

INFOID:0000000006217873

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

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.

Turn ignition switch ON wait at least 10 seconds.

2.

Turn ignition switch OFF and wait at least 5 minutes.

3.

Turn ignition switch ON, wait at least 10 seconds.

4.

Repeat step 2 and 3 for five times.

5.

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Go to 

EC-374, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000006217874

1.

CHECK ECM POWER SUPPLY

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check the voltage between ECM harness connector terminals.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> GO TO 2.

2.

DETECT MALFUNCTIONING PART

Check the following.
• 20 A fuse (No. 43)
• Harness for open or short between ECM and battery
• Loose or poor connection for each connector and harness

>> Repair or replace harness or connectors.

3.

CHECK INTERMITTENT INCIDENT

DTC No.

Trouble diagnosis name

(Trouble diagnosis content)

DTC detecting condition

Possible cause

P0603

ECM BACK UP/CIRCUIT
(ECM power supply circuit)

ECM back up RAM system does not 
function properly.

• Harness or connectors

[ECM power supply (back up) circuit is open or 
shorted.]

• ECM

ECM

Voltage

+

–

Connector

Terminal

Connector

Terminal

E80

156

E80

175

Battery voltage

P0603 ECM POWER SUPPLY

EC-375

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

Refer to 

GI-40, "Intermittent Incident"

.

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Repair or replace harness or connectors.

4.

PERFORM DTC CONFIRMATION PROCEDURE

1.

Turn ignition switch ON.

2.

Erase DTC.

3.

Perform DTC Confirmation Procedure.
See 

EC-374, "DTC Logic"

.

Is the 1st trip DTC P0603 displayed again?

YES

>> GO TO 5.

NO

>> INSPECTION END

5.

REPLACE ECM

Replace ECM.

>> INSPECTION END

EC-376

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

P0605 ECM

P0605 ECM

DTC Logic

INFOID:0000000006217875

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

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:
Before performing the following procedure, confirm that battery voltage is 11 V or more at idle.

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION A AND D

1.

Turn ignition switch ON.

2.

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Proceed to 

EC-376, "Diagnosis Procedure"

.

NO

>> GO TO 3.

3.

PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION B

1.

Turn ignition switch ON and wait at least 1 second.

2.

Turn ignition switch OFF, wait at least 10 seconds, and then turn it ON.

3.

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Proceed to 

EC-376, "Diagnosis Procedure"

.

NO

>> GO TO 4.

4.

PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION C

1.

Turn ignition switch ON and wait at least 1 second.

2.

Turn ignition switch OFF, wait at least 10 seconds, and then turn it ON.

3.

Repeat step 2 for 32 times.

4.

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Proceed to 

EC-376, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000006217876

1.

INSPECTION START

1.

Turn ignition switch ON.

2.

Erase DTC.

3.

Perform DTC Confirmation Procedure.
See 

EC-376, "DTC Logic"

.

Is the 1st trip DTC P0605 displayed again?

YES

>> GO TO 2.

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0605

Engine control module

A)

ECM calculation function is malfunctioning.

ECM

B)

ECM EEP-ROM system is malfunctioning.

C)

ECM self shut-off function is malfunctioning.

D)

ECM temperature sensor is malfunctioning.

P0605 ECM

EC-377

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

NO

>> INSPECTION END

2.

REPLACE ECM

Replace ECM. Refer to 

EC-535, "Removal and Installation"

.

>> INSPECTION END