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Infiniti QX56 (JA60). Manual - part 358

EC-84

< COMPONENT DIAGNOSIS >

[VK56DE]

POWER SUPPLY AND GROUND CIRCUIT

Refer to Wiring Diagram.

4. Also check harness for short to ground and short to power.
OK or NG

>> GO TO 13.

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

11.

CHECK ECM POWER SUPPLY CIRCUIT-VI

1. Disconnect ECM harness connector.

2. Disconnect IPDM E/R harness connector E119.

3. Check harness continuity between ECM terminal 111 and IPDM E/R terminal 7.

Refer to Wiring Diagram.

4. Also check harness for short to ground and short to power.
OK or NG

>> GO TO 12.

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

12.

CHECK 20 A FUSE

1. Disconnect 20 A fuse from IPDM E/R.

2. Check 20 A fuse (No. 53).
OK or NG

>> GO TO 16.

>> Replace 20 A fuse.

13.

CHECK GROUND CONNECTIONS

1. Turn ignition switch OFF.

2. Loosen and retighten ground three screws on the body.

Refer to

EC-85, "Ground Inspection"

OK or NG

>> GO TO 14.

>> Repair or replace ground connections.

14.

CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-II

1. Disconnect ECM harness connector.

2. Check harness continuity between ECM terminals 1, 115, 116 and ground.

Refer to Wiring Diagram.

3. Also check harness for short to power.
OK or NG

>> GO TO 16.

>> GO TO 15.

15.

DETECT MALFUNCTIONING PART

Continuity should exist.

BBIA0354E

Continuity should exist.

POWER SUPPLY AND GROUND CIRCUIT

EC-85

< COMPONENT DIAGNOSIS >

[VK56DE]

Check the following.

• Harness connectors F32, E2

• Harness for open or short between ECM and ground

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

16.

CHECK INTERMITTENT INCIDENT

Refer to

GI-35, "How to Check Terminal"

and

GI-38, "Intermittent Incident"

OK or NG

>> Replace IPDM E/R.

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

Ground Inspection

INFOID:0000000005149086

Ground connections are very important to the proper operation of electrical and electronic circuits. Ground

connections are often exposed to moisture, dirt and other corrosive elements. The corrosion (rust) can

become an unwanted resistance. This unwanted resistance can change the way a circuit works.

Electronically controlled circuits are very sensitive to proper grounding. A loose or corroded ground can drasti-

cally affect an electronically controlled circuit. A poor or corroded ground can easily affect the circuit. Even

when the ground connection looks clean, there can be a thin film of rust on the surface.

When inspecting a ground connection follow these rules:

• Remove the ground bolt or screw.

• Inspect all mating surfaces for tarnish, dirt, rust, etc.

• Clean as required to assure good contact.

• Reinstall bolt or screw securely.

• Inspect for “add-on” accessories which may be interfering with the ground circuit.

• If several wires are crimped into one ground eyelet terminal, check for proper crimps. Make sure all of the

wires are clean, securely fastened and providing a good ground path. If multiple wires are cased in one eye-

let make sure no ground wires have excess wire insulation.

PBIB1870E

EC-86

< COMPONENT DIAGNOSIS >

[VK56DE]

U0101 CAN COMM CIRCUIT

U0101 CAN COMM CIRCUIT

Description

INFOID:0000000005157950

CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-

tiplex communication line with high data communication speed and excellent error detection ability. Many elec-

tronic control units are equipped onto a vehicle, and each control unit shares information and links with other

control units during operation (not independent). In CAN communication, control units are connected with 2

communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.

Each control unit transmits/receives data but selectively reads required data only.

On Board Diagnosis Logic

INFOID:0000000005157951

This self-diagnosis has the one trip detection logic.

DTC Confirmation Procedure

INFOID:0000000005157952

1. Turn ignition switch ON and wait at least 3 seconds.
2. Check DTC.
3. If DTC is detected, go to

EC-86, "Diagnosis Procedure"

Diagnosis Procedure

INFOID:0000000005157953

Go to

LAN-44, "CAN Communication Signal Chart"

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

U0101
0101

Lost communication with
TCM

When ECM is not transmitting or receiving CAN
communication signal of OBD (emission-related
diagnosis) with TCM for 2 seconds or more.

• CAN communication line between

TCM and ECM
(CAN communication line is open or
shorted)

U1001 CAN COMM CIRCUIT

EC-87

< COMPONENT DIAGNOSIS >

[VK56DE]

U1001 CAN COMM CIRCUIT

Description

INFOID:0000000005149087

CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-

tiplex communication line with high data communication speed and excellent error detection ability. Many elec-

tronic control units are equipped onto a vehicle, and each control unit shares information and links with other

control units during operation (not independent). In CAN communication, control units are connected with 2

communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.

Each control unit transmits/receives data but selectively reads required data only.

On Board Diagnosis Logic

INFOID:0000000005149088

MIL will not illuminate for this self-diagnosis.

DTC Confirmation Procedure

INFOID:0000000005149089

1. Turn ignition switch ON and wait at least 3 seconds.
2. Check 1st trip DTC.
3. If 1st trip DTC is detected, go to

EC-87, "Diagnosis Procedure"

Diagnosis Procedure

INFOID:0000000005149090

Go to

LAN-44, "CAN Communication Signal Chart"

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

U1001
1001

CAN communication line

When ECM is not transmitting or receiving CAN
communication signal other than OBD (emis-
sion related diagnosis) for 2 seconds or more.

• Harness or connectors

(CAN communication line is open or
shorted)

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