Last Modified: 4-30-2014 6.6 J Doc ID: RM000000WIU006X
Model Year: 2006 Model: LX470 Prod Date Range: [05/2005 -           ]
Title: CAN COMMUNICATION: CAN COMMUNICATION SYSTEM: Short to GND in CAN Bus Line; 2006 MY LX470 [05/2005 -        ]

Short to GND in CAN Bus Line

DESCRIPTION

There may be a short circuit between the CAN bus line and GND when there is resistance between terminals 6 (CANH) and 4 (CG) or terminals 14 (CANL) and 4 (CG) of the DLC3.

Symptoms

Trouble Area

There is resistance between terminals 6 (CANH) and 4 (CG) or terminals 14 (CANL) and 4 (CG) of DLC3.
  • Short to GND
  • ECM
  • Gateway ECU
  • Translate ECU
  • Junction connector

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1.

CHECK CAN BUS LINE FOR SHORT TO GND (DLC3 SUB BUS LINE)

(a) Disconnect the J34 DLC3 sub bus line connector from the junction connector B side.

NOTICE:

  • Before disconnecting the connector, make a note of where it is connected.
  • Reconnect the connector to its original position.

(b) Measure the resistance of the DLC3.

Standard resistance:

Tester Connection

Condition

Specified Condition

D8-6 (CANH) - D8-4 (CG)

Ignition switch OFF

1 MΩ or higher

D8-14 (CANL) - D8-4 (CG)

Ignition switch OFF

1 MΩ or higher
NG

REPAIR OR REPLACE DLC3 SUB BUS LINE AND CONNECTOR (CAN-H, CAN-L)

OK

2.

CONNECT CONNECTOR

(a) Reconnect the J34 DLC3 sub bus line connector to the junction connector side.

NEXT

3.

CHECK CAN BUS LINE FOR SHORT TO GND (ECM MAIN BUS LINE)

(a) Disconnect the J31 ECM main bus line connector from the junction connector B side.

NOTICE:

  • Before disconnecting the connector, make a note of where it is connected.
  • Reconnect the connector to its original position.

(b) Measure the resistance of the DLC3.

Standard resistance:

Tester Connection

Condition

Specified Condition

D8-6 (CANH) - D8-4 (CG)

Ignition switch OFF

3 kΩ or higher

D8-14 (CANL) - D8-4 (CG)

Ignition switch OFF

3 kΩ or higher
OK

GO TO STEP 8

NG

4.

CONNECT CONNECTOR

(a) Reconnect the J31 ECM main bus line connector to the junction connector B side.

NEXT

5.

CHECK CAN BUS LINE FOR SHORT TO GND (GATEWAY ECU MAIN BUS LINE)

(a) Disconnect the J32 gateway ECU sub bus line connector from the junction connector B side.

NOTICE:

  • Before disconnecting the connector, make a note of where it is connected.
  • Reconnect the connector to its original position.

(b) Measure the resistance of the DLC3.

Standard resistance:

Tester Connection

Condition

Specified Condition

D8-6 (CANH) - D8-4 (CG)

Ignition switch OFF

3 kΩ or higher

D8-14 (CANL) - D8-4 (CG)

Ignition switch OFF

3 kΩ or higher
OK

GO TO STEP 10

NG

6.

CONNECT CONNECTOR

(a) Reconnect the J32 gateway ECU main bus line connector to the junction connector B side.

NEXT

7.

CHECK CAN BUS LINE FOR SHORT TO GND (TRANSLATE ECU SUB BUS LINE)

(a) Disconnect the T39 translate ECU connector.

(b) Measure the resistance of the DLC3.

Standard resistance:

Tester Connection

Condition

Specified Condition

D8-6 (CANH) - D8-4 (CG)

Ignition switch OFF

3 kΩ or higher

D8-14 (CANL) - D8-4 (CG)

Ignition switch OFF

3 kΩ or higher
OK

REPLACE TRANSLATE ECU

NG

REPAIR OR REPLACE TRANSLATE ECU SUB BUS LINE AND CONNECTOR (CAN-H, CAN-L)

8.

CONNECT CONNECTOR

(a) Reconnect the J31 ECM main bus line connector to the junction connector B side.

NEXT

9.

CHECK CAN BUS LINE FOR SHORT TO GND (ECM MAIN BUS LINE)

(a) Disconnect the E9 ECM connector.

(b) Measure the resistance of the DLC3.

Standard resistance:

Tester Connection

Condition

Specified Condition

D8-6 (CANH) - D8-4 (CG)

Ignition switch OFF

3 kΩ or higher

D8-14 (CANL) - D8-4 (CG)

Ignition switch OFF

3 kΩ or higher
OK

REPLACE ECM

NG

REPAIR OR REPLACE ECM MAIN BUS LINE AND CONNECTOR (CAN-H, CAN-L)

10.

CONNECT CONNECTOR

(a) Reconnect the J32 gateway ECU main bus line connector to the junction connector B side.

NEXT

11.

CHECK CAN BUS LINE FOR SHORT TO GND (GATEWAY ECU MAIN BUS LINE)

(a) Disconnect the G5 gateway ECU connector.

(b) Measure the resistance of the DLC3.

Standard resistance:

Tester Connection

Condition

Specified Condition

D8-6 (CANH) - D8-4 (CG)

Ignition switch OFF

3 kΩ or higher

D8-14 (CANL) - D8-4 (CG)

Ignition switch OFF

3 kΩ or higher
OK

REPLACE GATEWAY ECU

NG

REPAIR OR REPLACE GATEWAY ECU MAIN BUS LINE AND CONNECTOR (CAN-H, CAN-L)