Toyota Camry owners & service manuals

Toyota Camry (XV70): Check Bus 2 Lines for Short Circuit

Toyota Camry Repair Manual XV70 (2018-2024) / Power Source, Network / Networking / Can Communication System / Check Bus 2 Lines for Short Circuit

DESCRIPTION

There may be a short circuit between the CAN main bus lines and/or CAN branch lines when the resistance between terminals 18 (CA4H) and 17 (CA4L) of the central gateway ECU (network gateway ECU) is below 54 Ω.

Symptom

Trouble Area

Resistance between terminals 18 (CA4H) and 17 (CA4L) of the central gateway ECU (network gateway ECU) is below 54 Ω.
  • Short in CAN main bus lines
  • Central gateway ECU (network gateway ECU)
  • ECM
  • No. 2 CAN junction connector
  • No. 4 CAN junction connector

WIRING DIAGRAM

CAUTION / NOTICE / HINT

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

NOTICE:

  • Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output.

    Click here

  • Before measuring the resistance of the CAN bus, turn the ignition switch off and leave the vehicle for 1 minute or more without operating the key or any switches, or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.
  • After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.

    Click here

  • After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.

    DTC check procedure: Turn the ignition switch to ON and wait for 1 minute or more. Then operate the suspected malfunctioning system and drive the vehicle at 60 km/h (37 mph) or more for 5 minutes or more.

  • After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed as normal.

    Click here

HINT:

  • Before disconnecting related connectors for inspection, push in on each connector body to check that the connector is not loose or disconnected.
  • When a connector is disconnected, check that the terminals and connector body are not cracked, deformed or corroded.

PROCEDURE

1.

CHECK FOR SHORT IN CAN BUS LINES (NO. 2 CAN JUNCTION CONNECTOR)

(a) Disconnect the cable from the negative (-) battery terminal.

(b) Disconnect the A67 No. 2 CAN junction connector.

(c) Measure the resistance according to the value(s) in the table below.

*a

Front view of wire harness connector

(to No. 2 CAN Junction Connector)

*b

to No. 4 CAN Junction Connector

*c

to ECM

-

-

Standard Resistance:

Tester Connection

Condition

Specified Condition

Connected to

A67-10 (CANH) - A67-21 (CANL)

Cable disconnected from negative (-) battery terminal

108 to 132 Ω

No. 4 CAN junction connector

A67-11 (CANH) - A67-22 (CANL)

Cable disconnected from negative (-) battery terminal

108 to 132 Ω

ECM

Result

Proceed to

OK

A

NG (Line to ECM)

B

NG (Line to No. 4 CAN junction connector)

C
A

REPLACE NO. 2 CAN JUNCTION CONNECTOR
C

GO TO STEP 3

B

2.

CHECK FOR SHORT IN CAN BUS LINES (NO. 2 CAN JUNCTION CONNECTOR - ECM)

(a) Disconnect the A21 or A24 ECM connector.

(b) Measure the resistance according to the value(s) in the table below.

*a

Front view of wire harness connector

(to No. 2 CAN Junction Connector)

*b

to ECM

Standard Resistance:

Tester Connection

Condition

Specified Condition

A67-11 (CANH) - A67-22 (CANL)

Cable disconnected from negative (-) battery terminal

1 MΩ or higher

Result

Proceed to

OK (for A25A-FKS)

A

OK (for 2GR-FKS)

B

NG

C
A

REPLACE ECM

B

REPLACE ECM

C

REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 2 CAN JUNCTION CONNECTOR - ECM)

3.

CHECK FOR SHORT IN CAN BUS LINES (NO. 4 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION CONNECTOR)

(a) Disconnect the K128 No. 4 CAN junction connector.

(b) Measure the resistance according to the value(s) in the table below.

*a

Front view of wire harness connector

(to No. 4 CAN Junction Connector)

*b

to No. 2 CAN Junction Connector

Standard Resistance:

Tester Connection

Condition

Specified Condition

Connected to

K128-11 (CANH) - K128-22 (CANL)

Cable disconnected from negative (-) battery terminal

1 MΩ or higher

No. 2 CAN junction connector
NG

REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 4 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION CONNECTOR)
OK

4.

CHECK FOR SHORT IN CAN BUS LINES (NO. 4 CAN JUNCTION CONNECTOR)

(a) Disconnect the K127 No. 4 CAN junction connector.

(b) Measure the resistance according to the value(s) in the table below.

*a

Front view of wire harness connector

(to No. 4 CAN Junction Connector)

*b

to Central Gateway ECU (Network Gateway ECU)

Standard Resistance:

Tester Connection

Condition

Specified Condition

Connected to

K127-1 (CANH) - K127-12 (CANL)

Cable disconnected from negative (-) battery terminal

108 to 132 Ω

Central gateway ECU (network gateway ECU)
OK

REPLACE NO. 4 CAN JUNCTION CONNECTOR
NG

5.

CHECK FOR SHORT IN CAN BUS LINES (NO. 4 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

(a) Disconnect the K76 central gateway ECU (network gateway ECU) connector.

(b) Measure the resistance according to the value(s) in the table below.

*a

Front view of wire harness connector

(to No. 4 CAN Junction Connector)

*b

to Central Gateway ECU (Network Gateway ECU)

Standard Resistance:

Tester Connection

Condition

Specified Condition

K127-1 (CANH) - K127-12 (CANL)

Cable disconnected from negative (-) battery terminal

1 MΩ or higher
OK

REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)

NG

REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 4 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

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