Toyota Tundra Service Manual: Open in Bus 1 Main Bus Line

Toyota Tundra Service Manual / Power Source, Network / Can Communication / Can Communication System / Open in Bus 1 Main Bus Line

DESCRIPTION

There may be an open circuit in one of the CAN main bus lines when the resistance between terminals 23 (CA1H) and 8 (CA1L) of the central gateway ECU (network gateway ECU) is 70 Ω or higher.

Symptom

Trouble Area

Resistance between terminals 23 (CA1H) and 8 (CA1L) of the central gateway ECU (network gateway ECU) is 70 Ω or higher.
  • CAN main bus lines or connector
  • Central gateway ECU (network gateway ECU)
  • No. 1 CAN junction terminal
  • No. 1 CAN junction connector
  • No. 2 CAN junction connector
  • No. 7 CAN junction connector

This malfunction is not related to the lines of a CAN branch or to ECUs or sensors connected to a CAN branch.

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.

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  • 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.

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  • Some parts must be initialized and set when replacing or removing and installing parts.

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  • 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 OPEN IN CAN BUS WIRE (NO. 1 CAN JUNCTION CONNECTOR)

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

(b) Disconnect the No. 1 CAN junction connector.

*a

Front view of wire harness connector

(to No. 1 CAN Junction Connector)

*b

to No. 7 CAN Junction Connector

*c

to No. 2 CAN Junction Connector

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

Connected to

A72-2 (CANH) - A72-4 (CANL)

Cable disconnected from negative (-) battery terminal

108 to 132 Ω

No. 7 CAN junction connector

A72-6 (CANH) - A72-7 (CANL)

Cable disconnected from negative (-) battery terminal

108 to 132 Ω

No. 2 CAN junction connector

Result

Proceed to

OK

A

NG (No. 7 CAN junction connector CAN main wire)

B

NG (No. 2 CAN junction connector CAN main wire)

C
A

REPLACE NO. 1 CAN JUNCTION CONNECTOR
C

GO TO STEP 6

B

2.

CONNECT CONNECTOR

(a) Reconnect the A72 No. 1 CAN junction connector.

NEXT

3.

CHECK FOR OPEN IN CAN BUS WIRE (NO. 7 CAN JUNCTION CONNECTOR)

(a) Disconnect the No. 7 CAN junction connector.

*a

Front view of wire harness connector

(to No. 7 CAN Junction Connector)

*b

to No. 1 CAN Junction Terminal

*c

to No. 1 CAN Junction Connector

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

Connected to

R17-1 (CANH) - R17-4 (CANL)

Cable disconnected from negative (-) battery terminal

108 to 132 Ω

No. 1 CAN junction terminal

R17-2 (CANH) - R17-3 (CANL)

Cable disconnected from negative (-) battery terminal

108 to 132 Ω

No. 1 CAN junction connector

Result

Proceed to

OK

A

NG (No. 1 CAN junction terminal CAN main wire)

B

NG (No. 1 CAN junction connector CAN main wire)

C
A

REPLACE NO. 7 CAN JUNCTION CONNECTOR
C

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 7 CAN JUNCTION CONNECTOR - NO. 1 CAN JUNCTION CONNECTOR)
B

4.

CONNECT CONNECTOR

(a) Reconnect the R17 No. 7 CAN junction connector.

NEXT

5.

CHECK FOR OPEN IN CAN BUS WIRE (NO. 1 CAN JUNCTION TERMINAL - NO. 7 CAN JUNCTION CONNECTOR)

(a) Disconnect the No. 1 CAN junction terminal connector.

*a

Front view of wire harness connector

(to No. 1 CAN Junction Terminal)

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A73-3 (CANH) - A73-2 (CANL)

Cable disconnected from negative (-) battery terminal

108 to 132 Ω
OK

REPLACE NO. 1 CAN JUNCTION TERMINAL
NG

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 1 CAN JUNCTION TERMINAL - NO. 7 CAN JUNCTION CONNECTOR)

6.

CONNECT CONNECTOR

(a) Reconnect the A72 No. 1 CAN junction connector.

NEXT

7.

CHECK FOR OPEN IN CAN BUS WIRE (NO. 2 CAN JUNCTION CONNECTOR)

(a) Disconnect the No. 2 CAN junction connector.

*a

Front view of wire harness connector

(to No. 2 CAN Junction Connector)

*b

to No. 1 CAN Junction Connector

*c

to Central Gateway ECU (Network Gateway ECU)

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

Connected to

J187-1 (CANH) - J187-12 (CANL)

Cable disconnected from negative (-) battery terminal

108 to 132 Ω

No. 1 CAN junction connector

J187-3 (CANH) - J187-14 (CANL)

Cable disconnected from negative (-) battery terminal

108 to 132 Ω

Central gateway ECU (network gateway ECU)

Result

Proceed to

OK

A

NG (No. central gateway ECU [network gateway ECU] CAN main wire)

B

NG (No. 1 CAN junction connector CAN main wire)

C
A

REPLACE NO. 2 CAN JUNCTION CONNECTOR
C

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 2 CAN JUNCTION CONNECTOR - NO. 1 CAN JUNCTION CONNECTOR)
B

8.

CONNECT CONNECTOR

(a) Reconnect the J187 No. 2 CAN junction connector.

NEXT

9.

CHECK FOR OPEN IN CAN BUS WIRE (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 2 CAN JUNCTION CONNECTOR)

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

*a

Front view of wire harness connector

(to Central Gateway ECU [Network Gateway ECU])

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

J169-23 (CA1H) - J169-8 (CA1L)

Cable disconnected from negative (-) battery terminal

108 to 132 Ω
OK

REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)

NG

REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 2 CAN JUNCTION CONNECTOR)
    Navigation ECU Communication Stop Mode

    Open in Bus 2 Main Bus Line

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