Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM100000001GMB3
Model Year Start: 2020 Model: GR Corolla Prod Date Range: [01/2019 - 09/2022]
Title: NETWORKING: CAN COMMUNICATION SYSTEM (for Gasoline Model): Open in Bus 2 Main Bus Line; 2020 - 2022 MY Corolla Corolla Hatchback GR Corolla [01/2019 - 09/2022]

Open in Bus 2 Main Bus Line

DESCRIPTION

There may be an open circuit in one of the CAN main bus lines when the resistance between terminals 18 (CA4H) and 17 (CA4L) of the central gateway ECU (network gateway ECU) is 70 Ω or higher.

Symptom

Trouble Area

Resistance between terminals 18 (CA4H) and 17 (CA4L) 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)
  • ECM
  • No. 4 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.

    Click here 2019 - 2022 MY Corolla Corolla Hatchback GR Corolla [06/2018 - 09/2022]; NETWORKING: CAN COMMUNICATION SYSTEM (for Gasoline Model): HOW TO PROCEED WITH TROUBLESHOOTING

  • 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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  • 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 2020 MY Corolla Corolla Hatchback GR Corolla [01/2019 - 03/2019]; NETWORKING: CAN COMMUNICATION SYSTEM (for Gasoline Model): DIAGNOSIS SYSTEM 2020 MY Corolla Corolla Hatchback GR Corolla [03/2019 - 09/2019]; NETWORKING: CAN COMMUNICATION SYSTEM (for Gasoline Model): DIAGNOSIS SYSTEM 2020 MY Corolla Corolla Hatchback GR Corolla [09/2019 - 04/2020]; NETWORKING: CAN COMMUNICATION SYSTEM (for Gasoline Model): DIAGNOSIS SYSTEM 2021 - 2022 MY Corolla Corolla Hatchback GR Corolla [04/2020 - 09/2022]; NETWORKING: CAN COMMUNICATION SYSTEM (for Gasoline Model): DIAGNOSIS SYSTEM

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 MAIN BUS LINES (NO. 4 CAN JUNCTION CONNECTOR)

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

(b) Disconnect the I95 No. 4 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. 4 CAN Junction Connector)

*b

to Central gateway ECU (network gateway ECU)

*c

to ECM

-

-

Standard Resistance:

Tester Connection

Condition

Specified Condition

Connected to

I95-9 (CANH) - I95-20 (CANL)

Cable disconnected from negative (-) battery terminal

108 to 132 Ω

Central gateway ECU (network gateway ECU)

I95-10 (CANH) - I95-21 (CANL)

Cable disconnected from negative (-) battery terminal

108 to 132 Ω

ECM

Result

Proceed to

OK

A

NG (Line to ECM (for M20A-FKS))

B

NG (Line to ECM (for 2ZR-FAE))

C

NG (Line to central gateway ECU (network gateway ECU))

D
A

REPLACE NO. 4 CAN JUNCTION CONNECTOR
C

GO TO STEP 3

D

GO TO STEP 4

B

2.

CHECK FOR OPEN IN CAN MAIN BUS LINES (ECM - NO. 4 CAN JUNCTION CONNECTOR)

(a) Reconnect the I95 No. 4 CAN junction connector.

(b) Disconnect the A47 ECM connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A47-8 (CANH) - A47-18 (CANL)

Cable disconnected from negative (-) battery terminal

108 to 132 Ω

*a

Front view of wire harness connector

(to ECM)
OK

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NG

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

3.

CHECK FOR OPEN IN CAN MAIN BUS LINES (ECM - NO. 4 CAN JUNCTION CONNECTOR)

(a) Reconnect the I95 No. 4 CAN junction connector.

(b) Disconnect the A46 ECM connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A46-13 (CANH) - A46-26 (CANL)

Cable disconnected from negative (-) battery terminal

108 to 132 Ω

*a

Front view of wire harness connector

(to ECM)
OK

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NG

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

4.

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

(a) Reconnect the I95 No. 4 CAN junction connector.

(b) Disconnect the I53 central gateway ECU (network gateway ECU) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

I53-18 (CA4H) - I53-17 (CA4L)

Cable disconnected from negative (-) battery terminal

108 to 132 Ω

*a

Front view of wire harness connector

(to Central Gateway ECU (Network Gateway ECU))
OK

REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)

NG

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