Last Modified: 07-31-2024 6.11:8.1.0 Doc ID: RM100000001GMAZ
Model Year Start: 2020 Model: GR Corolla Prod Date Range: [01/2019 - 09/2019]
Title: NETWORKING: CAN COMMUNICATION SYSTEM (for Gasoline Model): DCM Communication Stop Mode; 2020 MY Corolla Corolla Hatchback GR Corolla [01/2019 - 09/2019]

DCM Communication Stop Mode

DESCRIPTION

Detection Item

Symptom

Trouble Area

DCM Communication Stop Mode

Any of the following conditions are met:

  • Communication stop for "DCM" is indicated on the "Communication Bus Check" screen of the Techstream.

    Click here 2019 - 2022 MY Corolla Corolla Hatchback GR Corolla [06/2018 - 09/2022]; NETWORKING: CAN COMMUNICATION SYSTEM (for Gasoline Model): PROBLEM SYMPTOMS TABLE

  • Communication stop history for "DCM" is indicated on the "Communication Bus Check (Detail)" screen of the Techstream. (The Lost Communication Time value for "DCM" is 6 or more.)

    Click here 2019 - 2022 MY Corolla Corolla Hatchback GR Corolla [06/2018 - 09/2022]; NETWORKING: CAN COMMUNICATION SYSTEM (for Gasoline Model): PROBLEM SYMPTOMS TABLE

  • Communication system DTCs (DTCs that start with U) that correspond to "DCM Communication Stop Mode" in "DTC Combination Table" are output.

    Click here 2020 MY Corolla Corolla Hatchback GR Corolla [01/2019 - 09/2019]; NETWORKING: CAN COMMUNICATION SYSTEM (for Gasoline Model): DTC COMBINATION TABLE

  • DCM (telematics transceiver) branch line or connector
  • Power source circuit of DCM (telematics transceiver)
  • DCM (telematics transceiver) ground circuit
  • DCM (telematics transceiver)

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 10 minutes 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 2020 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 - 03/2019]; INTRODUCTION: REPAIR INSTRUCTION: INITIALIZATION 2020 MY Corolla Corolla Hatchback Corolla HV GR Corolla [03/2019 - 09/2019]; INTRODUCTION: REPAIR INSTRUCTION: INITIALIZATION

  • 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

  • Inspect the fuses for circuits related to this system before performing the following procedure.
  • Before replacing the DCM (telematics transceiver), refer to Registration.*

    Click here 2020 MY Corolla Corolla Hatchback GR Corolla [01/2019 - 09/2019]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function, Gasoline Model): REGISTRATION

    • *: w/ Smart Key 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 BUS LINES (DCM (TELEMATICS TRANSCEIVER) BRANCH LINE)

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

(b) Disconnect the I72 DCM (telematics transceiver) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

I72-15 (CANP) - I72-16 (CANN)

Cable disconnected from negative (-) battery terminal

54 to 69 Ω

*a

Front view of wire harness connector

(to DCM (Telematics Transceiver))
NG

REPAIR OR REPLACE CAN BRANCH LINES OR CONNECTOR (DCM (TELEMATICS TRANSCEIVER))
OK

2.

CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

I72-4 (E) - Body ground

Cable disconnected from negative (-) battery terminal

Below 1 Ω

*a

Front view of wire harness connector

(to DCM (Telematics Transceiver))

(b) Reconnect the cable to the negative (-) battery terminal.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

I72-1 (+B) - Body ground

Always

11 to 14 V

I72-7 (IG2) - Body ground

Ignition switch ON

11 to 14 V

I72-8 (ACC) - Body ground

Ignition switch ACC

11 to 14 V
OK

REPLACE DCM (TELEMATICS TRANSCEIVER)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)