Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM1000000028EL7
Model Year Start: 2023 Model: Corolla Hatchback Prod Date Range: [11/2022 -           ]
Title: K120 / K121 (CVT): K120 CONTINUOUSLY VARIABLE TRANSAXLE SYSTEM: U012987; Lost Communication With Brake System Control Module Missing Message; 2023 - 2025 MY Corolla Corolla Hatchback [11/2022 -        ]

DTC

U012987

Lost Communication With Brake System Control Module Missing Message

DESCRIPTION

The TCM receives signals from the skid control ECU via CAN communication. When DTCs indicating a CAN communication system malfunction are output, repair the CAN communication system before performing troubleshooting for each corresponding ECU or sensor.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

Note

U012987

Lost Communication With Brake System Control Module Missing Message

No communication between the TCM and skid control ECU (brake actuator assembly) for 2.2 seconds or more (1-trip logic)
  • CAN communication system
  • Skid control ECU (Brake actuator assembly)
  • TCM
  • for Mexico Models: Comes on
  • except Mexico Models: Does not come on

DTC stored

SAE Code:

U0129

CONFIRMATION DRIVING PATTERN

HINT:

After repairs have been completed, clear the DTCs and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.

  1. Connect the Techstream to the DLC3.
  2. Turn the engine switch on (IG) and turn the Techstream on.
  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
  4. Turn the engine switch off and wait for 3 minutes or more.
  5. Turn the engine switch on (IG) and turn the Techstream on.
  6. Wait for 5 seconds or more with the engine switch on (IG).
  7. Enter the following menus: Powertrain / Transmission / Utility / All Readiness.
  8. Input the DTC: U012987.
  9. Check the DTC judgment result.

    Techstream Display

    Description

    NORMAL
    • DTC judgment completed
    • System normal

    ABNORMAL
    • DTC judgment completed
    • System abnormal

    INCOMPLETE
    • DTC judgment not completed
    • Perform driving pattern after confirming DTC enabling conditions

    N/A
    • Unable to perform DTC judgment
    • Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

    HINT:

    • If the judgment result shows NORMAL, the system is normal.
    • If the judgment result shows ABNORMAL, the system has a malfunction.
    • If the judgment result shows INCOMPLETE or N/A, perform the Confirmation Driving Pattern and check the DTC judgment result again.

CAUTION / NOTICE / HINT

NOTICE:

  • Perform registration and/or initialization when parts related to the continuously variable transaxle system are replaced.

    Click here 2023 - 2025 MY Corolla Corolla Hatchback [11/2022 -        ]; K120 / K121 (CVT): K120 CONTINUOUSLY VARIABLE TRANSAXLE SYSTEM: PRECAUTION

  • Check that no DTCs are stored after performing initialization.

    Click here 2023 - 2025 MY Corolla Corolla Hatchback [11/2022 -        ]; K120 / K121 (CVT): K120 CONTINUOUSLY VARIABLE TRANSAXLE SYSTEM: DTC CHECK / CLEAR

PROCEDURE

1.

CLEAR DTC AND PERFORM ROAD TEST

(a) Clear the DTCs.

Powertrain > Transmission > Clear DTCs

HINT:

Write down the currently output DTCs before clearing them.

(b) Start the engine and drive the vehicle at a low speed.

NEXT

2.

CHECK DTC OUTPUT (DTC U012987)

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Transmission / Trouble Codes.

Powertrain > Transmission > Trouble Codes

(e) Read the DTCs using the Techstream.

Result

Proceed to

DTC U012987 is not output

A

DTC U012987 is output

B
A

CHECK FOR INTERMITTENT PROBLEMS

B

GO TO CAN COMMUNICATION SYSTEM 2023 MY Corolla Corolla Hatchback GR Corolla [11/2022 - 03/2023]; NETWORKING: CAN COMMUNICATION SYSTEM (for Gasoline Model): DIAGNOSIS SYSTEM 2023 MY Corolla Corolla Hatchback GR Corolla [03/2023 - 08/2023]; NETWORKING: CAN COMMUNICATION SYSTEM (for Gasoline Model): DIAGNOSIS SYSTEM 2024 - 2025 MY Corolla Corolla Hatchback GR Corolla [08/2023 -        ]; NETWORKING: CAN COMMUNICATION SYSTEM (for Gasoline Model): DIAGNOSIS SYSTEM