Toyota Corolla Cross Owners & Service Manuals

Toyota Corolla Cross: Lost Communication With Brake System Control Module Missing Message (U012987)

Toyota Corolla Cross (2022-2025) Service Manual / Drivetrain / K120f (cvt) / Continuously Variable Transaxle System / Lost Communication With Brake System Control Module Missing Message (U012987)

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

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

    GTS 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

  • Check that no DTCs are stored after performing initialization.

    Click here

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) Enter the following menus:

Powertrain > Transmission > Trouble Codes

(b) Read the DTCs using the GTS.

Result

Proceed to

DTC U012987 is not output

A

DTC U012987 is output

B
A

CHECK FOR INTERMITTENT PROBLEMS

Click here

Click here

B

GO TO CAN COMMUNICATION SYSTEM

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