Toyota Yaris: Sfi System / Lost Communication with Brake System Control Module Missing Message (U012987)

Toyota Yaris XP210 (2020-2025) Reapir and Service Manual / Engine & Hybrid System / G16e-gts (engine Control) / Sfi System / Lost Communication with Brake System Control Module Missing Message (U012987)

MONITOR DESCRIPTION

The ECM and skid control ECU (brake actuator assembly) send and receive signals via CAN communication.

If a communication error occurs between the ECM and skid control ECU (brake actuator assembly), the ECM stores this DTC.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Note

U012987

Lost Communication with Brake System Control Module Missing Message

All of the following conditions are met for 2.2 seconds or more (1 trip detection logic):

  • Ignition switch ON
  • Auxiliary battery voltage is 10 V or higher
  • No communication between ECM and skid control ECU (brake actuator assembly)
  • CAN communication system
  • Skid control ECU (brake actuator assembly)
  • ECM

-

SAE: U0129

MONITOR STRATEGY

Frequency of Operation

Continuous

CONFIRMATION DRIVING PATTERN

  1. Connect the GTS to the DLC3.
  2. Turn the ignition switch to ON.
  3. Turn the GTS on.
  4. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
  5. Turn the ignition switch off and wait for at least 30 seconds.
  6. Turn the ignition switch to ON.
  7. Turn the GTS on.
  8. Wait 5 seconds or more.
  9. Enter the following menus: Powertrain / Engine / Trouble Codes.
  10. Read the pending DTCs.

    HINT:

    • If a pending DTC is output, the system is malfunctioning.
    • If a pending DTC is not output, perform the following procedure.
  11. Enter the following menus: Powertrain / Engine / Utility / All Readiness.
  12. Input the DTC: U012987.
  13. 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

    HINT:

    • If the judgment result shows NORMAL, the system is normal.
    • If the judgment result shows ABNORMAL, the system is malfunctioning.

CAUTION / NOTICE / HINT

HINT:

Read freeze frame data using the GTS. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE

1.

CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC U012987)

(a) Perform the Health Check using the GTS.

(b) Read the DTCs.

Result

Proceed to

U012987 is output

A

U012987 and other DTCs are output

B

HINT:

If any DTCs other than U012987 are output, troubleshoot those DTCs first.

A

GO TO CAN COMMUNICATION SYSTEM

B

GO TO DTC CHART

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