SFI SYSTEM, Diagnostic DTC:U0129

DTC Code DTC Name
U0129 Lost Communication with Skid Control ECU

DESCRIPTION

The Controller Area Network (CAN) is a serial data communication system for real time applications. This is a vehicle multiplex communication system which has a high communication speed (500 kbps) and a high level of ability to detect malfunctions. By pairing the CANH and CANL bus wires, the communication on the CAN is performed using the voltage differential between the wires.

DTC No. DTC Detection Condition Trouble Area
U0129

All of the following conditions are met for 2.22 seconds or more (1 trip detection logic):


  • (a) Ignition switch ON

  • (b) Battery voltage is 10.5 V or more

  • (c) No communication between ECM and skid control ECU

  • Wire harness (CANL and CANH circuit)

  • ECM

  • Skid control ECU

  • CAN communication system

CAUTION / NOTICE / HINT

Tech Tips

Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions when malfunctions are detected. 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 WHETHER DTC OUTPUT RECURS


    1. Connect the intelligent tester to the DLC3.

    2. Start the engine.

    3. Turn the tester on.

    4. Clear the DTCs Click here.

    5. Enter the following menus: Powertrain / Engine and ECT / DTC.

    6. Read the DTCs.

      Result
      Result Proceed to
      DTC U0129 is output A
      DTC is not output B

    A

    GO TO CAN COMMUNICATION SYSTEM Click here

    B

    CHECK FOR INTERMITTENT PROBLEMS Click here