SFI SYSTEM, Diagnostic DTC:U0129

DTC Code DTC Name
U0129 Lost Communication with Skid Control ECU

DESCRIPTION

The ECM and transmission control ECU communicate with each other via the CAN communication line. The skid control ECU also communicates with other computers through the ECM. If there is a problem in this communication, the ECM sets the DTC.

DTC No. DTC Detection Conditions Trouble Areas
U0129*1

All of following conditions met for 2.34 seconds or more (1-trip detection logic):


  • Ignition switch ON


  • No communication between ECM and skid control ECU

  • Wire harness (CANL and CANH circuits)

  • ECM

  • Skid control ECU

WIRING DIAGRAM

A011ADTE02

INSPECTION PROCEDURE

Go to CAN communication system for troubleshooting Click here.

Tech Tips


  • When DTCs indicating a CAN communication system malfunction are output, repair the CAN communication system before repairing each corresponding sensor.

  • Read freeze frame data using an intelligent tester. 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.

  • If the CAN communication malfunctions, there is no data output from the ECM. In this case, some of the freeze frame data are not correct and not identical with the ECM data, but the ECM data are correct.