SFI SYSTEM, Diagnostic DTC:U0129

DTC Code	DTC Name
U0129	Lost Communication with Skid Control ECU

DESCRIPTION

The ECM and skid 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	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 with actuator assembly	Wire harness (CANL and CANH circuits) ECM Skid control ECU with actuator assembly

DTC No.

DTC Detection Conditions

Trouble Areas

U0129

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 with actuator assembly

Wire harness (CANL and CANH circuits)
ECM
Skid control ECU with actuator assembly

WIRING DIAGRAM

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 the 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.