Advanced Diagnostics

Advanced Diagnostics - DTC U0029: F-CAN Malfunction (BUS-OFF (Engine Control Module (ECM)) (PGM-FI System (Engine Type: K24Z7))

General Description






The controller area network (CAN) transmits/receives pulsing signals to/from the control modules simultaneously by using two signal lines (F_CAN-H and F_CAN-L). When the engine control module (ECM) does not receive the signals via the F-CAN lines for a set time, the ECM detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type, OBD Status






Enable Conditions






Malfunction Threshold
The ECM does not receive any signals via the F-CAN lines for at least 1 second.

Possible Cause

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.

- F-CAN circuit F_CAN-H line open
- F-CAN circuit F_CAN-L line open
- F-CAN circuit F_CAN-H line short to ground
- F-CAN circuit F_CAN-L line short to ground
- ECM internal circuit failure

Diagnosis Details

Conditions for setting the DTC
When a malfunction is detected, the MIL comes on and a Pending DTC, a Confirmed DTC, and the freeze data are stored in the ECM memory.

Conditions for clearing the DTC
The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the battery.