DTC Advanced Diagnostics: U0029
DTC U0029:F-CAN Malfunction (BUS-OFF (Powertrain Control Module (PCM)))

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). The busoff error is checked for CAN bus node. If a permanent busoff defection is detected, the powertrain control module (PCM) detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type
Execution
Continuous
Sequence
None
Duration
1 second or more
DTC Type
One drive cycle, MIL on

Enable Conditions
Condition
Minimum
Maximum
Elapsed time since the 12 volt battery voltage reaches to a specified value
5.0 seconds
–
12 volt battery voltage [Battery]
10.04 V
–
Vehicle
ON mode
[ ]: HDS Parameter

Malfunction Threshold
Busoff error status for CAN node is set 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*1, F-CAN A_H*2 line open
F-CAN circuit F-CAN_L*1, F-CAN A_L*2 line open
F-CAN circuit F-CAN_H*1, F-CAN A_H*2 line short to ground
F-CAN circuit F-CAN_L*1, F-CAN A_L*2 line short to ground
PCM internal circuit failure

*1: Without CAN gateway
*2: With CAN gateway

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 PCM 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.