DTC Advanced Diagnostics: U0029-00
DTC U0029-00:CAN Gateway F-CAN ch A Bus Off

General Description

The CAN gateway performs self-diagnosis to detect the state where the CAN frame cannot be sent due to failure in the F-CAN line. If the bus-off occurs due to open and short circuit in the F-CAN line is detected for a prescribed time, the CAN gateway detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type
Execution
Continuous
Sequence
None
Duration
6 seconds or more
DTC Type
One drive cycle, MIL on or off (CAN gateway does not output MIL on/off request)

Enable Conditions
Condition
Minimum
Maximum
Elapsed time since the 12 volt battery voltage reaches to a specified value after the vehicle condition is turned to the ON mode
5 seconds
–
12 volt battery voltage [BATTERY]
10 V
–
[ ]: HDS Parameter

Malfunction Threshold
One of these conditions is met:
The F-CAN A line bus-off continues for at least 6 seconds.
The CAN frame transmission to the F-CAN A line does not complete within 6 seconds.

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.
CAN gateway F-CAN A_H line open (include connector loose connection or disconnection)
CAN gateway F-CAN A_L line open (include connector loose connection or disconnection)
CAN gateway F-CAN A_H line short to CAN gateway F-CAN A_L line
CAN gateway F-CAN A_H line short to ground
CAN gateway F-CAN A_L line short to ground
CAN gateway internal circuit short
Unit communicating on F-CAN A failure

Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected, a Pending DTC, a Confirmed DTC, and the freeze data are stored in the CAN gateway memory.

Conditions for clearing the DTC
The Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command.