DTC U0056-00 (CAN Gateway)
DTC U0056-00: CAN Gateway F-CAN ch C 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 an open or a 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 C line bus-off continues for at least 6 seconds.
- The CAN frame transmission to the F-CAN C 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 C_H line open (includes a loose or disconnected connector)
- CAN gateway F-CAN C_L line open (includes a loose or disconnected connector)
- CAN gateway F-CAN C_H line short to CAN gateway F-CAN C_L line
- CAN gateway F-CAN C_H line short to ground
- CAN gateway F-CAN C_L line short to ground
- CAN gateway internal circuit short
- Unit communicating on F-CAN C failure
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected, a 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.