Network
generic / SAE
U0173
Communication Bus "C" Off
A control module has detected that bus C is non-functional and shut its bus C interface off. Bus C is typically a tertiary segment used for diagnostics or specialized subsystems; modules on the segment fall silent simultaneously.
SystemNetwork
Typegeneric / SAE
GroupU0
Range / number1 / 73
Possible causes
- Bus C shorted to supply or ground high
- One failing module pulling bus C down medium
- Gateway module routing CAN messages incorrectly low
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Inspection / repair
- Difficulty: hard
- DIY: shop recommended
- Estimated cost: 80–1500 €
- Estimated time: 1–8 h
- Component: can bus wiring
- Component: control module
- MIL / check engine light
- limp mode possible
Sources
References
sae:J2012
iso:11898