Control Module Communication Bus "A" Off
A control module has detected that the communication bus is non-functional and has shut its bus interface off. Affects multiple modules at once because none can communicate; on most vehicles the dashboard lights up with several warning lamps simultaneously.
Affected components
- Can bus wiring
- Can terminating resistor
- Control module
Common causes
- High likelihood: CAN line shorted to supply or ground
- Medium likelihood: Terminating resistor failed
- Medium likelihood: One failing module pulling the bus down
Possible 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
Diagnostic notes
- The malfunction indicator lamp may illuminate
- Reduced-power or limp mode may occur
Related codes
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.