Communication Bus "B" Performance
The secondary communication bus (Bus B, often a chassis or comfort sub-bus) shows reduced performance — high error rate, intermittent dropouts, or framing errors. Bus is still alive but unreliable.
Affected components
- Can bus wiring
- Can terminating resistor
Common causes
- High likelihood: Marginal wiring or corroded connector
- Medium likelihood: EMI interference (aftermarket equipment)
- Low likelihood: Gateway module routing CAN messages incorrectly
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
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.