Vehicle Communication Bus Fault
Loss of communication between modules in the vehicle.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The vehicle's different computer modules aren't talking to each other like they should, causing potential issues with features like the dashboard, lights, or safety systems.
What the computer is actually seeing
The communication bus (like CAN bus) has a fault, meaning one or more modules fail to send or receive data properly, generally observed as a continuous high or low voltage instead of the expected data messages.
What a healthy reading looks like
Data messages are expected to pulse between 0 to 5 volts typically, depending on the protocol, with regular communication intervals of milliseconds between messages.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Inspect wiring and connectors for damage or corrosion; repair as needed. Decision: If repaired, clear codes and test drive. If not, proceed to next step.
- 22. Check for blown fuses related to communication modules; replace as necessary. Decision: If fuses were blown, clear codes and test drive. If not, proceed to next step.
- 33. Use a scan tool to identify which modules are communicating; check the response from each one. Decision: If one module is not responding, replace that module. If all are responding, proceed to next step.
- 44. Test the communication bus with an oscilloscope for a proper signal; look for incorrect voltages. Decision: If a fault is found in the bus signal, repair the bus. If the signal is good, investigate further into potential software issues.
Common causes
- Corroded or damaged wiring
- Faulty connectors
- Module malfunction or failure
Typical repair cost
$100-$400
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's usually okay to drive, but it can affect safety systems like traction control or ABS.
Will the problem come back?
If the underlying issue is not resolved, it could reappear after clearing the code.
Why does this code pair with others?
Communication issues often involve multiple modules, which can trigger several codes related to various systems.
Working a real vehicle right now?
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