Vehicle Communication Bus Fault
There’s an issue with the vehicle’s communication bus.
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 computer systems have trouble talking to each other, which can cause warning lights or random failures of features.
What the computer is actually seeing
If the communication bus sends incorrect data or no data at all from a module (like the body control module), it logs this fault.
What a healthy reading looks like
Normal communication voltage levels on the CAN bus should be around 2.5V in a resting state and should toggle around that when data is being transmitted.
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. Check the vehicle’s battery voltage; it should be 12.6V or higher. If low, charge or replace the battery.
- 22. Inspect all wiring and connectors involved in the CAN bus system for any damage or corrosion. Pay close attention to the grounds and power feeds.
- 33. Use a scan tool to check for related codes. Note any other communication codes or poor module data.
- 44. Verify if the issue is intermittent by wiggling the wiring harness while monitoring the data on your scan tool; note any changes.
- 55. If above checks are good, consider swapping the suspected faulty module with a known good unit to see if the code clears.
- 66. If the code doesn’t clear, further investigate the integrity of the wiring and connections leading to the module.
Common causes
- Damaged wiring harness in communication circuit
- Faulty vehicle control module
- Poor connections in connectors
- Low voltage to the control modules
- Interference from aftermarket electronics
Typical repair cost
$$ - $$$ (depending on diagnostics and module replacement if necessary)
Related codes
Frequently asked questions
Is it safe to drive with this code?
It may be drivable, but you could lose functionality in some electrical systems or features.
Will this code come back after clearing?
If the underlying issue isn’t fixed, yes, it will likely come back.
Why does this code appear with other communication codes?
Communication codes often indicate issues in the vehicle's network, with multiple systems failing to exchange data.
Working a real vehicle right now?
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