Control Module Communication Bus Off
Communication lost in the vehicle control module network.
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)
Your vehicle's computer is trying to talk to other computers and can't; it's like having a dead phone line between them.
What the computer is actually seeing
The control module detects a loss of communication with other modules, affecting systems that rely on shared data.
What a healthy reading looks like
Expected normal communication voltages are typically around 2.5V to 5V for CAN signals; anything consistently below 2.0V or above 5.0V indicates a problem.
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; ensure it's between 12.4V to 12.7V with engine off.
- 22. Inspect all related wiring and connectors for physical damage or corrosion; repair as necessary.
- 33. Using a scan tool, check for other communication codes in addition to U0005; focus on those codes first.
- 44. Check the ground connections for all involved modules; ensure they are clean and secure.
- 55. If everything checks out, go ahead and manually test the communication lines with an oscilloscope; you should see proper CAN signals.
Common causes
- Faulty control module
- Damaged wiring or connectors
- Poor ground connections
- Failed or disconnected bus lines
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's best to fix it soon; drivability may be affected and could lead to other issues.
Will this code come back?
If the underlying issue isn't resolved, yes, it likely will return.
Why does it pair with other communication codes?
Multiple codes often indicate there are issues with communication across several modules.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
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