Lost Communication with Vehicle Control Unit
The vehicle’s control unit isn’t communicating properly with other modules.
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)
There’s a problem with the data exchange between the vehicle's control modules, which can affect performance and functionality of systems like the transmission or brakes.
What the computer is actually seeing
The primary control unit detects a timeout or failure in receiving or sending data to another control unit within a specified timeframe, typically within milliseconds depending on the communication protocol.
What a healthy reading looks like
Normal communication response times should be less than 100 milliseconds for most modules.
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.
- 1Check battery voltage (12.6V or higher). If low, charge battery and re-test.
- 2Inspect wiring and connectors between affected control modules for damage or corrosion. Repair as necessary.
- 3Use a scan tool to check for other codes; if U0100 or U0140 are present, address those issues first.
- 4Check specific module’s ground and power supply, ensuring they meet manufacturer specifications.
- 5If all checks are normal and communication is still lost, consider replacing the faulty control module.
Common causes
- Damaged wiring or connectors between control modules
- Faulty control module that isn’t operating normally
- Low battery voltage affecting module communication
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive the vehicle with this code?
It’s moderate severity; drivability may be impacted so fix soon, especially if critical systems rely on the communication.
Can this code come back after repairs?
Yes, if the underlying wiring issues are not resolved or if multiple modules are faulty.
Why does this code pair with others like U0100?
Those codes often relate to similar communication failures, indicating problems with different modules.
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