Redundant Engine Control Module Communication Error
This code indicates an issue with the communication between engine control 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)
The engine control unit is trying to talk to another module, but something's blocking the message or causing it to be misunderstood.
What the computer is actually seeing
The main engine control module (ECM) detects a communication fault with a redundant or backup control module.
What a healthy reading looks like
Communication packets should be received within 100 milliseconds; if not received, the ECM will trigger this fault code.
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 wiring and connections between the ECM and any redundant modules. Look for broken wires, corrosion, or loose connections. If you find issues, repair them and retest.
- 22. Verify that the redundant module is powered up and operational. Check for any other fault codes in that module. If the module is not powered or is malfunctioning, replace it.
- 33. Use a scan tool to review communication data streams. Ensure that data packets are being transmitted and received without errors. If data is missing, focus on the CAN bus integrity.
- 44. If all checks are okay, consider updating or reprogramming the affected modules, as software corruption can result in communication errors.
Common causes
- Faulty wiring or poor connections in the CAN bus network
- Failed redundant module
- Intermittent faults due to vibration or temperature changes
- Insufficient power supply to one of the modules
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's moderate severity; the vehicle should be driveable but may have issues like reduced power or stability. Fix it soon.
Can this code come back after repairs?
Yes, if there's a persistent issue like intermittent wiring problems or if the new part fails.
Why does this code pair with other codes?
Multiple modules might be communicating in conjunction, and issues with one can trigger faults in others.
Working a real vehicle right now?
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