Data Link Missing, ECM
The engine control module (ECM) is not communicating properly with the data link.
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What it means (plain English)
The computer in the vehicle is having trouble talking to another module, which could affect performance or diagnostics.
What the computer is actually seeing
The ECM expects to receive a signal from another module showing it is connected and communicating. When this signal is absent for more than 2 seconds, it triggers the fault code.
What a healthy reading looks like
Normal communication data should be received constantly; voltage should be steady around 5V between modules. If communication drops, the signal may fall below 0.1V.
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 wiring and connectors between the ECM and any affected modules. Look for damage, corrosion, or loose connections. Decision point: If damaged, repair or replace the wiring.
- 2Verify power and ground at the ECM with a multimeter. Expected voltage should be around 12V on the power side and 0V on the ground. Decision point: If not within expected range, address power or ground issues.
- 3Check for other fault codes; additional codes can provide clues about the nature of the communication failure. Decision point: Note other codes for further diagnostics, if present.
- 4Inspect for updates or reprogramming needed for the ECM or other modules. Sometimes, an update resolves communication issues. Decision point: Program if needed, or replace the ECM if it’s faulty and other modules are confirmed working.
Common causes
- Damaged wiring or connectors between ECM and other modules
- Faulty ECM or other connected modules
- Poor ground connections
- Intermittent faults due to moisture or corrosion
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's not recommended to drive as communication issues can lead to engine performance problems.
Will this code come back if I clear it?
Yes, if the underlying issue isn't fixed, the code will reappear.
Why does this code show up with other codes?
Communication faults often affect multiple systems, leading to multiple related codes.
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