U049DInvalid Data Received From Glow Plug Control Module 2
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- U049D is logged when a controller, normally the engine control module, still hears from the second glow plug control module but cannot trust what it reports, for instance because a counter, checksum or plug status value is out of line. A second unit is found on diesels that split their glow plugs between two drivers. No manufacturer documents this code publicly; it mirrors U0407, which covers module 1. CARB 1968.2 obliges diesel OBD to verify that glow plugs respond to commands and draw proper current, a check the engine controller can only make with valid module data. A GM patent shows both controllers exchanging timed messages and flagging late ones as faults. U019C means the module is silent, U030B a software mismatch. Hard cold starts and a lit MIL are likely.
- What you may notice
- Check engine or glow plug warning light on
- Long cranking or misfire on cold starts
- White smoke until the engine warms up
- Likely causes
- LikelyCorroded or loose connector or data wire at glow plug module 2
- PossibleSupply voltage sagging while the glow plugs draw high current
- PossibleGlow plug control module 2 internally faulty
- RareModule or engine controller software not matched after replacement
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €80 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.