P06FCGlow Plug Control Module 2 to PCM Communication Circuit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- P06FC means the feedback or communication from glow plug control module 2 to the engine module is missing, or the line is open or shorted – the counterpart of P0683 for module 1. Depending on design the module reports over a single feedback wire (Bosch-type systems expect it inverse to the command line) or over the bus; GM and Ford report a lost bus link as U0106 rather than P0683. No manufacturer document available to us uses a second glow module – Ford's and GM's V8 diesels drive all eight plugs from one; the code suits systems with one module per cylinder bank. The description follows module 1 (P0683). The engine module then loses the plug status reports; implausible messages are P06FD. The plugs of module 2 then heat poorly or not at all, typically on one bank.
- What you may notice
- Check engine light, possibly glow plug/wait-to-start lamp
- Hard cold start, long cranking in frost
- Rough cold idle and white smoke, often one cylinder bank only
- Usually no symptoms when warm
- Likely causes
- LikelyFeedback or bus line open or shorted, connector corroded
- PossibleGlow module 2 without supply (does not transmit)
- RareGlow module 2 or engine module interface faulty
- 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.