P06F9Glow Plug Control Module 2 System Voltage
- 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
- P06F9 means the supply voltage of glow plug control module 2 is out of range – the counterpart of P052F for module 1. For module 1, Ford's 2023 Power Stroke flags below 6.5 V, above 16.5 V or an open supply after about 1 s; GM's L5P checks the same under P163C (below 6.0 V with ignition above 9 V, or implausible against ignition voltage, 4 s). An FCA bulletin shows P052F together with the glow plug open codes, because without supply no current flows. 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 (P052F). Check main feed, fuses and ground first.
- 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
- LikelyMain feed to glow module 2 open or high-resistance (fuse, fusible link, B+ wire)
- PossibleWeak battery or discharged auxiliary battery
- PossibleModule ground corroded
- RareCharging voltage too high
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €30 – €500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.