P069BCylinder 9 Glow Plug Control Circuit High
- 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
- Modern diesel glow systems switch each glow plug through its own power semiconductor (in a glow plug module or the engine module), so current and faults can be measured per plug; a faulty channel is switched off. CARB requires glow plugs to be checked for correct current and voltage drop and, since model year 2010, a single plug outside specification to be detected and named. P069B means the circuit to the cylinder 9 glow plug is shorted to battery voltage, so the driver cannot switch it off. GM's engine-module drivers detect an impedance to the supply below 0.5 Ω (0.14 Ω for low-resistance plugs) in 10 of 20 samples, lamps after two trips; Ford's 2023 Power Stroke sees 0 A in its measuring path while the plug is commanded on. A permanently powered plug can overheat and burn through. No manufacturer document available to us uses this code for cylinders 9 and above; the description follows cylinders 1–8.
- What you may notice
- Check engine and glow plug lamp
- Plug permanently powered, possible battery drain
- Plug burns through, then an open-circuit code
- Likely causes
- LikelyCylinder 9 plug wire touching battery positive (chafing in the harness)
- PossibleMoisture or corrosion in the module or plug connector
- PossibleDriver in the glow or engine module shorted (permanently on)
- RareGlow module software (GM bulletins)
- 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: €60 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.