P20CCExhaust Aftertreatment Fuel Injector A Control Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- Unlike the circuit codes, this one judges what the hydrocarbon doser actually does. On the 6.6 L Duramax LML/LGH, GM table 15OBDG09 sets it when the outlet of the oxidation catalyst runs more than 300 °C hotter than its inlet for 180 s although no regeneration is under way and more than 900 s have passed since the last one; that heat can only come from fuel the doser should not be delivering. It is a Type A fault, so the MIL comes on after one trip. To keep the nozzle free, the same GM software pulses it briefly at 100 Hz at set soot levels. CARB requires makers to flag any injection fault that stops the filter from regenerating. Stuck positions have separate codes (P20CF, P20D0).
- What you may notice
- Check engine light on
- Unexpectedly high exhaust temperatures, possibly white smoke or fuel smell
- Higher fuel consumption
- Likely causes
- LikelyDoser leaking or dribbling fuel into the exhaust while closed
- PossibleCoked nozzle tip with distorted spray
- RareExhaust temperature sensor before or after the catalyst reading wrong
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €300 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.