P00FFBody Control Module Requested MIL Illumination
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P00FF is an information code in the engine control module: the body control module has detected an emissions-relevant fault of its own and asks over the data bus for the check engine light. The engine module stores P00FF so that a generic OBD scanner can see why the MIL is on; the actual fault is stored in the body control module as B or U codes and must be read there. GM documents two cases – a 2020 Cadillac CT5 with climate flap actuator codes and 2025 full-size SUVs with U1962 – both cured by reprogramming the body control module, not by replacing parts. The mechanism matches other 'module requested MIL' codes such as P069E. P00FF itself causes no limp mode.
- What you may notice
- Check engine light on without an engine fault
- Other messages depending on the body module fault
- Driving behaviour unchanged
- Likely causes
- LikelyEmissions-relevant fault in the body control module or its sensors/actuators (own B/U codes)
- PossibleSoftware or calibration fault in the body control module
- RareCommunication fault on the data bus
- RareEngine control module 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: €0 – €300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.