P07FFCold Start Transmission Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P07FF means the transmission does not work as expected during the cold-start phase, shortly after starting with cold, thick fluid – for example a gear preselection or a clutch or valve response outside the expected window. The only documented user is Mercedes-Benz: its 2024 bulletin for the eight-speed dual-clutch gearbox 8G-DCT in the compact models (A-Class, CLA, GLA, GLB) names P07FF together with P0921, with reverse not available, a possible limp-home mode and the MIL; after switching off and on everything works again, and the fix was new control unit software. No thresholds or trip counts are published. It is not CARB's cold-start emission strategy, which concerns engine and catalyst heating (P050A ff), but a functional check of the transmission.
- What you may notice
- Reverse not available (message in the cluster)
- Check engine lamp on
- Limp-home mode shortly after a cold start
- Normal again after switching off and on
- Likely causes
- LikelyTransmission control module software misjudging the cold phase
- PossibleShift valve or hydraulics too slow with cold fluid
- RareWrong or aged fluid, low level
- RareFluid temperature sensor reading wrong
- 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 – €300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.