P21BECold Start Cylinder 9 Injection Timing
- 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
- A ninth cylinder exists only on V10, V12 and W12 engines, so P21BE is limited to a handful of models. Petrol engines in this class with direct injection include the 5.2-litre V10 of Lamborghini and Audi (Huracán, R8, S6 and S8) and the 6.3-litre W12 FSI of the Audi A8, which feeds its injectors from two high-pressure pumps and two rails. Whether their engine modules use P21BE is not documented publicly, and no other manufacturer source names the code. Its meaning follows from the series: during the cold-start heating phase the injection timing of cylinder 9 deviated from its target, a fault CARB wants reported apart from warm-engine faults. There is no cold-start injection pulse code beyond cylinder 8. Related: P021C (warm), P0209, P0309.
- What you may notice
- Check engine light after cold starts
- Slightly uneven idle while the engine is cold
- Likely causes
- LikelyDirect injector of cylinder 9 with deposits or slow response
- PossibleWiring or connector fault at injector 9
- RareLow pressure on the rail feeding cylinder 9 (engines with two rails)
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €200 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.