P2A40
Alternative Fuel System - Injector Leakage to Rail Detected
The AFCM detects pressure decay in the alternative fuel rail consistent with injector leakage. Even with all injectors commanded closed, fuel flows back into the rail.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: hard
Common causes
Ordered by how often each turns out to be the cause.
- Injector seat worn - leaks closedCommon
- Injector seal aged - external leak pathPossible
Parts involved
- Alt Fuel Injectors
- Alt Fuel Rail
P2A40 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.