P2DD5Fuel Injection Quantity B Lower Than Expected
- 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
- P2DD5 reports that the injection path the manufacturer calls B delivers less fuel than the engine control commanded. SAE leaves open what B is: a second injector set, an injector group or a separate operating mode. No manufacturer documents this code publicly. The underlying check is the one CARB has demanded from diesels since 2010: the module compares requested fuel with what airflow and lambda say was burned. GM does this for system A as an adaptation (FSA) with a lower threshold map, 200 of 400 samples, Type B; Ford diesels report a fueling error below -0.15 as P0171. P2DD6 is the opposite direction, P2DD7 the cold-start version. Expect weak pull and possibly rough running.
- What you may notice
- Check engine light on
- Less power, sluggish response under load
- Uneven idle
- Likely causes
- LikelyInjectors of group B coked or partly blocked
- PossibleSupply or rail pressure for this path too low (filter, pump)
- PossibleAirflow or lambda measurement off, so the computed fuel looks too small
- RareEngine control software or injector calibration data
- 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: €100 – €3,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.