OBD-II code · Powertrain (generic, extended)
P20D9 Exhaust Aftertreatment Fuel Supply Control Circuit Low
Aftertreatment fuel supply control line stuck low — short to ground. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
Is it safe to drive with P20D9?
Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.
Common causes
- Most likelyShort to ground
- Less likelyConnector pins corroded - high contact resistance
- Less likelyHarness chafing through insulation
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.7–3.5 h
- Emissions test
- Likely to fail
- Parts involved
- Aftertreatment Fuel Pump
Related codes
- P20D7Exhaust Aftertreatment Fuel Supply Control Circuit/Open
- P20D6Exhaust Aftertreatment Fuel Injector B Stuck Closed
- P20D8Exhaust Aftertreatment Fuel Supply Control Performance
- P20DAExhaust Aftertreatment Fuel Supply Control Circuit High
- P20DBExhaust Aftertreatment Fuel Supply Control Stuck Open
- P20DCExhaust Aftertreatment Fuel Supply Control Stuck Closed
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.