OBD-II code · Powertrain (generic)
P0091 Fuel Pressure Regulator A Control Circuit Low
Fuel pressure regulator A control voltage below expected range — 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 P0091?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyWiring shorted to ground
- Less likelyConnector pins corroded - high contact resistance
- Less likelyHarness chafing through insulation
Symptoms
- Check engine light on
- Hard start, no start, or stalling under load
- Power loss especially at high load or rpm
- Possible long cranking time
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–3 h
- Emissions test
- Likely to fail
- Parts involved
- Fuel Pressure Regulator, Regulator Wiring
Related codes
- P233BFuel Pressure Regulator C Control Circuit Low
- P2C03Fuel Pressure Regulator D Control Circuit Low
- P008EFuel Cooler Pump Control Circuit High
- P008FEngine Coolant Temperature/Fuel Temperature Correlation
- P0090Fuel Pressure Regulator A Control Circuit/Open
- P0092Fuel Pressure Regulator A Control Circuit High
- P0093Fuel System Leak Detected - Large Leak
- P0094Fuel System Leak Detected - Small Leak
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.