What does P0091 mean?
This code covers the electrical circuit of the fuel pressure regulator (or fuel pressure control valve). On common-rail diesels and direct-injection gas engines, the computer controls this valve to set rail pressure.
The control circuit voltage is lower than expected, which usually means a short to ground.
Codes are a starting point. They tell you which test failed, not which part to replace. Check for other stored codes and fix those in a sensible order.
Symptoms
- Check engine light
- Hard starting
- Low power
- Stalling
Common causes
- Failed regulator or control valve
- Wiring or connector fault
- Module driver fault (rare)
How to diagnose P0091
- Check valve resistance against spec.
- Check wiring between the valve and the computer.
- Compare commanded and actual rail pressure.
How to fix it
- Repair wiring
- Replace the regulator or control valve
Estimated repair cost
Likely repairs for P0091 run from about $100 to $700, depending on the cause.
| Repair | Typical range (parts + labor) |
|---|---|
| Diagnostic fee (scan + testing) | $100 - $200 |
| Wiring/connector repair | $100 - $400 |
| Fuel volume/pressure control valve (FCA/PCV) | $200 - $700 |
These are rough US estimates for an independent shop in 2026, based on typical parts prices and standard labor times. Dealers, big trucks, luxury brands and high-cost areas often run higher. They are not quotes. Use the repair cost estimator to adjust for your vehicle.
How serious is P0091?
High severity
Get it fixed before relying on the vehicle.
P0091 FAQ
What does P0091 mean?
P0091 stands for "Fuel Pressure Regulator 1 Control Circuit Low". This code covers the electrical circuit of the fuel pressure regulator (or fuel pressure control valve).
Can I drive with a P0091 code?
Get it fixed before relying on the vehicle.
How much does it cost to fix P0091?
It depends on the cause. The likely repairs for P0091 range from about $100 to $700 at an independent shop in the US, plus a diagnostic fee of roughly $100-$200. These are rough estimates; dealer prices and some vehicles run higher.
What is the most common cause of P0091?
The most common causes are: failed regulator or control valve; wiring or connector fault; module driver fault (rare).