P0090: Fuel Pressure Regulator 1 Control Circuit Open

What does P0090 mean?

The computer detects an open or disconnected control path for fuel pressure regulator 1. The number 1 identifies a regulator circuit, not cylinder 1 or necessarily the first pump on the vehicle.

Generic OBD-II definition: Fuel Pressure Regulator 1 Control Circuit Open. Confirm applicability in your vehicle service information.

Common causes

• Open regulator winding
• Broken control wire or unplugged connector
• Lost supply or poor terminal contact

Symptoms

• Difficult starting
• Reduced power
• Rough running or check engine light

Diagnostic focus

An open electrical path can prevent pressure control even when the pump is mechanically sound. Start with the harness before replacing the fuel-pressure hardware.

Can I keep driving with P0090?

Severity: High Avoid driving if the engine stalls, leaks fuel, or runs roughly. High-pressure fuel testing belongs with a qualified technician; never loosen a fuel rail or injector pipe to check pressure.

If the check engine light is flashing or the car runs badly, stop driving and have it checked.

Typical fixes

• Inspect the regulator wiring for heat damage and corrosion
• Check the circuit and valve continuity with the system de-energized and compare with factory values.
• Repair the verified wiring fault or replace a regulator that fails testing

Sources & review

• OBD-Codes.com: P0090
• TroubleCodes.net: generic code definitions

Definitions and diagnostic background checked 2026-11-06. Generic guidance, not a substitute for the service procedure for your exact year, engine, and transmission.