Faulty fuel pressure regulator control solenoid or its internal coil; Damaged or corroded wiring harness or connector at the regulator; Open or shorted circuit in the control wire between the PCM and regulator; Failed PCM driver for the fuel pressure regulator circuit (less common); Poor electrical ground connection for the regulator circuit; Aftermarket or incorrect regulator installed that does not match OEM specifications

DTC codes / P00xx · Fuel and air metering and auxiliary emission controls / P0090

P0090Fuel Pressure Regulator 1 Control Circuit

Q: What does code P0090 mean?

Fuel Pressure Regulator 1 Control Circuit. P0090 indicates that the powertrain control module (PCM) has detected an open, short, or out-of-range condition in the electrical circuit that controls the fuel pressure regulator, which is responsible for adjusting fuel pressure to the injectors. The PCM monitors the control circuit for expected voltage or current feedback and sets this code when the signal does not match the commanded value.

P0090 indicates that the powertrain control module (PCM) has detected an open, short, or out-of-range condition in the electrical circuit that controls the fuel pressure regulator, which is responsible for adjusting fuel pressure to the injectors. The PCM monitors the control circuit for expected voltage or current feedback and sets this code when the signal does not match the commanded value.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering and auxiliary emission controls

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Rough idle or stumbling during acceleration due to incorrect fuel pressure
Difficulty starting, especially when the engine is cold or hot
Reduced engine power or limp mode in some vehicles
Poor fuel economy or rich/lean running conditions
In rare cases, a no-start condition if the regulator defaults to a closed position

Common causes, most likely first

Faulty fuel pressure regulator control solenoid or its internal coil
Damaged or corroded wiring harness or connector at the regulator
Open or shorted circuit in the control wire between the PCM and regulator
Failed PCM driver for the fuel pressure regulator circuit (less common)
Poor electrical ground connection for the regulator circuit
Aftermarket or incorrect regulator installed that does not match OEM specifications

How to diagnose and fix it

Use a scan tool to command fuel pressure up and down while watching live data to confirm the regulator responds
Visually inspect the regulator connector and wiring for corrosion, chafing, or loose pins
Measure resistance of the regulator solenoid and compare to manufacturer specifications
Check for battery voltage and ground at the regulator connector with the key on
Perform a voltage drop test on the control circuit to rule out high resistance
If wiring and solenoid test good, test the PCM output with a oscilloscope or substitute a known-good PCM
Replace the faulty fuel pressure regulator or repair the wiring as needed, then clear codes and verify

Don't Replace the Regulator Before These Checks

A loose or corroded ground for the fuel pressure regulator circuit can mimic a failed regulator and set P0090, so always verify ground integrity before condemning parts.
Some vehicles use a fuel pressure control module that is separate from the regulator; a fault in that module can set P0090 even though the regulator itself is fine.
P0090 can be set by a momentary glitch in the circuit, so check for stored freeze-frame data and review the repair history before replacing components.
On certain engines, a mechanical fuel pressure regulator is vacuum-operated and has no electrical control circuit, so P0090 will not apply; confirm the system type first.
A failing fuel pump or restricted fuel filter can cause the regulator to work outside its expected range and indirectly set P0090, so always check actual fuel pressure.

Can I keep driving with P0090?

You can usually drive the vehicle with P0090 set, but expect reduced performance and possible stalling; avoid heavy acceleration or towing until the fault is repaired, and if the engine runs poorly or stalls, stop driving and seek professional diagnosis.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.