FuelSeverity High: diagnose before driving on

P0091Fuel Pressure Regulator 1 Control Circuit Low

What it means

The control circuit of fuel pressure regulator 1 reads a voltage that is too low, usually a short to ground or a missing supply.

Symptoms

No start, stalling or limp mode
Rail pressure doesn't follow the request

Common causes

Control wire shorted to ground
Missing supply to the regulator (fuse, relay)
Shorted regulator winding

What to check first

Check the regulator supply with the key on
Check the control wire for a short to ground
Measure the regulator resistance

Can I drive with P0091? Not recommended. P0091 can lead to stalling, limp mode or engine damage; diagnose it before driving further.

Generic OBD-II meaning. Manufacturer-specific meanings and checks can differ; always check the service information for the car.

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P0091: questions and answers

What does P0091 mean?

P0091: Fuel Pressure Regulator 1 Control Circuit Low. The control circuit of fuel pressure regulator 1 reads a voltage that is too low, usually a short to ground or a missing supply.

What are the symptoms of P0091?

No start, stalling or limp mode. Rail pressure doesn't follow the request.

What causes P0091?

Control wire shorted to ground. Missing supply to the regulator (fuse, relay). Shorted regulator winding.

How do you diagnose P0091?

1. Check the regulator supply with the key on 2. Check the control wire for a short to ground 3. Measure the regulator resistance

Can I drive with P0091?

Not recommended. P0091 can lead to stalling, limp mode or engine damage; diagnose it before driving further.