P0091 Fault Code

P0091 OBD-II Trouble Code Short Description

Fuel Pressure Regulator 1 Control Circuit Low

What does trouble code P0091 mean?

The P0091 fault code indicates an issue with the fuel pressure regulator 1 control circuit being lower than the expected voltage range. This can lead to problems with the fuel system, impacting the performance of the engine.

To resolve this issue, the following steps can be taken:

  1. Check the wiring and connections: Inspect the wiring and connectors related to the fuel pressure regulator to ensure they are intact and properly connected.

  2. Test the fuel pressure regulator: Use a multimeter to test the fuel pressure regulator and determine if it is functioning within the correct voltage range.

  3. Check for leaks: Any leaks in the fuel system can affect the pressure and cause this error code. Ensure there are no leaks in the fuel lines or connections.

  4. Replace the fuel pressure regulator: If all else fails, consider replacing the fuel pressure regulator to address the low voltage issue.

By following these steps, you can diagnose and fix the P0091 fault code, ensuring the fuel pressure regulator functions correctly and maintaining the optimal performance of your vehicle.


What are the symptoms of the P0091 code?

When a car encounters the P0091 fault code, it may exhibit the following symptoms:

  • Decreased engine performance
  • Engine stalling or hesitation
  • Difficulties starting the vehicle
  • Poor fuel economy
  • Check Engine Light illuminated on the dashboard


What causes the P0091 code?

P0091 - Fuel Pressure Regulator 1 Control Circuit Low

The P0091 fault code in cars is caused by the following reasons:

  • Faulty fuel pressure regulator
  • Clogged fuel filter
  • Wiring issues in the fuel pressure regulator control circuit
  • Poor electrical connection
  • Faulty engine control module (ECM)
  • Low fuel pressure
  • Fuel pump failure

It is important to diagnose and address the underlying issue causing the P0091 fault code to ensure proper functioning of the fuel system.

Possible Solutions

How to fix P0091?

To fix the P0091 fault code on cars, you can try the following steps:

  1. Check the fuel pressure regulator for any visible damage or wear.
  2. Inspect the wiring and connectors associated with the fuel pressure regulator for any signs of damage, corrosion, or loose connections.
  3. Test the fuel pressure regulator using a multimeter to ensure it is functioning correctly.
  4. Replace the fuel pressure regulator if it is faulty or not functioning within specifications.

If the issue persists after these steps, it is recommended to consult a professional mechanic for further diagnosis and repair.