OBD-II Error Code P0091: How to Fix It

Q: What does OBD-II code P0091 mean?

Code P0091 means the PCM detected a low voltage signal from the fuel pressure regulator 1 control circuit. This can cause poor fuel pressure regulation and engine performance issues.

Q: Can I drive with a P0091 code?

It is not recommended to drive with this code as it can lead to engine stalling, poor fuel economy, or even engine damage. Have it diagnosed and repaired promptly.

Q: What causes error code P0091?

Common causes include a faulty fuel pressure regulator, damaged wiring or connectors in the control circuit, a bad PCM, or a short to ground in the circuit.

Q: How do I clear code P0091?

After repairing the underlying issue, you can clear the code using an OBD2 scanner. If the fix was successful, the code should not return.

Q: Is P0091 the same as P0090?

No. P0090 is for a high voltage condition in the same circuit, while P0091 indicates a low voltage condition. They have different causes and fixes.

Abstract

Error code P0091 indicates that the Powertrain Control Module (PCM) has detected a low voltage condition in the fuel pressure regulator 1 control circuit. This can cause poor engine performance, stalling, or difficulty starting. The issue is often related to a faulty fuel pressure regulator, wiring problems, or an electrical short.