P0091 DTC Code: Explained and Resolved


When it comes to diagnosing and fixing issues in modern vehicles, Diagnostic Trouble Codes (DTCs) play a critical role. In this article, we will extensively cover the P0091 DTC code, shedding light on its meaning, causes, symptoms, and possible solutions. So, fasten your seatbelts as we dive deep into the world of automotive diagnostics.

Understanding the P0091 DTC Code

The P0091 DTC code specifically refers to a fuel pressure regulator control circuit malfunction. It is a generic code that can be found in vehicles equipped with onboard diagnostics systems, including OBD-II (On-Board Diagnostics Generation Two). The code itself is more commonly seen in fuel-injected vehicles, where it helps identify issues related to the fuel pressure regulator control circuit.

Causes of P0091 DTC Code

Several factors can trigger the appearance of the P0091 code. Let’s take a closer look at some of the most common causes:

  1. Faulty Fuel Pressure Regulator: A malfunctioning or worn-out fuel pressure regulator can lead to an incorrect fuel pressure reading, resulting in the P0091 code.
  2. Faulty Fuel Pressure Sensor: If the fuel pressure sensor is not functioning correctly, it may provide inaccurate readings to the vehicle’s engine control module (ECM), leading to the P0091 DTC code.
  3. Electrical Issues: The presence of a wiring or connector problem within the fuel pressure regulator control circuit can hinder its proper functioning and trigger the P0091 code.
  4. Fuel Delivery Problems: Issues with the fuel pump, clogged fuel lines, or a defective fuel injector can hinder the proper fuel delivery, causing the P0091 code to appear.

Symptoms of P0091 DTC Code

Detecting the P0091 DTC code is essential, as it can help prevent further damage to your vehicle. Here are some common symptoms associated with this code:

  • Check Engine Light: The illumination of the check engine light is often the initial indication of a potential issue. When the P0091 code appears, the check engine light will illuminate to notify you of a problem within the fuel system.
  • Engine Performance Issues: A vehicle experiencing a P0091 code may exhibit reduced engine power, hesitation, or rough idling due to an irregular fuel pressure supply.
  • Poor Fuel Efficiency: If your vehicle’s fuel pressure is not regulated properly, it may result in decreased fuel efficiency, potentially leading to frequent visits to the gas station.
  • Starting Problems: A faulty fuel pressure regulator control circuit may lead to difficulties starting the engine, requiring multiple attempts before the vehicle can be successfully started.

Resolving the P0091 DTC Code

Resolving the P0091 DTC code requires a systematic approach and, in some cases, the assistance of a professional mechanic. Here are a few potential solutions to consider:

  • Inspect and Replace Faulty Components: Begin by inspecting the fuel pressure regulator and sensor for any signs of damage or wear. If either component is found to be faulty, it is recommended to replace them to ensure proper functioning.
  • Check Fuel Pressure: Employ a pressure gauge to measure the fuel pressure and compare it to the manufacturer’s specified values. If the pressure is outside the acceptable range, further investigation and repairs are needed.
  • Verify Wiring and Connectors: Thoroughly inspect the wiring harness and connectors related to the fuel pressure regulator control circuit. Look for any signs of damage, loose connections, or corrosion. Repair or replace any affected components as necessary.
  • Clear the Code: After addressing the underlying issue, use an OBD-II scanner to clear the P0091 code. This will reset the vehicle’s system and confirm if the repair was successful.

Frequently Asked Questions

Q: Can I continue driving with the P0091 DTC code? A: While it is not advisable to ignore the P0091 code for an extended period, driving with the code alone generally won’t cause immediate harm to your vehicle. However, it is recommended to address the issue promptly to avoid potential engine performance problems or reduced fuel efficiency.

Q: Can I fix the P0091 DTC code myself? A: Depending on your automotive knowledge and experience, you may be able to diagnose and repair the issue causing the P0091 code. However, it is vital to proceed with caution and understand the steps involved. If in doubt, it’s always best to seek the assistance of a qualified mechanic.

Q: How much will it cost to fix the P0091 DTC code? A: The cost of resolving the P0091 code can vary depending on several factors, including the specific cause of the issue, the vehicle make and model, and labor rates in your area. It is best to consult with a mechanic to receive an accurate estimate tailored to your circumstances.


The P0091 DTC code can indicate a fuel pressure regulator control circuit malfunction, requiring your attention. By understanding the causes, symptoms, and potential solutions discussed in this article, you are better equipped to diagnose and resolve this issue. Remember, proper maintenance and timely repairs contribute to a vehicle’s longevity and performance.

About author


Meet Sam Mitchell, your experienced and reliable guide in the complex world of car fault codes. With a robust career spanning over 15 years as a professional car mechanic, John has the skills, knowledge, and practical experience to help you navigate car fault issues with confidence.


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