What is P0091 fault code? What is the description for the Fuel Pressure Regulator 1 Control Circuit Lower malfunction? How can I fix the P0091 fault? What are the causes and symptoms of the P0091 error code?
What is the P0091 Fault code? What does it stand for?
When the powertrain control module, (PCM), detects a low voltage signal coming from the electronic fuel regulator control circuit, a code P0091 will be triggered.
There may be more than one electronic fuel regulator on some vehicles. An error in the primary fuel pressure regulator will indicate a code violation. In some vehicles it could also refer the engine block containing 1st-cylinder.
The PCM controls the electronic fuel pressure regulator. The PCM drives the servo motor which positions the regulator with the ground signals and battery. The desired fuel pressure level can be achieved in this manner. The fuel pressure sensor can be found on the fuel injector rail. This sensor allows the PCM to monitor the fuel pressure, adjust the fuel pressure regulator voltage according to its needs. If the voltage of servo motor is higher, the valve will open and fuel pressure will increase.
Although the fuel pressure sensor and regulator are usually integrated into one housing, it may still be made up of separate components. If the voltage of the current fuel regulator is lower than what the PCM requires, the fault code P0091 is issued.
P0091 fault codes can be found on many vehicles, including but not limited to: Isuzu Mazda, Hyundai, Dodge Chrysler, Ford, GMC Chevrolet, Cadillac and Alfa Romeo.
Other fault codes that are related:
P0089 Performance Fuel Pressure Regulator 1.
P0090 Fuel Pressure Regulator 1 Control Circuit
P0092 Fuel Pressure Regulator 1 Control Circuit High
What is the P0091 Fault Code?
Here are some reasons why P0091 should be set.
- – Defective fuel pressure regulator
- – Defective fuel pressure sensor
- – Fuel filter restriction or other parts of fuel system
- – Fuel pressure regulator control circuit open or short circuit. This can be caused by damaged wires or loose connectors.
- – Low fuel levels or no fuel
- – Defective PCM
What are the symptoms of P0091 malfunction code?
You may experience the following symptoms if your vehicle has the code P0091:
- – Illumination at the check engine lights
- – Engine running very hard or not at all
- – An increase of fuel consumption
- Low engine performance
- – Vehicle slow acceleration and no power
- – Engine hesitation during acceleration
- – The exhaust emits black smoke
- – The vehicle can be switched to fail-safe mode
- – Setting other fault codes (engine misfires, idling etc.
How do I fix the P0091 fault code?
To determine if the code will return, it is important to first clear all codes. Then, a road test should also be performed. If the code returns, you should seek help from a professional to repair damaged, dented or melted wires. Also, inspect connectors for signs of corrosion. The fuel pressure regulator is responsible for the fault, but it should be checked before it can be replaced.
- Repair of damaged cables, connectors and open or brief circuits
- – Replacing a faulty fuel pressure regulator
- – Replacing a faulty fuel pressure sensor
- – Replacing the fuel filter
- – Replace the PCM if it fails to pass the testing procedures
How Serious Is the P0091 Fault Coding?
The P0091 code could be dangerous as it can affect the engine’s performance, potentially causing the engine to stop starting or leaving you stranded. This code can lead to internal engine damage or catalytic converter issues. This code should be removed as soon as it is established.
