P0191 – Fuel Rail Pressure Sensor Circuit Range/Performance

An OBD-II error code P0191 indicates a problem with the fuel rail pressure sensor circuit. The fuel rail pressure sensor is a crucial component in fuel injection systems, as it monitors the pressure of the fuel in the fuel rail and sends this information to the engine control module (ECM). The ECM uses this data to regulate the fuel injection and ensure the engine receives the appropriate amount of fuel for efficient combustion. If the ECM detects that the fuel rail pressure sensor’s signal is outside the expected range, it will trigger the P0191 code.

The P0191 code can be caused by various factors, including a faulty fuel rail pressure sensor, issues with the sensor’s wiring or connectors, or even problems with the fuel pressure itself. If the fuel pressure is too high or too low, it can lead to drivability problems and affect the engine’s performance. When the code is triggered, the Check Engine Light (CEL) will illuminate on the dashboard.

Fixes for OBD-II Code P0191

To fix the OBD-II code P0191, you can get along with the general outline of the steps to fix the problem:

  1. Check for Codes. Retrieve the specific code and check for any additional related codes using OBD-II scanner/reader (some of them are advices here). This will provide valuable information to narrow down the root cause of the issue.
  2. Inspect Wiring and Connectors. Thoroughly inspect the wiring and connectors associated with the fuel rail pressure sensor. Look for signs of damage, corrosion, or loose connections. Repair or replace any faulty components as needed.
  3. Test Fuel Pressure. Use a fuel pressure gauge to measure the fuel pressure in the fuel rail. Compare the readings to the manufacturer’s specifications. If the pressure is too high or too low, it may indicate a problem with the fuel pump, fuel filter, or pressure regulator.
  4. Check the Fuel Rail Pressure Sensor. Test the fuel rail pressure sensor using a digital multimeter. Verify if the sensor is within the specified resistance range. If it’s outside the range or shows no readings, the sensor may be faulty and should be replaced.
  5. Verify the Fuel System Components. Ensure the fuel system components, such as the fuel pump, pressure regulator, and fuel filter, are working correctly and not causing abnormal pressure conditions.
  6. Address Related Issues. If any related codes were identified, address those issues as well, as they may contribute to the DTC P0191.

Note: If you are not familiar with automotive diagnostics or lack the proper tools, it’s advisable to seek assistance from a qualified mechanic.

Related DTCs to P0191

There are some codes that likely would have been shown along with the aforementioned code: P0087, P0088, P0190, P0192, P0193, P0194.


The cost to fix OBD-II code P0191 can vary depending on several factors, including the make and model of the vehicle, the labor rates of the repair shop, and whether the issue requires a simple repair or more extensive diagnostics and replacement of parts. On average, the cost to fix the DTC P0191 can range from $100 to $300.

While the vehicle may still be drivable in some cases, it’s generally not recommended to continue driving with this code present. Ignoring the P0191 code can lead to potential problems and may affect the vehicle’s performance and fuel efficiency. To avoid further complications and potential damage, it’s best to have the issue diagnosed and repaired ASAP.

The OBD-II code P0191 is considered a moderately serious issue. While it may not result in immediate engine failure or safety hazards, it can lead to several problems that can affect the performance, fuel efficiency, and overall reliability of your vehicle.

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