P0191 Fault Code

Fuel Rail Pressure Sensor Circuit Range/Performance

• What does that mean?
• Symptoms
• Causes
• Solutions

The P0191 code indicates that there is an issue with the fuel rail pressure sensor circuit. This code typically arises when the sensor value is out of the expected range or has inconsistent performance. The fuel rail pressure sensor is crucial as it helps the engine control module (ECM) monitor the fuel pressure in the rail to ensure optimal engine operation. If the readings are incorrect, it can lead to performance issues, increased emissions, or hard starting.

What are the symptoms of the P0191 code?

Drivers may notice several symptoms associated with the P0191 code, such as:

• Engine performance issues, including reduced power and acceleration.
• Difficulty starting the engine, especially after it has been turned off.
• Stalling or rough Idling, which can affect overall drivability.
• Illuminated Check Engine Light (CEL) on the dashboard, indicating an error has been detected.

What causes the P0191 code?

Several factors can trigger the P0191 fault code, including:

• A faulty fuel rail pressure sensor that fails to send accurate readings.
• Damaged or corroded wiring and connectors in the fuel pressure sensor circuit.
• Blockages or leaks in the fuel system that affect pressure.
• A malfunctioning fuel pump that does not maintain proper pressure in the rail.
• ECM issues or software glitches that misinterpret sensor signals.

How to fix P0191?

To resolve the P0191 fault code, the following steps are typically recommended:

• Inspect the fuel rail pressure sensor for damage or deterioration and replace it if necessary.
• Check the wiring and connectors for signs of wear, corrosion, or loose connections and repair or replace them as needed.
• Test the fuel pressure using a gauge to ensure the fuel pump is functioning correctly and maintaining appropriate pressure.
• Inspect the entire fuel system for blockages or leaks that may affect pressure readings.
• Clear the fault code and perform a test drive to see if the code reappears, confirming that the issue has been resolved.