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Common Symptoms of a Faulty Fuel Rail Pressure Sensor

By R&D
Published on January 13th, 2025

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The Fuel Rail Pressure sensor is mounted in the fuel rail close to the injectors. Its primary purpose is to continuously measure the pressure in the fuel rails. The sensor incorporates a diaphragm strain gauge device in which resistance varies with pressure. The resulting changes in resistance influence the voltage drop across the sensor's terminals.

The sensor then transmits an electrical signal to the Engine Control Module (ECM) corresponding to the applied pressure. If the sensor malfunctions, the ECM is unable to make reasonable changes to the timing and amount of fuel being injected. This can result in reduced engine performance, poor fuel mileage, and potentially engine stalling or failure to start.

Common Symptoms of a Faulty Fuel Rail Pressure Sensor

This article highlights the typical symptoms of a faulty Fuel Rail Pressure sensor, to help you identify potential issues and their root causes.

What Causes Fuel Rail Pressure Sensor Failures?

Physical Damage: Collisions, severe vibrations from the road, and improper handling during maintenance cause physical damage to the sensor and prevent it from functioning properly.

Electrical Issues: A loose or damaged wire can disrupt communication between the sensor and the ECM, leading to intermittent or complete loss of sensor signal.

Corrosion and Contamination: Exposure to fuel, engine fluids, and environmental elements can cause corrosion of the sensor's metal components. Additionally, contaminants in the fuel system can clog or damage the sensor's sensitive elements, affecting its accuracy.

Wear and Tear: Over time, the sensor's internal components, such as the diaphragm and strain gauge, can deteriorate due to constant exposure to fuel and temperature fluctuations. This gradual degradation can lead to inaccurate readings and eventual sensor failure.

Common Symptoms of a Faulty Fuel Rail Pressure Sensor

Malfunction Indicator Light (MIL) or Check Engine Light (CEL) Illuminates

A malfunctioning Fuel Rail Pressure sensor may trigger the vehicle's On-Board Diagnostic (OBD2) system to illuminate the MIL and store a corresponding Diagnostic Trouble Code (DTC) in its memory. However, the MIL can illuminate for various issues, so your vehicle needs to be checked using a Scan Tool to determine the cause.

Engine Stalling

When the Fuel Rail Pressure Sensor malfunctions, it can continuously or intermittently send incorrect pressure readings to the ECM. This can lead to improper fuel delivery, causing the engine to stall unexpectedly. In more severe cases where the sensor has failed completely, it may prevent the engine from starting. This is because the ECM relies on accurate pressure readings to manage fuel injection, and without them, the engine may not receive the necessary fuel to start.

Poor Fuel Economy

A significant decrease in fuel economy and mileage is noticeable when the Fuel Rail Pressure sensor is not functioning properly. If the sensor sends a lower pressure value than normal, it will cause the ECM to control the delivery of more fuel to achieve the required pressure. In some cases, a faulty sensor can even cause fuel leaks, which not only reduce fuel economy but also pose a safety hazard.

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Identify a Faulty Fuel Rail Pressure Sensor with the Innova Scan Tool

The Innova Scan Tool quickly retrieves and identifies DTCs stored in your vehicle’s computers. Performing an OBD2 Scan lets you retrieve existing DTCs, the I/M Status of the vehicle, and any collected Freeze Frame data from these computers. Refer to the Innova Coverage Checker to determine the level of information supported on your particular vehicle by year, make and model. The Innova Scan Tool effectively diagnoses Fuel Rail Pressure sensor-related issues, helping you easily pinpoint and resolve problems.

Additionally, the Innova Scan Tool lets you view Live Data PIDs and presents OEM Enhanced Live Data, with advanced information for complete vehicle diagnostics. You can also read the Fuel Rail Pressure Input value to determine if the Fuel Rail Pressure Input value matches the actual fuel rail pressure or if it changes after many movements. The normal operating value of the fuel rail pressure sensor depends on your vehicle.