Low Pressure Fuel System Sensor Circuit
The engine detected a malfunction in the low pressure fuel system sensor (FP sensor) circuit. This sensor measures fuel pressure and reports it to the PCM; which uses this data to adjust fuel delivery. A circuit problem prevents accurate pressure readings.
What You Might Notice
- Malfunction Indicator Light (Check Engine) illuminated
- Engine will not start or difficult starting
- Hesitation or stumbling during acceleration
- Decreased fuel economy
- Rough idle or engine running lean
Most Common Causes
- 1
Open signal circuit wire
A broken, disconnected, or corroded wire in the FP sensor signal circuit prevents voltage from reaching the PCM. This is the most common cause.
- 2
Failed fuel pressure sensor
The FP sensor itself has failed internally or lost electrical continuity. The sensor may have reached end of life or been damaged.
- 3
Short to voltage or ground in signal circuit
The signal wire is shorted to power or ground, sending incorrect voltage signals to the PCM instead of the expected pressure reading.
- 4
Open power or ground circuit at sensor
The power supply or ground connection to the FP sensor is broken, preventing the sensor from receiving proper electrical power to function.
How to Diagnose It
- 1
Check Open signal circuit wire — A broken, disconnected, or corroded wire in the FP sensor signal circuit prevents voltage from reaching the PCM. This is the most common cause.
- 2
Check Failed fuel pressure sensor — The FP sensor itself has failed internally or lost electrical continuity. The sensor may have reached end of life or been damaged.
- 3
Check Short to voltage or ground in signal circuit — The signal wire is shorted to power or ground, sending incorrect voltage signals to the PCM instead of the expected pressure reading.
- 4
Check Open power or ground circuit at sensor — The power supply or ground connection to the FP sensor is broken, preventing the sensor from receiving proper electrical power to function.
How to Fix It
- 1
Inspect and repair signal wiring
Locate the FP sensor harness and connector. Check for corrosion, loose pins, broken wires, or damaged insulation. Repair or replace compromised wiring and reseat connectors firmly.
- 2
Replace fuel pressure sensor
If wiring is intact, the sensor itself has likely failed. Disconnect the old sensor from the fuel rail or fuel line and install a new OEM or quality aftermarket sensor with proper gasket or O-ring.
- 3
Check power and ground circuits
Use a multimeter to test the power and ground wires at the sensor connector for proper voltage (typically 5V or 12V depending on vehicle). Repair any open or shorted circuits found.
- 4
Clear code and perform road test
After repairs, erase the trouble code using a diagnostic scanner and test drive the vehicle to confirm the sensor reads correctly and the code does not return.
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