P0192Powertrain
Powertrain · SAE
Fuel Rail Pressure Sensor Circuit Low
Meaning
The fuel pressure sensor on the common rail outputs a voltage below the minimum operating range. The ECM interprets the signal as a short to ground or open signal wire.
Common causes
- Short to ground on the sensor signal wire
- Open circuit in the sensor supply or ground wiring
- Failed rail pressure sensor (drifting low)
- Corroded or loose connector
- Actual low rail pressure (correct signal, low pressure)
Symptoms
- Check-engine light on
- Hard start or no-start
- Rail pressure reading near zero even with engine running
- Severe power loss and possible black smoke
- Limp-home mode active
Severity
High: without correct rail pressure feedback the ECM cannot regulate injection; prolonged driving risks injector damage.
What to do
- Check supply voltage (typically 5 V reference) and ground at the sensor connector
- Measure signal voltage: below 0.5 V suggests short to ground or failed sensor
- Inspect wiring for breaks or chafing
- Replace the rail pressure sensor if the circuit tests good
- Verify actual rail pressure with an external gauge to rule out a real pressure loss