P0191: Fuel Rail Pressure Sensor CKT Range/Perf
- High fuel pressure
- Low fuel pressure
- Damaged FRP sensor
- Excessive resistance in the circuit
- Low or no fuel
- Wiring harness connector of the fuel pressure sensor
- Fuel Rail Pressure Sensor
- Vacuum leaks
The Fuel Rail Pressure (FRP) sensor is a diaphragm strain gauge device
in which resistance changes with pressure. The electrical resistance of a
strain gauge increases as pressure increases, and the resistance
decreases as the pressure decreases. The varying resistance affects the
voltage drop across the sensor terminals and provides electrical signal
to the Powertrain Control Module (PCM
) corresponding to pressure.
Strain gauge type sensors are consider passive sensors. A passive sensor
is connected to a voltage divider network so that varying the
resistance of the passive sensor causes a variation in total current
Voltage that is dropped across a fixed resistor in series with the sensor resistor determines the voltage signal at the PCM
. This voltage signal is equal to the reference voltage minus the voltage drop across the fixed resistor.
The FRP sensor measures the pressure of the fuel near the fuel injectors. This signal is used by the PCM
to adjust the fuel injector pulse width and meter fuel to each combustion cylinder.