P0191

DTC P0191 Fuel Rail Pressure (FRP) Sensor Performance

Circuit Description

The fuel rail pressure (FRP) sensor is installed to the fuel rail and it detects the fuel pressure in the fuel rail converts the pressure into a voltage signal and sends the signal to the ECM.

If the ECM detects that the actual fuel rail pressure does not change normally during engine running this DTC will set. (Sensor Signal Stuck Diagnosis).

If the ECM detects that the actual fuel rail pressure does not decrease normally for a certain time when the ignition switch is OFF or does not stay within the calculated range after the engine is stopped for a certain length of time this DTC will also set. This diagnostic will only run once per driving cycle within the enabling conditions. (Sensor Signal Offset Diagnosis)

Condition for Running the DTC

Sensor Signal Stuck Diagnosis:

^ DTCs P0192 P0193 P0642 and P0643 are not set.
^ The engine is running.
^ The fuel temperature is less than 194°F (90°C).
^ The desired fuel rail pressure is more than 2,900 psi (20 MPa).
^ The fuel supply pump is learned status.

Sensor Signal Offset Diagnosis:

^ DTCs P0112 P0113 P0116 P0117 P0118 P0182 P0183 P0192 P0193 P0500 P0652 P0653 P2228 and P2229 are not set.

AND either of following ignition switch event is met:

When the ignition switch is ON;

^ The battery voltage more than 10 volts.
^ The engine is not running.
^ The vehicle is stationary.
^ The barometric pressure is more than 11 psi (75kPa).
^ The intake air temperature is more than 19°F (-7°C).
^ The coolant temperature is more than 19°F (-7°C) and more than 9°F (5°C) below the averaged temperature.
^ The fuel temperature is more than 19°F (-7°C).

When the ignition switch is OFF;

^ The battery voltage more than 10 volts.
^ The engine is not running.
^ The vehicle is stationary.
^ The barometric pressure is more than 11 psi (75kPa).
^ The intake air temperature is more than 19°F (-7°C).
^ The coolant temperature is more than 19°F (-7°C).
^ The fuel temperature is more than 19°F (-7°C).

Condition for Setting the DTC

Sensor Signal Stuck Diagnosis:

^ The ECM detects that the actual fuel rail pressure does not vary more than 145 psi (1 MPa) when the differential pressure between the actual and the desired fuel rail pressure is more than 290 psi (2 MPa).

Sensor Signal Offset Diagnosis:

^ The ECM detects that the FRP sensor signal voltage is not within a predetermined range of the calculated rail pressure value.

Action Taken When the DTC Sets

^ The ECM illuminates the MIL when the diagnostic runs and fails. Refer to DTC Type Definitions for Action Taken When the DTC Sets - Type A.
^ The ECM limits fuel injection quantity. (Sensor Signal Stuck Diagnosis)
^ The ECM inhibits accelerator pedal control. (Sensor Signal Offset Diagnosis)
^ The ECM inhibits EGR control.
^ The ECM inhibits DPF regeneration control.
^ The ECM inhibits cruise control.
^ The ECM inhibits PTO control.

Condition for Clearing the DTC

^ Refer to DTC Type Definitions for Condition for Clearing the MIL/DTC - Type A.

Diagnostic Aids

^ If an intermittent condition is suspected refer to Intermittent Conditions in this section.
^ A skewed FRP sensor value can set this DTC. The FRP Sensor on the scan tool should read 0.9 to 1.0 volt after the engine has stopped running for a minimum of 30 seconds.

Notice: If the engine is cranked while the crankshaft position sensor and camshaft position sensor signals are lost, this DTC may set

Circuit/System Testing DTC P0191