DTC Advanced Diagnostics: P0191
DTC P0191:Fuel Rail Pressure Sensor Out of Range

General Description


The fuel rail pressure sensor senses fuel pressure and converts it into electrical signals. The powertrain control module (PCM) adjusts to a specified fuel pressure by controlling the high pressure fuel pump solenoid based on the fuel rail pressure sensor output signal. The fuel rail pressure sensor outputs low signal voltage at low fuel pressure and high signal voltage at high fuel pressure. If the fuel rail pressure sensor output voltage is a specified range for a specified time, the PCM detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type
Execution
Continuous
Sequence
None
Duration
Few seconds or more
DTC Type
Two drive cycles, MIL on

Enable Conditions
Condition
 
Vehicle
ON mode

Malfunction Threshold
The fuel rail pressure sensor output voltage [FUEL PRESSURE CONVERTED FROM PF SENSOR] is a specified range for few seconds.

[ ]: HDS Parameter

Possible Cause
NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
Fuel rail pressure sensor failure
PCM internal circuit failure

Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the PCM memory. If the malfunction returns in the next (second) drive cycle, the MIL comes on and a Confirmed DTC and the freeze data are stored.

Conditions for clearing the DTC
The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the 12 volt battery.