P0091 ISUZU - Fuel Pressure Regulator Solenoid 1 Control Circuit Low Voltage
Faulty fuel pressure sensor
Fuel pressure sensor harness is open or shorted
Fuel pressure sensor electrical circuit poor connection
Faulty Engine Control Module (ECM)
When is the code detected?
Fuel Pressure Regulator (FRP) feedback current less than 400mA
Engine Light ON (or Service Engine Soon Warning Light)
P0091 Isuzu Description
The Engine Control Module (ECM
) uses commanded fuel pump flow to determine a desired fuel rail pressure. The actual fuel pressure is monitored using the Fuel Rail Pressure (FRP) Sensor.