Fuel Rail Pressure Sensor Circuit Range/Performance
Table of contents
P0191 GMC Possible Causes
- Low or no fuel
- Faulty Rail Pressure (FRP) Sensor
- Faulty Rail Pressure (FRP) harness is open or shorted
- Faulty Rail Pressure (FRP) circuit poor electrical connection
- Faulty Fuel Pump
How do I fix code P0191 GMC?
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector’s pins.
Tech Notes
- There is a Factory Service Bulletin for the following GMC models:
- 2006-2010 GMC Savana
- 2006-2010 GMC Sierra
- 2006-2010 GMC Topkick
- GMC Factory Service Bulletin OBDII Code P0191
Cost of diagnosing the P0191 GMC code
The cost of diagnosing the P0191 GMC code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Engine will not start
P0191 GMC Description
The Fuel Rail Pressure (FRP) sensor has a 5-volt reference circuit, a signal circuit, and a low reference circuit. The Engine Control Module (ECM) monitors the voltage on the FRP sensor circuits. When the fuel pressure is high, the signal voltage is high. When the fuel pressure is low, the signal voltage is low. The fuel pressure regulator has a solenoid supply voltage circuit and a solenoid control circuit. The ECM controls the fuel pressure regulator, which regulates high pressure fuel that goes to the fuel injector rails and the injectors.