GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 Silverado - 4WD 🢒 DTC 🢒 DTC P0191

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P0191: Fuel Rail Pressure (FRP) Sensor Performance

Diagnostic Fault Information

Circuit

Short to Ground

High Resistance

Open

Short to Voltage

FRP Signal

P0192

P0088, P0191

P0193

P0193

FRP Low Reference

--

P0191

P0193

¹

FRP 5-Volt Reference

P0117, P011A, P0462, P0522, P0652

P0087, P0191

P0193

P0118, P0463, P0653, P2454

Fuel Pressure Regulator Solenoid Supply Voltage

P0088, P0090

P0088

P0090

P0087, P0191, P2510

¹ Opens circuit fuse or opens circuit.

Circuit/System 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.

Conditions for Running the DTC
    • DTCs P0016, P062F, P0116, P0117, P0118, P0192, P0193, P0652 or P0653 are not set.
    • The ignition is ON, after the engine has been OFF for greater than 20 minutes.
    • The coolant temperature is warmer than 40°C (104°F).
        OR
    • The ignition has been OFF greater than 60 seconds.
    • The fuel temperature is more than 60°C (140°F).
    • This diagnostic runs continuously within the above conditions.

Conditions for Setting the DTC

The FRP sensor is below 0.352 volt or above 0.650 volt within the Conditions for Running the DTC.

Action Taken When the DTC Sets

DTC P0191 is a Type A DTC.

Conditions for Clearing the MIL/DTC

DTC P0191 is a Type A DTC.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Important: 

   • You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
   • If you cannot duplicate the condition, operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
   • Disregard Freeze Frame/Failure Records if the engine RPM parameter displays greater than zero.

  1. Verify that DTCs P0652 or P0653 are not set.
    2. ⇒If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.
  2. Observe the Fuel Rail Pressure Sensor parameter with a scan tool. During engine cranking, the pressure should be at least 10 MPa. With the engine running at idle, the pressure should be close to the Desired Fuel Rail Pressure. As the engine speed increases, the Desired Fuel Rail Pressure and the Actual Fuel Rail Pressure should closely match each other.
  3. Engine running, observe the DTC information with a scan tool. DTC P0191 should not set.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

Important: Fuel pressure control will be disable if DTC P0087, P0088, P0192, or P0193 are set. Codes must be cleared to enable the device control.

  1. Turn OFF the ignition.
  2. Disconnect the ECM connector and the fuel pressure regulator connector.
  3. Test the fuel pressure regulator solenoid supply voltage circuit for a short to voltage.
  4. Disconnect the FRP sensor.
  5. Test the FRP signal circuit, the 5-volt reference circuit, and the low reference circuit for high resistance.
    6. ⇒If all circuits test normal, replace the FRP sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Fuel Injection Fuel Rail Fuel Pressure Sensor Replacement
    •  Control Module References for ECM replacement, setup, and programming