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 PerformanceDiagnostic Fault Information
Circuit | Short to Ground | Open or High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
5-Volt Reference | P0641 | P0641, P06A6 | P0641 | P06A6 |
Fuel Rail Pressure (FRP) Sensor Signal | P0192 | P0191, P0192 | P0193 | P0191 |
Fuel Line Pressure Sensor Low Reference | -- | P0641, P06A6 | -- | P06A6 |
Circuit/System Description
The fuel pressure sensor is located on the fuel line. The fuel pressure sensor monitors the fuel pressure in the fuel line. The fuel pump flow control module (FPCM) monitors the voltage signal from the fuel pressure sensor.
Conditions for Running the DTC
| • | The engine is running. |
| • | DTC P0192, P0193, P0231, P0232, P023F, P064A, P1255 or P06A6 are not active. |
| • | DTC P0641 has not failed this ignition cycle. |
| • | Fuel pump control is enabled and the fuel pump control state is normal. |
| • | The engine has been running for at least 5 seconds. |
Conditions for Setting the DTC
The FPCM does not detect a change in the fuel rail pressure (FRP) of at least 30 kPa (4.4 psi) when the fuel pump is operating at its minimum or maximum voltage limits for over 5 seconds.
Action Taken When the DTC Sets
DTC P0191 is a Type A DTC.
Conditions for Clearing the DTC
DTC P0191 is a Type A DTC.
Diagnostic Aids
Using the Failure Records data may help locate an intermittent condition. If you cannot duplicate the DTC, the information in the Failure Records can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can help determine how many ignition cycles that the diagnostic test reported a pass and/or a fail.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
Important: Verify that the fuel tank is not empty. Only perform this diagnostic if there is at least 2 gallons of fuel in the fuel tank. Clear the DTC, and start and run the engine. Verify that the DTC P0191 resets before proceeding with the circuit system testing. If the DTC does not reset, refer to diagnostic aids.
- Ignition OFF, disconnect the harness connector at the fuel line pressure sensor.
- Ignition OFF, test for less than 1 ohm between the low reference circuit terminal 2 and ground.
- Ignition ON, test for 4.8-5.2 volts between the fuel line pressure sensor 5-volt reference circuit terminal 3 and ground.
- Ignition OFF, install a 3A fused jumper wire between the 5-volt reference circuit terminal 3 and the signal circuit terminal 1.
- Ignition ON, observe the Fuel Pump Control Module Fuel Rail Pressure Sensor parameter. The scan tool should display between 4.8-5.2 volts.
- If all circuits test normal, replace the fuel pressure sensor.
| ⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the fuel pump flow control module. |
| ⇒ | If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the fuel pump flow control module. |
| ⇒ | If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the fuel pump flow control module. |
| ⇒ | If less than the specified range, test the signal circuit terminal 1 for a short to ground or an open/high resistance. If the circuit tests normal, replace the fuel pump flow control module. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for FPCM replacement, setup, and programming
