Diagnostic Instructions
DTC Descriptors
DTC P0090: Fuel Pressure Regulator Control Circuit
DTC P0091: Fuel Pressure Regulator Solenoid 1 Control Circuit Low Voltage
DTC P0092: Fuel Pressure Regulator Solenoid 1 Control Circuit High Voltage
Diagnostic Fault Information
Circuit
| Short to Ground
| Open/High Resistance
| Short to Voltage
| Signal Performance
|
FRP regulator High
| P0091
| P0090
| --
| --
|
FRP regulator Low
| P0091
| P0090
| P0092
| --
|
Circuit/System Description
High pressure fuel is regulated by the fuel rail pressure (FRP) regulator, which is a part of the high pressure fuel pump. The FRP regulator is a solenoid valve. The ECM provides battery voltage on the FRP regulator high circuit and ground on the FRP regulator
low circuit. Both circuits are controlled through output drivers within the ECM. When deactivated, both drivers are disabled. When activated, the FRP regulator low circuit driver connects the low circuit to ground and the FRP regulator high circuit driver pulse-width
modulates (PWM) the high circuit. The ECM monitors the voltage on the circuits to detect a failure.
Conditions for Running the DTC
• | DTC P0641, P0642, or P0643 is not set. |
• | The ignition voltage is between 6-18 volts. |
• | DTCs P0090, P0091, and P0092 run continuously when the conditions above are met for greater than 3 seconds. |
Conditions for Setting the DTC
P0090
• | The fuel pressure regulator voltage is between 2.7-4.5 volts with the fuel pressure regulator commanded OFF. |
• | The above condition is present for greater than 5 seconds. |
P0091
• | The fuel pressure regulator voltage is less than 2.7 volts with the fuel pressure regulator commanded OFF. |
• | The above condition is present for greater than 5 seconds. |
P0092
• | The fuel pressure regulator voltage is greater than 4.5 volts with the fuel pressure regulator commanded ON. |
• | The above condition is present for greater than 5 seconds. |
Action Taken When the DTC Sets
• | DTCs P0090, P0091, and P0092 are Type A DTCs. |
• | A message center or an indicator displays Reduced Engine Power. |
Conditions for Clearing the DTC
DTCs P0090, P0091, and P0092 are Type A DTCs.
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Fuel System Description
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 Verification
- Engine idling, observe the Actual Fuel Rail Pressure parameter with a scan tool. The pressure should be approximately 3,500-5,500 kPa (508-798 psi).
- Command an increase and decrease in fuel rail pressure with a scan tool. Observe the scan tool Actual Fuel Rail Pressure parameter. The Actual Fuel Rail Pressure should increase or decrease with each command.
- Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
- Ignition OFF.
- Disconnect the harness connector at the high pressure fuel pump.
- Engine operating, verify that a test lamp flashes between the FRP regulator low circuit terminal 1 and B+.
⇒ | If the test lamp is always ON, test the FRP regulator low circuit for a short to ground. If the circuit tests normal, replace the ECM. |
⇒ | If the test lamp is always OFF, test the FRP regulator low circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM. |
- Ignition ON, verify that a test lamp illuminates between the FRP regulator high circuit terminal 2 and ground.
⇒ | If the test lamp does not illuminate, test the FRP regulator high circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. |
- If all circuits test normal, test or replace the high pressure fuel pump.
Component Testing
Static Test
- Ignition OFF, disconnect the harness connector at the high pressure fuel pump.
Note: The DMM and test leads must be calibrated to 0 ohms in order to prevent misdiagnosis.
- Test for 0.49 Ω plus/minus 0.023 Ω of resistance at 20°C (68°F) between FRP regulator low circuit terminal 1 and FRP regulator hi circuit terminal 2.
⇒ | If not within the specified range, replace the high pressure fuel pump. |
- Measure the resistance between each terminal and the high pressure fuel pump housing. The DMM should display OL.
⇒ | If less than the specified value, replace the high pressure fuel pump. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.