P0090
DTC P0090, P0091, or P0092 (w/LLT)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC P0090
- Fuel Pressure Regulator Control Circuit
DTC P0091
- Fuel Pressure Regulator Control Circuit Low Voltage
DTC P0092
- Fuel Pressure Regulator Control Circuit High Voltage
Diagnostic Fault Information
Circuit/System Description
High pressure fuel is regulated by the high pressure fuel pump actuator, which is a part of the high pressure fuel pump. The high pressure fuel pump actuator is a solenoid valve. The ECM provides battery voltage on the actuator high control circuit and ground on the actuator low control circuit. Both circuits are controlled through output drivers within the ECM. When deactivated, both drivers are disabled. When activated, the high control circuit driver energizes the high pressure fuel pump actuator and the low control circuit driver pulse-width modulates (PWM) the low control circuit to ground.
Conditions for Running the DTC
* DTC P0641, P0642, or P0643 is not set.
* The ignition 1 signal parameter is between 10-18 V.
* DTCs P0090, P0091, and P0092 run continuously when the conditions above are met for greater than 2 s.
Conditions for Setting the DTC
P0090
* The high pressure fuel pump actuator voltage is between 2.7-4.5 V with the actuator commanded OFF.
* The above condition is present for greater than 5 s.
P0091
* The high pressure fuel pump actuator voltage is less than 2.7 V with the actuator commanded OFF.
* The above condition is present for greater than 5 s.
P0092
* The high pressure fuel pump actuator voltage is greater than 4.5 V with the actuator commanded ON.
* The above condition is present for greater than 5 s.
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 (LLT) ([1][2]Electrical Diagrams)Engine Controls Schematics (LF1) ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Fuel System Description (Fuel System Description)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing For Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Engine idling, observe the Fuel Rail Pressure Sensor parameter with a scan tool. The pressure should be approximately 3.5-5.5 MPa (508-798 psi).
2. Command an increase and decrease in fuel rail pressure with a scan tool. Observe the scan tool Fuel Rail Pressure Sensor parameter. The Fuel Rail Pressure Sensor should increase or decrease with each command.
3. 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
1. Ignition OFF.
2. Disconnect the harness connector at the G18 high pressure fuel pump.
3. Engine operating, verify that a test lamp flashes between the low control circuit terminal 1 and B+.
• If the test lamp is always ON, test the low control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
• If the test lamp is always OFF, test the low control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
4. Ignition ON, verify that a test lamp illuminates between the high control circuit terminal 2 and ground.
• If the test lamp does not illuminate, test the high control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
5. If all circuits test normal, test or replace the high pressure G18 fuel pump.
Component Testing
Static Test
1. Ignition OFF, disconnect the harness connector at the high pressure fuel pump.
Note: The DMM and test leads must be calibrated to 0 ohm in order to prevent misdiagnosis.
2. Test for 0.35-0.6 ohm at 20°C (68°F) of resistance between low control circuit terminal 1 and high control circuit terminal 2.
• If the resistance is less than 0.3 ohm or greater than 0.6 ohm, replace the high pressure fuel pump.
3. Test for infinite resistance between each terminal and the high pressure fuel pump housing/case.
• If not the specified value, replace the high pressure fuel pump.
Dynamic Test
Engine idling, command the Fuel Pressure Control to Increase with a scan tool. The Fuel Rail Pressure Sensor parameter should increase with each command.
If the Fuel Rail Pressure Sensor parameter does not increase with each command, replace the high pressure fuel pump.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Control Module References (Programming and Relearning) for ECM replacement, setup, and programming
* Fuel Pump Replacement (Service and Repair)