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
High Pressure Fuel Pump Actuator High Control	P0091	P0090	--	--
High Pressure Fuel Pump Actuator Low Control	--	P0090	P0092	--

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 actuator low control circuit driver connects the low control circuit to ground and the actuator high control circuit driver pulse-width modulates (PWM) the high control circuit. The ECM monitors the voltage on the circuits to detect a failure.

Conditions for Running the DTC

Conditions for Setting the DTC

P0090

P0091

P0092

Action Taken When the DTC Sets

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

Description and Operation

Fuel System Description

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Circuit/System Verification

Engine idling, observe the Actual Fuel Rail Pressure parameter with a scan tool. The pressure should be approximately 3.5-5.5 Mpa (508-798 psi). With the engine running at idle, the Actual Fuel Rail 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.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the high pressure fuel pump.
2. Engine running, verify that a test lamp flashes between the high pressure fuel pump actuator low control circuit terminal 1 and B+.

⇒	If the test lamp is always ON, test the high pressure fuel pump actuator low control circuit for a short to ground. If the circuit tests normal, replace the ECM.

⇒	If the test lamp is always OFF, test the high pressure fuel pump actuator low control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

3. Ignition ON, verify that a test lamp illuminates between the high pressure fuel pump actuator high control circuit terminal 2 and ground.

⇒	If the test lamp does not illuminate, test the high pressure fuel pump actuator high control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

4. If all circuits test normal, test or replace the high pressure fuel pump.

Component Testing

Static Test

1. Ignition OFF, disconnect the harness connector at the high pressure fuel pump.
2. Test for 0.49 ohm plus/minus 0.023 ohm at 20°C (68°F) of resistance between low control circuit terminal 1 and FRP regulator high circuit terminal 2.

⇒	If not within the specified range, 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 Actual Fuel Rail Pressure should increase with each command.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.