P0089

DTC P0087, P0088, or P0089

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 P0087
- Fuel Rail Low Pressure

DTC P0088
- Fuel Rail High Pressure

DTC P0089
- Fuel Pressure Regulator Performance

Circuit/System Description

The fuel rail pressure sensor detects fuel pressure within the fuel rail. The engine control module (ECM) provides a 5 V reference voltage on the 5 V reference circuit and ground on the low reference circuit. The ECM receives a varying signal voltage on the signal circuit.

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.

The high pressure mechanical fuel pump is driven by three lobes on the camshaft. The ECM uses the camshaft and crankshaft position sensor inputs to synchronize the high pressure fuel pump actuator with the position of each of these camshaft lobes. The ECM regulates fuel pressure by adjusting the portion of each pump stroke that provides fuel to the rail.

The ECM creates a feedback loop between the pressure sensor and the high pressure fuel pump actuator. If the difference between expected and actual inputs exceeds a calibrated value, or if the amount of correction exceeds a calibrated value, a DTC sets.

Conditions for Running the DTC

* DTCs P0090, P0091, P0092, P0191, P0192, P0193 are not set.
* The ignition 1 signal parameter is less than 18.1 V.
* The relative injected fuel mass is between 5.016-500 %.
* The deceleration fuel cut-off is inactive.
* The engine speed is greater than 25 RPM.
* The engine start temperature is greater than -48°C (-54.4°F).
* The DTCs run continuously when the above conditions are met for 2 s.

Conditions for Setting the DTC

P0087

The actual fuel pressure is 1.5 MPa (218 psi) less than the desired fuel pressure.

P0088

The actual fuel pressure is 2 MPa (290 psi) greater than the desired fuel pressure.

P0089
* The fuel pressure adjustment is greater than +2.5 MPa (+363 psi) or less than -2.5 MPa (-363 psi).
* The DTCs set when the above conditions are met for 4 s.

Action Taken When the DTC Sets

* DTCs P0087, P0088, and P0089 are Type A DTCs.
* A message center or an indicator displays Reduced Engine Power when DTC P0087 sets.

Conditions for Clearing the DTC

DTCs P0087, P0088, and P0089 are Type A DTCs.

Diagnostic Aids

* A condition with the fuel pump module will set these DTCs.
* A skewed fuel rail pressure sensor, or an intermittent condition in the fuel rail pressure sensor circuits may set these DTCs.
* Faulty fuel injectors may set DTCs P0087 or P0089.

Reference Information
Schematic Reference

Engine Controls Schematics ([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. Observe the DTC information with a scan tool. DTC P029D, P02A1, P02A5, P02A9, P0627, P0628, or P0629 should not set.

• If a DTC is set refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code (DTC) List - Vehicle).

2. Attempt to start and idle the engine.
3. Observe the DTC information with a scan tool. DTCs P0087, P0088, and P0089 should not set.
4. 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).
5. 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 commanded state.
6. 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

Note: Circuit/System Verification must be performed first or misdiagnosis may result.

1. Verify the correct low side fuel system pressure. Refer to Fuel System Diagnosis (Fuel System Diagnosis).
2. Remove the high pressure fuel pump and visually inspect the lobes on the camshaft for unusual wear.

• If the lobes appear normal, replace the high pressure fuel pump.
• If the lobes are worn, replace the camshaft.

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.

* Fuel Injection Fuel Rail Fuel Pressure Sensor Replacement (Service and Repair)
* Fuel Pump Module Replacement (Fuel Pump Module Replacement)
* Fuel Pump Replacement (Service and Repair)
* Intake Camshaft and Valve Lifter Replacement (Intake Camshaft and Valve Lifter Replacement)