Buick Regal: DTC P0089, P00C6, P053F, P228C, or P228D

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 Descriptors

DTC P0089

Fuel Pressure Regulator Performance

DTC P00C6

Fuel Rail Pressure Low During Engine Cranking

DTC P228C

Fuel Pressure Regulator Control Performance - Low Pressure

DTC P228D

Fuel Pressure Regulator Control Performance - High Pressure

Circuit/System Description

The high fuel pressure necessary for direct injection is supplied by the high pressure fuel pump. The high pressure fuel pump is mounted on the rear of the engine and is driven by a three-lobe cam on the intake camshaft. This high pressure fuel pump also regulates the fuel pressure using an actuator in the form of an internal solenoid-controlled valve. In order to keep the engine running efficiently under all operating conditions, the engine control module (ECM) requests pressure ranging from 2 to 15 MPa (290 to 2, 176 PSI), depending on engine speed and load. Output drivers in the ECM provide the pump control circuit with a 12 V pulse-width modulated (PWM) signal, which regulates fuel pressure by closing and opening the control valve at specific times during pump strokes. This effectively regulates the portion of each pump stroke that is delivered to the fuel rail. When the control solenoid is NOT powered, the pump operates at maximum flow rate. In the event of pump control failure, the high pressure system is protected by a relief valve in the pump that prevents the pressure from exceeding 17.5 MPa (2, 538 PSI).

The fuel rail pressure sensor provides the feedback necessary to the ECM to control the high pressure fuel pump and the fuel injectors. This sensor is diagnosed separately from the fuel pressure control system.

The ECM monitors the fuel rail pressure sensor and the high pressure fuel pump actuator to determine if the commanded and actual pressures are within a predetermined range during engine cranking and at all times while the engine is running. The ECM also monitors the fuel pump actuator to make sure it is operating within expected limits.

Conditions for Running the DTC

P0089, P228C, or P228D

• DTC P0016, P0017, P0090, P0091, P0092, P00C8, P00C9, P00CA, P0111, P0112, P0113, P0114, P0116, P0117, P0118, P0119, P0128, P0191, P0192, P0193, P0335, P0336, P0340, P0341, P0365, P0366, P0628, or P1682 is not set.
• The ignition voltage is greater than 8 V.
• The engine is running.
• The low side fuel pressure is greater than 250 kPa (36 PSI).
• The barometric (BARO) pressure is greater than 70 kPa.
• The intake air temperature (IAT) is warmer than -20ºC (-4ºF).
• The DTCs run continuously when the above conditions are met for 60 s.

P00C6

• DTC P0016, P0017, P0090, P0091, P0092, P00C8, P00C9, P00CA, P0111, P0112, P0113, P0114, P0116, P0117, P0118, P0119, P0128, P0191, P0192, P0193, P0335, P0336, P0340, P0341, P0365, P0366, P0628, or P1682 is not set.
• The ignition voltage is greater than 8 V.
• The engine coolant temperature is less than 65ºC (149ºF).
• The low side fuel pressure is greater than 300 kPa (44 PSI).
• The diagnostic runs once for each engine start.

Conditions for Setting the DTC

P0089

The high pressure fuel pump has exceeded it's control limits. This condition exists when the high pressure fuel pump actuator command is 0º or greater than 240º. The condition exists for greater than 10 s.

P00C6

The ECM detects that the fuel rail pressure is not rising greater than 3 MPa (435 PSI) or has fallen below 2 MPa (290 PSI) during engine cranking, depending on initial pressure when cranking begins.

P228C

The actual fuel rail pressure is 3 MPa (435 PSI) less than the desired fuel rail pressure. The condition exists for greater than 10 s.

P228D

The actual fuel rail pressure is 3 MPa (435 PSI) greater than the desired fuel rail pressure. The condition exists for greater than 10 s.

Action Taken When the DTC Sets

• DTCs P0089 and P00C6 are Type B DTCs.
• DTCs P228C and P228D are Type A DTCs.
• A message center or an indicator displays Reduced Engine Power.
• Scan tool control of the high pressure fuel pump is inhibited.

Conditions for Clearing the DTC

• DTCs P0089 and P00C6 are Type B DTCs.
• DTCs P228C and P228D are Type A DTCs.

Diagnostic Aids

• Any problem with the camshaft may set fuel pressure DTCs due to the location and design of the high pressure fuel pump. If camshaft position control DTCs are current or in history, a cam control issue may be the root cause.
• A faulty valve, plunger, or solenoid in the high pressure fuel pump may set a DTC. High pressure fuel pump damage will most likely be undetectable upon visual inspection.
• A restricted fuel feed pipe between the fuel feed pipe fuel pressure sensor and the high pressure fuel pump may set a DTC.
• A leaking or restricted fuel injector may set a DTC.
• A leak in the high pressure fuel system may set a DTC.
• Vapor lock may set DTC P0089

Reference Information

Schematic Reference

Engine Controls Wiring Schematics (LTG)

Connector End View Reference

Component Connector End View Index

Powertrain Component View

Powertrain Component Views

Description and Operation

Fuel System Description

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Attempt to start and idle the engine.

2. Observe the DTC information with a scan tool. DTCs P0089, P00C6, P228C, and P228D should not set.

• If any of the DTCs are set

Refer to Circuit/System Testing.

• Go to next step: If none of the DTCs are set

3. Engine idling.

4. Verify the scan tool Fuel Rail Pressure Sensor parameter is approximately 1.9 - 5.0 MPa (276 - 725 PSI).

• If not between 1.9 - 5.0 MPa (276 - 725 PSI)

Refer to Circuit/System Testing.

• Go to next step: If between 1.9 - 5.0 MPa (276 - 725 PSI)

WARNING: Road test a vehicle under safe conditions and while obeying all traffic laws. Do not attempt any maneuvers that could jeopardize vehicle control. Failure to adhere to these precautions could lead to serious personal injury and vehicle damage.

5. Road test the vehicle and perform a wide open acceleration from a stop until the transmission shifts into second gear. On manual transmission applications, shift to second gear or stop the test near 2, 500 RPM. Repeat the test at least three times.

6. Verify DTCs P0089, P00C6, P228C, and P228D do not set.

• If any of the DTCs set

Refer to Circuit/System Testing.

• Go to next step: If none of the DTCs set

7. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

8. Verify the DTC does not set.

• If the DTC sets

Refer to Circuit/System Testing.

• Go to next step: If the DTC does not set

9. All OK.

Circuit/System Testing

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

1. Remove the G18 High Pressure Fuel Pump.

2. Verify the lobes on the camshaft do not have unusual wear or are worn.

• If the lobes have unusual wear or are worn

Replace the Camshaft.

• Go to next step: If the lobes are OK

3. Test or replace the G18 High Pressure Fuel Pump.

Component Testing

1. Ignition OFF, disconnect the harness connector at the G18 High Pressure Fuel Pump.

NOTE: The DMM and test leads must be calibrated to 0 Ω in order to prevent misdiagnosis.

2. Test for 0.3 - 0.7 Ω at 20ºC (68ºF) between the high control circuit terminal 1 and the low control circuit terminal 2.

• If not between 0.3 - 0.7 Ω

Replace the G18 High Pressure Fuel Pump.

• Go to next step: If between 0.3 - 0.7 Ω

3. Test for infinite resistance between each terminal and the G18 High Pressure Fuel Pump housing.

• If less than infinite resistance

Replace the G18 High Pressure Fuel Pump.

• Go to next step: If infinite resistance

4. All OK

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• Camshaft Position Actuator and Camshaft Replacement - Intake
• Fuel Injection Fuel Rail Fuel Pressure Sensor Replacement
• Fuel Pump Replacement for G18 High Pressure Fuel Pump replacement
• Perform the Fuel Rail Pressure Relief Valve Reset procedure, if supported on the scan tool.

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