G5 L4-2.2L (2007)
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If the fuel pressure decreases more than the specified value, perform the following procedure:
1. Ignition OFF, relieve the fuel pressure. Refer to Fuel Pressure Relief. See: Fuel Filter/Fuel Pressure Release/Service and Repair/Fuel Pressure
Relief
2. Disconnect the chassis fuel feed hose from the engine compartment fuel pipe.
3. Install the J 37287 between the chassis fuel hose and the engine compartment fuel pipe.
4. Open the valve on the J 37287.
5. Ignition ON, command the fuel pump relay ON with a scan tool and bleed the air from the CH-48027.
6. Command the fuel pump relay ON with a scan tool.
7. Close the valve on the J 37287.
8. Monitor the fuel pressure for 1 minute.
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If the fuel pressure decreases more than 55 kPa (8 psi) within the specified time, locate and replace the leaking fuel injectors.
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If the fuel pressure does not decrease more than 55 kPa (8 psi) within the specified time, replace the fuel pump module.
3. Relieve the fuel pressure to 69 kPa (10 psi). Verify that the fuel pressure does not decrease more than 14 kPa (2 psi) in 5 minutes.
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If the fuel pressure decreases more than the specified value, replace the fuel pump module.
4. Operate the vehicle within the conditions of the customer's concern while monitoring the fuel pressure with the CH-48027. The fuel pressure
should not drop off during acceleration, cruise, or hard cornering.
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If the fuel pressure drops off, test, inspect, and repair the items listed below. If all items test normal, replace the fuel pump module.
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Restricted fuel feed pipe
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Restricted or plugged fuel filter
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Restricted or plugged strainer
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Inspect the harness connectors and the ground circuits of the fuel pump for poor connections.
5. If the fuel system tests normal, refer to Symptoms - Computers and Control Systems. See: Computers and Control Systems/Testing and
Inspection/Symptom Related Diagnostic Procedures/Symptoms - Engine Controls
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. See: Computers and Control Systems/Testing and
Inspection/Diagnostic Trouble Code Tests and Associated Procedures/Verification Tests and Procedures
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Fuel Filter Replacement (RPO NT7) Fuel Filter Replacement (RPO NU6)
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Fuel Hose/Pipes Replacement - Chassis
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Fuel Injector Replacement
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Fuel Pump Module Replacement (RPO NT7)
Fuel System Diagnosis (RPO NU6)
Fuel System Diagnosis (RPO NU6)
Diagnostic Fault Information
Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. See: Testing and Inspection/Initial Inspection and Diagnostic
Overview/Diagnostic Starting Point - Vehicle
Circuit/System Description
The control module enables the fuel pump relay when the ignition switch is turned ON. The control module will disable the fuel pump relay within 2
seconds unless the control module detects ignition reference pulses. The control module continues to enable the fuel pump relay as long as ignition
reference pulses are detected. The control module disables the fuel pump relay within 2 seconds if ignition reference pulses cease to be detected and the
ignition remains ON.
The fuel tank stores the fuel supply. The electric fuel pump supplies fuel through a fuel filter located in the fuel pump module to the fuel injection
system. The pump provides fuel at a higher rate of flow than is needed by the fuel injection system. The fuel pressure regulator, located in the fuel tank,
maintains the correct fuel pressure to the fuel injection system.
Circuit/System Verification
Important:
