Cobalt L4-2.4L (2007)
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Inspect the harness connectors and the ground circuits of the fuel pump for poor connections.
2. Verify that the fuel pressure does not decrease more than 34 kPa (5 psi) in 1 minute.
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If the fuel pressure decreases more than the specified value, perform the following procedure:
2. Ignition OFF, relieve the fuel pressure. Refer to Fuel Pressure Relief. See: Fuel Filter/Fuel Pressure Release/Service and Repair/Fuel Pressure
Relief
3. Install the J 37287 between the fuel feed pipe and the fuel rail.
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 and then OFF 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 34 kPa (5 psi) within the specified time, locate and replace the leaking fuel injector(s).
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If the fuel pressure does not decrease more than 34 kPa (5 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: Powertrain Management/Computers and Control
Systems/Testing and Inspection/Symptom Related Diagnostic Procedures/Symptoms - Engine Controls
Repair Instructions
Important: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure. See: Powertrain
Management/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
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Fuel Hose/Pipes Replacement - Chassis
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Fuel Injector Replacement
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Fuel Pump Module Replacement
