Malibu V6-3.6L (2010)
1. Ignition ON, engine OFF, command the fuel pump relay ON with a scan tool. You should hear the fuel pump turn ON and OFF.
‹› If the fuel pump does not operate, refer to Fuel Pump Electrical Circuit Diagnosis (See: Powertrain Management/Computers and Control
Systems/Testing and Inspection/Component Tests and General Diagnostics/Fuel Pump Electrical Circuit Diagnosis).
2. Ignition OFF, all accessories OFF, install a CH 48027 - Gauge. Refer to Fuel Pressure Gauge Installation and Removal (See: Fuel Pressure
Gauge Installation and Removal).
3. Ignition ON, engine OFF, command the fuel pump relay ON with a scan tool. Verify the fuel pressure is between 386-427 kPa (56-62 psi) and
does not decrease more than 34 kPa (5 psi) in 1 minute.
Circuit/System Testing
Note:
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The fuel pump relay may need to be commanded ON a few times in order to obtain the highest possible fuel pressure.
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DO NOT start the engine.
1. Ignition ON, engine OFF, command the fuel pump relay ON with a scan tool and observe the fuel pressure gauge while the fuel pump is operating.
Verify the fuel pressure is between 386-427 kPa (56-62 psi).
‹› If the fuel pressure is greater than the specified range, replace the fuel tank module.
‹› If the fuel pressure is less than the specified range, test, inspect, and repair the items listed below. If all items test normal, replace the fuel tank
module.
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Restricted fuel feed pipe
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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.
‹› 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).
2. Install the J 37287 - Shut-off Adapter between the fuel feed pipe and the fuel rail.
3. Open the valve on the J 37287 - Shut-off Adapter.
4. Ignition ON, command the fuel pump relay ON with a scan tool and bleed the air from the CH 48027 - Gauge.
5. Command the fuel pump relay ON and then OFF with a scan tool.
6. Close the valve on the J 37287 - Shut-off Adapter.
7. Monitor the fuel pressure for 1 minute.
‹› If the fuel pressure decreases more than 34 kPa (5 psi) within the specified time, locate and replace the leaking fuel injector(s).
‹› If the fuel pressure does not decrease more than 34 kPa (5 psi) within the specified time, replace the fuel tank 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.
‹› If the fuel pressure decreases more than the specified value, replace the fuel tank module.
4. Operate the vehicle within the conditions of the customer's concern while monitoring the fuel pressure with the CH 48027 - Gauge. The fuel
pressure should not drop off during acceleration, cruise or hard cornering.
‹› If the fuel pressure drops off, test, inspect, and repair the items listed below. If all items test normal, replace the fuel tank module.
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Restricted fuel feed pipe
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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 - Engine Controls (See: Powertrain Management/Computers and Control Systems/Testing and
Inspection/Symptom Related Diagnostic Procedures/Symptoms - Engine Controls).
Repair Instructions
Perform the Diagnostic Repair Verification (See: Powertrain Management/Computers and Control Systems/Testing and Inspection/Diagnostic Trouble
Code Tests and Associated Procedures/Verification Tests and Procedures) after completing the diagnostic procedure.
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Fuel Injector and Fuel Rail Replacement (See: Powertrain Management/Fuel Delivery and Air Induction/Fuel Injector/Service and Repair/Fuel
Injector and Fuel Rail Replacement)
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Fuel Line Replacement - Chassis (See: Powertrain Management/Fuel Delivery and Air Induction/Fuel Supply Line/Service and Repair)
