GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2005 🢒 ION 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 Fuel System Diagnosis

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 an in-line fuel filter 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. A separate pipe returns unused fuel to the fuel tank.

Step

Action

Values

Yes

No

1

Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Important: Inspect the fuel system for damage or external leaks before proceeding with this diagnostic.

  1. Turn ON the ignition, with the engine OFF.
  2. Command the fuel pump relay ON with a scan tool.

Does the fuel pump operate?

--

Go to Step 3

Go to Fuel Pump Electrical Circuit Diagnosis

3

Important: Verify that adequate fuel is in the fuel tank before proceeding with this diagnostic.

  1. Turn OFF the ignition.
  2. Turn OFF all accessories.
  3. Install the SA9127E Gage Bar Set with the Fuel Pressure Adapter and the Drain Hose. Refer to Fuel Pressure Gage Installation and Removal .
  4. Turn ON the ignition, with the engine OFF.

    5. Important: DO NOT start the engine.

  5. Command the fuel pump relay ON with a scan tool.
  6. Observe the fuel pressure gage with the fuel pump commanded ON.

Is the fuel pressure within the specified range?

345-414 kPa (50-60 psi)

Go to Step 5

Go to Step 4

4

Is the fuel pressure more than the specified value?

414 kPa (60 psi)

Go to Step 8

Go to Step 9

5

Important: The fuel pressure may vary slightly when the fuel pump stops operating. After the fuel pump stops operating, the fuel pressure should stabilize and remain constant.

Monitor the fuel pressure gage for 5 minutes.

Does the fuel pressure decrease by more than the specified value?

55 kPa (8 psi)

Go to Step 7

Go to Step 6

6

  1. Operate the vehicle within the conditions to reproduce the original symptoms.
  2. Monitor the O2 and the Fuel Trim parameters with a scan tool.

Do the scan tool parameters indicate a lean condition?

--

Go to Step 9

Go to Symptoms - Engine Controls

7
  1. Turn OFF the ignition.
  2. Relieve the fuel pressure. Refer to Fuel Pressure Relief .
  3. Remove the fuel pressure gage from the fuel pressure test connection.
  4. Disconnect the fuel feed hose from the engine compartment fuel pipe. Refer to Metal Collar Quick Connect Fitting Service .
  5. Connect the fuel feed hose to the inlet side of SA9127E-7 Fuel Pressure/Flow Adapter.
  6. Connect the fuel pressure gage to the SA9127E-7 .
  7. Connect the return hose from the SA9127E-7 to the ON/OFF valve side of the SA9127E-7 .
  8. Place the return hose into the fuel filler pipe.
  9. Open the valve on the SA9127E-7 .
  10. Turn ON the ignition, with the engine OFF.
  11. Command the fuel pump relay ON for a minimum of 10 seconds with a scan tool.
  12. Close the valve on the SA9127E-7 .
  13. Monitor the fuel pressure gage for 5 minutes.

Does the fuel pressure decrease by more than the specified value?

55 kPa (8 psi)

Go to Step 12

Go to Step 11

8

Inspect the return side of the fuel filter for a restriction.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 12

9

Inspect the following components for a restriction:

    • The fuel filter
    • The fuel feed pipe

Did you find and correct the condition?

--

Go to Step 13

Go to Step 10

10

Inspect the harness connectors and the ground circuits of the fuel pump for poor connections. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 13

Go to Step 12

11
  1. Turn OFF the ignition.
  2. Raise the fuel rail with the fuel pipe connected. Refer to Fuel Injection Fuel Rail Assembly Replacement .
  3. Turn ON the ignition, with the engine OFF.
  4. Command the fuel pump relay ON with a scan tool.
  5. Locate and replace the leaking fuel injector. Refer to Fuel Injector Replacement .

Did you complete the replacement?

--

Go to Step 13

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12

Replace the fuel pump module. Refer to Fuel Pump Module Replacement .

Did you complete the replacement?

--

Go to Step 13

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13

Operate the system in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step 3