GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2002 🢒 VUE - FWD 🢒 Engine 🢒 Engine Controls - 3.0L (L81) 🢒 Fuel System Diagnosis

System Description

The engine control module (ECM) enables the fuel pump relay when the ignition switch is turned ON. The ECM will disable the fuel pump relay within 2 seconds unless the ECM detects ignition reference pulses. The ECM continues to enable the fuel pump relay as long as ignition reference pulses are detected. The ECM 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 attached to the primary fuel tank module, supplies fuel through an in-line fuel filter to the fuel injection system. The fuel pump provides fuel at a higher rate of flow than is needed by the fuel injection system. The fuel pressure regulator, a part of the secondary fuel tank module, maintains the correct fuel pressure to the fuel injection system. A fuel return pipe attaches between the in-line fuel filter and the secondary fuel tank module. When the fuel pressure exceeds the set point of the fuel pressure regulator, excess fuel flows to the low-pressure siphon jet pump on the secondary fuel tank module. The return fuel creates a venturi action inside the siphon jet pump. The venturi action causes the fuel to be drawn from the secondary side of the fuel tank though the fuel transfer tube to the primary side of the fuel tank. The electric fuel pump also supplies fuel to the high-pressure siphon jet pump, which is attached to the primary fuel tank module. The high-pressure siphon jet pump supplies fuel to the reservoir of the primary fuel tank module. The fuel pressure regulator also maintains fuel pressure in the fuel return pipe, which reduces the time to prime the low-pressure siphon jet pump.

Step

Action

Values

Yes

No

1

Did you perform the Diagnostic System Check-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

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?

364-405 kPa (53-59 psi)

Go to Step 4

Go to Step 8

4

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.

Observe 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 6

Go to Step 5

5
  1. Operate the vehicle within the conditions to reproduce the original symptoms.
  2. Observe 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

6
  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 chassis fuel hose from the engine compartment fuel pipe.
  5. Connect the fuel feed hose to the inlet side of SA9127E-7 using the J 43937 3/8 inch Male Fuel Pressure Adapter Line.
  6. Connect the return hose from the SA9127E-7 to the outlet side of SA9127E-7 .
  7. Place the other end of the return hose into the fuel filler pipe.
  8. Close the valve on the SA9127E-7 .
  9. Turn ON the ignition, with the engine OFF.
  10. Command the fuel pump relay ON for a minimum of 10 seconds with a scan tool.
  11. Record the fuel pressure.
  12. Command the fuel pump relay OFF.
  13. Observe 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 15

7
  1. Turn OFF the ignition.
  2. Open the valve on the SA9127E-7 .
  3. Remove the SA9127E-7 .
  4. Connect the fuel feed hose to the engine compartment fuel pipe.
  5. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  6. Disconnect the fuel feed pipe from the fuel filter inlet.
  7. Connect the fuel feed pipe to the inlet side of SA9127E-7 using the J 43937 3/8 inch Male Fuel Pressure Adapter Line.
  8. Connect the return hose from the SA9127E-7 to the outlet side of SA9127E-7 .
  9. Place the other end of the return hose into the fuel filler pipe.
  10. Open the valve on the SA9127E-7 .
  11. Turn ON the ignition, with the engine OFF.
  12. Command the fuel pump relay ON for a minimum of 10 seconds with a scan tool.
  13. Close the valve on the SA9127E-7 .
  14. Record the fuel pressure.
  15. Command the fuel pump relay OFF.
  16. Observe 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 19

Go to Step 17

8

Is the fuel pressure more than the specified value?

405 kPa (59 psi)

Go to Step 14

Go to Step 9

9
  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 chassis fuel hose from the engine compartment fuel pipe.
  5. Connect the fuel feed hose to the inlet side of SA9127E-7 using the J 43937 3/8 inch Male Fuel Pressure Adapter Line.
  6. Connect the return hose from the SA9127E-7 to the outlet side of SA9127E-7 .
  7. Place the other end of the return hose into the fuel filler pipe.
  8. Connect the fuel pressure gage to the SA9127E-7 .
  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.

Is the fuel pressure more than the specified value?

380 kPa (55 psi)

Go to Symptoms - Engine Controls

Go to Step 10

10
  1. Turn OFF the ignition.
  2. Remove the SA9127E-7 .
  3. Connect the chassis fuel hose to the engine compartment fuel pipe.
  4. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  5. Disconnect the fuel feed pipe at the fuel filter outlet.
  6. Connect the inlet side of SA9127E-7 to the fuel filter outlet using the J 43937 3/8 inch Female Fuel Pressure Adapter Line.
  7. Place the return hose from the SA9127E-7 into the fuel filler neck.
  8. Open the valve on the SA9127E-7 .
  9. Turn ON the ignition, with the engine OFF.
  10. Command the fuel pump relay ON for a minimum of 10 seconds with a scan tool.

Is the fuel pressure more than the specified value?

380 kPa (55 psi)

Go to Step 16

Go to Step 11

11
  1. Turn OFF the ignition.
  2. Remove the SA9127E-7 .
  3. Remove the return hose from the SA9127E-7 .
  4. Connect the chassis fuel hose to the engine compartment fuel pipe.
  5. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  6. Disconnect the fuel feed and return pipes at the fuel filter inlet.
  7. Connect the fuel feed pipe to the inlet side of SA9127E-7 using the J 43937 3/8 inch Male Fuel Pressure Adapter Line.
  8. Connect the fuel return pipe to the outlet side of SA9127E-7 using the J 43937 5/16 inch Male Fuel Pressure Adapter Line.
  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.

Is the fuel pressure more than the specified value?

380 kPa (55 psi)

Go to Step 18

Go to Step 12

12
  1. Turn OFF the ignition.
  2. Remove the J 43937 5/16 inch Male Fuel Pressure Adapter Line from the fuel return pipe and the SA9127E-7 .
  3. Connect the return hose from the SA9127E-7 to the outlet side of SA9127E-7 .
  4. Place the other end of the return hose into the fuel filler pipe.
  5. Open the valve on the SA9127E-7 .
  6. Turn ON the ignition, with the engine OFF.
  7. Command the fuel pump relay ON for a minimum of 10 seconds with a scan tool.
  8. Close the valve on the SA9127E-7 .

Is the fuel pressure more than the specified value?

380 kPa (55 psi)

Go to Step 17

Go to Step 13

13

Inspect the rear fuel feed pipe on the fuel tank for damage and for a restriction.

Did you find and correct the condition?

--

Go to Step 20

Go to Step 19

14

Inspect the fuel return pipe from the fuel filter to the fuel tank for a restriction.

Did you find and correct the condition?

--

Go to Step 20

Go to Step 17

15
  1. Turn OFF the ignition.
  2. Open the valve on the SA9127E-7 .
  3. Remove the SA9127E-7 .
  4. Connect the chassis fuel hose to the engine compartment fuel pipe.
  5. Raise the fuel rail, with the fuel line connected. Refer to Fuel Injector and Fuel Rail Replacement .
  6. Turn ON the ignition, with the engine OFF.
  7. Command the fuel pump relay ON with a scan tool.
  8. Locate and replace the leaking fuel injector. Refer to Fuel Injector and Fuel Rail Replacement .

Did you complete the replacement?

--

Go to Step 20

--

16

Replace the chassis fuel feed pipe. Refer to Fuel Hose/Pipes Replacement - Chassis .

Did you complete the replacement?

--

Go to Step 20

--

17

Replace the secondary fuel tank module. Refer to Secondary Fuel Tank Module Replacement .

Did you complete the replacement?

--

Go to Step 20

--

18

Replace the fuel filter. Refer to Fuel Filter Replacement .

Did you complete the replacement?

--

Go to Step 20

--

19

Replace the primary fuel tank module. Refer to Primary Fuel Tank Module Replacement .

Did you complete the replacement?

--

Go to Step 20

--

20

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3