GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1998 🢒 Express 🢒 Body and Accessories 🢒 Instrument Panel, Gauges, and Console 🢒 Fuel Gage Inaccurate or Inoperative

Fuel Gage Inaccurate or Inoperative Gasoline

Step

Action

Value(s)

Yes

No

1

Did you perform the Instrument Cluster System Check?

--

Go to Step 2

Go to Instrument Cluster System Check

2

Perform the fuel gauge system test with the Tech 2.

Does the fuel gauge respond appropriately to the Tech 2 commands?

--

Go to Step 3

Go to Step 4

3
  1. Disconnect the pump and sender connector.
  2. Place the ignition switch in the RUN position.
  3. Place jumpers in harness connector cavities E at CKT 1581 (PPL) and F at CKT 470 (BLK).
  4. Hook the red leads of the J 33431-C to each jumper.
  5. Set the resistance to 40 ohms, and then to 250 ohms.

Does the fuel gauge indicate near E then near F?

--

Go to Step 6

Go to Step 7

4
  1. Disconnect VCM connector C1 (BLU).
  2. Place the ignition switch in the RUN position.
  3. Hook one red lead of the J 33431-C to harness connector C1 cavity 9 for CKT 30 (PPL).
  4. Connect the other red tester to a good ground.
  5. Set the tester resistance at 0 ohms.
  6. Observe the fuel gauge.
  7. Set the tester resistance at 90 ohms.
  8. Observe the fuel gauge.

Does the fuel gauge indicate EMPTY, and then FULL?

--

Go to Step 8

Go to Step 5

5

Inspect CKT 30 (PPL) for opens or shorts to ground between VCM connector C1, cavity 9 and IPC connector cavity B2.

Is there an open or short to ground in CKT 30 (PPL)?

--

Go to Step 10

Go to Step 9

6

Replace the fuel sender.

Is the repair complete?

--

Go to Instrument Cluster System Check

--

7

Repair the open/short circuits in CKT 1581 (PPL) or CKT 470 (BLK).

Is the repair complete?

--

Go to Instrument Cluster System Check

--

8

Replace the VCM.

Is the repair complete?

--

Go to Instrument Cluster System Check

--

9

Replace the IPC.

Is the repair complete?

--

Go to Instrument Cluster System Check

--

10

Repair the short or open in CKT 30 (PPL)

Is the repair complete?

--

Go to Instrument Cluster System Check

--

Fuel Gage Inaccurate or Inoperative Diesel

Step

Action

Value(s)

Yes

No

DEFINITION: The fuel gauge indicates well above empty when the vehicle runs out of fuel, or the fuel gauge indicates well below full after filling the tank.

1

Was the Instrument Cluster System Check peformed?

--

Go to Step 2

Go to Instrument Cluster System Check

2
  1. Disconnect the connector at the fuel tank level sender.
  2. Place the ignition in the RUN position.
  3. Jumper the test leads from a J 33431-C between cavity A for CKT 1589 (PPL) and cavity D for CKT 1057 (BLK) of the tank connector.
  4. Adjust the resistance of the tester to 40 ohms.
  5. Observe the fuel gauge.
  6. Adjust the resistance of the test to 250 ohms.
  7. Observe the fuel gauge.

Does the fuel gauge indicate EMPTY, and then FULL?

--

Go to Step 3

Go to Step 4

3

Replace the fuel tank level sender.

Is the fuel gauge accurate and operative?

--

Go to Instrument Cluster System Check

Go to Step 4

4
  1. Turn the ignition switch to the OFF position.
  2. Disconnect the connector at the electronic variable orifice Passlock™ module.
  3. Connect a fused jumper wire between the Passlock™ module connector, cavity B1 for CKT 451 (BLK/WHT), and ground.
  4. Place the ignition switch in the RUN position.
  5. Adjust the resistance of the J 33431-C to 40 ohms.
  6. Observe the fuel gauge.
  7. Adjust the resistance of the test to 250 ohms.
  8. Observe the fuel gauge.

Does the fuel gauge indicate EMPTY, and then FULL?

--

Go to Step 5

Go to Step 6

5

Repair the open in CKT 451(BLK) between the Passlock™ module connector, cavity B1, and ground G101.

Is the fuel gauge accurate and operative?

--

Go to Instrument Cluster System Check

Go to Step 6

6
  1. Remove the jumper wire between the Passlock™ connector B1and ground.
  2. Connect a jumper wire between the Passlock™ module connector, cavity B5 for CKT 1057 (ORN/BLK), and ground.
  3. Adjust the resistance of the J 33431-C to 40 ohms.
  4. Observe the fuel gauge.
  5. Adjust the resistance of the test to 250 ohms.
  6. Observe the fuel gauge.

Does the fuel gauge indicate EMPTY, and then FULL?

--

Go to Step 7

Go to Step 8

7

Refer to Passlock Diagnostic System Check in Variable Effort Steering.

Is the fuel gauge accurate and operative?

--

Go to Instrument Cluster System Check

Go to Step 8

8
  1. Disconnect the test lead of the J 33431-C from the fuel tank level sender connector, cavity D for CKT 1057 (BLK).
  2. Connect the lead to ground.
  3. Adjust the resistance of the J 33431-C to 40 ohms.
  4. Observe the fuel gauge.
  5. Adjust the resistance of the test to 250 ohms.
  6. Observe the fuel gauge.

Does the fuel gauge indicate EMPTY, and then FULL?

--

Go to Step 9

Go to Step 10

9

Repair the open in CKT 1057 (BLK) between the fuel tank level sender connector, cavity D, and the Passlock™ module connector, cavity B5.

Is the fuel gauge accurate and operative?

--

Go to Instrument Cluster System Check

Go to Step 10

10
  1. Place the ignition switch in the OFF position.
  2. Reconnect the Passlock™ module.
  3. Reconnect the fuel tank level sender.
  4. Disconnect the connector at the fuel sender buffer module.
  5. Jumper the test leads of the J 33431-C to the fuel sender buffer module connector, cavity L for CKT 30 (PPL), and ground.
  6. Adjust the resistance of the J 33431-C to 0 ohms.
  7. Observe the fuel gauge.
  8. Adjust the resistance of the test to 90 ohms.
  9. Observe the fuel gauge.

Does the fuel gauge indicate EMPTY, and then FULL?

--

Go to Step 11

Go to Step 20

11
  1. Using a voltmeter, backprobe the fuel sender buffer module connector, cavity A.
  2. Connect the black lead of the voltmeter to ground.
  3. Place the ignition switch in the RUN position.

Is the voltage greater than the specified value?

10 V

Go to Step 13

Go to Step 12

12

Repair the open in CKT 39 (PNK) between the fuel sender buffer module connector, cavity A, and GAUGES fuse 4 at the IP fuse block.

Is the fuel gauge accurate and operative?

--

Go to Instrument Cluster System Check

Go to Step 13

13
  1. Using a voltmeter, backprobe the fuel sender buffer module connector, cavity B for CKT 705 (GRY).
  2. Connect the black lead of the voltmeter to ground.

Is the voltage within the specified range?

4.5-5.5 V

Go to Step 17

Go to Step 14

14
  1. Using a voltmeter, backprobe the Passlock™ module connector, cavity B6 for CKT 705 (GRY).
  2. Connect the black lead of the voltmeter to ground.

Is the voltage within the specified range?

4.5-5.5 V

Go to Step 15

Go to Step 16

15

Repair the open in CKT 705 (GRY) between the Passlock™ module connector, cavity B6, and the fuel sender buffer module connector, cavity B

Is the fuel gauge accurate and operative?

--

Go to Instrument Cluster System Check

Go to Step 17

16

Refer to Passlock System Check in Variable Effort Steering.

Is the fuel gauge accurate and operative?

--

Go to Instrument Cluster System Check

Go to Step 17

17

Connect an ohmmeter between the Passlock™ module connector, cavity M for CKT 451 (BLK/WHT), and ground.

Is the resistance less than the specified value?

5 ohms

Go to Step 18

Go to Step 19

18

Replace the fuel sender buffer module.

Is the fuel gauge accurate and operative?

--

Go to Instrument Cluster System Check

Go to Step 20

19

Repair the open in CKT 451 (BLK/WHT) and splice S112.

Is the fuel gauge accurate and operative?

--

Go to Instrument Cluster System Check

Go to Step 20

20
  1. Reconnect all of the disconnected components.
  2. Disconnect the connector at the instrument cluster.
  3. Connect a fused jumper wire between the instrument cluster connector, cavity B17, and the instrument cluster harness connector, cavity B17, for CKT 39 (PNK).
  4. Connect a fused jumper wire between the instrument cluster connector, cavity B13, and the instrument cluster harness connector, cavity B13, for CKT 451 (BLK/WHT).
  5. Connect the red lead of a J 33431-C to the instrument cluster connector, cavity B2 for CKT 30 (PPL).
  6. Connect the other lead of the tester to ground.
  7. Adjust the resistance of the tester to 0 ohms.
  8. Observe the fuel gauge.
  9. Adjust the resistance of the test to 90 ohms.
  10. Observe the fuel gauge.

Does the fuel gauge indicate EMPTY, and then FULL?

--

Go to Step 21

Go to Step 22

21

Repair the open in CKT 30 (PPL) between the instrument cluster and the fuel sender buffer module connector, cavity L.

Is the fuel gauge accurate and operative?

--

Go to Instrument Cluster System Check

Go to Step 22

22
  1. Connect a fused jumper wire between the instrument cluster connector, cavity B17, and B+.
  2. Leave the fuse jumper wire connected between the instrument cluster harness connector, cavity B13, and the instrument cluster connector, cavity B13, for CKT 451 (BLK/WHT).
  3. Connect the red lead of the J 33431-C to the instrument cluster connector, cavity B2 for CKT 30 (PPL).
  4. Connect the other lead of the tester to ground.
  5. Adjust the resistance of the tester to 0 ohms.
  6. Observe the fuel gauge.
  7. Adjust the resistance of the test to 90 ohms.
  8. Observe the fuel gauge.

Does the fuel gauge indicate EMPTY, and then FULL?

--

Go to Step 23

Go to Step 25

23

Repair the open in CKT 39 (PPL) between the instrument cluster and the IP fuse block.

Is the fuel gauge accurate and operative?

--

Go to Instrument Cluster System Check

Go to Step 24

24

With an ohmmeter, measure the resistance between the instrument cluster harness connector, cavity B13 for CKT 451 (BLK/WHT), and ground.

Is the resistance greater than the specified value?

5 ohms

Go to Step 25

Go to Step 26

25

Repair the open in CKT 451 (BLK/WHT)/CKT 551 (TAN/WHT) between the instrument cluster and ground G101.

Is the fuel gauge accurate and operative?

--

Go to Instrument Cluster System Check

--

26

Replace the instrument cluster. Refer to Instrument Cluster Replacement .

Is the fuel gauge accurate and operative?

--

Go to Instrument Cluster System Check

--

Fuel Gage Inaccurate or Inoperative Gasoline Export

Step

Action

Value(s)

Yes

No

1

Did you perform the Powertrain OBD System Check?

--

Go to Step 2

Go to

2

Does the fuel gauge indicate well above empty when the vehicle runs out of fuel or does the fuel gauge indicate well below full after filling the tank?

--

Go to Step 3

Go to

3
  1. Place the ignition switch in the OFF position.
  2. Disconnect the connector at the fuel pump and sender.
  3. Place the ignition switch in the RUN position.
  4. Jumper the test leads from a J 33431-C
  5. Adjust the resistance of the tester to 40 ohms.
  6. Observe the fuel gauge.
  7. Adjust the resistance of the tester to 250 ohms.
  8. Observe the fuel gauge.

Does the fuel gauge indicate EMPTY, and then FULL?

--

Go to Step 5

Go to Step 4

4
  1. Place the ignition switch in the OFF position.
  2. Disconnect connector C1 at the vehicle control module (VCM).
  3. Turn the ignition switch to the RUN position.
  4. Connect the red lead of the J 33431-C
  5. Connect the other lead of the tester to ground.
  6. Adjust the resistance of the tester to 0 ohms.
  7. Observe the fuel gauge.
  8. Adjust the resistance of the tester to 90 ohms
  9. Observe the fuel gauge.

Does the fuel gauge indicate EMPTY, and then FULL?

--

Go to Step 13

Go to Step 6

5

Replace the fuel pump and sender. Refer to Fuel Sender Assembly Replacement in Engine Controls.

Is the repair complete?

 

Go to

--

6
  1. Turn the ignition switch to the OFF position.
  2. Disconnect the connector at the instrument cluster.
  3. Connect a fused jumper wire between the instrument cluster connector cavity B17, and the instrument cluster harness connector, cavity B17, for CKT 39 (PNK) wire.
  4. Connect a fused jumper wire between the instrument cluster harness connector, cavity B13 for the BLK/WHT (451) wire, and the instrument cluster harness connector, cavity B13, for CKT 451 (BLK/WHT) wire.
  5. Connect the red lead of a J 33431-C
  6. Connect the other lead of the tester to ground.
  7. Adjust the resistance of the tester to 40 ohms.
  8. Observe the fuel gauge.
  9. Adjust the resistance of the tester to 250 ohms.
  10. Observe the fuel gauge.

Does the fuel gauge indicate EMPTY, and then FULL?

--

Go to Step 7

Go to Step 8

7
  1. Locate the open in the CKT 30 (PPL) between following components:
    2. • The Instrument Cluster
    • The VCM connector C1
  2. Repair the open in the CKT 30 (PPL) between following components:
    3. • The Instrument Cluster
    • The VCM connector C1

Is the repair complete?

--

Go to

--

8
  1. Connect a fused jumper wire between the instrument cluster connector, cavity B17, and B+.
  2. Keep the fused jumper wire connected between the instrument cluster connector, cavity B13, and the instrument cluster harness connector, cavity B13, for CKT 451 (BLK/WHT).
  3. Connect the red lead of a J 33431-C
  4. Ensure that the other lead is still connected.
  5. Adjust the resistance of the tester to 0 ohms.
  6. Observe the fuel gauge.
  7. Adjust the resistance of the test to 90 ohms.
  8. Observe the fuel gauge.

Does the fuel gauge indicate EMPTY, and then FULL?

--

Go to Step 9

Go to Step 10

9
  1. Locate the open in the CKT 39 (PNK) between the following components:
    2. • The Instrument Cluster
    • The IP Fuse Block GAUGES Fuse 4
  2. Repair the open in the CKT 39 (PNK) between the following components:
    3. • The instrument cluster
    • The IP fuse block  GAUGES Fuse 4

Is the repair complete?

--

Go to

--

10

With an ohmmeter, measure the resistance between the instrument cluster harness connector, cavity B13 for CKT 451 (BLK/WHT), and ground.

Is the resistance greater than the specified value?

5 ohms

Go to Step 12

Go to Step 11

11
  1. Locate the open in CKT 451 (BLK/WHT)/CKT 551 (TAN/WHT) between the following components:
    2. • The instrument cluster
    • Ground  G101
  2. Repair the open in CKT 451 (BLK/WHT)/CKT 551 (TAN/WHT) between the following components:
    3. • The instrument cluster
    • Ground  G101

Is the repair complete?

--

Go to

--

12

Replace the instrument cluster. Refer to Instrument Cluster Replacement

Is the repair complete?

--

Go to

--

13
  1. Reconnect the VCM connector C1.
  2. Turn the ignition switch to the RUN position.
  3. Use a voltmeter in order to measure the voltage at the fuel pump and sender harness, cavity F for CKT 470 (BLK).

Is the voltage in the specified range?

4.5-5.5 V

--

Go to

14
  1. Turn the ignition switch to the OFF position.
  2. Disconnect the VCM connector C301.
  3. Turn the ignition switch to the RUN position.
  4. Use a voltmeter in order to measure the voltage at the VCM connector C301, cavity 19 for CKT 470 (BLK).

Is the voltage in the specified range?

4.5-5.5 V

Go to Step 16

Go to Step 14

15
  1. Locate the open in CKT 470 (BLK) between following components:
    2. • The fuel pump and sender
    • Connector C301
  2. Repair the open in CKT 470 (BLK) between following components:
    3. • The fuel pump and sender
    • Connector C301

Is the repair complete?

--

Go to

--

16
  1. Turn the ignition switch to the OFF position.
  2. Disconnect the VCM connector C3
  3. Turn the ignition switch to the RUN position.
  4. Use a voltmeter in order to measure the voltage at the VCM connector C3, cavity 19 for the CKT 470 (BLK) wire.

Is the voltage within the specified range?

4.5-5.5 V

Go to Step 17

Go to

17
  1. Turn the ignition switch to the OFF position.
  2. Disconnect the VCM connector C301.
  3. Connect the red lead of the J 33431-C
  4. Connect the black lead of the J 33431-C
  5. Turn the ignition switch to the RUN position.
  6. Adjust the resistance of the tester to 40 ohms.
  7. Observe the fuel gauge.
  8. Adjust the resistance of the test to 250 ohms.
  9. Observe the fuel gauge.

Does the fuel gauge indicate EMPTY, and then FULL?

--

Go to Step 18

Go to Step 19

18
  1. Locate the open in CKT 1581 (PPL) wire, or the CKT 470 (BLK) wire between the following components:
    2. • The fuel pump and sender
    • Connector C301
  2. Repair the open in CKT 1581 (PPL) wire, or the CKT 470 (BLK) wire between the following components:
    3. • The fuel pump and sender
    • Connector C301

Is the repair complete?

--

Go to

--

19
  1. Turn the ignition switch to the OFF position.
  2. Disconnect the VCM connector C3.
  3. Connect the J 33431-C
  4. Connect the J 33431-C
  5. Turn the ignition switch to the RUN position.
  6. Set the resistance of the J 33431-C
  7. Observe the fuel gauge.
  8. Set the resistance of the J 33431-C
  9. Observe the fuel gauge.

Does the fuel gauge indicate EMPTY, and then FULL?

 

Go to Step 20

Go to Step 21

20
  1. Locate the open in CKT 1589 (PPL) wire or CKT 470 (BLK) wire between the following components:
    2. • Connector C301
    • VCM connector C3
  2. Repair the open in CKT 1589 (PPL) wire or CKT 470 (BLK) wire between the following components:
    3. • Connector C301
    • VCM connector C3

Is the repair complete?

--

Go to

--

21

Refer to Diagnostic Information and Procedures in Engine Controls.

Is the fuel gauge accurate and operative?

--

Go to

--