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For 1990-2009 cars only

Fuel Gage Inaccurate or Inoperative Gas

Diagnostic Aids

    • Verify that the fuel level is in the same range as the customer concern.
    • For intermittent diagnosis, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
    • Refer to Fuel Level Specifications in order to verify the correct readings for the fuel level sensor. The Fuel Level Remaining parameter is available on the scan tool in the PCM EVAP data list.

Test Description

The numbers below refer to the step number on the diagnostic table.

  1. This step tests for a high resistance in the signal circuit and the low reference circuit of the fuel level sensor.

  2. DTCs will be set in the PCM when you perform this diagnostic table.

Step

Action

Value(s)

Yes

No

Schematic Reference: Instrument Cluster Schematics

1

Did you perform the Instrument Cluster Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Instrument Cluster

2

  1. Disconnect C301.
  2. Connect the J 33431-C Signal Generator and Instrument Panel Tester between the signal circuit and the low reference circuit of the fuel level sensor on the female terminal side of the connector.
  3. Turn the ignition ON, with the engine OFF.
  4. Important: Verify the J 33431-C resistance settings with a DMM.

  5. Vary the resistance on the J 33431-C from 40-250 ohms.
  6. Refer to Fuel Level Specifications in order to convert from resistance to fuel gage display.

Does the fuel gage display the correct fuel level?

--

Go to Step 4

Go to Step 3

3

  1. Install a scan tool.
  2. Turn the ignition ON, with the engine OFF.
  3. Important: Verify the J 33431-C resistance settings with a DMM.

  4. Vary the resistance on the J 33431-C from 40-250 ohms.
  5. Refer to Fuel Level Specifications in order to convert from resistance to fuel level percentage.
  6. Important: Turn the ignition OFF momentarily between the resistance settings in order to quickly update the scan tool display.

  7. With the scan tool, observe the Fuel Tank Level Remaining parameter in the PCM Enhanced EVAP Data data list.

Does the Fuel Tank Level Remaining parameter display the correct fuel level percentage?

--

Go to Step 10

Go to Step 5

4

Inspect for the following items:

    • A high resistance in the signal circuit or the low reference circuit of the fuel level sensor between C301 and the fuel level sensor
        Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
    • A poor connection at the harness connector of the fuel level sensor
        Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.
    • A misaligned fuel level sender
    • A deformed fuel tank

Did you find and correct the condition?

--

Go to Step 15

Go to Step 7

5

Test the signal circuit of the fuel level sensor for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 6

6

Test the low reference circuit of the fuel level sensor for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 9

7

  1. Remove the fuel level sender.
  2. Inspect for the following items:
  3. • The fuel level sender is stuck, perhaps due to an interference with the fuel strainer.
    • The fuel tank contains foreign material, for instance ice.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 8

8

  1. With the J 39200 DMM, measure the resistance of the fuel level sensor while moving the float arm.
  2. Observe both the analog and digital displays on the DMM.

Does the resistance change smoothly across the specified range?

40-250 ohms

Go to Diagnostic Aids

Go to Step 13

9

Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 14

10

Test the fuel level signal circuit to the IPC for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 11

11

Inspect for poor connections at the harness connector of the IPC. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 12

12

Replace the IPC. Refer to Instrument Cluster Replacement .

Did you complete the replacement?

--

Go to Step 15

--

13

Replace the fuel level sensor. Refer to the appropriate procedure:

    •  Fuel Level Sensor Replacement in Engine Controls - 4.3L
    •  Fuel Level Sensor Replacement in Engine Controls - 5.0L and 5.7L
    •  Fuel Level Sensor Replacement in Engine Controls - 8.1L

Did you complete the replacement?

--

Go to Step 15

--

14

Important: Program the replacement PCM.

Replace the PCM. Refer to the appropriate procedure:

    •  Powertrain Control Module Replacement in Engine Controls - 4.3L
    •  Powertrain Control Module Replacement in Engine Controls - 5.0L and 5.7L
    •  Powertrain Control Module Replacement in Engine Controls - 8.1L

Did you complete the replacement?

--

Go to Step 15

--

15

  1. Use the scan tool in order to clear the PCM DTCs.
  2. Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2

Fuel Gage Inaccurate or Inoperative Diesel

Diagnostic Aids

    • Verify that the fuel level is in the same range as the customer concern.
    • For intermittent diagnosis, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
    • Refer to Fuel Level Specifications in order to verify the correct readings for the fuel level sensor.

Step

Action

Value(s)

Yes

No

Schematic Reference: Instrument Cluster Schematics

1

Did you perform the Instrument Cluster Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Instrument Cluster

2

  1. Disconnect C301.
  2. Connect the J 33431-C Signal Generator and Instrument Panel Tester between the signal circuit and the low reference circuit of the fuel level sensor on the female terminal side of the connector.
  3. Turn the ignition ON, with the engine OFF.
  4. Important: Verify the J 33431-C resistance settings with a DMM.

  5. Vary the resistance on the J 33431-C from 40-250 ohms.
  6. Refer to Fuel Level Specifications in order to convert from resistance to fuel gage display.

Does the fuel gage display the correct fuel level?

--

Go to Step 3

Go to Step 4

3

Inspect for the following items:

    • A high resistance in the signal circuit or the low reference circuit of the fuel level sensor between C301 and the fuel level sensor
        Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
    • A poor connection at the harness connector of the fuel level sensor
        Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.
    • A misaligned fuel level sender
    • A deformed fuel tank

Did you find and correct the condition?

--

Go to Step 20

Go to Step 5

4

Test the signal circuit of the fuel level sensor for an open, for a high resistance, or for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 20

Go to Step 6

5

  1. Remove the fuel level sender.
  2. Inspect for the following items:
  3. • The fuel level sensor is stuck perhaps due to an interference with the fuel strainer.
    • The fuel tank contains foreign material, for instance ice.

Did you find and correct the condition?

--

Go to Step 20

Go to Step 11

6

Test the low reference circuit of the fuel level sensor for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 20

Go to Step 7

7

Test the fuel sender buffer module ignition 1 voltage circuit for an open, for a high resistance, or for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 20

Go to Step 8

8

Using a DMM measure the voltage between the instrument cluster and the fuel sender buffer module.

Does the voltage measure greater than the specified value?

8.0 V

Go to Step 9

Go to Step 12

9

  1. Disconnect the fuel sender buffer module.
  2. Measure the voltage at the passlock 5 volt reference circuit. Refer to Circuit Testing in Wiring Systems.

Is the voltage at the specified value?

5 volts

Go to Step 16

Go to Step 10

10

Test the Passlock module 5 volt reference circuit for an open, for a high resistance, or for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 20

Go to Step 15

11

  1. With the J 39200 DMM, measure the resistance of the fuel level sensor while moving the float arm.
  2. Observe both the analog and digital displays on the DMM.

Does the resistance change smoothly across the specified range?

40-250 ohms

Go to Diagnostic Aids

Go to Step 18

12

Test the ground circuit of the fuel sender buffer module for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 20

Go to Step 13

13

Test the fuel level signal circuit to the instrument cluster for an open, for a high resistance, or for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 20

Go to Step 14

14

Inspect for poor connections at the harness connector of the IPC. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 20

Go to Step 17

15

Inspect for poor connections at the harness connector of the passlock module. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 20

Go to Step 19

16

Replace the fuel sender buffer module. Refer to Fuel Sender Buffer Module Replacement .

Did you complete the replacement?

--

Go to Step 20

--

17

Replace the IPC. Refer to Instrument Cluster Replacement .

Did you complete the replacement?

--

Go to Step 20

--

18

Replace the fuel level sender. Refer to Fuel Sender Assembly Replacement in Engine Controls - 6.5L.

Did you complete the replacement?

--

Go to Step 20

--

19

Replace the passlock module. Refer to Theft Deterrent Module Replacement in Theft Deterrent.

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 2