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SMU - Revised Fuel Gage Inaccurate or Inoperative Diagnostic Procedure

Subject:Revised Fuel Gage Inaccurate or Inoperative Diagnostic Procedure

Models:1999 Chevrolet Cavalier
1999 Pontiac Sunfire


This bulletin is being issued to revise the Fuel Gage Inaccurate or Inoperative diagnostic procedure in the Engine Controls sub-section of the Service Manual. Please replace the current information in the Service Manual with the following information.

The following information has been updated within SI2000. If you are using a paper version of this Service Manual, please make a reference to this bulletin on the affected page.

Diagnostic Aids
    • Ensure that the fuel level is in the same range as the customer concern.
    • For intermittent diagnosis, refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.

Test Description

The number(s) below refer to the step number(s) in the diagnostic table.

  1. This step tests for a high resistance in the signal circuit and the ground circuit of the fuel level sender.

    2.

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

Step

Action

Value(s)

Yes

No

SCHEMATIC REFERENCE: Engine Controls Schematics (2.2L) or Engine Controls Schematics (2.4L) in Engine Controls

1

Did you perform the Instrument Cluster System Check?

--

Go to Step 2

Go to Diagnostic System Check - Instrument Cluster

2
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Select the PCM display DTCs function on the scan tool.

Does the scan tool display any DTCs?

--

Go to Diagnostic Trouble Code (DTC) List (2.2L) or Diagnostic Trouble Code (DTC) List (2.4L) in Engine Controls

Go to Step 3

3

With the scan tool, select Instrument Panel Cluster, Special Functions and command the fuel gauge UP.

Does the fuel gauge complete a full sweep when commanded?

--

Go to Step 4

Go to Step 12

4

  1. Turn OFF the ignition.
  2. Disconnect the fuel level sender.
  3. Connect the J 33431-C Signal Generator and Instrument Panel Tester between the signal circuit of the fuel level sender and the ground circuit of the fuel level sender.
  4. Turn ON the ignition, with the engine OFF.

    5. Important: Verify the J 33431-C resistance setting with a DMM.

  5. Set the resistance on the J 33431-C to 40 ohms.

Does the fuel gauge display at or below empty?

--

Go to Step 5

Go to Step 6

5

Inspect for the following items:

    • A poor connection at the harness connector of the fuel level sender. Refer to Intermittents and Poor Connections Diagnosis and Connector Repairs in Wiring Systems.
    • A misaligned fuel level sender.
    • A deformed fuel tank.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 8

6

Test the signal circuit of the fuel level sender for a high resistance. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 7

7

Test the ground circuit of the fuel level sender for a high resistance. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 10

8
  1. Remove the fuel level sender.
  2. Inspect for the following items:
    3. • A stuck fuel level sender (i.e. the fuel strainer interfering with the sender float arm).
    • Foreign material in the gas tank (ice).

Did you find and correct the condition?

--

Go to Step 14

Go to Step 9

9
  1. With the J 39200 DMM, measure the resistance of the fuel level sender 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 11

10

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

Did you find and correct the condition?

--

Go to Step 14

Go to Step 13

11

Replace the fuel level sender. Refer to Fuel Level Sensor Replacement in Engine Controls (2.2L) or Fuel Level Sensor Replacement in Engine Controls (2.4L).

Did you complete the replacement?

--

Go to Step 14

--

12

Replace the IPC. Refer to Instrument Panel Cluster (IPC).

Did you complete the repair?

--

Go to Step 14

--

13

Important: Program the replacement PCM.

Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement in Engine Controls (2.2L) or Powertrain Control Module (PCM) Replacement in Engine Controls (2.4L).

Did you complete the replacement?

--

Go to Step 14

--

14

  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