GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2002 🢒 Cavalier (CNG) 🢒 Body and Accessories 🢒 Instrument Panel, Gages, and Console 🢒 Fuel Indicator Lamp Inoperative - Alternative Fuels

Circuit Description

The fuel gage select switch assembly contains two components. The fuel gage select switch is used to indicate to the Alternative Fuels Engine Control Module (AF ECM) that the operator of the vehicle has requested the fuel gage display the level of fuel for the DORMANT or non-operating fuel system. The fuel indicator lamp (FIL) is used by the AF ECM to indicate to the operator of the vehicle which fuel system is in use. When illuminated the vehicle is operating on gasoline.

The fuel indicator lamp (FIL) is supplied power by the ignition relay and the ground path is supplied by the AF ECM . The AF ECM will supply ground to the FIL for a two second bulb check at ignition ON during CNG operation or continuously during gasoline operation when the ignition is in the ON or RUN positions.

Test Description

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

  1. The System Check MUST be performed before proceeding with this diagnostic table. Failure to perform the System Check will result in mis-diagnosis.

    2.

  2. This step checks for proper operation of the FIL.

    3.

  3. The FIL should only stay illuminated when the engine is operating on gasoline.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Alternative Fuels (Engine Controls)

2

  1. Turn the ignition OFF and wait 30 seconds.
  2. Observe the fuel indicator lamp (FIL) located in the fuel gage select switch button.
  3. Turn the ignition ON leaving the engine OFF.

Did the FIL illuminate for a two second bulb check and then go OFF?

Go to Step 3

Go to Step 4

3

  1. Start and idle the engine.
  2. Observe the fuel indicator lamp (FIL) located in the fuel gage select switch button.

Is the fuel indicator lamp illuminated while the engine is running?

Go to Fuel Indicator Lamp Always On - Alternative Fuels

System OK

4
  1. Remove the fuel gage select switch from the instrument panel. Refer to Alternative Fuel Gage Selector Switch/Fuel Indicator Lamp Replacement .
  2. Disconnect the fuel gage select switch connector.
  3. Connect the J 35616-200 12-V Unpowered Test Lamp between GROUND and the switch power circuit terminal .
  4. Observe the test lamp with the ignition ON.

Is the test lamp illuminated?

Go to Step 5

Go to Step 7

5
  1. Connect the J 35616-200 between the switch power circuit terminal and the Fuel Indicator Control circuit terminal.
  2. Observe the test lamp as you turn the ignition ON while leaving the engine OFF.

Did the test lamp illuminate for at least a two second bulb check?

Go to Step 8

Go to Step 6

6
  1. Turn the ignition OFF and wait 30 seconds.
  2. Disconnect the AF ECM connectors.
  3. Test the Fuel Indicator Control circuit for continuity between the AF ECM connector terminal and the fuel gage select switch connector terminal.
  4. Inspect for proper terminal contact at the AF ECM and the switch connectors.
  5. Test the Fuel Indicator Control circuit for a short to voltage.
  6. Repair wiring or terminals as necessary.

Was a wiring or terminal repair necessary?

Go to Step 10

Go to Step 9

7

Repair the open fuel gage select switch power supply circuit between the switch terminal and the ignition relay The open condition may be a disconnected CNG harness connector.

Is the repair complete?

Go to Step 10

--

8

Replace the fuel gage select switch assembly. Refer to Alternative Fuel Gage Selector Switch/Fuel Indicator Lamp Replacement .

Is the replacement complete?

Go to Step 10

--

9
  1. Replace the AF ECM. Refer to Alternative Fuels Engine Control Module Replacement .
  2. Program-flash- the replacement control module with the correct vehicle software and calibration.

Is the replacement complete?

Go to Step 10

--

10
  1. Remove all test equipment except the scan tool.
  2. Connect any disconnected components, fuses, etc.
  3. Using a scan tool clear DTC Information from the AF ECM and the gasoline control module (VCM/PCM or ECM).
  4. Turn the ignition OFF and wait 30 seconds.
  5. Start the engine and operate the vehicle.
  6. Observe the fuel indicator lamp and the MIL.
  7. Observe vehicle performance and driveability.
  8. After operating the vehicle inspect BOTH control modules for stored DTCs.

Does the vehicle operate on CNG with normal driveability, no FIL/MIL illumination and no stored DTCs?

System OK

Go to Diagnostic System Check - Alternative Fuels (Engine Controls)