The fuel gage select switch assembly serves 2 purposes. The fuel gage select switch is used to indicate to the Alternative Fuels ECM that the operator of the vehicle has requested that 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 Alternative Fuels 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 Alternative Fuels ECM and the ground path is supplied through the alternative fuels engine harness ground. The Alternative Fuels ECM will supply power to the FIL for a 2 second bulb check at ignition ON during CNG operation or continuously during gasoline operation when the ignition is in the ON or RUN positions.
The numbers below refer to the step numbers on the diagnostic table.
The System Check MUST be performed before proceeding with this diagnostic table. Failure to perform the System Check will result in misdiagnosis.
This step checks for proper operation of the FIL.
The FIL should only stay illuminated when the engine is operating on gasoline.
The AFO Signal and AFO Signal Command parameters both indicate the state of the alternative fuels operation circuit. The Signal parameter is the state of the enable circuit as monitored by the gasoline control module. The Command parameter is the state of the enable circuit as commanded by the Alternative Fuels ECM.
Step | Action | Yes | No | ||||||
---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | |||||||||
Were you sent here from other diagnostic service information? | Go to Step 2 | Go to Diagnostic System Check - Alternative Fuels (Engine Controls) | |||||||
Did the FIL illuminate for at least a two second bulb check? | Go to Step 3 | ||||||||
Is the fuel indicator lamp ON while the engine is running? | Go to Step 4 | System OK | |||||||
Is the engine operating on GASOLINE? | Go to Step 5 | Go to Step 6 | |||||||
5 |
Was one of the listed causes found and repaired? | Go to Step 10 | |||||||
6 |
Is the test lamp illuminated while the engine is running? | Go to Step 7 | Go to Step 8 | ||||||
7 |
Was a wiring repair necessary? | Go to Step 10 | Go to Step 9 | ||||||
8 | Replace the fuel gage select switch assembly. Is the replacement complete? | Go to Step 10 | -- | ||||||
9 |
Is the replacement complete? | Go to Step 10 | -- | ||||||
10 |
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) |