Fuel Mode Operation

2004 Oldsmobile Bravada AWDSECTION Fuel Mode Operation
WARNING: This page is about a different car, the 2004 GMC Sierra and 2004 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The PCM opens the AF enable circuit when operating on CNG. When the AF enable circuit is open the FICM will operate the CNG injectors based upon the PCM pulse width signals. The FICM will convert the FRT, FTP and FTT sensors voltage signals to PWM signals that the PCM monitors for fuel trim and fuel gage adjustment. The PCM also monitors the FICM status signal circuit for proper FICM operation.

RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.