Fuel Mode Operation (KL6 and KL8): Notes

The PCM grounds the AF Enable circuit when operating on CNG. When the AF Enable circuit is grounded the FICM will operate the CNG injectors based upon the PCM pulse width signals. The FICM will convert the FRP and FRT sensors voltage signals to independent PWM signals that the PCM monitors for fuel trim adjustment. The PCM also monitors the FICM Diagnostic Input circuit for proper FICM operation.