FICM Diagnostic Circuit
The PCM monitors the FICM diagnostic circuit in order to set FICM related DTCs. The FICM diagnostic circuit is a 5 volt circuit that is pulse width modulated by the FICM in order to communicate diagnostic information to the PCM. The FICM Diagnostic Data table indicates the various PWM signals created.
FICM Diagnostic Data
| Diagnostic Data | PWM Duty Cycle |
|---|---|
| gasoline operation | 25 % |
| CNG operation | 50 % |
| no input activity for more than 5 seconds | 56.25 % |
| FRT high voltage | 62.5 % |
| FRT low voltage | 68.75 % |
| FRP high voltage | 75 % |
| FRP low voltage | 81.25 % |
| CNG injector fault | 87.5 % |
| FICM internal fault | 93.75 % |