Cat 312cl intake filter plugged

2005 with 3400hrs. Machine runs and operates fine but the monitor displays 'Intake Filter Plugged'. New filters didn't do the trick so i was wondering if anyone knows what controls this read out. Sensor or solenoid and where is it located at? I have not been able to find any useful information on the internet. Any help is greatly appreciated. Thank you

Cat 312cl intake filter plugged