^ I have the same issue since replacing 2 of my PDC sensors to get the system working again and yes they are clean. I get a lot of false PDC warnings - I was tooling around in DIS once and couldn't find anything to calibrate - I may try again next time I have it hooked up or try running INPA but yeah I feel like some are hyper sensitive and honestly the PDC sucks because of that.

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2018 Ram 2500 6.7L Cummins 68RFE
19k miles -Bright White/Black - Big Horn Sport - Crew Cab Short Bed
2013 X5 35D (CEO's) - Born on 5/17/2013 -
82k miles - Alpine White/Cinnamon Brown/Premium Pkg, Sport Activity/Premium Pkg and Sound/20" Style 214/Running Boards