Pretty dangded close. Once had a CJD delaership tell me the reason my Liberty diesel was throwing codes for the EGR system wasn't because the EGR valve was fubar - but because I'd installed an air filter restriction indicator on the air filter housing - and that to fix it, instead of simply removing the indicator and plugging the hole (should have seen the customer rep's face when I suggested that
), I needed to order an entirely new air filter housing for $150.
Got my keys back, hightailed it out of their, and haven't been back since.