what are reasons for a dealer to void a cars warranty? or is there a way to tell if a used vehicle has voided its manufacturers warranty?

It's been in an accident, the airbag/s have been deployed...someone other than a dealer did an oilchange/maintenance.

i'll explain mazda's system, thinking that most other manufacturers are similar



mazda will warranty the car, until they find out it is a salvage title. two reasons, one enough damage was done that the car was considered destroyed at some point, so its like it doesnt exist. secondly, they, or you have little way of knowing what was damaged, its easy for a salvaged car to have broken parts that look like a warranty repair but arent because it was damaged by an accident



that is basically the only formal policy. you can call mazda, or a dealership with the vin number and they can run the warranty history and tell you if its clear or not.



i have seen in extreme cases where the warranty gets voided for other reasons. if the car has been tampered with, or the owner makes a ton of claims. we've had situations where the car is technically under warranty but we know not to warranty anything on the car, cause the owner is that big of a douchebag. in these cases a change of ownership would make the warranty valid again

Usually if it's an engine thing they check for signs that you used any aftermarket parts, and that will void the warranty. I've heard of cases where aftermarket wheels voided the warranty on this guy's suspension.