Here are some of the most common reasons extended warranty claims are denied:
The part(s) in question were not covered by the warranty.
The part(s) in question failed due to preexisting conditions.
The part(s) in question failed due to aftermarket modifications (e.g., a lift kit damaging your suspension).
The vehicle was driven too long while repairs were needed.
The vehicle was not properly maintained.
The claim was filed during the mandatory waiting period.