Adding carpet will not cause a failure.
There is only 1 type failure on Kwikee steps built in the past 15 years. THE MOTOR. ALL other Failures are not at the step but the various wiring and door magnet type controls that malfunction causing the step to not work. To keep the step from failing(Motor) just
1. Keep the Step mechanism and pivot joints CLEAN and lubed. This means hosing off any mud or debris and then lubing it.
2. Since Kwikee is the largest step supplier in the industry, I have seen more motor failures, even under warranty. This is a defect in the motor armature and nothing can be done to prevent this. BUT, this will happen more often if the steps are not free and clean and lubed. I have not replaced a new type step controller in years. The linkage can break but this is usually caused by lack of maintenance or hitting something with step extended. Doug