Typically does the whole unit fail or can just a part be replaced as in a potentiometer replacement that I read about in another thread?

I hate the idea of "pluck and chuck" instead of really repairing the defective item.

My reason for suspecting the TA is my ASR light stays on without any noticed abnormal ASR behavior. I only get a code 5 on the computer and resetting only lasts about 1-2 days depending on how aggressive I am with the throttle. The car has already had the TA replaced by the PO 5 years ago?

Anyone have any details on this?