.It mean"He has had a car"="He had a car'?
NO. The two sentences have different shades of meaning..
1. He has a car/ He has got a car: He owns a car
2. He has had a car: At some point in his life he possessed a car, we don't know whether or not he possesses one now (as bhai said)
3. He had a car: At some past time, which is probably clear from context, he possessed a car. He may or may not possess one now; only context will make that clear.
There are situations in which it may be possible to use either #2 or #3 without a significant difference in meaning. That is
not to say that #2 = #3.
'He has had a car for ten years' means that his possession of a car began ten years ago and continues today. 'He had a car for ten years' tells us that this ten-year period was in the past.
Context is vital.