drive problem

Nice easy one for a first post

I have been looking to buy a Prius for some time, all my knowledge is based on what I have read, I have never driven one or consciously even seen one that I can remember.

They certainly are a tad expensive second hand but I have an opportunity to buy a faulty one.

The fault is that under "heavy" acceleration the engine revs, it seems to disconnect from the drive system. My understanding (probably incorrect) is that there are no bands or clutches associated with the drive chain, a planetary set dictates which way power is transfered and electronics decide where the power comes from. My first thought was that this could be a problem with the traction control but as the engine revs up I fear this is not the case.

I think that the problem may be associated with the electric motor drive system, allowing the engine to spin the motor, this only happens for a few seconds then the car will accelerate normally. It sounds very similar to "flair" where a slipping clutch or badly adjusted band in a normal automatic gearbox will allow engine revs to increase during a gear shift.

I haven't seen the car and I do not have any more information about it. I do not know what questions to ask the guy that is selling it that will help me diagnose what may be wrong. The car is a 2002.

I am really looking for some suggestions, it would be wonderful if someone had seen the same problem.

I have no worries about fixing it if the problem is mechanical but an electronic fault worries me somewhat as the electronics are probably all sealed up and potted making any kind of diagnosis difficult.

All input gratefully accepted and appreciated.

 

I did wonder if it may actually not be faulty.

One bit of information I missed out is that when the engine flairs the "hybrid" light comes on, whatever that means.