This guy should let you read the codes. I don't know what he means about defuser.
If you are still interested in the car, stick your head in the boot and there should be a silver box under the parcel shelf. It has a red led which should be flashing codes in a loop. From memory it will just repeated flash small dashes, and will leave a gap between each code. Probably best to grab a pen and paper for this. You'll know once it's looped.
This should at least tell you what errors the 4wd system is throwing up. Multiples things can go wrong, G sensor, speed sensor, ETS pressure switch etc etc.
The good thing with the 32 4wd system is you can just keep it in 2wd mode by pulling the fuse, so it's no constant 4wd like a 33 or 34.
And if you really want you could probably get a shop to convert the car to rwd, or do that yourself. Just depends on if you think the car is a good deal for what it is.
I'd also check the rear of the car out if it has a gts-t badge on it, might of been in a rear ender and they bought a gts-t boot to replace the stuffed one.