AW4 won't shift after pressure washing...

My brother pressure washed his 89 XJ engine and undercarage and after driving it around a while, it quit shifting. After checking anything he could think of and letting it set for several hours (overnight) it started shifting after about an hour of driving it around.

What is the likely cause of this?? I would hate to be wheeling with him and have this happen after splashing through some water or mud.

Any ideas of where to look??

Any help would be appreciated.

Thanks,
Paul

tps, trans electrical connectors, and pcm are common to have issues with water best thing I have done to help is waterproofing spray and contact grease usually keep things working right

As above, relube all the connections to get the water out.

Pressure washers operate from 1100 to 2500 psi - they will force water into the connections which disables the electronics. Automotive water tight connectors can't and won't keep a seal much past simple immersion.

Pass the word around and help your buddies keep from coding out or not even starting - don't use pressure washers.

Pressure washers are really good at killing the TPS sensor.

lawsoncl said:

Pressure washers are really good at killing the TPS sensor.

Click to expand...

x2. The tranny needs a functioning TPS to shift.

The whole pressure washer thing is a lie. Just dont squeeze the trigger at the wash and run on low pressure. As far as high pressure use it on anything outside or under the vehicle. Then relube the lock cylinders with graphite.
Pressure washers are only bad if youre a bad washer.