So I've been trying to chase down the solution to my P1516 code on a '99 XJ8. I realize it shows as a "Gear change PARK / NEUTRAL driving malfunction".

Initially that is the problem I tried to solve for. Went through all the multi-plugs and micro switches etc.

I have no running/shifting issues but the failsafe would appear at a consistent spot on the highway.

It had 20" wheels (don't ask). I just changed them to 18" and now it appears much sooner on test drives. I believe original size was 17".

Can my problem have something to do with wheel speed sensor or something along those lines????

This thing is killin me.

Thanks for your help.

 

Only possible thing of import would be tire diameter. Usually tire side wall is much smaller when going to large wheels, leaving nearly the same outer diameter - how much has this changed between the two different wheel sizes and stock?

 

There was a noticeable difference between the overall diameter of the 20's and stock.

 

Was there anything unusual about this 'consistent spot on the highway', such as a bumb, excess grooving, strange crown in the road, etc.? I'm looking for something that might disturb a loose connection for one of the many sensors - and lower profile tires will transmit more of that shock to the suspension, frame and sensors.

Probably drawing at straws here, but something has to correlate with your symptoms.

 

Ok, so had a trip with no code. Then the next trip it came on so something wasn't right.

Got back in a bit frustrated and jammed it into "D". 40 miles and no error!

Since it's a Gear change PARK / NEUTRAL driving malfunction, I'm guessing it's not quite making good contact with "drive" on the J-gate. That at least makes more sense.

All the gear selections light up so is there something specific I should check or bite the bullet and get a new J Gate?????

I feel there's a little hope!