My 92/93 AJ6 convert has a trans warning light that doesn't go out when starting the car cold or hot and shifts through all gears with a "thump". After driving stop n' go on errands, it goes out and shifts properly for the remainder of the errands trip. I understand it may be related to the TPS on the throttle body and have checked it for possible wiring issues, cleaning contacts etc. Replaced the trans relay in the trunk 2 months ago...no change. Car had TPS replaced years ago @ 150K miles. Car has 225K now. Think I should bite the bullet and just buy a new one?
Dave in AZ

 

Dave,

As we know the XJS trans warning light is often a fail-safe to protect the transmission when there's a problem elsewhere. I would get the fault codes pulled and see where is the underlying issue.

Good luck

Paul

 

Yes. It could be a failing solenoid on the valve body (somewhat pricey and complicated to replace), could be a bad transmission ECU (cheap and easy), or something else.

Its worth having checked out. The transmission is a common ZF transmission not unique to Jaguar.

 

Its your dirty TPS. Its not giving correct values to the module so it will go into limp mode. It may already have to small holes drilled into the TPS housing. I already went through this with my car.
https://www.jaguarforums.com/forum/x...cation-214280/

 

Brewtech...thx for personal input, I agree. I'll try spray TPS, and contacts again. Curious about your "drill holes" comment. What's that all about?
Dave in AZ

 

The sensor is housed inside of the red plastic cover. With the car up in the air, reach the TPS and drill two small holes on the bottom horizontal surface(lowest point) Grab a can of electronic cleaner with a straw. Insert the end of the straw inside one of the holes and spray the inside of the housing until the fluid running out of the other hole comes out clean. No need to remove the sensor, plus from now on, oil will make its way out via the snakebite holes, preventing oil from pooling inside the housing.

 

Its easier working from underneath the car

 

Brewtech... clever idea! Next time I get to friend's garage who has a lift. BTW, sprayed the crap out of everything before going out on errands. Light was on when leaving my garage. 20mi later, 1st stop, light was out when leaving and stayed out for remainder of trip. Life in a an old Jag.

Dave in AZ

 

Excellent. Now you know where the problem occurs. Transmissions and module along with relays are pretty reliable. Its the TPS what stops talking to the system, so the Transmission does what it should to essentially make you fix the issue and prevent you from driving it. Just tap through and dont drive the drill bit too far into the housing. You could damage the sensor inside.