P1642 & P1797.....As best I can tell, both these faults have to do with a short circuit, or bad ECM or TCM.

I was just driving around town, and the dash lit up, along with the trans going into limp mode.

I have the brake light on, traction control failure, Transmission failure, and restricted performance messages, along with the check engine light.

I have physically checked for the harness rubbing anywhere. I read and was told that the TCM could cause all of this to happen, and they are known for failure.

I have a used TCM coming, but will I need to have it flashed at the dealer, or is it self learning?........Boy do I hope this solves the problem.......Convertible weather is here!Now is not the time to be driving an X Type sedan........Thanks.......Mike

 

All those faults occurring simultaneously make me think low voltage. Have your battery load tested and alternator checked.

I haven't seen any mention of TCM failure on this forum, so I don't know where you got the info that it's a common problem. If you have a matching VCATS number TCM it might be plug and play but it would not surprise me if a reflash was required.

 

My battery is just a month old, and I load tested it with my trusty VAT 28, and it is showing good. The alternator is putting out over 100 amps, so I kinda think the charging system is ok.

Being on disability kinda puts a crimp on me even going to an independent, so I do with what I read off of Google, and this forum.

It initially happened suddenly, while accelerating down an on ramp(it jerked 3 times), about 20 miles away,(that is when the check engine light went on)on my way home. It didn't go into trans limp mode until I was about 2 miles from my house. I have been getting a failsafe mode message about twice a week, for the last few weeks, so I kinda think something was in the works.......

Who knows though.....These cars are so electrically over engineered it can be anything....Any other ideas are appreciated......Mike

 

Have you cleaned/checked the electrical connections at the bulkheads, main fuses and ground strap? There have also been some reports of corrosion in the batt. cables.

 

Not sure if the 1999 would be the same as my 1997 but ................

I had identical issues and I'm pretty sure it was due to problems with the J Gate. On my car, there are three small microswitches which are operated by movement of the gear lever. Each has a metal lever - like the top right here :





On my car, the years had taken their toll and two of the metal levers had fallen off. I replaced the levers, and since then (touch wood) - all has been good.
Of course, it could have just been disconnecting and reconnecting the plugs that solved it.
But - the CAN goes trough the J Gate, so a good (and cheap) place to start !!

 

I give up! I cleaned the grounds in the trunk, sprayed some contact cleaner in the plugs of the ECM and TCM, did a hard reset, and still had the codes.

It drove flawlessly for 30 miles, even with the check engine light on, and I pulled over for fuel. I started the car back up, and the check engine light went out.

I trust this car about as far as I can throw it, yet I still really dig it. She is kind of like a hot girlfriend, that causes you grief all the time. Do you keep her, or does there come a time when enough is enough? I haven't reached that time, but I know this girl is not good for my emotional health.

I had a hot girl like her before, and married her. After 39 years I still know she is not good for my health. I will keep you apprised of what is happening, but having the check engine light go out just before I turned into the Jaguar dealer tells me she wants me to keep her.....IDEAS????........Mike