2001 X308 made in September 2000. Has had a hard shift into 5th with p1722 fault good then limp mode. Has happened 95% of drives. Speed sensors were replaced with fluid a month ago and still barely moves if at all until slamming into 5th gear and limp mode. Now a few times he shifted fine until after a few miles then would slam into 5th.
Question is could it be the 2001-2003 Jaguar XJ8 TCM transmission computer? I'm leaning towards that. Any thoughts would be great.
Matt

 

What is the voltage across the battery terminals with the ignition in the OFF position when checked with a voltmeter?

 

What should it be? I'll have my guy check it tomorrow.
Matt

 

12.6 or more

 

The battery voltage reading depends on when it is taken. If the alternator is good, the reading may be about 13 V immediately after engine switch off. A few hours later, it will read around 12.6 V (which means 100% charged). Due to battery drain by the electronics, the voltage will go down over time (if the car is sitting). I have recorded the voltage readings (car sitting) as follows:

After 1 day - 12.50 V
After 3 days - 12.45 V
After 1 week - 12.35 V
After 10 days - 12.30 V

I have had no problem starting the engine even with the battery voltage reading of 12.20 V.

 

12.5 is fine. It's been this way for 6 months. I bought a guaranteed transmission "computer" on
EBay. It'll be here in a couple days. I'll post what happens. I would be thrilled if this is the issue. And sad it took 6 months to figure it out. It hardly moves a few feet if at all before it slams into gear 5th. We shall see soon.
Matt
PS Bought the Jaguar from town 50 miles away from a guy who had a transmission repair place under him saying he could replace the cable from the shifted to the transmission, he included the used part when I bought the car before he replaced it because I could do it myself. The cable was fine problem was the end bolted to the transmission. Replaced that and problem stayed the same.

 

Computer didn't help. Guy is going to check the wiring and plug connection looking for a problem. Going to check for feedback as well.
Matt