Twice recently, while stopped at a light, my transmission shifted by itself into neutral. My gearshift knob was in Drive and the "D" indicator light began to flash and the engine would simply rev when pressing on the accelerator. Fortunately, I rotated the gearshift control knob into neutral (to match the condition), and rotated again back to "Drive" which seemed to clear the issue and I was back on my way. Also recently, and also twice, while driving at around 30 mph, the same thing happened and was cleared the same way. A CEL indicator has come on but I don't have a code reader. Trying to get some ideas what might be going on. FWIW, my intelligent stop-start has been disabled by a dead battery for 3 years.

I'll be heading to my local independent Jaguar mechanic for him to diagnose and repair but would like to hear from anyone with an educated guess as to what might be the cause of the transmission shifting.

Thanks in advance and I'll update this post when the issue is resolved.

Thomas

 

Weak main battery? Do you still have origonal main battery? (check the terminal for stamped date)

 

That was my first thought as well. I've owned the car 3 years and never have replaced the battery. It was a NAPA brand so likely put in by the original owner of the car and not the dealership. Given the Florida heat and its toll on car batteries, I just replaced it. We'll see.

 

UPDATE
Took the car to Bob Sellers Auto Clinic in Daytona Beach, FL. He specializes in Jaguar repair. SDD scan indicated a few complaints from the Transmission Control Module (TCM) which is located inside the shifter. He replaced it with a used one for $500 and charged $130 labor. Car shifts flawlessly now.
Thomas