Hello
I am new to this forum and I write with the hope that you may have had the same little trouble with your Xj6/x300 and might be able to help me.

I have had the car for three years, starting at 89,000 miles, and runs very well, except that about once a day, it will suddenly quit working and, when I restart it, the gearbox problem light is on. I drive it about a block in limping home mode, stop the engine and restart it again, and the light turns off and the car works great until the next time, that can be in five minutes or five days.....

It usually happens after you crest a hill, but can happen in plains too
There is not any signal of these failures ever in the car's computer.
We changed the gearbox speed sensor once, about two years ago and the car worked great for about a month, and the routine started again...

If we change the oil in the gearbox, it works for about amonth without trouble. Also, I changed the engine oil last week and the car quit eight times the following day, and the day after that got settled in the routine of an average of one daily failure

I have also noticed that when it is about to quit, there is quite a bit of hunting in the tachometer and in the battery charge reader

We enjoy the car very much and have almost just accepted this as a quirk, but should not be like that

Has this happened to your Xj6? Any ideas?

Thank you very much

 

Well, if what you mean by tach hunting is that the tach seems toi be varying and NOT truly indicating engine speed, then I would guess the problem is the CKPS. It will also give transmission failures, since the transmisison controller looks for reasonabllenee between the engine and transmission speeds. There are enough failures that some folks (not me, yet!) carry a spare.
Good Luck, and let us know how it works out

 

Hello

Thank you Ross.
I will see into this CKPS

However, when I mention hunting, i think that not only the gauges do, but, also, the engine speed and charge

Francisco

 

Gotcha. I assume you have no codes? I wonder if the engine is surging or if the transmission is hunting gears, resulting in engine speed changes. The ckps would most likely make the tach dive to zer. Another "idea"= check the power connections at the bulkheads for tight and corrosion free. Check the ground straps on the engine and the cattery. Good luck.