Moved to the XJ40 section. Thought that you would get a better response here.

 

Welcome !
It sounds like a solenoid problem

 

You may be in limp home mode. On the driver's side of the transmission you will see an octopus looking thing with wires going up towards the shifter. Loosen the three bolts so that you can move the rotary switch, but do not remove the bolts. Put the ignition in the run position and without the motoring running. Move the rotary switch until the light goes out and re-tighten the bolts. Do not move the rotary switch very much. I would be surprised if you had to go a 1/4 of an inch in either direction.

This should put you back in normal mode. You will eventually need to to replace the switch. It's only a temporary fix--maybe weeks, maybe a year.

That's my guess and it's free to try.

 

Ken, You are my hero!!!

 

If it turns out to the be the problem. If on Monday he says that didn't get it, I'll be standing here scratching my head like a monkey doing a math problem.

 

LOL, you'll be like a professor trying to solve the most ordeal phenomenonsand henceFIFA World's BesT player ....Errrr what was that [&:]oh yes hence Nobel prize

 

LOL

 

What is this limp mode I hear so much about? What exactly is it and why does it happen? I describe my problem in the "Overheating?" thread I posted. My local techinitian checked it for any overheating problems and everything was fine. He said the fan clutch was a little slow and replaced it. So I'm now pretty sure its a tranny problem but didn't have the time to leave it there so he can check it out. I don't remember exactly what he said, but he did mention this limp mode. I did notice that this only happens in Indio (I work in Oceanside and drive to Indio every weekend to visit) where the temperature is much hotter.

 

I will have to check into the 1989 model. You don't have the rotary switch on the side of the transmission. During 88 & 89 Jaguar used a linear switch in the j-gate housing of the shifter. Let me do some home work on this one.

 

Hey Russ...did you ever solve the limp mode problem? I'm chasing one on my '90 xj6 as we speak??? Replaced the TCU and cleaned the harness going into the trans. I'm going to try the rotary switch twist tomorrow.
Thanks Frank

 

The most common reason for the transmission control module to default to "limp home" mode and illuminate the gearbox failure warning is a faulty throttle position sensor.

The throttle position sensor is located on the underside of the throttle body, and its' sliding cotact is rotated by throttle shaft and butterfly opening. That's how the electronically controlled transmission konws when to downshift (unless the full throttle kickdown switch is depresses). That transmission has no mechanical kickdown cable or vacuum modulator.

Normally, failure of the throttle position sensor will cause the 'check engine " light to come on. If it has already been illuminated for a while (uncorrected code 39 is a common example), then you will have to read each code and clear it to read the next one. The TPS may cause limp home without the check engine light, I'm not sure about that but I doubt it.

About the only other problem with these transmissions not shifting corrctly is when water gets inside the Transmission control unit (TCU). It is located behind the right side underdash panel. There are points of water ingress on the 1993 and 1994 cars that cause all sorts of problems, and this is one of them. There is an old factory bulletin that describes the installation of a water shield for the TCU to help with this problem. It doesn't happen often, but was common enough to inspire a factory band aid.

The only real knock against '93-'94 XJ6 is engine oil burning on start-up from oil leaking past the valve stem seals. Those cars, and their successors which used the same transmission and similar engine, are nearly indestructable. All of the problems are minor, only the expense and scarcity of some of the components is sometimes a nuisance.

 

Hey Jeepster,

No problem, although I wouldn't be too concerned about the TCU, it's not really that common for it to get a shower.

One point along this thread to consider, there are the occasional items for XJ40 that might be a problem to get in the future. The TPS was hard to get for a while, I haven't tried lately. Once I had to buy an earlier style and change the plug 'cause I couldn't get the '94 item. The fuseboxes are discontinued, and those frequently corrode from getting wet due to the same water leaks. And I think the DBC10009 combined relay is no longer supplied, that's the one that fails and kills your parking lights.

Whether TaTa spins Jaguar off to a new owner or keeps it, the parts supply for older models is likely to be low on their priority list of customer satisfaction concerns. We might end up doing a little more hunting for used parts in the future. It's not a big enough issue to change my mind about the reliability of these cars, there just isn't that much that can kill them other than the rust. It's just an issue to keep in mind, in my opinion.

 

'94 has many unique parts as well. That's what will get really tough are the one year only items.