I recently became the proud new owner of a 1990 Jaguar Vanden Plas (my very first Jag). I’m planning on restoring the car as much as possible with a few minor modifications (mostly cosmetic). I have the dreaded transmission symbol on the dash and it’s in limp mode. I have read the e-book on trouble shooting it. However, I’m stumped. I think it’s an electrical issue. I’ve currently got most of the interior out of the car to access the electronics. I keep seeing these black (what I assume to be) built in fuses that go to most of the relays and I don’t know how to tell if they are blown or not…I love the car but am becoming increasingly discouraged. Please help me figure this out.
If you can post pictures of the items you are referring to this might help us to identify them, hope you get n top of the issues as the cars are a lovely thing to drive once properly sorted.
How would I add a pic from my phone since that’s my only way of doing anything these days… they are like a black built in fuse that is cylindrical and has two wires coming into most of them, but, not exiting them. Also, if it’s a ride height issue and I think the SLS System was “mostly” removed is there a sensor I should look at since the car does sit low.
Also, what all can cause the transmission to go into limp mode?
The seventh icon from the left, in your typing window, is for the pictures. I moved you to the XJ40 category.
David
Zachery,
If you own a 1990 XJ6 VdP, you are on the wrong list. You car is more modern than the Series I, II, or III XJ6s or XJ12S discussed on this list. You should be on the XJ40 list.
We don’t have “load leveling”, SLS, Limp Mode or any other fancy modern stuff on our XJs. 
Please try the XJ40 list. That is where your model is discussed.
Paul
Zachary,
Those are diodes with trimming resistor, not fuses. Diode allows current to travel in one direction only.
Dick
Paul M Novak.
you always do this! Every time someone who has an XJ40 comes here for help, you send him to the XJ40 forum. THIS IS THE XJ40 SECTION!!! STOP DOING IT, OK? Jeeeez!!!
Am I correct in thinking that if they are “swelled” that they have went bad? Can the car still function with out them or could I just splice the two wires together? I’ve tried most everything to get the car out of limp mode except replacing the TCM, TPS (cleaned and reinstalled) Rotary Switch (which I cleaned even though all the contacts internally looked great)… can any one please tell me what all will cause the trans to go into limp mode? Is there a ride height sensor that could cause this and where would it be? A brake sensor? Anything…
I have a '94 MY car and there’s a relay in the TCM. I opened up the module and resoldered the cracked joints. It’s one of the things that can cause the limp home mode.
Paul just replied via Email while I changed the category. Also, if I were you I’d appreciate that he takes the time each and every time… and even if he were wrong, Jeez…
Also people will be better off knowing what their car is and where to find help!
David
Zachary,
The diode and resistor is encased in shrink wrap. Heat is applied and the black plastic tubing conforms to the shape of the contained item(s). Then (probably Lucas/Rist) applies the markings. No, there may appear to be swelled but they’re not. Testing of a diode is by a VOM meter or a diode tester. It’s a very simple procedure. Google the process. If you do remove one from its wrap and it tests OK, put it back in the wrap and bind it up with electrical tape. Don’t remove them ! ! ! They protect the circuit and wiring.
Have you checked the brake switch? That damn little switch affects so many different functions.
Happy Motoring,
Dick
1 Like
Joe this post was originally in the XJ (S1,S11,S111) section.
How will I know if the brake switch is bad? I do know that everytime I apply the brakes, the brake light on the dash comes on.
The red ‘brake light’ is informing you that there is a problem in the braking system, probably nothing to do with the brake switch.
Things to check;
With the engine off turn the key to position 11 press the VCM button a code should come up it may show PAD which indicates that either the wear sensors detect that the pad(s) are low and require replacing or the wires to the sensor are broken.
Brake fluid level.
Do you hear the Teves pump fire up when you turn on the ignition?
Does it fire up every time the brake pedal is activated? This might indicate that the nitrogen sphere is U/s
Let us know what transpires.
What is the Teves pump, yes it lights up everytime the brake pedal is pushed. Also I don’t believe the ABS is working because the brakes lock. I have indeed seen the PAD on the when I did the VCM. Will these cause the trans to go into limp mode?
If you go to the top of this page there is a series of headings, one is ‘ebook’ this will take you to the old site where there is a good write up on the XJ40.
The other thing that you could do with is purchase a manual which gives a good insight into the various systems of the ‘40
