Hello everyone

i am new to the forum and trying to figure out why my 2007 XJ 2.7D is stuck in park after I spilt a fizzy drink onto the centre consul.

Update
heres what I’ve checked so far
1. Brake light fuse in boot/trunk fuse box ok
2. Brake switch fuse in cabin fuse box ok
3. Gear selector actuator operates as expected when I send direct power to the 2 wires in the actuator itself.
4. I removed the gear selector unit from the car and placed it on a warm radiator overnight in case it was still wet or damp from the fizzy drink contamination. The whole unit is bone dry now.

The only thing I can think of now is the circuit board on the gear selector shown in the photo below is. This is where the fizzy drink dripped through and contaminated the board just underneath where the gear selector numbers are.

the only thing I haven’t done is locate the brake switch as I’m not sure where to locate this at the moment. I’ve read that if this switch doesn’t work then the actuator won’t kick in. I would have thought that if this was the case, then the brake lights wouldn’t work either, but they do in fact work without fault.


2nd update following further investigation
Since my last addition I have managed to dig a little deeper and in addition to my previous findings mentioned above, I have also checked the following

5. Gear stick know was a bugger to come off as it was smothered in locktite on the knob thread. This resulted in the knob just turning and had come loose from the metal threaded post it sits on. To get this off, you need to pull the knob away from the shaft with almighty force and if you’re lucky, it will come detached. I was lucky and it came away despite almost giving up and cutting it off. £30 for a second hand replacement forced me to try harder. Putting it back together with a blob of glue did the job and saved me some cash.

6. having removed the gear knob it now allowed me access to the circuit board under the black gear selector trim and enabled me to remove debris and grime which had fallen down there over the past 13 years. Look out for the hidden screw which you will need psychic powers to find which you will find under black wheel and I don’t mean the screw in the centre of the wheel, there’s another hidden one which you will only find if you rotate the wheel and dive into the core is that the gear stick slides along through the wheel. Anyway once you check for fizzy drink damage and burn colours on the circuit board you are also able to check the tiny little switch which operates the actuator. I thought I had found my culprit here as there was a very old raisin or sultana stuck at the trigger switch. Having cleared all of the crud out, all was reassembled and tested again.

7. Sadly all of the above checks still failed to pull the gear selector out of park so the next step was to locate the brake pedal switch and check to see if that was working. On my XJ there are two switches, a green one near the higher part of the pedal and also Blue switch almost identical in shape positioned just below the green one. Both springy brake switches were in contact with the brake pedal. I reckon that if I removed them both from their seated position that the springy contacts would be fully extended and this would then allow my selector to push into gear. But this was not to be and once again it did not make any difference.


In conclusion it looks like it could be a dodgy brake switch but not sure which one does what, do I replace the green switch, the blue switch or both? Any suggestions are welcome.

If this fails I guess I may as well just purchase a complete second hand selector unit from eBay and hope that fixes the problem.

I will keep you posted in case anyone else has a similar problem. I will also add a couple more photos of the dismantled selector unit.


How the selector separates from the base

Another view

Note the screw in the middle of the wheel, there is another hidden screw which you will find if you turn the wheel round to view through the gear shaft channel. Not sure if the correct terminology.

Once you get the top part separated you can then check for raisins and sultanas caught around the actuator switch

This is a top down view of the selector unit

If you look closely you will see the little switch poking out through the shadows.

This is the actuator switch after been removed and cleaned.

These are the two switches which were attached to the brake pedal which I guess one of them sends power to the little actuator switch when the brake pedal is pressed, the other I guess sends a signal to the brake lights. I’m not sure about this yet though.



I’m still stuck 🤔🥴😊



Jaguar XJ 2.7D gear selector stuck in park





any advise would be grateful please
cheers Colin

 

I'm not sure that I can provide any good advice at all, and I could be way off base here. However, it does appear that what we're trying to do here is to activate the 'Gearshift Interlock Solenoid' which would apparently permit the operator to manually glide through the gears as long as the ignition switch is at least in the 'On' position, and the brake switch is activated. For the time being, I would ignore the brake switches as you didn't spill the drink on those. As you can see from the electrical diagram, the 'Gear Position Switch' from the 'Transmission Control Module' seems to be a very important player here. Actually, depending on which gear is selected (Park, Reverse, Neutral, Drive, 5th, 4th........), the 'Transmission Control Module' provides a coded binary signal to the 'J-Gate Module'. There is also the 'Mode Switch' on the 'J-Gate Module' which may also come into play. If that circuit board under the column was actually the 'J-Gate Module' perhaps it was damaged from the spilt drink as it certainly stands to reason. Anyways, good luck!

 

Thanks for the electrical diagram and guidance. After everything I’ve done so far, I decided to order a second hand unit from EBay. That should arrive next week if all goes well. Also the rest the brake switches too as they were pretty cheap.

Fingers crossed that a replacement unit does the trick.

thanks again for you support

rgds Colin

 

Having had a similar issue I think you are assuming it's an electrical and not a mechanical issue. The issue on my 05 XJ8 was caused by the shifter cable guide bolt coming loose and falling off. With the extra slack in the cable any one of the shift sensors is not being read properly Likely the interlock switch. Cheap fix, install a new bolt.

 

Having had a similar issue I think you are assuming it's an electrical and not a mechanical issue. The issue on my 05 XJ8 was caused by the shifter cable guide bolt coming loose and falling off. With the extra slack in the cable any one of the shift sensors is not being read properly Likely the interlock switch. Cheap fix, install a new bolt.

 

hello and thanks for the reply back to my problem.

You are correct, I am assuming it is linked to an electrical fault instead of mechanical as I have had no previous warning of the problem until I spilt a fizzy drink onto the consul.

Starting the car up the very next morning was when the problem began. If swapping the unit over doesn’t work, I will take your advice and look at the loose bolt in the shifter cable mechanism.

thanks again for your help
Regards Colin

 

Friends, after the OP spilt the drink over the console, he stated that he could no longer shift out of 'Park' the next morning. I mean, it would only be logical to surmise that some damage had likely occurred inside the console. If the board that was shown in the photo was indeed the J-Gate module, and if that board was adversely affected by the spilt drink,, then it's not going to matter in the slightest how well the 'Gear Position Switch', the 'Brake Switch' or the 'Ignition Switch' were functioning (mechanically or otherwise). I mean, electronics typically does not cope well at all in damp conditions as water is obviously a conductor of current. If that circuit board was indeed doused with the drink, there could have been well over a hundred shorts across the entire board at that instant. Something on that order would be bound to damage the electronics throughout that board. Lest we forget, the J-Gate module is the one that activates the 'Gearshift Interlock Solenoid", and a faulty J-Gate module will obviously prevent that action from occurring.

 

Final update on my sticking gear selector...

A replacement selector unit fixed the problem however it also seemed to damage the brake pedal switch too unless this was coincidental.

I paid £140 plus £10 shipping for the entire selector unit from EBay plus I bought a red and green brake pedal switch for less than £20.

moral of the story is NEVER SPILL ANY AMOUNT IF LIQUID ON YOUR CENTRE CONSUL in particular around the gear selector.

thanks again for everyone’s support with the fault finding tips.

Cheers
Colin

 

Looks like money well spent, and I'm glad that the problem was resolved. Good job!