Andre, Steve,

I think we may be getting somewhere. If I remember correctly I wasn't seeing ground and 12V respctively on those pins when in P.
So, could it be that is causing the ECM to believe something different than the BCM?
If so, I might just manually ground the RU pin in Park, and see if the issue clarifies itself some more.
If I remember right I had about 10V on RS and 11V on RU, at least one should always be 0V right?

Andre, thanks for the tip with the Pin Out pages, I hadn't realized that they hold the answer I was looking for.

Spoke too soon:
CC8-4 RU is only grounded for N. All other positions are B+ ie ignition 12C
CC8-5 RS is 12V at P or N, rest is grounded.

Oh well.

Cheers,

Lincoln

 

Hi guys,

I shorted the relay for the starter and it turns.
Car doesn't start because that doesn't give gas and spark.
But at least we can discount any issue with the starter or its connections.
Also, I tested the relay and its known good.

So, something prevents the "ok to start" signal being sent.
The gearbox illumination assembly doesn't show the selected gear anymore and the upper portion around P is no longer lit.

I tested the dual linear switch again knowing the pin outs now and at least in P it is ok.
The RU and RS pin outs are also as should be

My next step is to order up a new illumination module, unless someone has a clever idea how to test this one?
They are on eBay for £50, so no reason not to buy one and see if it solves the issue.
If not, then it could be the dual linear switch, but that is part of that £50 eBay deal, so 2 birds etc.

I think it was Steve who asked, I can't hear petrol pump when the ignition is turned on. That would track to something preventing spark and gas, right?


Cheers

Lincoln

 

The illumination module is the key. If it's damaged as you say it can't complete a system check, and it's also the key to the scroll of death and non start, the can bus error can be this part.

The one pictured was fragged, but I refurbed it by re-soldering the wires and replacing the bulbs. Might be possible?
If parts/tracks on the pcb are damaged then a second hand unit would be the best option. It may require new bulbs I can send you a few.



I did ask earlier on in this thread if it was damaged. I'm confident once this is replaced it should start. Good luck

 

I removed the gearbox illumination module and tried to find any damaged traces or loose connections, at least to my eyes it looked fine. The bit where it looks a little burned was only on the protective layer at the top, I couldn't measure a short anywhere there.

I'm still trying to get a replacement out of England, in Germany they just want silly money for these parts.
I found a document which says how you can do some rough trouble shooting of the CAN Network with a multimeter (see attachment).

Basically measure between Pin 6 and 14 on the Data Link Connector (or OBD2 Port) and it should read 60 Ohms, mine reads infinity Ohms.
So I assume that the CAN Bus is disturbed somewhere.
Strangely when I measure the green to green wires on the illumination module I get 0.0 Ohms, same on the yellow to yellow.
Its pretty much just guess work right now, but I suppose I could measure the resistance between pin 6 and the relevant pin into the gearbox illumination connector, maybe the open is somewhere prior to that. At least I should be able to measure if one half of the CAN is open and one is OK?

Comments, suggestions? I'm just trying to keep myself busy while I wait for replacement part :-)

Cheers

Lincoln

 

Hi all,

things often look different in the cold light of day, with a bit more light and a more careful measurement, I get 60 Ohms from Pin 6 to Pin 14 of the OBD connection.
Also if I measure the green to yellow on the gear illumination module whilst plugged in I get 60 Ohms, whilst it was removed from the system I measure 38K Ohms.

So my CAN Network is in fact intact, which is a relief.
Have now finally ordered the replacement parts for the dual linear switch and the gearbox illumination module, so we will know more during the week.

Thanks again for all the help so far,

Lincoln

 

Evening All,

Just got my new used parts from Southwest Jaguar, and tried installing the illumination module
Removed negative pole of the battery, removed old illumination module, installed new, did a hard reset for luck, and reconnected.
Absolutely no change.
Tried installing the Dual Linear Switch of the new (used) gear selector with the same procedure, no change.
Looked forlornly at my Jaguar.

Anyone got any tips?
For reference, it doesn't start. Similar to another thread, I do hear a clicking from an area near the glove box when I turn the igntion key.
Error messages: Gearbox Fault, Engine Failsafe Mode, Incorrect Part Fitted.

If I jumper the starter relay, the starter turns over.

Its still bloody snowing here, so I've not checked all the earths and connections.
BTW: I can't access the car with OBD (PLX Kiwi), would IDS or Mongoose work better? My Jag dealer will charge me 500 to look at the car so it might be worth my while to get my own dealer reader?

Thanks,

Lincoln

PS: Anyone wanna buy a very nice Blue XJR? Hardly used.....

 

Have you checked the full can bus? there are several sections you have to check not just between the Instrument cluster and the gear selector.

 

Hi Andre,

I was of the opinion that if I measure 60 Ohms then I was checking the complete bus as it has 120 Ohms end resistances on both ends.
Or do you have another tip how to do so?

Cheers

Lincoln

 

Evening all,

Spurred on by Red Octobers comments on the "won't start, just clicks" thread, I set about measuring the starter relay again.
The upshot is the BPM controlled signal goes to Ground when I turn the key, exactly as it should. So BPM, dual linear switch, key transponder module are all ok.
However the 12v feed to the relay circuit (not the load, the switching part) is missing. It is showing 0v an 0 ohms to Gnd.
It is fed by fuse 5 (10 Amps) in the engine control compartment. Here there is 12V and the fuse is ok.
This fuse also drives the fuel injection relay (where I measure 0.23V instead of 12V), the ECM and the CATS module.

Does anyone know, is this harness all one piece from fuse to relay? Or does it have a connector somewhere which may be loose?
Also where is the CATS module? Inside the cabin, or in the engine bay? I'd like to see if this gets 12v.

Next step: trace the cable from fuse 5 to relay and figure out where the 12v goes to 0v.

Cheers.
Lincoln

 

wow this is turning into a proper saga!!
lots of great input from the forum.. just like to get back to basics, check & clean engine to body earth cable located n/s of engine/gearbox join (underneath) as the faults you describe could be caused by this.

hope you sort it soon..

 

Sorrymissed your question. I don't have any details about the CAN bus, butthe instrument cluster isn't able to communicate with the devices downstreambased on your symptoms, and the ODBII connector (before the Instrumentcluster) doesn't allow any communication as well to the ECU. This can either becaused by a tripped inertia switch, cabling or a faulty device.

A dealer tool in experienced hands might help further to pinpoint the problem area.

 

The style of the Jaguar wiring diagrams for this model is to show all splices, connectors and taps involved in any wire.

Try a new fuse anyways. It is doubtful that the fuse is good given the 0 ohms to ground. It should have fried with a direct short to ground. It will likely fry again since the short is confirmed by the 0.23v to the fuel injection relay.

 

Thanks Plums, Avos, RobXJR6!
I'll give a new fuse a go. I did measure the resistance and inspect it but its a cheap part.

I found the harnesss connection points, seems to be quite close to the fuse box, will trace the wires here and see.

I think the fails make sense in this context.
no power to the ECU ==> no OBD response
no power to starter/injection relay ==> no start
no power but CAN connection to ECU ==> incorrect part fitted (and puts the blame on the gearbox, as it is beside this in the CAN loop).

its -10C here, so it may be the weekend before I venture out again.
Thanks to everyone who helped during this odyssey!!

Lincoln

 

Great News! We are almost there.

Today I figured out I had been making a mistake on the engine managment vs engine compartment fuse box.
Now that I measure the correct fuse, there is no switching power to the starter relay neither at the fuse nor at the relay.
Removed Fuse Box to investigate and check the wires. Found a wire to the headlights which was damaged and cut and spliced it to repair. That explains why my headlights didn't work once after a car wash, but sadly does not fix the problem.

Once I found the correct fuse box guide I could recognize that relay 7 (ignition +) was not closing.
I jumpered the relay and could get the intercooler pump to pump, the engine to turn over and the OBD working. It reports P1230 Voltage to Petrol Pump relay too low. (Battery is at 11.7V, will be swapped out ASAP).
Also the gearbox fault, the engine failsafe and the incorrect part fitted all went away.

I raised relay 7 a little and stuck a GND to the GND pinof the switching circuit and everything came to life. So I know that the switched GND number 6 is not coming to the pin.
I tried to measure the GND pin on the relay to the pin on the back of the fuse box, but get an open. I think this is because of the diode, I need to remeasure with red on the pin and black on the fuse box.
Also the pin LS7-9 green connector, yellow and white cable does not switch to ground. It is routed through the inertia switch, so I might press that again, in case I tripped it.

Also the ground circuit is grounded on the EMS bulkhead ground stud, I cleaned the LH EMS ground stud and will do the same on the bulkhead ground stud when I find it. Looks like its in the middle of the engine bay, behind the throttle body.

But for now my plan is, install a pre-charged battery, jumper the relay number 7, start the car and get the car to my garage, where we can take things further.

Also with the relay jumpered when I stand on the brake the interlock solenoid clicks and everything works as it should.

Thanks everyone for your help so far, it only took me 4 weeks to find a fairly simple fault. :-D
Cheers,

Lincoln (who is tremendously excited, in a way you just don't get with cars that work everyday )

 

Evening all,

I attached a charged battery, and jumpered the relay number 7, but it would not start.
So I went back to basics and asked myself why relay 7 doesn't get ignition switched ground.
The ignition switch switches ground, so I removed the lower cowl and measured that it does indeed get and switch ground.
Then I measured that this grounded line goes to FC1 Pin 14, a 54 way thru panel connector by the glovebox (LHD). This then goes to the intertia switch connector CA6 and back out.
So far all is well, I measure GND at each point and when I turn the key from 2 to 1 to 0, it loses GND as it should.
This then goes back across the car to FC3 pin 2, which is hidden under the footrest on the drivers side. Here I also measure GND on Pin 2, switchable with ignition.
So everything inside the car is fine ( I will start putting all the bits back together now).
But when I measure between FC3-2 connector (ie the male side to Pin 2, if that makes sense), and the connector LS7-9 (green plug on the back of the fuse box), I get an open.

So my question is: when the 54-way thru panel connector beside the footrest (LHD) goes thru the panel, where does it go?
I assume somewhere into the wing area?
I'm thinking my next move should be remove the left wing and trace that wire to the fuse box.
Anyone got any better ideas?

I think I'm getting very close to finding the issue, especially if I know that there is no connection between 2 pins, which should be connected, maybe its as simple as a broken wire or loose connector somewhere.

Cheers,

Lincoln

 

Update: JEPC tells me this connection goes to the Forward Harness, see picture.

I found an VandenPlas Forward Harness for sale in the US and it looks to have a big 54 way connector on this area. I have also highlighted the green connector where I don't measure ground.

If anyone has a good picture of how this connection looks, please let me know.
I'm wondering if just the wheelarch liner can be removed or if the wing/fender has to come off.

Actually looking at how the Forward Harness is routed and the plastic grommet thing in "Forward_Harness_3", which looks like the air filter inlet grommet on the opposite side, its more likely that the wire is damaged somewhere at the front, near where the headlight wire was damaged.

I think I'll put operation wing/fender removal on hold for a while until I can verify the wire at least back to that grommet area.
This would also make sense in terms of being disturbed or chewed on by a marten or a weasel as a root cause.

But if someone has pics of the fender area, please post.

Thanks

Lincoln

 

Recently I had a look on my forward harness, under the left front fender, and the label states that is for non-North America , probably on your green label it's the same. The NA don't have headlights leveling and this is probably one reason that the harnesses are different. Try on ebay.de, I seen a few cars for parts there, you will need the exact chassis no match.

 

Thanks Flay,
I'll make sure to get a non-US 98 XJR harness, I know of two that are breaking at the moment in Germany.
But first I want to verify that the fault is indeed in this part.
I checked in the electrical guide for all LS3 connected wires and apart from a Yellow White, there is only one white Yellow wire, so I will tap into this white yellow wire and measure back to the footwell and foward to the connector at the fuse box.
That should narrow down the area to find a break.

Also I see that the pin 1 on this LS3 connector has to do with the brake switch and as that is clearly releasing the interlock when I jumper the igntion + relay, I think a loose 54 way connector behind the wing is very unlikely. I can't imagine a situation that would cause pin1 to be connected and pin 2 to not have connection, so that job goes further down the list of priorities (not least because I'm scared of not being able to relaign it properly).

So, number one theory right now, somewhere in the forward harness there is damage to that white and yellow wire, possibly chewed open.

Cheers

Lincoln

 

Great detective work. It isn't my model so I can't help with the 'physical' stuff but I can't fault your electrickery.
Keep us informed.

 

Thanks Steve,

your vote of confidence is a nice boost on a Monday morning.
I'm just getting back into troubleshooting electrical stuff, been a desk jockey for too long!
I was measuring the wrong plug for about an hour on Sunday until I finally figured it out.

Will post back with whatever I find, apparently racoons have been seen in the area. God only knows what they eat on Jaguars.

Cheers

Lincoln