Hi everybody.

A long time lurker and very thankful gleaner of info from here. But time for me to come forward and be known. No surprise, I have a problem.

I have a 1994 X300 XJR6 auto. My pride and joy! Until a rampant white van decided to T bone me in the side!

I won't bore you with the sorry saga. But no surprise, once the court case and insurance finally got settled it had been off the road for a couple of years.

The accident damage is now sorted which required welding in a replacement centre pillar and a couple of new doors.

It was when I came to turn it around the fun began. It will not start! The immobiliser will not disengage.

The battery was disconnected before welding.

But assuming it could have been welding damage? I replaced the security module in the boot, along with body control module under the dash, with matching key and ignition barrel.

It still would not start.

I have gone through every fuse and relay and junction block in the car, all check out ok.

It still wont start.

In fact, everything seems to work, including the fob, central locking and security (the indicators flash and get the little beep) and the alarm most definitely works!

But the Engine Check light refuses to stay on which I understand means the immobiliser is still engaged.

It still wont start.

I then went for broke and swapped out a complete set of modules from a working car:

ECU, Body processor, Security and locking, key and barrel, exciter ring and control module, and even the transmission control module (ya never know?)

It still wont start. (I think you can probably spot a pattern?)

I even got an auto electrician to come and have a look (at least that's what he called himself). His assessment? It won't start.

I am feel sure that the fault is a minor one? But as always, finding it is the problem. I have literally gone down every rabbit hole I can find and I am finally admitting defeat.

I need some knowledgeable eyes on the car. Someone familiar with X300's. Rather than a general auto electrician, as I know these have some model specific issues.
I am in Swanley, Kent. (beer can be supplied)

Any suggestions would be very much appreciated. As I really don't want to scrap the car, which is the way things are looking at the mo.

Thanks for taking the time to wade through my sorry tale.

 

Inertia switch?

 

The immobilizer was my first thought here too, although I would have thought your 'electrician' and your rabbit hole tunneling would have highlighted this already, as it has come up a lot in the forum.
It's definitely worth checking though. It's the big button to the left of the ECU, make sure it's pressed down to re-engage the switch/circuit.

 

Hi
Thanks for the suggestion. I think I may have checked this? But it was some time ago?
I also managed to weld-fry the electronics on my Land Rover and went through a similar fault finding process with that. And I may be confusing the two?
But I will definitely have a look! Sometimes it is the most obvious we can overlook?
Oh, Land Rover all fixed. Which somehow makes the problem with the Jag all the more irritating as I would rather have the Jag running than the mud plugger. But such is life

Thanks

 

Unfortunately, no. Just checked and it's not the inertia switch.

There is one symptom I am getting which although I suspect may not be related? But it might prompt a thought with someone?
When I turn the key and everything lights up as it should. I am getting 10 bips coming from the centre consul. And the heater/aircon display is showing an error. But after the bips it displays as normal.

The journey continues.

 

The CLIMATE CONTROL is detecting an ERROR.
You can get the codes from the module manually but you might have a NETWORK fault related to the NO START?

 

I haven't spent much time on the climate control bips as I didn't think it was the reason it won't start? But always ready to be corrected.
I am reasonably handy, but delving into the dark arts of electronic systems is a bit above my pay grade. Which is why I have come to the conclusion I need more knowledgeable eyes on the car.
But thanks for the response.

 

Sorry to hear of your travails, Huggy. I'm not familiar with the action of the immobiliser but going back to basics, does the engine turn over with the key, and if so do the plugs spark and is there fuel reaching the engine?

 

North America did not get RFID keys until 1998MY Jaguars so info from the U.S. and Canada is going to be limited.

 

Thanks for your suggestions. During my rabbit hunt I did check the basics and run a live feed to the starter relay and it works fine.
The problem is with the immobiliser I am reasonable sure. As the telltale light on the dash for Engine Check going out implies the immobiliser is not disengaging? When the immobiliser is locked it cuts power to the starter, fuel and ignition. Which is what I am seeing.

Unfortunately mine is definitely a UK model with the all dancing, all singing security system. From what I understand the X300 got a major update from the XJ40 system? But what also came with it is a fragile system with some unique bugs. And Jaguar in their infinite wisdom claimed back from all the dealers the unique diagnostics that could interrogate the system. The X308 had a redesign and this system can be interrogated by more available diagnostics.

 

If you have had your central pillar replaced, there must have been a decent amount of grinding and welding action around the sill, along which a fairly substantial wiring loom runs. The accident itself could have damaged it too. Have you checked the loom for damage?

 

I was very careful to unclip the loom and move it as far away from work area as possible. As soon as I became aware of the problem, it was the first thing I checked and all is good. I also checked the plugs attached just in case they had been pulled loose?

Thankfully the damage was limited to just bending the centre post and doors. So a careful un-pick of the seams and I didn't have to cut too deep.

 

Here's a few suggestions

1. The Check Engine Light status comes from the Engine ECU. The engine ECU receives a Data signal from the Security/Locking module (hard to test without specialist gear), and then provides a common output of a Ground signal to the BPM and the Check Engine light. I don't know if it would work but you could try grounding the pin at the ECU or BPM and see if that overrides the immobiliser?
If you haven't already done so, it would be worth doing continuity tests of the cables between these modules pin to pin using the electrical diagrams as your guide.

2. In the Jaguar IDS Diagnostics system for the X300, there is a function called "One Shot Fueling". This overrides the immobilisser to allow engine start. This would only help confirm your diagnosis (which I think is correct BTW). You would need to find someone local who has IDS.

3. There is a forum member called @XJRengineer who has the capability to reprogram ECU to eliminate the immobiliser function. You could contact him and ask for costs

Good Luck

 

Hi
I have heard mention of "One shot fueling" But not how to do it. But if access to the Jaguar IDS system is required, probably why I have not seen instructions on how to do it?

I have mild dyslexia and my eyes are not as clear as they once was, and trying to follow the wiring diagrams and pin id marks is a big struggle. But I agree, I do suspect that the issue could be a continuity problem in the circuitry?..... Somewhere?

Thank you very much for the suggestion of contacting XJRengineer. I would have no problem living without the immobiliser if I can get it running again! I shall contact him and see if he can help?

Thanks!

 

My thoughts are check the safety neutral switch located on the left side of the transmission that may be bad and that will prevent the car from starting. the impact may have damaged it internally.

 

Hi
The car drove perfectly well after the impact. And for some time after I was able to start and move it right up until I put it into the workshop for the big repair.
I have checked the module to the side of the gear lever and all seems ok? And the red light is showing correctly.

But from what I understand. If that was the fault. Even though the starter circuit would not work, the Engine Check light on the dash would stay on? Indicating the immobiliser had disengaged?
If I am wrong in this assumption perhaps someone could advise?

 

Check out the post below, there is the wiring diagram on post #8 which would be worth checking out. It shows the wiring diagrams for engine start up.
It sounds like something is not connected in there, so you might need to confirm everything is hooked up as it should be.
Hopefully a continuity test on the relevant circuits should reveal the problem.

https://www.jaguarforums.com/forum/x...starts-223346/

 

Hi
I have had a quick look at the post you suggest, that actually looks rather helpful. Great.
I have put aside some time tomorrow to give attention to the beast, and I shall investigate further using this info.
Thanks

 

I don't know if you have already seen the Jaguar Security System section of the manual that I have attached. Not much help but it does give some insight.
The key components are
The key with transponder chip.
The Security & Locking Control Module (SLCM) which must be configured to the key.
The key transponder exciter coil located around the ignition barrel.

On ignition on the exciter ring around the ignition switch is energised and the key transponder chip is read and the digital data is passed to the SLCM where it is compared with the expected key data. If the data matches the SLCM communicates with the Body Processor Module to enable cranking directly and enable injection via the ECU. Once this is complete the key transponder and all the associated circuitry plays no further part while the ignition remains on. The security signals are digital communication pulses and not simple high or low steady voltages. The Check Engine light should remain on at the end of this initialisation sequence and if it is not on the sequence has failed. Are there any error codes present ?

You have already replaced the key components with known working units so I would agree with Brendan's advice "it would be worth doing continuity tests of the cables between these modules pin to pin using the electrical diagrams as your guide" as if the modules are known to be OK then the fault must lie elsewhere.
.

 

Thanks for you insights. All good info, and helps me understand what is going on. Not least that the system uses a digital pulse the register the key. Which is why my continuity test didn't help at all.
At one point I did wonder if somehow the key transponder code had been lost? Which was one of the main reasons I ended up swapping the whole kit over from the other car. As least I would have a known good point to work from.
The only error code I am getting is a generic, you have an ignition problem.
I am going to try a continuity test, though because of my eyesight this is problematic for me. And there is no one I am able to call upon locally to help.
I am coming to the realisation that my last chance to get the car working again is if XJRengineer can disable the immobiliser for me?