Aye, there's basically just 2 areas for the fault to be in:


1) If the starter relay (or beeper) energises when you turn the key, then the fault is in the high power feeds from the battery through the false bulkhead stud & to the starter motor itself-or the ground strap from the engine.

2) If the starter relay does not energise (or your beeper does not beep!) when you turn the key, then the fault lies in the area of the BPM & ignition switch/key/key transponder module.

 

Red October, SteveinFrance,

thanks very much, I'll try this tonight and let you know.

westway, sorry for hijacking your thread!!!

Lincoln

 

Update: For the last two days I have been unable to duplicate the problem. I have taken the car twice for an errand. I traveled approximately 20 miles on both occasions being careful not to shut off the engine for frear I would get stranded. When I returned home I let the car set for about 10 to 15 minutes and started the car. Then throughout the day after the car starts without incident. Without the malfunction I cant go any further. Im a little paranoid because I don't want to be stranded again.

If we all agree that the BPM has been eliminated. The connector to the starter has been eliminated. The Starter Relay eliminated can we assume it is a key or or the key transmitter? If so can the key transmitter be bypassed or enabled? Does anybody have any history in the key or transmitter having intermittent issues like what is happening to me? I'm really perplexed on this one. Thanks again for those who have sent in suggestions.

 

If the starter relay clicks (even better if you've connected a meter to it and get 12V when you try to start) then the whole chain of security/exciter ring/BPM is working.
The car's telling the starter to start but the starter doesn't work.
You've changed the starter motor so the only thing wrong is electrical supply to the starter.

 

OK I finally got it to malfunction. Put the key in after a short drive and about 40 minutes of standing. Turned it once nothing turned it twice nothing. So I beat on the steering column with my fist just beyond the key and it started. Shut it off and it started. So is it a short in the transponder or a bad transponder? My question is reading the previous posts I thought if the BPM and the relay clicked clicked the key and the transponder were working? Apparently something is going on in the steering column. Help!

 

I have combed through the manual and I don't find a sensor or a transmitter in the steering column. However I found this: Ignition key interlock solenoid. Its a small box looking thing near the ignition switch in the steering column behind the steering wheel. Could this be the culprit? Do you know what this solenoid does?

Thanks

 

Hi westway,

maybe have a look at the thread below, its about an exciter ring in the steering column.
https://www.jaguarforums.com/forum/x...er-ring-53165/
You might have moved it when you hit the column with your hand.
here's a pic of it from the jag parts site:

Cheers

Lincoln

 

This has turned out to be a nightmare. Beating on the column doesn't work as it malfunctioned once again Yesterday when it wouldn't start I beat on the steering column and it started. Today I had to go to the store and was in it for only about 20 min. I came out and it started. I came home and let it set for 1/2 hour to 45 minutes and tried to start it. It wouldn't start. I beat on the column and that didn't work this time. It ALWAYS malfunctions after I drive it somewhere and let it sit for About a 1/2 hour or so. It always
starts in the morning or the first start of the day.

Update: After setting an hour I tried to start it. The first start failed.
Then I hit it the second time and held the key in the start position.
Suddenly after a moment it cranked. But it took more than the usual
rotations of the starter then it fired. I shut it down and it started right
up. QUESTION: Could it be a bad contact in the ignition switch? Can I install a bypass start button? Im thinking all I have to do is connect a start button on the solenoid poles. Has anyone ever done this? Then I'd only have to put the key in and turn it to the on position then hit the button. Thanks again for all the help. But this car is way over engineered.

Marv

 

To get back to basics - are you hearing the starter relay click when you turn the key and it doesn't turn over?
If so it isn't the keyswitch, it is starter supply or ground.
Thumping the steering wheel could jolt a bad connection at the starter.

 

The problem could be the reader/exciter coil which sits around the ignition switch. The immobilisation system on these cars is quite complex, and works in the following manner:

The actual ignition key has a uniquely coded transponder in the head of the key-the code on this is read from an exciter/reader coil sitting around the ignition switch, and the signal from this coil is passed to the Key Transponder Control Module (KTCM).

The KTCM checks to see if a valid ignition key is present in the switch, and when it receives the expected signal from the exciter/reader ring around the ignition switch it then signals the BPM to enable the fueling, ignition & cranking functions.

If the KTCM doesn't receive the expected signal, then the fueling, ignition & cranking functions will all be inhibited & the engine cannot be started-you cannot simply 'hot-wire' it either as the KTCM disables several functions that would allow the engine to be started.

If the KTCM is not receiving the correct identification signals from the transponder in the key, then it could well be the exciter/reader ring itself. Verify this by trying the spare key when you get the malfunction-if the spare key gives the same malfunction, then the exciter/reader ring could be at fault.

Another thing to consider is the actual wires in the steering column-as the column moves in & out electrically when you insert the key, there's the very real possibility that over the years the connecting wires have fractured internally due to fatigue stress with the constant back-forth movement of the steering column.

 

If the starter relay clicks it isn't anything to do with the security stuff, it's starter supply.

 

Update: After 10 days and no malfunctions here is what I have concluded. Thinking back now when this started the coolant reservoir developed a leak. It started leaking out of the bottom where the sensor plugs in. It would drip onto the exhaust manifold near the steering shaft. Steam would come up around the hood and I would relieve the pressure and the drip would go away. I ordered a new tank and 10 days ago I pulled the old one and installed the new one. This is when then starting issues have apparently ceased. Can anyone explain this as the tank is on the opposite side of all the electronics and the starter. Right now I'm just happy the car starts but would like to know why. Is there something under the hood that is sensitive to condensation to cause the problem.

Thanks

 

Well Im back.... after 5 weeks of flawless starting it wont start today. Ran a quick errand and I am stuck in a shopping center with the same ridiculous problem. BCM Clicks and won't start. I replaced the reservoir (see above) and its been fine for 5 weeks. PLEASE PLEASE tell me what is wrong this lemon of a car. I hear a click under the back seat simultaneous to the click near the BCM. Is this normal? I'm totally frustrated!!!!

 

After 2.5 hours of trying to start the car I went home and came back 3 hours later. The car started right up like nothing was ever wrong. This car is driving me nuts

 

Westway,

I feel your pain, although mine just refused to start all the time.
One thing I found handy was when I was working on the car alone (or stranded alone) was to add a small beeper into the key areas of the starting circuit (like say at the ground pin on the starter relay).
This allows you to determine if the car is setting that relay or not, mine was not but there was so many other relays which trigger around the same time it was hard to know.

You might sound a bit like CoCo the Clown if your car beeps all the time, but it will for sure help you determine if it is in the starter circuit (SLCM, BPM all those bits) or if it is in the solenoid area.

Let me know if you need more info and I can take you through what I did.

Lincoln

 

Perhaps a relay? Try switching them around in the area you hear clicking.

Intermittent problems are the absolutely most difficult to diagnose and fix, but are usually fairly simple to fix once you find the problem.

A frustrating problem doth not a lemon make.

 

Thanks dsnyder but I tried that early on. That would have been an easy fix. I have found that nothing on this car is simple. Lincoln Ill keep that in mind. Im not sure Im following you. A beeper wont fix the problem. Is it to isolate the electronic device that is malfunctioning? If so what was your issue specifically? Thanks guys

 

Ok- back to the key (transponder) possibilities- do you have more than one key?

If you take off the steering column housing, you will see where the exciter ring is around the ignition switch (it's really easy to remove then) remove the ring, then try to start the car and see if it responds the same as when you have problems. I DID have an issue with my ignition switch on my X300 so that is definitely a possibility- you can check that as well while you are in there. (all of this will take less than 30 minutes)

 

Westway,

You're right it won't fix it, it's designed to isolate where the problem is occurring.
At the top of this page our friend Red October explains the 2 halves of the starter circuit. The half that energies the starter relay and the half that makes the engine turn over.

If you have a beeper parallel to the starter relay and when you try to start and it doesn't start, there are 2 situations
1) it beeps, means all the electronics are fine and your problem is a dodgy earth, power stud, solenoid etc
2) it doesn't beep means somewhere the signal to start is getting lost --> we can then trace which one it might be.

My problem was the wire which supplies constant power to the starter relay was corroded through (the "ok to start" signal is an ignition switched ground).
So my electronic doo hickeys were all fine, I was missing the +12V to the relay.
I think I'm the only person ever to have that fault, but my beeper helped me find it.
My thread has "incorrect part fitted" in the title, it's long but there's a good bit on the starting circuit there.
I chose a beeper as so many other things tick and click in the car, it was a recognisable noise for me.

Cheers

Lincoln

 

Ok guys here's a new twist

This came from another forum. It makes sense but I still don't know. He goes on to say USA cars do not have an immobiliser. Personally if I could bypass the security system it wouldn't bother me. So how do I check if the ECU relay is staying alive and what causes it to do this? Anyone care to comment?

COPY: Now for something different. Are you or the tech. aware that the
ignition lock not only moves in a rotational sense, but a
horizontal direction too? I ask because if the lock and switch do
not truly shut the car down, the starter will not be allowed to
crank the engine simply because a still active ECU 'thinks' the
engine is still running.

The quickest way to find out if my guess is right will not be quick
at all I'm afraid. The only way you'll find out it is to check and
see if the ECU relay is staying live when the starter won't work,
and for that you'll have to wait for the next failure.