I would assume the x300 and x305 to be identical in this respect.
What I found by searching the forum and web is, that the quiescent current should be 43mA.
I measured 110 to 120mA on mine. It drops down to this level a few seconds after locking the car, however it doesn’t go any lower than that. Not even when left over night.
The other thing I found is, that it drops to 30 to 40mA when I draw the fuse for the securit system (I think it is #4 in the fuse box in the boot).
Now I am wondering if the specified 43mA are for cars without security system. If it is for car with security system, mine is drawing far too much current, and also the 30 to 40 mA that remain would still be a little on the high side, as it doesn’t leave that much head room. It would leave only 10 to 15mA for the security system which seems a little low.
30 - 40mA is what you should be expecting when the car has gone to to sleep and is locked.
In your case I would check the alarm chirp sounder. The internal battery is a known problem and could be the reason why you are seeing a higher than normal quiescent draw.
What relates to fuse #4 as this is the problem the drain sould be about 30ma.
If you don’t have the JTIS go to www.jagrepair.com and check the Electrical Guide for your car.
Neil,
It is fuse number 4 in the boot fuse box. It is for the security system. Quiescent current drops from 115 to 35mA when I remove that fuse.
I have the Jaguar service manual for my car, but the security system is not covered (probably intentionally).
I would have thought that the security system would need most of the 43mA that are specified, so I am surprised to see that I am still at 35mA with the fuse removed.
Also, the question is why the security system draws 80mA. An internal battery in the alarm chirp was suggested by Jim, and since my workshop manual doesn’t cover it, I was wondering where the chirp is an what battery it uses and how it can be replaced.
It’s a small sounder in the wheel arch if I recall correctly. The battery is internal to the unit and I believe they are sealed units. Easy way to prove is to disconnect the sounder and then see what the draw is.
Ok, I’ll see if I can find it.
I assume the battery is to make sure it works even with the power disconnected. So is it a clue to a bad battery that pulling the fuse didn’t set of the Alarm?
Harald, somewhere in the back of my SINGLE remaining brain cell IIRC the FET drivers in the Body Control Module can and do go Short Circuit and continuously drain to earth.
That’s where I’d start, unplug it and see if the drain current drops. There is chapter and verse in the Archives on how to open the BCM and on replacing them.
Others with more non alcoholicly damage brain may well chip in with more on this! Come on Bob & Ross.
I think I have removed the fuse for the BCM as well, but I will double check to be sure it was for the BMC. It did not make any difference though.
Regarding the alarm sounder, I had a look at the parts catalogue and now belive to have a passive one without internal batteries. But I’llt try and get access to it and check this as well.
For now I have removed the fuse for the alarm system and was surprised to find out the car still starts. If no other adverse effects emerge, I think I could live without the alarm. Don’t think anyone would steal an XJ12 these days, buying it is only a tiny percentage of the cost involved
Harald, IIRC one of the vagaries of the BCM is that it manages the lighting modules etc. along with others and I think the s/cct LED driver can sink current from those via their individual fuses.
I may be talking bullsh*t but I’m sure this has occurred in the dim and distant past since I joined J-L in 1996/7 when I had a XJ40 which like many suffered a number of annoying electrical issues.
Regards Neil
Neil:
And why do you think MY brain is not alcoholically damaged?
As I recall, one of the current drains in an X-300 was the immobilizer not powering down because of a dodgy lateral key switch. The forum archive is awash with the lateral key switch saga that nearly drove Steve (JagsonGas) crazy.
Fortunately, I have no personal experience since it was assumed that US cars did not need immobilizers because we are not so morally depraved as to go around stealing each other’s cars on a regular basis like you Europeans!
Ok, I removed the chirp sounder - no effect. It is one without a battery, so that seems logical. No news on the BMC front.
I am in Germany and it is a German car, so it does have an immobiliser and the lateral key switch sounds like a possible problem. I’ll try and find out more about this.
Seriously, Harald, if you need some better references to the archived lateral key discussions, just say so. I am pretty sure it will be easy to find and a little slower to sift through.
And yeah, Gary, occasionally someone does shoot someone stealing his car!
