Hi all, looking for some help with my 2000 XJR where the battery runs down over 3-4 days so that the car needs to be jumped. Runs and starts fine as long as it's driven. Newer battery that tests fine. Only odd thing going on with the car is that when parked the drivers mirror needs to be readjusted up every time and I've seen it move on it's own on occasion.
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I've tested the voltage across all the fuses in all 5 boxes and each is <= 0.1mv but I'm seeing a parasitic draw of 0.35A. I've tried pulling the fuse for the door controller in case the mirror circuit was the problem, no change.

2 questions:

1/ How much parasitic draw is normal?
2/ How long will it take for all the circuits to sleep if I start pulling fuses? I'm thinking that's the next thing to try. Pull all the fuses from each box in turn, wait long enough to know everything's asleep and remeasure

Thanks
Mike

 

These questions have a vague ring... about 25mA and system sleeps just over 30 minutes....but its been a long time since I last needed to know it, so not 100%.

Alternator is generating 13.8 - 14.4V to the battery, and all your earth points are in good fettle?

 

I am not certain if a hard reset will clear the issue, but it may be worth a try.

 

Acceptable current drain and sleep times

 

“How much draw is normal” really depends on who you ask.
.030ma - .050ma seems to be the sweep of X # of people’s answers. Obviously the lower the number the better.

As stated by Sean, 30 minutes is about right. Before you go too far down the rabbit hole of diagnosing the draw, start with these first. Make absolutely sure the glovebox door isn’t slightly open enough for the light inside to remain on.

Lubricate the ignition key lock cylinder and work it quite a few times as that little metal door has to *snap* shut when you pull the key out every single time or else the modules will not go to sleep.

Lubricate the trunk key cylinder and drivers door lock cylinder and work them several times. This won’t prevent any modules from going to sleep but, it’s good practice every so often. Put your phone in the trunk with video recording towards the 2 lights to make sure they turn off when the trunk is shut.

Other than that, I would have all 4 doors wide open and using a screwdriver, latch all 4 door locks as if they were closed, then use the key in the drivers door to manually lock and arm the system. Watching the amp meter, you’ll see it go to sleep between 15 & 30 minutes. The door mirror reset every time could be a clue that the door module is not happy also.

Good luck.

 

This is for XK8 but should also apply to XJ8 (from the Service Training Course 682):

 

Thanks all. I didn't realize the security system needed to be armed to allow the other systems to go into sleep mode. Once I added that to my test it brought the overall load down to 100mA before pulling any fuses.

After a day of testing it's looking like the driver's seat control module may be the culprit. I'm going to retest with a fully charged battery to confirm. Nice to see they are interchangeable between sides so I should be able to confirm if it's a module issue fairly easily.

 

That is a lot of work to determine that vampire's location. My hat is off to you.

 

I retested this weekend and the drivers seat module draws 44mA while the passenger one draws 16mA when sleeping. I switched them over and the higher load switched to the other side. Both are higher than the numbers quoted above of 0.5mA. With both seat modules disconnected the draw is 48mA so still higher than the 20-30mA above.

Interestingly, after switching modules, the door mirror weirdness appears to have stopped. I'm thinking that was something to do with the memory circuitry for the drivers seat position and the middle connector that's used only on the drivers side.

The module may have issues but I'm also wondering if I've got something keeping the car awake. I had checked the glove box and trunk lights and no problems there. I've lubricated the ignition key lock cylinder to make sure the little metal door is closing and inserting/removing the key appears to trigger movement of the steering columns etc as expected. Anyone know of the BPM is responsible for sending the other modules to sleep?

 

Hi guys, just for future reference....

When figuring out that arming the car might be a good idea other that just waiting, it then dropped the last bit down to 0.01A, I don't have the best amp meter so this could be somewhere 10-19mA i guess.

I have had a logger connected to see if something suddenly wakes up and draws amps, the logger now says 0, before it measured -0.11A

My car is a 2000 euro spec XJR.

My problem seem to be a faulty but new battery. It is a cheaper 5-year warranty "unbranded" local brand. Never again :-)

 

Do you have an intelligent sounder or a passive alarm sounder? If it's an intelligent sounder, a common problem is the inbuilt Ni-Cad batteries going dead and the car constantly is trying to charge the dead batteries. All UK cars have intelligent sounders. However, I believe US cars have passive sounders.

 

The system is not drawing any power right now, but maybe good to check anyway. How do i know what type of sounder i have, and are the types interchangeable without mods? Or can i change battery cells to newer type?

 

You have to look at it, looks like this:



The internals are sealed so it is not possible to replace the batteries (NiCd). I do not know whether one can just plug in a "stupid" sounder.

 

Have a look at this to replace batteries if required.