Hello,
RE my 2002 3 Series Touring 218i (2L). The battery, which is new, drains when the car is parked at a rate of ca. 3A. It does this most of the time, but not all the time. If I leave it for, say, a week, there will be sporadic periods of hours or even a day or more when it drains at less than 100 mA, but then it will start draining at 3A again.
Any ideas /suggestions please? I suspect a relay (just guessing), but then everything seems to work.
Thanks
Richard
Hi Richard, and welcome to the forum.
Really, there's no guessing with parasitic draw; you have to test, or you have to ask ISTA (BMW's diagnostic computer system).
Unfortunately, with an E46, ISTA's not going to be of much help, because the energy diagnosis really began with the E60, I think.
So you're going to need to test, using a multimeter, car asleep, door latches rolled (to make the car think it's closed.
Then you pull fuses, one at a time, until the draw goes away.
Okay, you want guesses....I'll do my best:
Any aftermarket electronics (?)
Final Stage Resistor
Hood switch
Wet or corroded amplifier plug....does any electrical device NOT work?
Chris Powell
Racer and Instructor since, well. decades, ok?
Master Auto Tech, owner of German Motors of Aberdeen
BMWCCA 274412
German Motors is hiring ! https://www.bimmerforums.com/forum/s...1#post30831471
Thanks Chris,
Car is standard; no fancy electronics. Everything I have checked works, but I could be missing something perhaps. I don't have an ammeter capable of measuring 3A, my little multimeter only does up to 0.25A, so I have to measure the drop in voltage over at least 10 hours to detect the drop. I could start by pulling the most likely fuses though, so thanks for that suggestion.
Regards,
Richard
another option to try would be checking current draw across the fuses after the car is asleep.
if you do a google search on vw parasitic draw test you'll find a video and writeup about this process.
'95 325iS - auto to manual swap done!
I have zero experience trying to test current draw with a .25 amp tester over a period of 10 hours. Not quite sure how that would work. I can tell you that if a multimeter tries to measure amperage beyond its capabilities, it usually blows the fused circuit. I'd have to recommend a better test device.
Chris Powell
Racer and Instructor since, well. decades, ok?
Master Auto Tech, owner of German Motors of Aberdeen
BMWCCA 274412
German Motors is hiring ! https://www.bimmerforums.com/forum/s...1#post30831471
I recommend you buy/borrow a digital volt/ohm meter that’ll measure the necessary current. Then, disconnect the battery’s ground/earth connector and connect the meter’s leads to the battery and the ground/earth cable. Allow the car to go to sleep. Start pulling fuses one at a time. Something major is kaput if you’re car’s pulling 3 amps of current.
I actually own half a dozen multimeters, including two which are amp-clamps. It has seemed that after a while, the amp-measurement goes awry. Hopefully that won't happen with my new Fluke:
https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1
But you really need to be able to read instantaneous draw, so you can know when you've found the culprit.
Chris Powell
Racer and Instructor since, well. decades, ok?
Master Auto Tech, owner of German Motors of Aberdeen
BMWCCA 274412
German Motors is hiring ! https://www.bimmerforums.com/forum/s...1#post30831471
Start with the fuses for the radio. I have similar issues. One short was in the tail lights but if I left the car go about 10 days I would lose the radio and then the whole works. Then start looking for info on the k-bus.
ME:"I want to make my car faster and lighter"
THEM:" Get out and let someone else drive"
Fluke makes some of the best test equipment. Use Fluke test equipment troubleshooting Navy electronix.
You need to do this. There are vids on youtube to show you how to do it. From my research it will be limited to a few areas but they are a pain to get at. All involve grounds and most time corrosion. It is time consuming but a friend and a 12 pack gets it done in most cases. FYI on some Porsches if you leave the keys in it draws this much and the battery is dead in hours. Ask me how I know? (twice, can't fix stupid).
If you have a Bentley, the wiring diagram helps a little but the amp draw and fuse pull is where you are going to end up. That is why I suggest the fuses for that radio as you would be surprised how much junk goes through there. Best of luck!
ME:"I want to make my car faster and lighter"
THEM:" Get out and let someone else drive"
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