BMW Forums : BimmerForums banner

2002 E46 330d - parasitic battery leak

5K views 16 replies 7 participants last post by  thegoodbadandugly 
#1 · (Edited)
E46 330d - parasitic battery leak * FIXED*

i am having a dead battery after leaving my car alone for 3 days. i have had a new battery fitted and the problem persists. alternator output has been checked.

i have read several posts on here about how to try to find the leak. i have also read and tried to follow the wikihow guide

http://www.wikihow.com/Find-a-Parasitic-Battery-Drain

i follow the instructions:

- set the meter to read DC current.
- disconnect the negative lead.
- connect one meter probe to the battery post
-connect the other meter probe to the negative cable.

but i dont get any readings on my multimeters ( i have tried 2 meters)
on any of the settings.

other things to note:
the alarm goes off when the battery lead is taken off. when the meter is connected as above i cant get the alarm to switch off (the alarm or car dont respond to the key buttons) the boot lights or any light for that matter dont work.

i must be doing something very wrong or my car is configured different.

advice is so very desperately needed. i need the car daily now for the school run and cant have an unreliable car..
 
See less See more
#2 ·
What you have to do is put the meter in circuit so that you can read the current. If your alarm is going off, then your meter is not set up correctly. Most meters require you not only change to amps, but also move the +ve lead to a different socket. Did you do this?
 
#3 ·
hi

one meter has the wires fixed. my old trusty rapitest.

on the other which i bought from argos today for £25, the only one they do. the black wire goes to 'com' and the red wire to a hole marked 'mA' (fused 200mA max) the settings are on A (with a dash and dotted line under) i tried all numbers in this setting 2m, 20m, 200m

when you say the meter has to be in circuit.. isnt that what i am doing? by breaking the circuit and then connecting the meter to the two ends (cable and battery post)

isnt the meter supposed to complete the circuit again and let the current thru. but it doesnt seem to be
sorry to sound thick.. neal.
 
#10 ·
hi

did as gildersol said and i am now getting a reading.

the reading i am getting is 0.029 when the multimeter is set at 2m.
(black lead connected to 'com' and red led connected to '10A' jack)

i have read that the BMW E46 should have a reading of 0.040 when asleep and mine is below that.

any ideas as to what is goin on?
 
#11 ·
*************************FIXED****************************

even after getting the reading that suggested that there was no leak i still kept the multimeter connected and started to pull fuses to see if it dropped further.
when i pulled the 30A fuse for the radio the reading dropped to 0.005.

as i have an after market Sony stereo and 2 amps in the boot. these needed checking.
put the fuse back in (reading returned back to 0.029)
disconnected the feed for the amps and the reading stayed at 0.029.
pulled the stereo out and checked the wiring , no cuts or nicks. all wired ok.
then remembered that the switched live and constant live sometimes have to be switched over as they end up the wrong way round on certain cars.
switched the switched and constant wires around and hey presto..
reading dropped to 0.005.
turned on the stereo, checked it when the car is running and when off. all ok now.

and it didint cost me anything except the price of a new mutimeter.. which will always come in handy if you own a BMW...
 
#13 ·
Help with parasitic drain

Hi, I really need some help
I have a 20a multimeter but get the same issue when i connect it (one cable to the battery earth and the other to the earth lead) i get no reading, can anyone explain in an idiots guide what is ment by "Leave your -ve lead disconnected on the battery and try the +ve tap and chassis ground in the engine bay"
 
#14 ·
Set meter to DC 20A range
Make sure leads are plugged into the correct sockets on the meter for reading amps (may be marked 'com' and '20A')
Disconnect the negative cable from the battery
touch one meter lead to the battery -ve post
touch other meter lead to the clamp on the end of the now disconnected negative cable.

If you get no reading, and you have already tried this a different way, you may have blown the fuse in the meter.
 
#17 ·
The big problem is that you are breaking the power supply to the vehicle when you connect the meter in series to the car. This means that if something is sticking on such as a relay or an ecu then you are removing the power supply to it and this can reset the sticking component. You need to run the vehicle with as many consumers switched on as possible for a while and then when you park the vehicle up connect the meter in to the car without breaking the circuit, i.e make up a jumper lead to ground to enable you to connect in the meter, then remove the jumper lead. Usually thins means having to unbolt the -ve terminal from the body of the car and not the battery so you can stay connected to the -ve post of the battery throughout. Remember though, you may have to try a few times to catch the fault in the act. Be careful.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top