Sleep mode for parasitic drain testing?

[95maxrider]

How do I get my 1998 M3/4/5 to go into "sleep" mode? I'm trying to track down a parasitic drain, and my drain is staying at about 70 mA even after the trunk has been shut for more than 30 minutes. What is the official name for the sleep mode, I can't find any info about it in my Bentley manual? How long is it supposed to take to go into sleep mode? Is there a test to see if the car is going to sleep or not? Does the car need to be locked to go into sleep mode? Thanks!

[shogun]

Maximum closed current by vehicle
E31 50mA
E32 50mA
E34 40mA
E36 30mA
E38 50mA
E39 40mA
E46 40mA
E52 50mA
E53 40mA
Z3 30mA

Performing Closed Current Draw Test
• Select proper measuring device (DISplus, MoDic or DVOM)
-Remember amperage draw in excess of 10A will damage DVOM.
-Use inductive amp probe of DISplus when amperage draw is high.
-When using DISplus inductive probe, clamp on negative battery cable with arrow pointing away from battery. Switch off all consumers.
-(It is not necessary to disconnect B- from body when using inductive probe)
• Connect (-) test lead to negative battery terminal and (+) test lead to a known good ground.
• Ensure all systems are OFF !
• Be sure DVOM is on and set in proper mode.
• Disconnect battery ground lead from body.
• Observe meter reading, wait for vehicle to enter sleep mode.
• Identify faulty circuit by disconnecting fuses, relays, control modules or connectors, observing meter readings.
• Defective circuit is found when current is below maximum closed current for vehicle being tested.

see Closed Circuit Current Draw Testing http://www.e38.org/battery.pdf

[M3AN]

~16 minutes.

Doors/trunk open is fine, just don't change their state in that 16 mins. Make sure you disconnect or short the truck switch so the car thinks it's closed (not necessary for sleep but better for tracking down drain).

[Thomas525]

How do I get my 1998 M3/4/5 to go into "sleep" mode? I'm trying to track down a parasitic drain, and my drain is staying at about 70 mA even after the trunk has been shut for more than 30 minutes. What is the official name for the sleep mode, I can't find any info about it in my Bentley manual? How long is it supposed to take to go into sleep mode? Is there a test to see if the car is going to sleep or not? Does the car need to be locked to go into sleep mode? Thanks!

That's your parasitic drain there. You are running at 2x what you should have in your car. I'm chasing one on my end too.

[shogun]

Doors/trunk open is fine, just don't change their state in that 16 mins.

On the E32 and E34 it is usually said that the doors must be closed for the test and then 16 minutes waiting, otherwise the general module = ZKE would not go into sleep mode, as the interior light is also controlled by the GM.
Is that different on the E36? Or maybe the comments for the E32/E34 with regards to this are wrong in the net?

[R Shaffner]

When I had to track down a leak on an e34, I used a multi-meter that had an amp setting. It couldn't handle much current so I did the following:

I removed the rear seat so I could get to the battery and those relays/fuses.
I rolled down the rear windows and opened the hood so I could get to the battery, fuses, and relays.
I loosened the clamp to the neg battery post and rested it on top of the post.
I connected one wire of the multi-meter to the clamp and the other to the post (using alligator clips).
I closed the doors and waited for 20 minutes, for the car to go to sleep.
I reached through the rear window and lifted the neg clamp off the battery post, while leaving the meter wires connected (so just the lower level of amps went through the meter).
I noted the amp reading, and removed fuses and relays as needed to find where the draws were coming from.
When done I reached through the window again to put the neg clamp on the post (or disconnect the meter) before opening a door.

I too don't know about the e36. If you need to go into the trunk then I agree, make the car think the trunk is closed.

I hope some of that helps.

[M3AN]

On the E32 and E34 it is usually said that the doors must be closed for the test and then 16 minutes waiting, otherwise the general module = ZKE would not go into sleep mode, as the interior light is also controlled by the GM.
Is that different on the E36? Or maybe the comments for the E32/E34 with regards to this are wrong in the net?

I have no idea about the 32/34 but if you're concerned then close the doors and keep the windows down, doors don't need to be open to test anyway, just hood and trunk.

You can also observe sleep mode kicking in (or not I suppose) if you have your mm in series across the negative terminal of the battery.

[Thomas525]

When I had to track down a leak on an e34, I used a multi-meter that had an amp setting. It couldn't handle much current so I did the following:I removed the rear seat so I could get to the battery and those relays/fuses.I rolled down the rear windows and opened the hood so I could get to the battery, fuses, and relays.I loosened the clamp to the neg battery post and rested it on top of the post.I connected one wire of the multi-meter to the clamp and the other to the post (using alligator clips). I closed the doors and waited for 20 minutes, for the car to go to sleep.I reached through the rear window and lifted the neg clamp off the battery post, while leaving the meter wires connected (so just the lower level of amps went through the meter).I noted the amp reading, and removed fuses and relays as needed to find where the draws were coming from.When done I reached through the window again to put the neg clamp on the post (or disconnect the meter) before opening a door.I too don't know about the e36. If you need to go into the trunk then I agree, make the car think the trunk is closed.I hope some of that helps.

Is there a need to wait for the car to go to sleep, you just disconnect the negative terminal entirely ? Then you can proceed with the alligator clips and multimeter. Of course all trunks and doors closed but windows open for convenience. All relays and dmes connected.

[shogun]

Probably you did not read the link I posted above, see page 33 the diagram:
Performing Closed Current Draw Test
Select proper measuring device (DISplus, MoDic or DVOM)
-Remember amperage draw in excess of 10A will damage DVOM.
-Use inductive amp probe of DISplus when amperage draw is high.
-When using DISplus inductive probe, clamp on negative battery cable with arrow pointing away from battery. Switch off all consumers.
-(It is not necessary to disconnect B- from body when using inductive probe)
• Connect (-) test lead to negative battery terminal and (+) test lead to a known good ground.
• Ensure all systems are OFF !
• Be sure DVOM is on and set in proper mode.
• Disconnect battery ground lead from body.
• Observe meter reading, wait for vehicle to enter sleep mode.
• Identify faulty circuit by disconnecting fuses, relays, control modules or connectors,observing meter readings.
• Defective circuit is found when current is below maximum closed current for vehicle being tested.

[R Shaffner]

To find the unwanted draw of current, you need to read the amperage after the car "goes to sleep." (In other words, the car is still using higher current for a few minutes after the doors are closed and you've left it alone. You're not worried about those things -- they are not the problem. You let them stop before you can track down the issue that's causing the problem.)

So you need to be ready to measure the current while keeping the battery connected. If you lift the negative clamp off the post too soon, you'll send too much current through the meter (which one like mine cannot handle). If you cut battery power entirely you won't be able to measure anything. When you put the clamp back on those other systems will activate again and you've have to wait for it to enter sleep mode again.

That's why you need to wire the meter in parallel with the normal connection. That means the negative post is connected to the body ground AND to the meter that is connected to ground. After the car goes to sleep (20 min to be safe), you can disconnect the normal negative connection and read the current that is going through the meter.

The approach Shogun shared works, of course. In that case you'd connect the meter from the neg post to the body while the clamp is still on. The only problem with that is that it's hard to connect something else to the post while the normal clamp is on all the way. That's why I loosen the clamp and leave it touching the post, while I connect the meter to both the post and the clamp. I leave that heavy neg wire connected to the body, and just lift/hold the clamp off the post after it enters sleep mode, when I want all the current to go through the meter.

[Thomas525]

Thanks Shaffner and Shogun. Basically, Shaffner, you are saying that the battery needs to be connected for sleep mode to take place after 16-20 minutes. If the clamp is removed before that, the sleep mode will be interrupted, and merely resume after you reconnect your dmm in series. So is there any point in connecting the multimeter leads in parallel ( switching to series once the clamp is lifted off the battery post) from the beginning? Can we just wait 20 minutes, disconnect the clamp, and connect the multimeter in series? Thanks.

[M3AN]

Reconnecting the battery will wake the car back up.

Just put your mm in series and wait 20 mins. As I said above, if you sit there and watch the display of the mm you'll see the car go to sleep.

[tjm3]

Just put your mm in serial and wait 20 mins. As I said above, if you sit there and watch the display of the mm you'll see the car go to sleep.

It's as simple as this!!! The only way to do it easier is to use an amp clamp (read 'inductive amperage probe') and no need to disconnect anything.

[R Shaffner]

Thanks Shaffner and Shogun. Basically, Shaffner, you are saying that the battery needs to be connected for sleep mode to take place after 16-20 minutes. If the clamp is removed before that, the sleep mode will be interrupted, and merely resume after you reconnect your dmm in series. So is there any point in connecting the multimeter leads in parallel ( switching to series once the clamp is lifted off the battery post) from the beginning? Can we just wait 20 minutes, disconnect the clamp, and connect the multimeter in series? Thanks.

Yes - that's it. If you disconnect the battery completely the car will "wake up" when reconnected. If you have the kind of meter that can handle the "awake" current, you can just disconnect the battery and connect the meter. My meter can't handle that many amps.

So I use this simple method as way way to rig the meter in parallel with the clamp/post. Then when I lift the clamp from the post, after it goes to sleep, the lower level of current goes through the meter and I can trace the fault.

NOTE: This is assuming that the current draw during sleep mode isn't real high. You should check it immediately after you lift the clamp. If it's more than what your meter can handle, then you'll need to rest the clamp back on the post and do that repeatedly until you find the circuit that's drawing current. (That is, you'd remove several fuses, lift the clamp, check the meter, if current is still high replace the clamp, replace those fuses, remove other fuses and repeat until the current is low. Then you figure out which of the disconnected fuses is in the problem circuit, etc.)

I should also note that one of the circuits is the one that connects the computer that controls the sleep/awake modes. If you pull that fuse and reconnect it, the car will be awake again for another 15-20 minutes. So I'd be careful to check that circuit last. It should have some draw, but a low amount that wouldn't drain the battery. That is, test everything else first and the computer circuit last.

[Thomas525]

Yes - that's it. If you disconnect the battery completely the car will "wake up" when reconnected. If you have the kind of meter that can handle the "awake" current, you can just disconnect the battery and connect the meter. My meter can't handle that many amps.

What kind of awake current are we talking about? What's the highest you have ever seen ? Nothing that is not running on the car (when it is not supposed to) can draw 10 amps which is the limit of these cheap dmm, even with a static draw. And M3AN and tjm3 thank you I will do that its more straightforward.

[JDStrickland]

I have not been paying attention, but you need to have all of the doors and trunk open and wait for the car to time out. If the car is closed, it wakes up when you open anything -- doors or trunk, or hood. You want to leave the car opened up so you can check stuff after is times out, this takes 16 minutes.

[johnf]

If the initial surge is a concern, you might look into a low current, clamp-on DC ammeter which you can clip over the battery terminal, after the surge, without interrupting the circuit.

The Uni-T 210E is an inexpensive unit that people have used, at least for a while. I found it was a good to learn on. I had one for a week before the carry bag failed.

The least expensive, durable and accurate unit I know of is the Benning CM 11. It is a nice little tool.

[R Shaffner]

What kind of awake current are we talking about? What's the highest you have ever seen ? Nothing that is not running on the car (when it is not supposed to) can draw 10 amps which is the limit of these cheap dmm, even with a static draw. And M3AN and tjm3 thank you I will do that its more straightforward.

I forget the details for that car -- about what's on when it's awake and how those things time out. (The one I worked of was my brother's.)

There are many fuses that are 10 amp and higher, meaning individual circuits could be at 10 amps or more. If you have several things running (or the car has several things running through different circuits) they could easily total more than 10 amps from the battery. And if you have a short in anything, it could be a little or a whole lot.

My meter couldn't handle more than 10 amps, which is why I went through the procedure I've described.

[M3AN]

Way to over-complicate things.

Just...

Turn everything off and remove accessories (lighter socket, radar detector etc, etc)
Open a front window (for access if something goes wrong)
Close all doors
Open trunk and hood
Disable/short trunk switch
Disable/short hood switch(s) if they're connected to anything

- At this point your vehicle is ready for diagnosis and is pre-sleep but will have very low draw (way less that 10A) because everything is off.

Connect your mm in series between negative post and black battery cable (use the fused connection on your mm). Reading should be below 1A.
Wait ~16 mins, reading should drop down to low mA (<200mA) - if you mm errors at this stage or shows no reading switch to the unfused connection (and wait another ~16 mins)
Start testing, do not open doors, turn anything on or change state of trunk/hood switches.

[R Shaffner]

Well, that approach isn't simple. The complication comes from the awake/sleep modes, the limitation of some meters, and the fact that you don't know how much the draw might be or where it's coming from. Could be from several things. And the current could be 10 amps or higher before or after sleep mode. (It was on one e34 I fixed.)

[R Shaffner]

If you find that the unwanted drain is coming from an always-on circuit (not through the key switch), you might use this approach to convert it:

https://www.bimmerforums.com/forum/s...n-quot-Circuit