Please Help, Massive Battery Drain on S55 AMG
Thread Starter
Junior Member
Joined: Aug 2018
Posts: 67
Likes: 6
E63 / S55 / SL55 / E550
Please Help, Massive Battery Drain on S55 AMG
Hey folks, I have an '06 S55 AMG pulling about 2.5A when it should be sleeping. My mechanic narrowed it to the Audio Gateway. I'm destroying brand new (strong) batteries, beyond recharging, within weeks.
I've researched these forums extensively, and I'm hoping it might just be the nav disc. I read the next step is to disable the nav disc reader altogether. I've read others suggesting buying the T3 battery brain to force the AGW to sleep--I'd rather not go this route unless absolutely necessary. Sounds like it would just be an interim step while diagnosing anyway. And I really don't want to disable my entire audio system. Seems like replacing the AGW is complicated and involves reprogramming? Please tell me there could be a simple solution to this.
Another important observation, one night my car was making a siren sound (different than the alarm system) that was coming from the panel that housed the navigation disc unit. It sounded very strange, like a rhythmic alert. Nothing could make it stop. Eventually it just did on it's own. I think it's somehow related. Can't find much info at all on a trunk alarm sound on the W220.
My mechanic noticed the optical cable is still awake when the car is off. Any suggestions would be most appreciated. A side note, not sure if this carries any relevance, but I did replace the COMAND screen unit a few months back because it had gone dead and would not power on.
Thanks,
John
I've researched these forums extensively, and I'm hoping it might just be the nav disc. I read the next step is to disable the nav disc reader altogether. I've read others suggesting buying the T3 battery brain to force the AGW to sleep--I'd rather not go this route unless absolutely necessary. Sounds like it would just be an interim step while diagnosing anyway. And I really don't want to disable my entire audio system. Seems like replacing the AGW is complicated and involves reprogramming? Please tell me there could be a simple solution to this.
Another important observation, one night my car was making a siren sound (different than the alarm system) that was coming from the panel that housed the navigation disc unit. It sounded very strange, like a rhythmic alert. Nothing could make it stop. Eventually it just did on it's own. I think it's somehow related. Can't find much info at all on a trunk alarm sound on the W220.
My mechanic noticed the optical cable is still awake when the car is off. Any suggestions would be most appreciated. A side note, not sure if this carries any relevance, but I did replace the COMAND screen unit a few months back because it had gone dead and would not power on.
Thanks,
John
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'06 MB S55 AMG; '04 Audi Allroad 4.2; '05 BMW M3 Conv.; '92 MB 500E
I haven’t heard of this before, but I suspect that COMAND rebuild. I don’t know if you’ve seen this...https://w220.ee/MOST_Audio_Gateway or this https://w220.ee/MOST#Normal_wake-up_.28all.29. But both the COMAND and AGW should be widely available used (and fairly cheap), so you can get one, the other or both and swap them in to see if the problem persists. Could also be a bad ground, which I’d also check. But I’d start with the cheapest option, which I would guess is an AGW swap. Looks like it can be programmed if you have a box. Try www.car-part.com for the parts, and of course eBay.
Please keep us posted.
GL,
maw
P.S. Rereading your post, I’m almost certain the COMAND rebuild is the offending component. It wouldn’t be the first time the internet tried to profit off of “almost new / rebuilt” OEM components with millions of R&D behind them. Stated differently, your “side note” is THE PROBLEM and you have your mechanic on a goose chase when you know the problem is what you did. I’ve never heard of a bad AGM (a pretty dumb device), but I’ve heard about plenty of bad COMAND systems. The ‘06 even came with an extended “lifetime” 10yr warranty from the factory, which is shown on the VMI from my ‘06. You probably should have gone with a used COMAND over a “rebuild”.
Please keep us posted.
GL,
maw
P.S. Rereading your post, I’m almost certain the COMAND rebuild is the offending component. It wouldn’t be the first time the internet tried to profit off of “almost new / rebuilt” OEM components with millions of R&D behind them. Stated differently, your “side note” is THE PROBLEM and you have your mechanic on a goose chase when you know the problem is what you did. I’ve never heard of a bad AGM (a pretty dumb device), but I’ve heard about plenty of bad COMAND systems. The ‘06 even came with an extended “lifetime” 10yr warranty from the factory, which is shown on the VMI from my ‘06. You probably should have gone with a used COMAND over a “rebuild”.
Last edited by maw1124; Aug 3, 2019 at 12:33 PM.
Thread Starter
Junior Member
Joined: Aug 2018
Posts: 67
Likes: 6
E63 / S55 / SL55 / E550
Still in the dark on this one. Don't even know where to start. Maybe just have the AGW connected to an accessory power source? Was hoping someone here has experienced and resolved something similar.
Senior Member
Joined: Feb 2003
Posts: 443
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'03 S55 (79K miles)
Fan
The command unit has an internal fan that spins as soon as you get in the car and turn it to ACC. Is it possible that the fan is spinning and contacting the case at the back of the command head end?
