W220 Massive Battery Drain
Thread Starter
Junior Member
Joined: Aug 2018
Posts: 67
Likes: 6
E63 / S55 / SL55 / E550
W220 Massive Battery Drain
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.
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.
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
Last edited by eurdone; Aug 2, 2019 at 03:26 AM.
Senior Member
Joined: Apr 2019
Posts: 428
Likes: 96
From: Houston
001 s600, 94 sl600
The Command unit is malfunctioning and keeping the Optical Fiber network "live" which is an extra parasitic drain. It is also "waking up" other components increasing the drain. I suggest some robust drain testing by pulling fuses one at a time (in logical order) while monitoring the battery drain. Since most everything is 'fused', this should absolutely locate the 'drain.'
Somewhere there is a relay (mechanical or solid-state) stuck 'ON.'
Somewhere there is a relay (mechanical or solid-state) stuck 'ON.'
The Command unit is malfunctioning and keeping the Optical Fiber network "live" which is an extra parasitic drain. It is also "waking up" other components increasing the drain. I suggest some robust drain testing by pulling fuses one at a time (in logical order) while monitoring the battery drain. Since most everything is 'fused', this should absolutely locate the 'drain.'
Somewhere there is a relay (mechanical or solid-state) stuck 'ON.'
Somewhere there is a relay (mechanical or solid-state) stuck 'ON.'
pulling fuses is something that works on cars with little electronics
also, after each pull you would have to wait the car to go asleep, block door sensors, hood sensor ect
Thread Starter
Junior Member
Joined: Aug 2018
Posts: 67
Likes: 6
E63 / S55 / SL55 / E550
Still at a total loss on this one... Any other ideas? I read a faulty fan can fry the AGW. Also some people have said water damage can be the issue, but I don't think the trunk has been exposed to water.
Senior Member
Joined: Apr 2019
Posts: 428
Likes: 96
From: Houston
001 s600, 94 sl600
There are numerous electronic and electro-mechanical devices in this car and the best way to locate the fault is by using the Mercedes Diagnostic Software and a competent MBZ tech. Using the Dealer facilities (I include the competent techs as Dealer facilities)will likely be far lower cost and much, much faster.
Trending Topics
There are numerous electronic and electro-mechanical devices in this car and the best way to locate the fault is by using the Mercedes Diagnostic Software and a competent MBZ tech. Using the Dealer facilities (I include the competent techs as Dealer facilities)will likely be far lower cost and much, much faster.
MB World Stories
The Best of Mercedes & AMG
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
