battery drain playing games :wallbash:

[Bonifatich]

Battery drain playing games on me

Hello gentlemen,

My problem is I can't understand what in the end bleeds the battery. Identified suspects are
- COMAND,
- memory seat control modules,
- OCP
but they are playing games with me on who is it still doing it.

It all started in cold weather about 5 weeks ago, battery went flat.

Replaced with brand new, went flat again in 2 days. Decided to learn what its all about. Bought voltometer, read a ton of threads and identified COMAND, memory seat controls and OCP -- all at once. (can't be?!)

Contacted COMAND UK, got it repaired. Seats were disconnected, fuse #64 was inserted BUT No start in 3 days again.

Read the V meter, COMAND bleeds. Arh, took COMAND back to the guys, we tried update SW, but COMAND refused to update, bagger, nevermind.

In the mean time I had seats disconnected, fuse # 64 out, fuse # 9 out. The current is 0.02A - alright.

Yesterday connected COMAND, connected the passenger seat control module (driver's not), inserted fuse #9, fuse #64 and the current reads 0.02A - exhilarated.

Assembled the car together BUT the b*&£$ decided,
- COMAND now refuses to talk to the steering wheel in fact it is fully independent wouldn't even shut upon switching the car off and taking ignition key out.
- and there is a buttery drain of 0.68A

I disconnected the passenger seat and the current dropped to 0.02A.

So WTF is going on? In other words, before the assembly the final suspect was drivers seat only, after the assembly its both seats now. I don't get it.

I am still calm but feel like kicking the car on the nuts.

Any suggestions?

 

[TDE1]

You have my sympathies.

Mine's been with MB 3 weeks now for a 1.3amp drain. They sourced it to the ECUs for boot closure, command, and some sort of battery module. Told me on Weds that they have now identified another issue with passenger seat module. Original quote was £2,000 odd, now likely to be a further £400 minimum.

They have another car in which, after 4 MONTHS is still not sorted.

Apologies, don't mean to dishearten you, just wanted to assure you that you're not alone! If I could offer any technical advice, I would. I can only suggest a soft kick on it's nuts with your slippers on.

 

[Bonifatich]

Thanks for the sympathy and a kind of discouraging encouragement but any idea at least why COMAND decided to become independent?

Otherwise it all started when the local MB dealer told me £300/2h to diagnose and if lucky to find the fault, I got offended by these prices so decided to DIY it.

Well, I can still drive it, its just now i freeze my bol*&cks when sitting down on leather seats because can't use "heated seats" function anymore. I can buy replacements seat modules and install new ones but the current is still out there playing hide and seek with me…arrrhh

Anymore ideas gentlemen?

Lets brain storm…PLEASE!!!!

I CAN hunt it down I have the suspects. In the end I have the control of it but its just down to their sequence I believe that I need to work out.

 

[TDE1]

My VERY limited understanding of mine (an '05 w211), is that modules / ECUs don't communicate with each other as you would expect.

I took mine to the local Indy first and he tried to explain it to me (the Luddite that I am.) He likened it to the way a tv controller communicates with the telly. Nothing in-between them that you can easily detect, so when they get out of sequence or fail, it's quite a badger to get right. Now he may have been spinning me a yarn, but the reaction I had from MB when I took it in was sort of "well we'll do our best, but..."

In the weeks leading up to my decision to get it sorted, I just pulled the fuse on Comand. This left with me with the occasional convenience functions warning, but at least it would start. Are you seats not operating after a few minutes' run?

Again, sorry I'm no sparky, and good luck.

 

[Bonifatich]

Well driver's seat operates fine if connected but because it is a prime suspect for battery drain it is disconnected. I am just lazy diving under a seat each time I want to drive the car and disconnect when I arrive. If I forget to disconnect I risk to kill the battery inconveniently.

Passenger seat is all the fun. First the seat stopped going back and forward, now I've discovered it wouldn't lean back and forward too but that should be another thread so I am not touching this topic yet.

ECU's I understand are Engine Control Units which I know nothing of.

I am going to keep testing I just need more knowledge to understand how three suspects: COMAND, seats and OCP are playing me up.

 

[Bonifatich]

Today done further testing and can now confirm driver's seat module is causing COMAND and OCP to stay awake indefinitely at 1.45A.

Disconnecting the seat module allows for COMAND and OCP to sleep and current drops to 0.02A which is a pass.

So how or why does driver's seat module keeps COMAND and OCP awake?