Water in ecu/Sam
Thread Starter
Newbie
Joined: Mar 2022
Posts: 7
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W211 e280cdi sport(om642)
Water in ecu/Sam
Hi everyone, first time post here. To cut a long story short, I parked my car (downward facing) on the driveway and gave it a wash with a bucket and hose. Started the car, drove it for about 20 seconds and noticed a bit of smoke coming out the exhaust. So turned round, pulled in and turned the engine off. Thought that's strange, so tried to start the car. Turned the key to crank position, nothing happened to turn the engine. Instead the cooling fan came on full speed, esp failure warning came up, car was locked in park and no glowplug light, which normally comes on before it starts. Total nightmare, which I can only presume has happened by washing it, although I've washed loads of cars in the same point with no problem. Anyway, I removed the front Sam and can see a bit where it looks like it has been arcing, so have one ordered another one up.
My questions are could a Sam and not the ecu cause this problem? Does the Sam need coded to the car? Does anyone have a wiring diagram or link to somewhere I can view one, so that I can identify the wiring/relays, etc? Any hints or tips are welcome, I still can't believe this has happened.
Thanks, John.
My questions are could a Sam and not the ecu cause this problem? Does the Sam need coded to the car? Does anyone have a wiring diagram or link to somewhere I can view one, so that I can identify the wiring/relays, etc? Any hints or tips are welcome, I still can't believe this has happened.
Thanks, John.
Out Of Control!!
Joined: Apr 2019
Posts: 11,921
Likes: 6,769
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
Handwash then SAM arcings...
"No crank, water in ECU & SAM... no scan"
Before jumping to any organ transplant surgery... check what valid fault codes are being reported?
Do you have picture of your circuit board trouble spots? Good views from both sides
It may be your best interest to get your existing unit repaired than getting a new/used replacement SAM coded to work in your car.
The best options all depends on what the real issues and DTC's indications...
Before jumping to any organ transplant surgery... check what valid fault codes are being reported?
Do you have picture of your circuit board trouble spots? Good views from both sides
It may be your best interest to get your existing unit repaired than getting a new/used replacement SAM coded to work in your car.
The best options all depends on what the real issues and DTC's indications...
Last edited by CaliBenzDriver; Mar 19, 2022 at 02:32 PM.
MBWorld Fanatic!
Joined: Jan 2014
Posts: 3,965
Likes: 1,315
From: Republic of Texas
'99 and '05 E55 AMG
You can pull the ECU and open it up clean out any water dry it thoroughly and then reseal it with thermal grease. The Sam you can pull fuses and relays and open it up as much as possible and once again spray it with the water displacing contact cleaner. You should have a hard plastic cover over the ECU and a flexible rubber cover over the ECU and the Sam. This has been discussed before on this forum. You can find a fuse and relay diagram for the w211 using advanced search.
Thread Starter
Newbie
Joined: Mar 2022
Posts: 7
Likes: 1
W211 e280cdi sport(om642)
"No crank, water in ECU & SAM... no scan"
Before jumping to any organ transplant surgery... check what valid fault codes are being reported?
Do you have picture of your circuit board trouble spots? Good views from both sides
It may be your best interest to get your existing unit repaired than getting a new/used replacement SAM coded to work in your car.
The best options all depends on what the real issues and DTC's indications...
Before jumping to any organ transplant surgery... check what valid fault codes are being reported?
Do you have picture of your circuit board trouble spots? Good views from both sides
It may be your best interest to get your existing unit repaired than getting a new/used replacement SAM coded to work in your car.
The best options all depends on what the real issues and DTC's indications...
Sam circuit board, showing water drop and arcing damage.
This is the only picture I have of the front SAM board, if you look up and right from the water droplet, there is a dark bit where it looks like the two connections have arced and joined. I've ordered another used SAM but if it doesn't work, I could try repairing this. Thanks.
Thread Starter
Newbie
Joined: Mar 2022
Posts: 7
Likes: 1
W211 e280cdi sport(om642)
You can pull the ECU and open it up clean out any water dry it thoroughly and then reseal it with thermal grease. The Sam you can pull fuses and relays and open it up as much as possible and once again spray it with the water displacing contact cleaner. You should have a hard plastic cover over the ECU and a flexible rubber cover over the ECU and the Sam. This has been discussed before on this forum. You can find a fuse and relay diagram for the w211 using advanced search.
Thread Starter
Newbie
Joined: Mar 2022
Posts: 7
Likes: 1
W211 e280cdi sport(om642)
Hi, thanks for the reply. I was curious how to reseal the ecu if I open it, never heard of thermal grease but will have a search. The picture above is the one I took of the Sam when I opened it. There was a drop of water on the board and a little bit of damage so will at least need repaired. It's mad but I have the weather shields fitted that go over each side to cover the ecu and Sam. I think it must have just overloaded them, as there are holes in them for drainage. Going to make up some kind of extra water deflection once I get the car running again. I'll try the advanced search, I had a bit of a look but couldn't see anything for my model. Would be great to find one as doing any repairs is difficult, as I don't know what I'm looking at. Thanks for the reply.
Just a quick update. Got a secondhand front Sam unit with same part number and fitted it to the car, it then fired up straight away. Relieved is an understatement. Never needed to code anything or touch the ecu, which was my worry.
Thanks for all the help👍
