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Discussion Starter #1
Long story short, I went on a long 3 week trip and came back to my car battery being dead. I replaced the battery and drove the car around no issues. Then I took a 1 week trip to come back and notice the car battery was drained again ! So I took the new battery back to the store to get it recharged (fresh under warranty). I put the battery back in the car, and noticed my windows can't raise or lower. I will work in short increment spurts. Like stutter, maybe goes up 1/16th of an inch every 3 seconds.

I ordered a iCarsoft ODB scanner to further troubleshoot. Im putting over 12.6 volts on battery, and well over 13.5 volts with the car running idle.

I get roof top warning, SRS warning, Brake Pad warning on the cluster. My headlights will flicker. I cannot adjust the electric seat or pop the trunk.

I my scanner arrives this weekend but I figured id see if my suspicion is plausible until then. If so maybe its the rear SAM and I may just clean it up or find a used one same w209 and plug and play. (praying its that easy).
 

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Low voltage can cause all sorts of gremlins, and can even damage the SAMs and instrument cluster. Hopefully in your case, it's just a current drain and the fixing that and getting a properly charged battery will solve all of this.
 

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The new battery still does the same thing, and the battery is putting out good volts. I'll update once I get an OBD hooked up.
 

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Well looks like its confirmed. I got a laundry list of faults from the OBD II scanner. Here is what I got on my 2005 CLK 320 W209 Cabriolet.

B1028 rear SAM is sending no data
B1031 Control module OCP sending no data
B1030 UCP not sending data
B1029 AAC not sending data
B1026 EZS & SCM not linked via CAN BUS
B1040 ICM not sending data

B1051 Circuit 30 under voltage 10.5V
B1022 Circuit 58d short circuit
B1003 component M13 short circuit

Talk about frustration. I'm hoping the B1051 circuit 30 is a quick fix up front. Im hoping maybe swapping or cleaning the rear SAM solves most of the stuff above. Geez. Hopefully front SAM is ok and only the back needs replaced. Maybe a few fuses im about to check the fuses now.
 

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Before replacing the rear SAM I am going to try to see if its something running too the module. For example B1028 rear SAM is sending no data. Yet the rear SAM controls the power windows, and the power windows do raise (but i have to keep pressing the raise button over and over, its like im giving it a few seconds to "catch its breath" before the window raises another inch, then it stops, ill wait and i can raise it maybe another inch or so after.

Being that the rear SAM controls windows and softtop (which the Top is completely unresponsive), im beginning to think maybe the rear SAM isnt the problem. The front SAM also has issues with headlights not able to stay on. This sucks because the battery is brand new 12.6 Volts.

I swapped it out, drove the car without a hitch, zero issues. Parked it for maybe 2 weeks tops and it all dies, which tells me something is drawing power from that battery EVEN BEFORE the orginal replacement. The replacement seemed like a fix, but in reality just delayed the inevitable.

My question is, if a Mercedes is sitting with a dead battery for too long; can it ruin the front and/or rear SAMS ? Some searches say yes, some say no.

Kind of like when i search "if i swap SAMs with identical part number, do i have to reprogram" Some say YES some say NO.

When i do find this information out i will be sure to share it, so hopefully someone comes along and can know if this happens to them.
 

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Erratic voltage can damage the SAMs.

A used SAM from the same car with the same options and same "facelift" version ( i.e. through MY2004 or MY2005+) will be plug and play. Otherwise, coding is needed.
 

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Discussion Starter #7
Update: As of Sunday 9-28-2020

Before just swapping out SAMs I wanted to do more pinpointing. I used a multimeter while the car was asleep to test every single fuse, to try to pinpoint where the parasitic draw was. Turns out its coming from the rear SAM fuse #8 (brown 7.5 amp). The fuse is responsible for Antenna Amplifiers (and or Security Alarm).

This fuse was pulling ~90 mA which must have been the culprit. So I pulled the fuse, started the car right up. All the previous warnings went away. My windows roll up and down fine, the soft top comes down and up with no issues. Now because I dont have the fuse, I cannot use my electrotonic key to open, close, or lock the car. Other than that, the car runs and performs fine.

So my next step is to figure out why these Antenna Amplifiers are drawing so much power (even after the car is turned off) and how to fix it, so that i can eventually use my electronic key again. I am happy to share this experience with the group.

**Note also a big part was my battery, it was at 12.45V to 12.5V, but I took it off and bumped it up to 12.6V when I did my test. I really believe for the Mercedes W209 that battery needs to be 12.6V to keep all those electronics happy.

If anybody has messed with a Antenna Amplifier let me know, I see on a schematic that they reside upfront of the car just under the hood infront of the dash.
 

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Low voltage can cause all sorts of gremlins, and can even damage the SAMs and instrument cluster. Hopefully in your case, it's just a current drain and the fixing that and getting a properly charged battery will solve all of this.
Its exactly as you stated Rudeney, once i found the current drain, and bumped the battery up higher than 12.5V it eliminated the gremlins. Now I just have to figure out why the Antenna amplifiers are drawing too much current while the car is off. I read on the chart that fuse can also be for the Alarm system.
 

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I doubt it's the antenna amp that is causing the problem. A much more common problem is failure of the ATA siren. It has a built-in backup battery that end up dying and then pukes acid all over the siren's circuit board. Try unplugging the siren. It's located under the fender shroud, behind the front right side wheel. Unplugging it will have no effect on anything except you won't have an alarm siren.
 
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