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Need a second opinion to confirm my 2003 W211 E240 rear SAM condition. Please view the attached circuit board images.
Is it fried? Should I replace SAMs?
Backstory: Reversed battery polarity caused the car to go nuts! ALL fuses and relays on dashboard side, footwell and boot pre-fuses, engine and rear SAMS are fine (or seem to be).
The car engine runs but gearbox handle is locked, solid fuel and temp indicators, SBC warning and other indicators are on, reverse light turns on once battery is attached etc. The clock turns full circle then stops.
Any tried and confirmed solutions are welcome.
Many thanks.
Ps: that was the first time ever I reverse battery polarity. Great lesson.
Yeah, it's done. I had similar view after lightning hit my car, and every broken module had chips blown.
I bought used modules according to old part numbers, and everything worked just fine.
That clock spinning is normal when battery is connected, it goes to 12 o'clock and starts counting.
yes, this should be the easiest solution. I’ve never rebuilt any modules for my cars as I’ve not had the need, but I’ve replaced various chips like these in pinball machines. Every bad chip had a burn mark like you are showing..
Ive not looked into to the availability of these chips, but if you are good with hot air soldering, you could even try to fix the modules that way. Depending what chips they are, no programming may be needed.
Got a used rear SAM from the junk yard off a 03 or 04 W211 Elegance. Replacement SAM’s’ Model no. Starts 03 545 99 01 while mine starts with 02 545 etc.
Glad to say Most functions work except for erratic throttle, SBC screaming warning, radio (fuse blown), AC’s fan blower (bad resistor?) and gear shifter is locked in place.
I’ve disconnected the battery terminals and SBC big plug (Read on a forum it could help). Will see tomorrow if it helps.
Otherwise, will take out front SAM for examination.
yes, this should be the easiest solution. I’ve never rebuilt any modules for my cars as I’ve not had the need, but I’ve replaced various chips like these in pinball machines. Every bad chip had a burn mark like you are showing..
Hi Balistyle,
I can solder, however, sorting the chips and coding will be a pain.
I was lucky to find a donor car. Thankfully, most function are back.
I have replaced the rear and front SAM units (see images of damaged front SAM). Good news is more functions are back including the AC blower.
SBC warning is still on and gear lever still locked. I am wondering if it is perished or requires software solution (reset or coding ) or replace the actual unit?
if I had to replace the SBC unit, does it have to be from the same donor car or, any unit will fit? of the same model and year, of course. Is mercedes-Benz diagnostic software SDS a necessity for unit replacement? (I’m working on the car in my home garage and do not have the software at hand).
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