clb0099

Hey everyone,

I had started another thread about this but I figured it was best to start a fresh one with better details. So as many of you know last year my 2007 Mercedes S550 base model had the transmission rebuilt. The torque converter, and all the other internals were replaced. Over the last 13 months the transmission has worked flawlessly. Prior to the transmission being replaced I had the tcm, valve body , alternator , starter, starter battery, main battery, all the engine pulleys, oil filter housing gasket, engine oil cooler gasket, serpentine belt, hood release cables, ax compressor, and finally the parking brake module.
Over the last 4 weeks I experienced the serpentine belt snap (twice) which at the time my mechanic believed to be from oil dripping onto the belt causing it to become weakened. The second time the belt snapped was cause of a seized ac compressor.
With all this second the car was driving fine except for when the hood release cables were replaced. The cables had failed and of course when my mechanic went to run the new cable he had to go throw the driver’s side wheel liner. When he did that he said he had to move out of the way the front sam so that he could run the new hood release cable. When I first picked up my car I noticed check engine light on the cluster. I texted him and said that it appeared. He said that I had a transmission code prior to him working on it. Needless to say that wasn’t completely correct as I had no codes prior to the cables being installed. Which leads me to my next issue. My transmission ended up going into limp mode and is now stuck in second gear. So being that I wanted diagnosed properly I sent it to mercedes independent mechanic who was highly recommended. Well after the car was there for over a week I get a call yesterday saying that the brake module plug is faulty. The brake module has been faulty since day one and even after replacing it recently it seems like there is a canbus issue yet the car has always been fine and shifted with out an issue. The mechanic went onto explain to me that he wants to fix that plug but that might not fix my shifting problem lol. I am sorry but this line from a mechanic is almost as good as someone saying you might be low on headlight fluid. I went on to explain to the mechanic that brake module has never worked and that had zero to do with the transmission being put into limp mode. Once I said that the mechanic had nothing to say. After this I lost full confidence in this guy and will be towing the car home and trying to check the front sam connections first before I make a decision on where to send it next.
Anyone think it might be the Front sam connections? If so anyone know specifically which fuse/relay in the Front sam controls the transmission? I am paying the useless mechanic $200 for doing a scan with the star which I have. I should have gone with my gut and tried to tinker with it prior to bringing it anywhere.

BOTUS

half the world's connections are at the wiring to the front SAM, it could well be you need to get some wriggle room to do a bonnet cable - then of course Mercedes have no clue at all on how to get water to drain from a windscreen - but that said incredibly the 221 is the only model where the SAM filling with water is actually unusual

the gearbox throwing codes is normal - mine has done it on and off for 8 years, usually showing the speed sensor faults that are designed in to the electroplate - although perversely it hasn't done it for about 3 years, I don't think the F SAM or trans error codes have much to do with anything

bugs on wiring for the brakes sound dangerous and about the only bit you should focus on fixing - but i have no idea of the component you are talking about....

the AC going pop is usually over gassed and under lubed - so that is likely a main issue that shouldn't have happened - at this age the condenser will have got a hole and the gas is likely weeping out (along with the oil)

I hate to hear the drive belt called after a lake in hyde park, it makes my skin crawl

on the trans there are four things aside from mechanically fixing the clutches and O rings

TC the electro-mechanical lock up fails on all mercs (causing stalling and bad shifts) 2k
The electronic valve body AKA electroplate has two speed sensors that are made to be about as durable as a baked bean 1k
At 100k the 6 solenoids are gummed up with swarf and it'll have ripped the O rings inside to bits - replace 400
ISM electronic selector will have hit its fake software limit 1000

a few allegedly did suffer the trans cooler fault where engine coolant takes out the whole box and of course if its the V12 these were designed a bit better and it will need its second rebuild of the day before you have reached the end of this post

these are strange cars and I have NEVER met anyone that has a remote clue how to work on them !!!

clb0099

Botus,

Thanks for the response. So the ism was replaced along with the other parts you mentioned. What makes me think it’s the front sam issue is that it’s the only thing that was touched during the installation of the hood release cables. It could be just bad timing that something else went out but I don’t think so. I have found links that point to the front sam being it.. there is a particular fuse that it related to the transmission. Here are the 2 links that make me think it’s related heavily. If I can’t figure it out I will send it to the guy who has full knowledge of my car.
https://www.slkworld.com/threads/u01...for-me.527775/

BOTUS

OK, so of course if the F SAM is faulty lots of things will misbehave - as I said it has a lot of fingers in the pie

coding a new one there isn't that much - when mine was updated Merc SCN configured after the update these bits
Washer nozzle heater
Windscreen wiper
Air condtioning
Heated Steering wheel
Aux fan coolant

buy one of the correct part number off ebay and have a play ?

Fuses – Box in the Engine Bay – Front SAM Control Unit – N10/1

FUSE AMERE RATING PURPOSE
F20 10 Control Unit N3/9 or N3/10
F21 20 Circuit 87 – Fuel Pump Relay
F22 15 Connector sleeve
F23 20 Rear SAM Control Unit Fuse Box
F24 25 CDI Control Unit N3/9
F25 7.5 Instrument Cluster – Dashboard
F26 10 Left headlight – lamp unit
F27 10 Right Headlight – lamp unit
F28 7.5 EGS Unit Transmission control unit.
F29 5 Rear fuse box and relay module Rear SAM N10/2
F30 7.5 Fusel System Control Unit , Engine Control Unit N3/9 N3/10 N118
F31 5 Refrigerant Compressor
F32 15 Transmission oil pump control unit N89
F33 5 ESP Control Unit, Battery Management, Power Electronics
F34 5 Braking System N30/6
F35 5 Electric parking brake -A13
F36 10 Data link connector – 16 PinX11/4
F37 7.5 EIS Control Unit N73
F38 7.5 CGW Central Gateway control unit, Audio, Sound
F39 7.5 Instrument cluster
F40 7.5 Upper control panel N72/1
F41 30 Wiper motor M6/7
F42 30 Master wiper motor M6/6
F43 15 Front cigar lighter with ashtray illumination
F44 – Unused
F45 5 Power electronics pump M13/8
F46 15 ABC Control Unit N51/2 or AIRMATIC N51
F47 15 Steering column adjustment motor up or down
F48 15 Steering column adjustment motor in / out
F49 10 Steering column N80
F50 15 AAC Unit N22/1
F51 5 COMAND Display
F52A 15 Horns
F52B 15 Horns
F53 – Unused
F54 40 Air Recirculation AC
F55 60 Electric Air Pump
F56 40 AirMatic Compressor Pump A9/1
F57 30 Wiper Heater R2/10
F60 5 Power Steering A91-1
F61 7.5 SRS Airbag Restraint System N2/7
F62 5 Night View Assist N101
F63 15 Fuel Filter Sensor B76/1
F64 10 NECK PRO Head Restraint Solenoids Y24/12 – Driver, Y24/13-Passenger
F65 15 Outlet in glove box
F66 7.5 DTR Unit A89

clb0099

Botus,

I been told to check relays, fuses, and connections. F28 7.5 amp fuse has to do with the transmission. Thank you for your input. Also this what I bought to replace the ac compressor in my car. All installed let’s hope it’s something minor.

clb0099

Botus,

so I swapped out the front fuse/sam and the only issues is now the air conditioner/ heat doesn’t kick on. apparently there is no power going to the blower motor regulator. The next issue is the front ashtray cigarette lighter illuminates but when I plug a phone charge in it doesn’t power on. Ninja did the scn coding for the front sam.