I need help with my 2009 W221 with 140k miles. I was driving it and I stopped at a 4 way stop then engine stopped/died, rear wheels locked, wouldn’t shift nor start anymore. Towed to an Indy, after 3 weeks mechanic told me the car doesn’t communicate with his scanner and he thinks it’s the ECU.
Has anyone had experience with this issue before?
Prior to this, the fuel pump was replaced, weeks before and after 2 weeks the left headlight stopped working. Not sure if it is connected with the issue now.
Thank you in advance for your help.

First up.... get it away from the guy who doesn’t have the correct tools to communicate with your car.

It is pissed about something. A good MB shop will go right to it.

wow - sounds like the guys kit is old and rubbish - should have given a you clue when they picked the car up....

could be lots of separate normal issues

stalling is often cause by the CPS (crank position sensor) wearing out - DIY $50
once the engine is off on later software it puts it in park - But it can also have the usual ISM on the gearbox fail if around 110k miles - this is more like $1100

sounds like the guys kit is old and rubbish - of course the symptoms you wrote, could be something far more catastrophic

Thank you. I will look for another shop. Will try replacing CPS as well.
I appreciate it.

ISM is the intelligent servo module - its sits on the outside of the gearbox and moves the selector to get the various park, reverse, and forward gears - they ALL go wrong - it usually throws a message "do not shift gears drive to workshop" on the instrument cluster - this issue needs dealer kit to code in the replacement part. Anywhere from 110k miles they tend to give up at any point.... 600 to 800 for the part then fitting and coding is a lot

dealers are NOT allowed to sell you the part - in merc speak its "a theft dependent part" - which really means they put in what should be illegal protectionism / monopolising, to force you to be ripped off by franchised dealerships for purchase and fitting of the part - they did this by making it hard to fiddle with, to code in chassis details and without the coding it locks the immobiliser circuit so the car won't start - other people can do it these days with naughty software - but getting the part will be the complex bit

but you should understand whats wrong before throwing money at it

no one will have comms to the ISM if they don't have posh diagnostic kit... basic scanners won't talk to much of the car - and if its the deliberate merc trick of switching itself off in software (after x uses) - you may not get comms anyway - there is a software update for this ISM module, but no one told me ifs its really the add more activation's before pretending it must switch off - I suspect it maybe - the park brake module on mine responded positively to flashing an update for the same idea - another Merc trick - claiming its a safety system - so to reduce danger, we turn it off in case its worn out - yes sure !!!!!

you should have given us the details of the funny message when it stopped - its all pertinent to the advice we can offer - I guessed it was the ISM because that's what they do on this model....

...the CPS is a normal every 50k mile bit of fun where they go odd - often getting worse with a long drive and stumbling and stalling at low revs - then refusing to start a hot engine - leave to go cold and it often works again (till it plays up again and again)






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Yes I remember seeing that message when the car stalled.
Thank you for this information.
I appreciate it.

updated post 5 with more info and less typos

Thank you for the elaborate response. I appreciate it much. I will have it towed to the stealership tomorrow and decide if I will keep it or junk it based on stealerships findings and repair costs.

dealer will take $2000 min out your wallet

and likely list another 6k of stuff they say it MUST have

the automotive world is a sick mess these days - flash the counter on the ISM to a higher limit -likely you can't but that's the issue it needs (what's the worst that part being odd can achieve ...oh I found it hard to get to park once, after all you should always apply the park brake - its the law in europe anyway !) and for a $50 dollar sensor that needs one small euro socket and 20 mins if you know how

I still wonder what problem got solved by giving them an ISM.

I got to replace the crank position sensor twice in the E-55. Once in the 221 S-65. Should probably replace it in the 222 car.

the software switch on the new ISM is on count one - rather than the fake switch off in software count yours reached

its the deliberate merc trick of switching itself off in software (after x uses) - by claiming its a safety system they can flex the law..... rather than being found to be outright right criminals, like they were with the emissions scandal - so to reduce danger, we turn it off in case its worn out and won't work reliably. So can some one explain to me - when was being unable to get out of park a serious safety concern ?

its ALL part of obfuscation and massive theft globally by corporations that secretly run the world - throw in enough confusion, doubt, complexity, cost, miss placed blame and time-wasting and you can get away with anything - does anyone really believe the "emissions scandal" wasn't actually deliberate ? billions of dollars in fines, all tax deductible so only society misses out (twice first the pollution, then the continues decline in societal functionality), its not the car companies getting poorer.... corporate culpability, really means paying off your mates to leave with 10 million dollar back handers (but not until after they help set you up with another one, that's yet to come out), and these fake investigations with hangers on getting work for 3 years to drink coffee. Where's the money gone ? vanished in to the pockets of the rich - its just as much a scam as covid, the current fake inflationary mess, old fashioned fake 20 year recessions they'd engineer in - its just massive theft and you are paying



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