Mercedes w204 c220 cdi 2012 no communication with all ecu's

[Imymalik]

Hi guys this is my first post I hope somebody can help me with a problem with my 2012 mercedes c220 cdi.
Right so I will start from the beginning I bought the car with a fault off somebody I had no ignition & no start eventually turned out to be a faulty eis module I had that repaired the car now starts & drives but with a few faults.
The radiator fan is running constantly
Head unit is in anti theft mode
Abs,traction control,airbag,engine management lights are all illuminated.
Indicators,wipers or horn dont work.
And finally I can not communicate with any ecu ,abs ecu or airbag ecu.
Only thing I can get comms on is instrument cluster.
Since then I have had a new eis fitted to no avail & most recently I have fitted another engine sam unit in from a donor car without coding but is exactly the same obviously I cant code anything in until I can access the ecu's.
Sorry for the long post ,any input/help would me much appreciated.
Many thanks in advance.

 

[nickgar]

There are times unfortunately, when you have to bite the bullet and take your car to a good Mercedes independent or main dealer to sort out problems. Reading your post, this appears to be one of them.

 

[Chrishazle]

As above. You need the official MB Star/Xentry system to interrogate the car, if you can find a local MB independant garage that has that exact system it will be a lot cheaper than an MB main dealer. I've just had to do exactly this when the dashboard mysteriously lost its programming, local indie sorted it very quickly.

 

[Imymalik]

Yes well i thought I'd try these forums first you never know somebody might have experienced something similar.But yes I will get it booked in to a merc specialist.
I've got merc care over in pudsey,leeds so will give them a shout

 

[markjay]

Welcome.

Just to say that the first thing to check when there are multiple unrelated faults is the battery voltage and the battery condition overall. Then, the next possible fault will be the front SAM (which you have replaced, but haven't coded?). These are the two most common causes for multiple unrelated faults. Other options are poor earth contact or corroded connections or the battery management module etc.

But of course the faults may be unrelated. If you don't have STAR, you could buy an MB-Specific code reader such as iCarsoft MB v2, and it will read the fault codes (if it can connect to the ECUs), and you can then erase them and see which ones come back, but keep in mind that reading fault codes is not the same as actually diagnosing the root cause of the fault.

But start with the battery. Check the battery voltage, and trickle-charge it overnight if you can.

EDIT: You mentioned coding, I am assuming you are aware that this requires genuine STAR with active online subscription?

 

[Imymalik]

Welcome.

Just to say that the first thing to check when there are multiple unrelated faults is the battery voltage and the battery condition overall. Then, the next possible fault will be the front SAM (which you have replaced, but haven't coded?). These are the two most common causes for multiple unrelated faults. Other options are poor earth contact or corroded connections or the battery management module etc.

But of course the faults may be unrelated. If you don't have STAR, you could buy an MB-Specific code reader such as iCarsoft MB v2, and it will read the fault codes (if it can connect to the ECUs), and you can then erase them and see which ones come back, but keep in mind that reading fault codes is not the same as actually diagnosing the root cause of the fault.

But start with the battery. Check the battery voltage, and trickle-charge it overnight if you can.

EDIT: You mentioned coding, I am assuming you are aware that this requires genuine STAR with active online subscription?

Hi thank you for your reply.
The battery is actually not so good I did charge it overnight and it was completley dead after a few days.
I also noticed when I checked the voltage on running the car it was stuck on 14v not fluctuating I dont know if this is what its supposed to do.
I managed to get a donor car and since I have swapped the clock spring and ecu esl and eis just incase but to no avail.
I am going to try 1 last thing before it goes to an indie.
Its a fuse relay box located next to the battery.
Pls see pics.
You mentioned battery management module.where is this located?

 

[Jigglyjohnson]

What u show is the pre fuse box which supplies most of the different fuses and relay units on the car. If u have no comms with any ECU you will first need to check whether you have a power supply to a certain ECU just pick one and check. ( will need a wiring diagram ) if the power supply is there you need to check the can system which is the communications network and see if that has a voltage. If you have npower at the unit then you need to back trace as to where it gets its supply from normally a relay in one of the sam units

 

[Imymalik]

What u show is the pre fuse box which supplies most of the different fuses and relay units on the car. If u have no comms with any ECU you will first need to check whether you have a power supply to a certain ECU just pick one and check. ( will need a wiring diagram ) if the power supply is there you need to check the can system which is the communications network and see if that has a voltage. If you have npower at the unit then you need to back trace as to where it gets its supply from normally a relay in one of the sam units

Hi, funny thing is the car starts and drives and I've swapped the full ecu set including sam unit key eis esl e.t.c and its exactly the same abs tps monitor and cruise control faults come up 1st thing .
I've done all I can do now its over at an indie so see what happens.
Strange though never come across anything like this before

 

[Jigglyjohnson]

Brake light switch ?

 

[Imymalik]

*UPDATE* problem fixed turned out to be damaged wires under the drivers and passengers side footwell under dashboard.