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MB Paul
MB Paul, Mercedes Technician
Category: Mercedes
Satisfied Customers: 3567
Experience:  Qualified Mercedes Benz Diagnostic Technician - 20+ years experience - Workshop Foreman for Mercedes
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Had an 09 Mercedes c300 towed into the shop and I can't read

Customer Question

Had an 09 Mercedes c300 towed into the shop and I can't read codes from the ecm because it is said to be unavailable and there is a message in the dash thatvsays remove your key
JA: Just to clarify, what's the exact code? And have you tried to reset it?
Customer: How would I know, my computer says that then vehicle isn't equipped with an ecm
JA: Are you fixing your C300 yourself? What have you tried so far?
Customer: It was brought to the shop that I work at, so it is not my vehicle, and I just need to find out why the dash says to remove the key and why the ecm is unavailable to read codes from
JA: Anything else you want the mechanic to know before I connect you?
Customer: How do u fix the remove your key message so that I can read the codes and start the vehicle I already tried to clean the connection of the negative battery cable to the frame and that didn't help.anything
Submitted: 2 months ago.
Category: Mercedes
Expert:  Chad Farhat replied 2 months ago.

Hi, I'm Chad. Welcome to JustAnswer. I'm reviewing your question and I will be posting your reply ASAP.

Expert:  Chad Farhat replied 2 months ago.

Hey how are you

1- have you checked all fuses , inside & outside the car

2- get to the ECM and unplug it ,inspect connectors for backed out pins not making a good contact , any melting or burned spots

3- what scanner are you using on it , bmw or equivalent or just code reader ?

Please let me know

Thank You

Chad Farhat

ASE Certified Technician

Customer: replied 2 months ago.
The ecm terminals are all OK. There is only one fuse in the fuse box on the drivers side of the instrument panel and the fuse is in 116. I am using a Max me computer purchased from matco tools and I pay $110 a month so that I can activate a lot of modules and utensils in all of the vehicles
Expert:  Chad Farhat replied 2 months ago.

There is more than one box , i sent you locations

Customer: replied 2 months ago.
I checked all of the fuse boxes except for the one in the middle because I pulled everything out of the trunk and removed a mule that was just behind the back seat in the trunk and there wasn't a battery in the trunk, there is only the battery under the hood and all of the fuses checked out OK
Expert:  Chad Farhat replied 2 months ago.

there is no Battery in trunk only fuses

what i sent you are fuses location

not sure on this one ,if all fuses are good and ecm connector good & you cant read it , then ECM bad

Expert:  Chad Farhat replied 2 months ago.

you are good or you still need help

Customer: replied 2 months ago.
i found that pin 16 at the ecm is getting power but pin 15 isn't getting any power with the key in the on position and the power to pin 15 comes from the front sam module but there is no power going to fuse in the sam module that sends the power to pin 15 at the ecm, where does the power that is supposed to be at the front sam module for the pin 15 come from
Customer: replied 2 months ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Expert:  Lou P. master tech replied 2 months ago.

Hello , different tech here, are you still needing help?

Lou P.

Customer: replied 2 months ago.
I STILL NEED HELP
Customer: replied 2 months ago.
THE FRONT SAM MODULE ISN'T GETTING ANY POWER ON THE CIRCUIT THAT SENDS POWER TO THE ECM WHEN THE KEY IS IN THE ON POSITION SO MY NEXT STEP IS TO REMOVE THE IGNITION SWITCH AND SEE HOW IT IS WORKING UNLESS THE POWER IS SUPPLIED TO THE FRONT SAM MODULE ON THE ECM CIRCUIT FROM SOMETHING OTHER THAN THE IGNITION SWITCH.I FIT IS THEN I WILL NEED TO KNOW WHERE ELSE IT WOULD COME FROM
Customer: replied 2 months ago.
Why are you guys wasting my time. i am either gonna get some help from you guys or i will be cancelling my subscription and asking for a full refund. why would a master tech transfer me to another tech
Customer: replied 2 months ago.
still waiting for the answer on what sends power to the sam module that then sends power to pin 15 on the ecm
Customer: replied 2 months ago.
can i get a wiring diagram for what is supposed to send the power to relay 87m on the front sam module
Customer: replied 2 months ago.
forget about that relay diagram, i am getting no power to fuses 4 5 6 on the front sam module and i would like to get adiagram on where the power to those 3 fuses comes from and i am having a hard time getting one from alldata
Customer: replied 2 months ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Customer: replied 2 months ago.
THE DIAGRAM THAT I HAVE SAYS THAT FUSE 5 PINK/RED WIRE'S POWER COMES FROM THE REAR SAM MODULE AT PIN 7 BUT THE REAR SAM MODULE DOESN'T HAVE ANY PINS THAT ARE ANY WHERE NEAR PIN 7 BECAUSE ALL OF THE PINS THAT IT HAS ARE IN THE 40'S AND HIGHER
Customer: replied 2 months ago.
WITH ALL DUE RESPECT, THANKS FOR NOTHING. I FOUND THE ELECTRONIC STEERING LOCK TO BE FAULTY SO I WILL BE INSTALLING A NEW ONE AND THEN SEEING IF THE ELECTRONIC IGNITION SWITCH WILL ALSO NEED TO BE REPLACED. I HAVE ALREADY PAID FOR A MONTHS MEMBERSHIP SO I WILL GIVE IT A TRY FOR A MONTH BUT UNLESS YOU START HELPING ME WITH DIAGNOSING THE VEHICLES PROBLEMS THEN I WILL CANCEL WHEN THE FIRST MONTH ENDS.
Expert:  Lou P. master tech replied 2 months ago.

I am soooo sorry. After I asked if you needed help I got called away and was not able to be online. I am so sorry. This is not normal of any of us. I will be back online in the morning and go over your story and see what I can do to help. It does very much sound like a steering lock. Those have been failing quite frequently if not the lock then the ignition switch. The difference is if you can hear the lock zip locked and unlocked when inserting the key. Again I'll go over your story more thoroughly in the am. So sorry for the delay. Lou P.