[saleen351]

Ok. Everybody says different...Which is right?
I need a main engine controller unit for 2002 ML500. They sell used ones on ebay and they say that I can recode the VIn with DAS. Is that true or do I need to get involved with the stealership to get the brand new one.. Stealership says there is no way used controller will work on it. They say that it must be a virgin controller and must be preordered for specific VIN... What is your opinion?
Thank You

 

[43sqd]

Ok. Everybody says different...Which is right?
I need a main engine controller unit for 2002 ML500. They sell used ones on ebay and they say that I can recode the VIn with DAS. Is that true or do I need to get involved with the stealership to get the brand new one.. Stealership says there is no way used controller will work on it. They say that it must be a virgin controller and must be preordered for specific VIN... What is your opinion?
Thank You

saleen, what the seller is telling you is correct, but, but but what that means is that you have one of two choices.

The first one is that you would have to find an independent mechanic who has a Mercedes Star Diagnosis Scanner. Then has the proper software and knows how to transfer data from your present ECM to the replacement ECM.

Or the alternative is to take the replacement ECM to a M/B dealer and ask them to transfer the data from one ECM to the other. Of course that can be done, but no dealership will do this for you, insomuch as they are in the business of making money and not doing you favors because you want to make things financially easier on yourself.

Either scenario poses a problem. If you choose the independent mechanic you have the possibility of him losing the original data during the transfer process. The other scenario is M/B, and it will cost you.

What this is all about is the ECM and the DAS (Drive Authorization System) must be compatible (version coded) with each other and without that, the engine will probably crank but will never start and run.

Please read the two pdfs below so you can better understand as to what is involved.

So the big question is, what is wrong with your truck that makes you believe you need another ECM?

 

[saleen351]

Thanks for your quick and great reply. I have this vehicle more than 3 months and never able to drive except first day. When I got it first I knew that something wrong with it. The throttle response was not good and it was responding after like 5 secs. I scanned it and found that throttle sensor was bad. I thought it was something easy. I replaced the sensor but nothing changed. I check the wires from the ecu to the sensor and they are good. But only 5 v coming to the sensor instead of I believe it should be in the range of 0.2-0.5 v Then I realized that if you touch to brake pedal there is no throttle at all. I changed the switch also. But nothing.. When you lock the vehicle rear license plate lights are always on and they drain the battery all the time. I sent the vehicle two different good local mechanics. They both said main engine controller unit must be changed. This is my problem and I really appreciate for your response. Thank You

 

[43sqd]

Thanks for your quick and great reply. I have this vehicle more than 3 months and never able to drive except first day. When I got it first I knew that something wrong with it. The throttle response was not good and it was responding after like 5 secs. I scanned it and found that throttle sensor was bad. I thought it was something easy. I replaced the sensor but nothing changed. I check the wires from the ecu to the sensor and they are good. But only 5 v coming to the sensor instead of I believe it should be in the range of 0.2-0.5 v Then I realized that if you touch to brake pedal there is no throttle at all. I changed the switch also. But nothing.. When you lock the vehicle rear license plate lights are always on and they drain the battery all the time. I sent the vehicle two different good local mechanics. They both said main engine controller unit must be changed. This is my problem and I really appreciate for your response. Thank You

You do not need a new ECU, so don't consider getting a used one or a new one.

What is happening here is that you have a wiring problem with the license plate lights and possibly other things, that is causing the battery to be drained. Once you go below 10.5 volts in the battery, you will lose your throttle settings, causing the problem you are having.

Start the truck and let it idle until you reach operating temperature. Then follow the instructions below to the letter. After the first start after following the instructions, see if you have throttle response. Then post back with the results.

Please answer the following questions and please don't lump all your responses in one paragraph.

1. do you have a spare wheel carrier attached to the tailgate?

2. do the license plate light only illuminate when the truck is turned off?

3. does this happen only when the headlights have been turned on; either in the manual position or the auto position?

4. with the aid of someone else, do the license plate lights illuminate when you step on the brake pedal? Do this while the egn. is running and while the eng. is off.

5. after turning the eng. off are there any other lights on in the instrument cluster or any other switches on the dash?

If the throttle response is fixed, remove fuse #9 in the eng. compartment fuse relay box until the next time you use the truck as this will prevent the battery draining. It will then have to be reinserted the next time you use the truck and you will have to do this every time until the elec. problem is resolved.