ECU question
 

For a couple of months my 2008 Mercedes Benz E320 Bluetec was giving an engine light that these generic OBD scanners from Autozone was showing as "DPF restriction".
I brought the car to a claimed "European Cars Specialist" who told me the problem not to be related to DPF but a malfunctioning backflow sensor.
This sensor was replaced but the engine light still on and even driving the car in highways for 10 days would not clear the engine light.
I brought the car back to the same shop and then the same mechanic said that the sensor was not sending a signal strong enough to the ECU.
Latter on he said that he found the harness (wires) to and from the ECU to be in short which caused the ECU to be damaged. "This harness" he said "travel through a hot area and caused to cook your harness" he said.
About the ECU he was to get it replaced but he could not buy or install/reprogram because has to be "someone licensed by MB to do this job" he said. "Mercedes will not sale it to me and I will not able to reprogram without Mercedes license" he said.
"I would get this job done for you for $2700.00 if not this issue from Mercedes Benz" the mechanic said.
As it is my first time dealing with a issue like this in my MBs cars, I have some questions"
1 - Does these troubleshooting results sounds real or not ?
2 - If real would the car run and drive normal as it is today?
3 - What would be the most common symptoms that I should notice with a problem like this? In highways my mpg is always 37 - 39 mpg.
I appreciate and reply to help me in this matter which is new to me.
Thanks everyone.

Sounds like this guy doesn't know what he's doing if he doesn't even have a star-laptop available for proper programming. I'd take it to the dealer and avoid that shop.

A "european cars specialist" should be properly equipped to work on cars within the last 13 years.......

I agree with you about this shop knowledge in Mercedes cars.
I decided to get my car for a dealer because I had already bring my car for two other "European Specialists" shops and none one of them were able to get my car running as a Mercedes car should.
Thanks for your reply.