stenodinson

Thanks SunnyRayToronto. Before I opened my ECU, I read your post several times along with your photos. Those were very helpful to muster up the courage to open up my own ECU.

Based on your root cause analysis I looked at my crystal very carefully. The solder was holding and didn't look there were any cold-solders.

BTW -- I managed to remove the lid without damaging it so I sealed it back up with Permatex automotive grade black silicone. The ECU looks untouched and is running great.

It's interesting because it seems to me that the lid is not electrically connected to ECU's metal heatsink. I measured the resistance on the sealing compound that they used for the lid and heatsink and it was non conductive. Seems like Mercedes missed an opportunity to limit EMI with a Faraday Cage. Kinda surprising.

stenodinson

One more note for anyone who opens their ECU in future is to remember to reset the adaptive shifting points of your transmission afterwards. After resealing the ECU lid to its heatsink, I left it to dry for a day. Once I re-installed the ECU, the car ran quite sluggishly until I did the transmission reset.

You can find instructions here.

stenodinson

Thanks SunnyRayToronto. Yes, my crystal was fine. No problem with the solder joints.

For anyone who finds this post, I used Permatex automotive grade black silicone to reseal the ECU lid with its heatsink. I let it cure for 24 hours and then reinstalled. The car was quite sluggish until I did the adaptive shifting transmission reset.

safetsula

Hello,
I have problem with ECU of benz w210, because when I tried in bench EIS connection with ESL the key is Ok, but when we put in the car the key go on in second position but don't on the car. We tried complete the other system of EIS ESL and ECU and the car can ON. Some body told us that need to renew ECU. How can we do it ?

Mamtz1

Sometimes ECU are messed up when someone "tune" the ECU for performance improvements,... my ECU was never tuned, flashed, chipped or altered in anyway. A short in main wiring harness can lead to ECU failure. Common faults are like blown output stages (no power to injectors) which is generally easy and cheap to fix. Complex issues like damaged EEPROM (bad tuning-flashing) or faulty ECU programming are more expensive to fix. ECU replacement usually happen due to leaking cam magnet sensor (I had a bit of oil at cam magnet but none in main harness wire) because of Mercedes-Benz Dealership would rather replace entire ECU when oil is found in plug rather than to just clean it out (much higher profit margins).[/QUOTE]