Max_Power

Hello, anyone had any issues with Renntech ECU mods? I had one done for my 2011 E550 and it worked great for a while. A noticeable difference and seemed worth the money. However, the other day I had a major issue with the car. As I was talking off from a slow down (red light turned green about 100 feet in from of me) the transmission gave out completely as it was up shifting. I was dead in the water...the car could only coast to the side of the road with traction control lights on the dashboard warning me about something. The car returned to normal operation after shutting it down and restarting it. The dealer claims the only thing the computer reads is a bad torque calculation which they claim can only come from the ECU (Renntech mod) Any thoughts?
tia
Ken

efathalla

That's why I'd don't tune my 2016 S63.

RENNtechHQ

That is a rare issue with the early 550 software version. A re-tune will fix the problem. Where did you purchase your ECU Upgrade?

meccamilla

something similar happened to mine, so i sent it back and it still does it from time to time, the lights come on on the dash and i lose pretty much all power until i pull over and restart the car then its good again, its a real pain because ive already sent my ecu away once to get fixed and it never fully fixed it