Renntech HHT - Check Engine Light
I received my Renntech HHT yesterday and flashed the ECU. No issues with the flash to the new tune.
When I reverted back to the stock tune, several systems claimed to have functions limited, such as:
1. Active Brake Assist
2. Mercedes Me
3. Active Blind Spot Inoperable
4. Traction Control
5. Engine Oil Cannot be Measured
I started the car, drove around, tried the cycle over again and the check engine light is still on.
Has anyone else ran into issues like this?
Any ideas on what I should tty?


