I recently bought a second hand A6 1.8T quattro and got a EML warning. Got it diagnosed and there were 5 error codes. One was to do with brake light switch (got it replaced) and fault with Knock Sensors . The car is driving fine and is right now giving no driving problems ( feels like so !!! )

One of the error codes

17794 P1386 Internal Control Module Knock Control Circ.Error

needs Engine Control Module (ECM) to be replaced which will cost around 800 quids at Audi workshop only. The guy is an independent Audi specialist and according to him, its Ok to drive it as it wont affect daily driving. I still have the EML on and its a disturbing sight while driving

Could someone please help with this error code as to is there any other way to get rid of it? Is it OK to have error with Knock Control and still drive the car?

Kindly guide.