Question

My scanner came up with a code C342D on my 2009 BMW 328i 3 series and I can't figure what's wrong with it

Answer 1

Can you get the powertrain code "P"  what you may have   342D is the model code

Answer 2

The code C342D is not a valid OBDII code. There is no information in the factory service manual for the C342D code. It's possible that the OBDII scanner is not compatible with your vehicle. Please double-check the code number or check with another OBDII scanner.