P0420 Volkswagen - why is dtc data missing on computer

Question

My car won't turn on epc light is on and so is my check engine light. I hooked up a obd 2 analyses and it's saying that the dtcs are missing from computer what do I do

Answer 1

P0420 Catalsyt below threshold Bank 1

The engine needs to be turned on, when the lightning bolt is illuminated when the engine is on you need to have the charging system check. You will not have a data stream with the engine not running.