It's not so strange. About a year after purchasing my Sportage I received a sticker in the mail from Kia. The instructions were to place the sticker under the dash just above the OBD-II connector. The sticker read something like this...

"Vehicle must be running to read diagnostic codes."

This never made sense to me. What if you have a "fatal" error that prevents the engine from running? How do you read the code? And I've never encountered this on any other OBD-II compliant vehicle.

Anyway, in all the times I tripped a CEL I always simply turned the ignition to ON and read the code. And it always worked. I never started the engine to read it. But I can't explain why in your case it refused to spit out the code.

BTW, P0301 is misfire on cylinder 1.