Why do my Cadillac evap stay in the not ready status, although I have no code on it?

Question

When I put the code reader on the Evap system and the o2s stays in the not ready status.

Answer 1

The EVAP system will be the last monitor to run. In order for the EVAP system to run the fuel has to be more the 1/4 to 3/4 fuel in the tank. less than a 1/4 the EVAP will not run more than 3/4 the EVAP will not run. and the 02 monitor has to run before the EVAP system run.