My in car OBC pick up is dead.

What is your question?

My Toyota Corolla 2005 140i has a P0505 fault which showed when I checked with my meter,I then went about checking,and cleaning parts involved with this error reading,also changing the thermostat which was suspect,I then tried to take another reading with OBC meter,but it didn't even light up.I checked the meter,on another car,it worked ok,I also checked 7,5amp fuse,it was fine,what else can I check ? Help needed.Thank you.