Picked up my 201 from maintenance, got a CO alarm on my sensorcon right on start up. I figured it might be blowing exhaust back in because I did start down wind of the exhaust. Opened some ventilation. Kept an eye on it during taxi and run up but the alarm was still blaring. I figured the only way to find out if it’s ground CO or a leak is in the air. So, I took off around the pattern. Normally these ground CO alarms would reduce in climb and clear up once leveled off. It was 50-70 on th