Ck engine light came on & stayed on, although no other symptoms of car problems.

If its a used car when you bought it, it may be just letting you know that you need your oil changed. Mine does that about every 3500 miles.

this is an obd2 trouble code table, it can help you understand the meaning of code. http://chinasinoy.com/service/diagnostic-trouble-code-table-33.html for p0446,you can try: Replace Vent valve Repair open, short, or resistance problem in control circuit Repair open, or short, or resistance problem in power circuit Replace PCM

After they put your car on the machine, the light will stay off if it was the oil changing thing but if it isn't it will eventually come back on.