what is the manufacturer code P 1506

The Check Engine light is a yellow light on the dash which should illuminate when the ignition key is turned on and go out a second after the engine starts. It is usually a yellow outline of an engine, some car manufactures make it confusing and just have the words "Service Engine Soon" http://www.google.com/images?hl=en&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&biw=1280&bih=615&gbv=2&tbs=isch%3A1&sa=1&q=check+engine+light&aq=0&aqi=g10&aql=&oq=+check+engine+light