Reading CEL with a voltmeter

[dmc67]

Ok guys first off I am not gunna swear my CEL is on but when I first start the car it's on for a few secs and goes off. But the reason I wanna check is b/c I am idle surging badly.

What does the voltage meter have to be set on? I am thinking DC. and what numbers? I have 2 meters an analog and a digital analog has 2.5 50 200 for settings and digital has 20 200 and 300 under the DC category. I also bought the lil buzzer like they said to on this thread http://www.vfaq.com/mods/wayback/BradBauer/electrical/code.html but I cant tell the beeps apart. Any help here would be appreciated.

Thanks,

 

[huafist]

When the ECU recieves power, it turns the CEL on for 5 seconds and then turns it off. It's a diagnostic "hey, I'm working fine!" thing. If your CEL doesn't come on at all when you turn the key, then either the ECU isn't receiving power or is dead.
If you're going to use a voltmeter to check ECU codes, make sure you use an analog meter. You can't read the pulses well with a DMM. Before I started using a logger, I just used an LED to read the codes.
The ECU is the least likely cause of idle surge you'll have. Check for boost leaks, clean your throttle body, check the EGR, and check the ISC coils.