Idle issue and check engine light.. From alternator?

[MAXX RS4]

So about 2 weeks ago my alternator died out as I was driving down and exit ramp from the highway. Last night I installed a new one and started it up and it ran fine except for a high idle around 1200rpm(took it for a 5 mile trip).

Today, as I was moving my car around positioning it for winter storage the idle was still high and after about 15 minutes it was still doing that. Next thing the chekc engine light came on.

Why would this have happened and what could it be? Wouldn't be related to swapping out the alternator would it?

 

[b dub]

wont know til ya pull the code dude

 

[MAXX RS4]

I never had a check engine light that didn't go away on its own.

Where do I go to get it pulled for free? Also, is there a tool I can rent to do it myself?

I heard that I could possibly fry my 02 sensors if it's spitting out a lot of raw fuel or something like that. Is that true?

 

[STAMPEDE3]

Autozone pulls codes I think.
A code scanner can be bought for under $100.

But until you pull the codes no one can really help, it could be thousands of things.

Even if the CEL goes away the code is still there.
They have momentary faults and hard faults. but codes should be stored in the computer.

 

[mustangdan429]

yes, even if the light goes out it stores it in history.