I just had my CEL come on and had the code read at Autozone. It shows up as P0603, which the guy looked up as "keep alive memory". My quick research shows this as either a battery cable connection or the ECM (PCM?) is bad and would need replacement. The guy at AZ's display also indicated ECM replacement.

Here's my question: I also recently (a couple months ago) had a problem where nothing would happen when I would try to start the engine. The dash lights and indicators would come on, but the engine did nothing. Eventually, pulling the key out and putting it back in once or twice would resolve the issue, almost like something in the ignition was loose (although it felt normal).

Is there any chance the 2 are related? I think my battery is about 3 years old, but it's been extremely hot here (110) and my car has been out in the sun pretty much every day. The battery seems fine as the car starts up with no problem.

The search I did says to charge the battery and clean the terminals, then erase the code. How do I erase the code?

 

Update for anyone who is interested: I checked the battery this morning and the positive terminal was heavily corroded. I replaced it (and the battery which appeared to be bulging a bit and was still in the free replacement period) and the CEL is off. If it returns, I will update the thread.

Hope this helps someone else.

 

Your symptoms would indicate a bad battery.
Glad you got it figured out.
Cheers!