OEM battery (pretty old) 1st morning that it got below 40° and acted like dead battery, didn't quite crank over, clock had lost time (alien abduction??).
Put a small charger on for just a few minutes, and it started. Shut off and meter showed 12.4
Dead again 30 minutes later, started again after charging a little, but now the check engine light is on, Drove a few minutes at low speed. Shut off and this time it restarted, engine light still on.
Drove an hour+ on the highway with check engine light on, and then shut off. 30 minutes later, restarts OK, the check engine light is gone!. After setting a few hours, 12.5v and restarts fine.
Computer glitch? or is the check engine light supposed to respond to voltage problems ?

 

Welcome to the forum!

Do you have the ability to check the stored diagnostic codes to see if the code was related to system voltage? There are codes related to the Keep Alive Memory (KAM) and other voltage-related codes, so it is possible that's why the CEL was on. But there should be a history code available even though the CEL is not currently illuminated.

I hope you plan to replace the battery which seems to be warning you that it will leave you stranded soon.

-Rod

 

next morning voltage was 12.6 but it wouldn't start and voltage then dropped to 12.2
bought a new battery. Not too surprising, except for the involvement of the CEL.
Anyway, thanks Rod
Bill