Erratic check engine coming up occasionally
With winter coming my mileage pre charge is going to around 32miles per charge. At summer time I got around 42miles.
Now recently the check engine lit up few times. So far I have seen lighting up twice on while I turned on and start driving with gas, and other one purely on electric. Therefore it does not appear to gas emission issue.
The volt 2013 manual says it lights up when there is a potential impending issue with emission/gas mileage or some other issue. I am wondering what exactly this is. Is there a code?
I am contemplating whether purchasing service manual can give some clue. Owner's manual has just basic information.
Dealer charges like 160$ just to look at it (highway robbery)