C1242 code

Hello. Just had the "Check Engine" light come on today, and I stopped in the local auto parts store and found 2 codes:

C1242 - ABS $29 - Open Circuit In IG2 Circuit

P0171 - ECM - Bank 1 System Too Lean

It looks like the latter code (P0171) has happened before (I bought the car used), and I got some cleaner for the Mass Air Flow sensor which will hopefully help.

Any suggestions on C1242? It was a very hot day here and I was in the middle of a bunch of little trips when the "Check Engine" light came on, don't know if that would matter.

Edit to add: 2005 Prius. No other lights or anything came on. Added some detail to codes above.

 

Thanks for the link. I replaced the 12v battery with a new Optima one just last year. System Check Mode shows proper aux battery voltages according to this procedure:
Toyota Prius: How to Check the 12v Auxiliary Battery Health - PriusDIY.com

Not sure what else I am capable of doing. Should I take it in, for someone to check the brake control power supply, etc.? Or just clear the code and see if it comes back?