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.
Try looking at this: https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/repair%20manual/04pruisr/05/21avn/cic12414.pdf
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?
