Electrical

[Skysoldier]

I have two 12 volt long Iife batteries under my front door step instead of the factory one. 2020 Jayco 26Y. This causes the check engine light to come on after a while. The code it trips reads 24 volts. My Jayco has the ability to use the house batteries to start the engine in case V-10 battery fails. I reset and check engine light will reappear.
Does Jayco know about this abnormality?

[RetiredOne]

Is it possible the batteries are connected in series, instead of parallel? Are you talking about the batteries in the coach entry stairs?

[Skysoldier]

Yes
Thank you for the idea. I thought I wired them in parallel, but I will check.