How to replace 12V battery in C-Max Energi

[DanHolt32]

So I watched several videos on YouTube showing how to replace the 12V battery, but have serious concerns about all of them, or their videography was terrible (cell-phone videos).  

 

I produced my own video of the process showing the steps called out in the service manual, including disabling the HV battery (easy) and removing the orange connector that sits right over the 12V battery (also easy once you know how).  No other video did this, so they teach you to just turn the battery on its side and pull it out. 

 

My used C-Max, which was Ford serviced its whole life has the orange wiring harness all scratched up because the service guys were also ignoring this step.  Let me know if this video works for you to get your battery removed:

 

[homestead]

Good video.

One thing I did on my Hybrid when I changed the 12v battery, I had the guys at the ford dealer hook up a portable jumper to the plus and minus connections under the hood before disconnecting the battery.  By doing this the car never loses 12v power so none of the programming was lost.  You just have to be careful with the +12v cable on the battery when you remove it since it is still hot.  After connecting the new battery remove the portable jumper from under the hood.

Edited February 20, 2022 by homestead

[Lacienega]

Wow, didn't know the Energi is so much harder than the SEL to replace the battery. Much more cable in the way.

 

I had my battery out for 2 hours (because I brought it to the dealer for core exchange) and thought for sure all my setting were gone, but for some reason everything was still the same as before. Maybe the HV battery takes over for some time to keep all the settings incl. time, radio stations, history.....?

Edited February 20, 2022 by Lacienega

[stolenmoment]

When my 12v had it's little episode recently, the radio stations and such were kept, but the "EV+" and "My View" memory was gone.  Different memory technologies, I suppose; it's likely all local to the device itself and not kept in some central memory module.

[cr08]

On 2/20/2022 at 9:07 AM, stolenmoment said:

When my 12v had it's little episode recently, the radio stations and such were kept, but the "EV+" and "My View" memory was gone.  Different memory technologies, I suppose; it's likely all local to the device itself and not kept in some central memory module.

 

Correct. The ACM (AM/FM/Sirius tuner, handles your radio presets) actually stores them in the AsBuilt data which is in non-volatile RAM. The APIM (handling stuff like your Bluetooth pairings, saved navigation info, etc..) stores most of that stuff in the onboard NAND flash which won't be lost on power loss.

However as you've noted with the other features like EV+, MyView, and other things you have set in the IPC (the gauge cluster) are lost on power loss. This may also include your vehicle settings like 'Home light', unit configuration, the 'MPGe' display setting, etc. so those are worth checking.