Possible battery issue

[Oakmax]

Hello all,

I purchased a used 2016 Cmax Energi a couple of years ago. It had been operating normally until it was rear ended while parked. The damage wasn't super severe, but I did have to have the rear liftgate and bumper replaced. Also, the front grill of the vehicle was damaged when it was pushed into the car in front of it. 

 

A few weeks after I got the car back, on one of the first hot days of the summer, I had the a/c blowing and I got the "Yellow Wrench" indicator light on the dashboard. The vehicle drove fine and there were no other issues. After stopping the vehicle and letting it sit overnight, the yellow wrench went away.

 

I continued to commute to work in the vehicle (about 40 minutes) without any incident. Then on a warm day I used the a/c again, and after a while, the yellow wrench came back. But then it went away again after letting the car sit.

 

Then I went on a particularly long drive on a hot day. I held off on using the a/c for about 30 minutes, but then I had to put it on. After a while with the a/c on, the yellow wrench came on, then the check engine light came on. Of course I turned the a/c off. Then eventually the Battery Light came on. Then the center console said something about shutting down. So I turned everything that was an accessory off and the console came back fine and the battery light went off. I was out in the middle of nowhere so I was a bit nervous.

 

I was able to limp to my destination and shut the car off for a while. When I restarted it, everything appeared fine. No warning lights.

 

Until I drive again for about 40 minutes using something that drains the battery. Then I get the wrench. Even headlights will do it.

 

12 Volt voltage reading at jumper posts is 12.3 resting.

voltage reading with car on is 14.5

 

12 volt reading via et mode after morning commute is 12.9v

There are no DTC codes in ET mode.

Took it to autozone and they could't read any codes either.

 

I don't know if this was a pre-existing condition that the car had prior to the accident or if something might have happened during the accident/repair.

 

Any thoughts?

Thanks for your help.

 

 

 

Edited October 28, 2021 by Oakmax

[cr08]

Best thing right now is to get a code reader (my personal preference: Cheap Bluetooth OBD dongle and use the ForScan app on your smartphone OS of choice. ForScan will read Ford specific codes that standard readers may not) and check them as this happens. Get the wrench light, safely pull over, check what codes there are.

 

Without that, it is purely a guessing game what is going on especially with a prior accident in the mix. The codes will at least help narrow it down some especially if there's repeats each time it occurs.

[Oakmax]

Thank you. That sounds like a good first step.

[Oakmax]

Ok. Thank you for giving me a thread to pull on.

 

I purchased an OBD scanner and I received the following error codes upon starting the car.

 

Secondary OBD Control Module C

U0198:00-2F.   Lost Communication with Telematic Control Module A

 

Accessory Protocol Interface Module

U0198:00-0B.   Lost Communication with Telematic Control Module A

U3000:04-0A   Control Module

-System Internal Failures

 

DC to DC Converter Control Module

U0412:00-28.     Invalid Data Received from Battery Energy Control Module A

 

It seems like there is some bad communication between the DC to DC converter and maybe the charging system?

This seems consistent with losing power to the 12V electrical system while driving. Maybe the DC/DC converter isn't charging the 12V battery appropriately.

 

Might this be a loose connector somewhere?

 

 

 

 

Edited October 30, 2021 by Oakmax

[16redsel]

Maybe your original premise is the problem. I have a 2016 Hybrid SEL 66000 mi. original battery. I noticed

the time between pressing the engine off button, and when the system would power down (w/o opening doors) was getting

shorter. Was about 10 min. in past but now just over 3 min.

   Dealer load tested battery and CCA was low. I had it replaced. Now I worry less about yellow wrenches and I think the shutdown

interval is a good indicator.

 

[Oakmax]

I think you are suggesting that the 12V battery is at end-of-life and is no longer capable of being sufficiently charged via the dc/dc converter. Is that accurate?

 

I will continue to monitor the car until I can get a good reading while the wrench light or check engine light is on.

 

[homestead]

On 10/30/2021 at 8:41 PM, 16redsel said:

Was about 10 min. in past but now just over 3 min. 

 

I think this is a normal situation for C-max.

My car's timer was 10 min. after installing new battery and BMS reset and a few years later it is down to 2-3 minutes.

No problems even last year when it was hardly driven.  Original battery was working fine but was replaced because it was 5 yrs old.

[cr08]

Must be lucky with my '13 Energi then. My 12v battery is either 4 1/2 or more years old (when I bought the car) or as old as the car as the BMS counter registers the same age as the manufacture of the vehicle. But with that said I still get a good 10-15 minutes of the radio key-off and it shuts off -without- the 'powering off to save battery' message so assuming just the normal 15 minute timeout. Haven't had the need to jump start it either. Then again I do keep mine plugged in every night and it trickle charges the 12v battery at this time.

[homestead]

Yes mine is a hybrid. So energi's may have more headroom with the hvb.