High Voltage Battery Warning

[Gros Ventre]

Note that there are two 12vdc batteries. There is a small one under the rear pax side seat. It is a "keep alive" battery to maintain power to key computer circuits when the main 12vdc battery is under heavy load (which drops its output voltage).

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[Harry Dangler]

San Tan Ford in Gilbert. He said it was the regular battery, so I am assuming it's the one under the hood. When I go pick it up I will post back if it was otherwise. I did not attempt to talk about plane tickets, but he did offer a rental car for in town use only. I did not mention previously, but when I was waiting 4 hours for the tow truck I uber'd to Autozone and rented a code reader. Clearing the code at the user level did not fix the problem. Hopefully the Forscan will do better. I went out and got a 160$ windows computer just to keep in the truck to run the dealer level program. Lol. Pretty soon I am going to have to pull a trailer just for all the spare parts to keep me going in the back country.... that was not in the sales pitch.

Good infor Thanks

 

[Wood]

Update to the ongoing saga... Dealer replaced main start battery, everything else checked good. Did not even make it 2 miles and got a service warning for same high voltage problem. Truck kept running though. I drove 6.5 hours on it, then parked overnight. The next morning it posted the same critical fault and the truck would not start. Looking at Ford Pass, about 7 hours after I turned truck off it started to shut things down, like remote start and monitoring, because the battery was getting low. About 3 hours later is when i tried to leave. So whatever is draining the battery killed a brand new battery in less than 10 hours. Temp was 68 deg, so that rules out any temperatureI had the brand new spare Optima battery with me, but putting that in did not fix the problem. Nor did the 20 min disconnect/hard reboot. Forscan and OBD wiz also let me down as there were no codes being shown despite every warning on the dash being lit up. I chalk that up to me not knowing how to use Forscan though. Another tow to dealer, San Diego this time. This will be the first Powerboost they have had in for service, so I am not expecting much. Starting the lemon law paperwork for a return....

 

[Gros Ventre]

Try disconnecting both the 12vdc main battery and the smaller 12vdc "Keep Alive" battery underneath the rear pax side seat. I had a case where the dealer could not get the truck to run after maintenance. It was likely one of their first PowerBoost's like yours. I mentioned the likely "Keep Alive" nature of this smaller battery. They had tried to reset the truck by de-energizing the main battery to no avail. After I mentioned the possible "Keep Alive" feature of this battery they tried de-energizing both the main & small battery and it worked fine after that. So look at this smaller battery also.

 

[Wood]

Try disconnecting both the 12vdc main battery and the smaller 12vdc "Keep Alive" battery underneath the rear pax side seat. I had a case where the dealer could not get the truck to run after maintenance. It was likely one of their first PowerBoost's like yours. I mentioned the likely "Keep Alive" nature of this smaller battery. They had tried to reset the truck by de-energizing the main battery to no avail. After I mentioned the possible "Keep Alive" feature of this battery they tried de-energizing both the main & small battery and it worked fine after that. So look at this smaller battery also.

OK, I will let them know if that comes up. But one of the techs last time said that keep alive only works for 20 min, so that is what I have been doing. Basically kepping it disconnected until nothing in the truck turns on anymore, which has always been right at 20 min. Who knows what else is still connected with this dumb thing though...

 

[Gros Ventre]

Well, your tech might be correct... But my bet is so long as it has 12vdc, it keeps its circuits powered. For a battery of this kind of service, the battery is large enough to to go for several weeks... So I'd bet it goes for more than 20 minutes... It's purpose is to maintain certain memory circuits powered, thus it has a very low load...

 

[wcsmith55]

Update to the ongoing saga... Dealer replaced main start battery, everything else checked good. Did not even make it 2 miles and got a service warning for same high voltage problem. Truck kept running though. I drove 6.5 hours on it, then parked overnight. The next morning it posted the same critical fault and the truck would not start. Looking at Ford Pass, about 7 hours after I turned truck off it started to shut things down, like remote start and monitoring, because the battery was getting low. About 3 hours later is when i tried to leave. So whatever is draining the battery killed a brand new battery in less than 10 hours. Temp was 68 deg, so that rules out any temperatureI had the brand new spare Optima battery with me, but putting that in did not fix the problem. Nor did the 20 min disconnect/hard reboot. Forscan and OBD wiz also let me down as there were no codes being shown despite every warning on the dash being lit up. I chalk that up to me not knowing how to use Forscan though. Another tow to dealer, San Diego this time. This will be the first Powerboost they have had in for service, so I am not expecting much. Starting the lemon law paperwork for a return....

I have had all the same problems 3 times.. been to the dealer 2 times they just reboot the system. Dont you all think this should be a recall. Ibought this truck because it was perfect for pulling our travel trailer. I have very little confidence right now.

 

[Wood]

Exactly. I bought mine to do overlanding and I can barely make it out of the driveway.... My sister in -law works at a Ford dealer and said you have to have a lot of documentation to get a buy back going. I am on the phone with them now, painful. 1-800-392-3673.

 

[True North]

Try disconnecting both the 12vdc main battery and the smaller 12vdc "Keep Alive" battery underneath the rear pax side seat. I had a case where the dealer could not get the truck to run after maintenance. It was likely one of their first PowerBoost's like yours. I mentioned the likely "Keep Alive" nature of this smaller battery. They had tried to reset the truck by de-energizing the main battery to no avail. After I mentioned the possible "Keep Alive" feature of this battery they tried de-energizing both the main & small battery and it worked fine after that. So look at this smaller battery also.

How much did you charge your dealer for you to fix your truck?

 

[Gros Ventre]

As it turned out, he expended nearly 12 hours of labor... Since it was a result of his work, no charge for that time was made. It was my comment about the nature of the Keep Alive battery that enabled him to get the truck back on the road.

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