WARNING: Be Sure to attach a Charger (especially on a Hybrid) to prevent Electrical Load Shedding during updating

[huunvubu]

Electrical Load Shedding on Late-model Vehicles Explained

From the above article:

This example involves a 3-year-old Ford Focus and its distressed owner who was something of a DIY mechanic that had a somewhat disturbing propensity for experimenting with his vehicles' programming. Long story short though; this customer had just acquired the Ford Focus, and since (as he claimed) the car felt a bit "sluggish", he thought he would reprogram the ECU to restore the cars' performance.

Since he owned a high-end, Ford-specific scan tool and bought the relevant software from an official Ford source he set to but before the reprogramming could complete, his scan tool (as he put it) went crazy and started displaying messages about electrical sub-systems either shutting down or being altered. He also managed to record a total of 22 trouble codes, including 9 UXXXX codes before the electrical system shut down completely, hence the need for a recovery truck to deliver the car to us.

We no longer have the complete list of trouble codes so we can't reproduce it here, but suffice it to say that almost all of the non-UXXXX codes related to low system voltages, or body control functions like seat adjustments, power window operation, navigation, audio, and/or infotainment system failures. All the UXXXX codes involved communication failures between various control modules, and/or failures of one or more CAN bus systems.

Fortunately for this car’s owner, this writer had seen this type of issue before, so the first order of business was to test the battery, which showed a state of charge of just more than 10 volts. The terminals and cable ends were clean, tight, and free of corrosion, but to be on the safe side, we replaced the battery and since the system had shut down in the middle of an ECU reprogramming event, we hooked up a clean power supply and reprogrammed the ECU from scratch. We then reset the charging system to recognise the new battery, and the Focus fired up immediately.

It is perhaps worth noting that when we scanned the Focus again after performing some relearning procedures and a drive cycle, all but 3 of the UXXXX codes had resolved themselves.

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[MakinDoForNow]

Electrical Load Shedding on Late-model Vehicles Explained

From the above article:

Yes, someone posted a copy from repair manual that told tech's to put charger on with a steady 13.1v to insure load shedding did not occur during updates.

 

[Tom 71 Maverick 24]

An old-school guy like me would logically think that a good, fully charged 12 volt car battery could hang on during an ECU flash/update. And I would be wrong - this, coupled with the numerous "dead battery" and "sleep mode" issues I've read about on these newer vehicles, tell me that what used to be the norm is no longer the case.

Yes, put that trickle charger on your battery before loading a tune or doing anything with the ECU or other on-board computers. The margin of safety of a large, fully-charged battery is no longer a given.

 

[huunvubu]

Yes, someone posted a copy from repair manual that told tech's to put charger on with a steady 13.1v to insure load shedding did not occur during updates.

I too saw that but the tech who came to do my updates didn't have a working charger (he stated it burnt out hooking it up to a vehicle at an auction) so after I insisted he attached a jumper cable from the Ford Mobile Service Van to the Jump points under the hood.

I felt if I didn't insist the updates would have been done without that safety backup to prevent load shedding.

Others on this site have also stated that they saw their tech not install any charger when doing the updates which is why I pointed it out.

 

[huunvubu]

An old-school guy like me would logically think that a good, fully charged 12 volt car battery could hang on during an ECU flash/update. And I would be wrong - this, coupled with the numerous "dead battery" and "sleep mode" issues I've read about on these newer vehicles, tell me that what used to be the norm is no longer the case.

Yes, put that trickle charger on your battery before loading a tune or doing anything with the ECU or other on-board computers. The margin of safety of a large, fully-charged battery is no longer a given.

The problem for the hybrid is that Ford doesn't do fully charged on it. Mine was at 26% charge even though I drive daily.

 

[Tom 71 Maverick 24]

The problem for the hybrid is that Ford doesn't do fully charged on it. Mine was at 26% charge even though I drive daily.

I've seen numerous posts about that on the Hybrids. And it makes no sense. A lead acid battery (old school liquid - sealed, or otherwise) survives best when fully charged, and has some tolerance for overcharge to a certain extent. The newer AGM type have similar science, but from what I've read, have less tolerance to overcharging. Still, fully charging a battery that is critical to every function on the vehicle should be the norm.

 

[Zed79]

Yes, someone posted a copy from repair manual that told tech's to put charger on with a steady 13.1v to insure load shedding did not occur during updates.

This in not new manuals have been telling Techs to install chargers when flashing back in the 90s just like almost every phone, laptop or other battery device.

Guys willing to risk bricking a client car because he can not replace a $20-50 dollar charger should be looking for new work. stop at Walmart or any parts store.

 

[REMUB40]

Ford came to my house twice for reprogramming. They hooked up a charger both times. No issues. I suspect that this I why some people have had issues afterwards.

 

[MetalsGeek]

I recently had 5 recall updates done by a mobile tech, and I topped off my 12V battery with a Noco G3500 charger before he arrived. However, it did occur to me that the hybrid typically powers the 12V charging system from the HV battery whenever the key is ON (engine off). It would then follow that hybrids should not have load shedding issues during programming if the HVB is healthy. However, the process of re-flashing system modules might shut down their normal function temporarily, so this implication might not hold. Does anyone know the truth? All the apparent secrecy surrounding software behavior is really frustrating.

 

[Deano777]

So I am new to the Maverick world (is is supposed to be built July 15). I am learning as much as I can before I get it. I see a lot of 12v battery posts; if I were to habitually put it on a trickle charger when it is paked at night, would that be a good preventive measure? What is everyone’s opinion?

 

[paneubert]

So I am new to the Maverick world (is is supposed to be built July 15). I am learning as much as I can before I get it. I see a lot of 12v battery posts; if I were to habitually put it on a trickle charger when it is paked at night, would that be a good preventive measure? What is everyone’s opinion?

Most likely not necessary every night, but monitoring the battery voltage after it has been sitting a while after the last drive (so you get a more accurate voltage reading versus taking a reading right after a drive) might inform some sort of regular schedule. Maybe you end up doing it every Friday night to Saturday morning or something.

 

[jerrisn]

Electrical Load Shedding on Late-model Vehicles Explained

From the above article:

This is exactly what the dealer did earlier this month when they performed my recalls. They connected my vehicle to their 2024 Escape, and the engine ran the entire time while they updated my computers.

 

[Headbanger]

So I am new to the Maverick world (is is supposed to be built July 15). I am learning as much as I can before I get it. I see a lot of 12v battery posts; if I were to habitually put it on a trickle charger when it is paked at night, would that be a good preventive measure? What is everyone’s opinion?

Opinions will vary on this, however here‘s mine. It’s probably not necessary every night if you do a lot of driving, but certainly can’t hurt if you do. I keep one on mine as often as I can. Takes a minute or so and gives me piece of mind.

 

[MakinDoForNow]

This is exactly what the dealer did earlier this month when they performed my recalls. They connected my vehicle to their 2024 Escape, and the engine ran the entire time while they updated my computers.

FYI on hybrid if you want ice to run all the time put it in park and set the e-brake. You can get out of car with keypad and not get double honk followed by shutdown. Go open gate, walk across road to mail box or what ever.

 

[tom_tucker]

So I am new to the Maverick world (is is supposed to be built July 15). I am learning as much as I can before I get it. I see a lot of 12v battery posts; if I were to habitually put it on a trickle charger when it is paked at night, would that be a good preventive measure? What is everyone’s opinion?

C'mon man, stay out of the weeds. Time to relax, you're buying a new car. 18 months, I haven't had to charge jack squat. No issues whatsoever. Original battery never changed, deep sleep messages went away and were never an issue to begin with.

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