[UPDATED with Ford Norway's Response] Reports of Steep Downhills / Descents Overheating Mach-E

[dbsb3233]

Or it resets because of key off, wait five minutes (timer), key on. ?‍

Could be. The Mach-E does appear to have some sort of timer that takes it from "almost off" to fully off after turning off the car. Like 10 minutes or something?

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[dbsb3233]

Curious: if you go down one of these steep hills for long enough, does the battery meter tick back up? When you get the error, is the battery full?

Yes, the battery meter ticks back up with enough downhill grade (in my experience, the break-even point with climate control on seems to be around 5% downhill grade).

But no, reports have shown it happening well below 100% SOC. For instance, one person reported the problem occurring coming down from a Mt Evans climb in CO. Definitely no chargers at the top. You burn a lot just to get up to the top of the mountain first.

 

[Rt1AWD]

Is it so hard for Ford to make a stand that simulates different regenerative conditions to give a clear answers on the ptoblems like this?

 

[trutolife27]

Very interesting that there are no updates to this thread since July! This happened to me yesterday in the Great Smoky Mountains National Park. I descended from Newfound Gap (elevation just over 5,000 feet) to Sugarlands Visitor Center (elevation about 1,500 feet), with a 20 minute stop at Chimney's Picnic Area. At about 2,000 feet my Mach-E beeped, displayed a red error message on the drive display area ("vehicle drive disengaged" or something similar), and stopped regenerative breaking. I was in Unbridled mode but did not have one pedal driving engaged.

I continued to coast down the hill, slowing via brakes, and turned into SVC parking area. (Thankfully there were no obstructions and the second parking spot was available - rare on an October afternoon.) The vehicle would not turn off; pressing the power button resulted in it blinking. I tried to be nonchalant since my wife and grandson were with me and had another agenda at SVC, so when the car finally did turn off we walked into the Visitor Center. When we returned after about 15 minutes, the car started and we drove home with no problems.

I plan to report this to my dealer and plan a service visit / 10,000 mile maintenance event next week.

You are right to report this to your dealer and get it in for service right away. Trust me I have first-hand knowledge on this happening to someone else and it was way worse.

 

[buzznwood]

Don’t forget that Unbridled mode has the most aggressive regenerative braking. Switching to Whisper mode might reduce the chance of over-heating on descent. Or, if you have a GT and the battery is cool enough, SoC is right, etc. Unbridled Extend might help. These are all guesses on my part since I am still a charter member of the Grumpy thread.

The drive modes just change the amount of lift off regen you get, with less in whisper and oddly more in unbridled. As I have the power meter on the dash I don't really seen a visual bump between the modes when lifting off, maybe if Ford had not made the bar microscopic in size I would , it is not a huge difference. I can't comment on 1pd as I have it switched off. I live in a hilly area simply going down hills with the cruise control on quickly kicks in regen which increases as needed which results in a very stable cruise control speed.

Once Ford finally do an OTA for the power meter to all vehicles we may get a better picture if it is down to regen as owners will have been able to see if they spent most of the way down a mountain pass at maximum regen, quite why the power wasn't even there from the start just shows Ford has a very long way to go in UI design of the driver dash when it comes showing important information with this vehicle.

 

[Kamuelaflyer]

An obvious question is... Do many (or all) of us have this potential problem sitting in ours, but we just haven't experienced it yet because we haven't gone down long steep switchbacks where we keep hitting regen hard into the sharp corners?

It does appear the problem (overheating of some kind?) clears itself and returns to normal after it's allowed to rest and cool down, so that's good. But still.

A good question Tim. I routinely drive to Kona and start out with about a 6,000-foot descent in just under 7 miles. No problems with that (yet. Knock on wood.). Engage mode with 1pd on.

 

[MachTee]

Coming from a Tesla, one of the things I like in the MME is that full regen is still available at 100% SoC thanks to the 10% buffer. In a Tesla, there's 0 regen from 95-100%, and it slowly regains as it drops towards 90%. Cold weather also severely limits regen in a Tesla. Remains to be seen how the MME does in the cold.

Just thinking to myself mostly, but the question is, does the MME have the ability to completely shut off or limit regen? If it doesn't, perhaps the car freaks out during a long steep decline and the SoC approaches 110% (including the buffer)? I realize there were reports of this happening at well under 100% SoC.

 

[dbsb3233]

A good question Tim. I routinely drive to Kona and start out with about a 6,000-foot descent in just under 7 miles. No problems with that (yet. Knock on wood.). Engage mode with 1pd on.

I've done a number of descents from over 11,000' summits without any problem, but always on interstate highways using gentle, consistent regen. Not hard regen. So far the problem pattern appears to be when there's a series of many switchbacks. People repeatedly hit the regen hard on those tight 180' turns over and over, with speed-ups in between each one. I'm guessing that's the difference.

 

[macchiaz-o]

Actually yeah, you’re right. The motors are probably the culprits here, in which case Unbridled Extend on a GT *might* be a help, but there isn’t much else that will help unless the car has a software update to prevent this.

Usually? But not necessarily in this case? See @RonTCat's hint here:

https://www.macheforum.com/site/threads/mt-washington-climb.7266/post-243554

 

[dbsb3233]

Usually? But not necessarily in this case? See @RonTCat's hint here:

https://www.macheforum.com/site/threads/mt-washington-climb.7266/post-243554

Oh wow, I never saw that post. Well that's curious then. I wonder what's actually triggering it?

 

[Tyldum]

From what I gather it's simply software control over when to charge the 12V battery.
The 12V needs constant management and is crucial to the operation of the car. In this case it could be that the cooling drains the 12V during regen.

On an ICE the alternator will constantly charge it when the engine runs, but for an EV it must be managed from the HVB.

Pure speculation, but if the 12V dies while in motion you might damage the motors similar to having to engage towing mode if being towed...

 

[lightnin]

Update: I had my car in for service to correct the drive train disengagement problem. As I understand it, the fix they put on was TSB 21-2245, which doesn't sound exactly like my problem. Does anyone know the TSB to fix the overheating while regenerating going down hill problem (a la Norway)? (The last post above sounds logical to me: 12 V battery discharged due to running cooling fans - the red 12 battery icon was lit on my dash for a while after the problem occurred.)

 

[macchiaz-o]

Update: I had my car in for service to correct the drive train disengagement problem. As I understand it, the fix they put on was TSB 21-2245, which doesn't sound exactly like my problem. Does anyone know the TSB to fix the overheating while regenerating going down hill problem (a la Norway)? (The last post above sounds logical to me: 12 V battery discharged due to running cooling fans - the red 12 battery icon was lit on my dash for a while after the problem occurred.)

I do believe that 21-2245 is the correct one for the downhill issue where the software doesn't correctly handle very high values of regen, with the resulting software panic resulted in an overreaction and vehicle shutdown.

https://www.macheforum.com/site/thr...d-mil-with-dtc-p1a10-u0293-and-or-u1011.8323/

The red 12V battery icon stays lit while the car is in Accessory mode instead of Ready (to drive) mode. This is relatively normal... Just saw it today on mine while I was filling tire pressure.

 

[lightnin]

I do believe that 21-2245 is the correct one for the downhill issue where the software doesn't correctly handle very high values of regen, with the resulting software panic resulted in an overreaction and vehicle shutdown.

https://www.macheforum.com/site/thr...d-mil-with-dtc-p1a10-u0293-and-or-u1011.8323/

The red 12V battery icon stays lit while the car is in Accessory mode instead of Ready (to drive) mode. This is relatively normal... Just saw it today on mine while I was filling tire pressure.

Thanks for the quick update! I will test this at my first opportunity...which may be a few weeks...

 

[lightnin]

Thanks for the quick update! I will test this at my first opportunity...which may be a few weeks...

I tested this last weekend. During the original failure, I had driven up to about 5,500 feet then started down to 1,300 feet, with 2 15 minute stops; the failure occurred at about 1,600 feet elevation. During the test last weekend, I drove up to the Clingman's Dome parking log (about 6,280' elevation) and descended without stopping all the way to Gatlinburg: an uneventful journey, so I guess TSB 21-2245 *did* fix the problem. Yay! (Only caveat is that it was about 15 degrees F colder last weekend than on the day of the drive train failure.)

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