Oh boy. Recall required software update "failed." The next day, car (coincidentally?) throws an unrelated CEL, goes into limp mode

[MRGTX]

Relevant info about my: It's a 2020 GT, 6spd, 300A package, Ford Racing CAI/TB/Calibration, 4.09 axle ratio, and lots of other mods but nothing else that seems like it could be related.

Yesterday, I had my car in the shop for an oil change and to finally have the recall (from May 27th, 2022) taken care of. This recall is the "Mustang Manual Gear Position Sensor - PCM SOftware Update" which could result in the loss of the rear view camera, traction control, and a bunch of driver aids that I don't have anyway...but it's not an impending failure that would strand me and I've had no sign of a problem so I wasn't too worried about it.

It's a good thing because the service advisor popped out to the waiting room to say "...Hey, we couldn't update your car's software for the recall. We tried several different programmers and each time, it would say 'update failed.'" I asked if the Ford Racing calibration could have something to do with it and they seemed pretty sure that this wasnt the problem. At this point, I had been stranded in the waiting room for hours and I needed to get out of there so I said that we could take a look at it next time.

SOOoo...today, I was heading to the drag strip for my one (and likely only) chance to run the car this summer...and 20 minutes into the drive, sitting in neutral waiting for traffic at a construction site, the car shuddered, almost stalled, and the dreaded wrench pops up and the car goes into "limp home mode.... "

I pulled the car over in the next parking lot and shut it off while I was looking around for something unplugged, etc. Unfortunately, I didn't bring the tuning pad with me...but I found nothing wrong. Started it up again and it ran normally, wrench light gone. I plugged it in when I got home and found P05A1 code which is related to the Active Grille Air Shutter Position Sensor...??

So my questions are:

Why would the recall software update fail? What could cause that?

Is this related to the spontaneous CEL/P05A1 code?

Does a base trim 300A GT even have active shutters in the grille?

Thanks for any help, insight, advice...

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[ice445]

Yeah, all non performance pack GT's have the shutters. If I had to guess, the shutter motor is having problems returning to the open position. The limp mode was probably from them getting stuck closed (or close to) and the engine got too hot (over 240F CHT). Were you monitoring your temps at the time? Highly doubt the failed update caused anything, but I suppose nothing is impossible. When they did my car they said they were having issues communicating at first, but I guess it was more a bad cable than anything and they eventually figured it out. For the record, a shutter related code can't cause limp mode on its own. They're pretty easy to remove if you want, although the "proper" method is to take the bumper off and remove the shutter blades themselves or tie them open (and disconnect the motor of course). If you just remove the whole assembly you're removing the "air scoop" part as well which isn't ideal.

As for why the update failed? If I had to guess, it's because you have a higher than standard axle ratio flashed to the car. I doubt Ford has set up the update to understand that, since almost nobody has modified that value. And the entire purpose of the update is to update the active rev matching software.

 

[MRGTX]

Thank you for your input!

All of that makes sense. While the hypothesis about overheating due to the slats remaining closed is a sound one, I don't believe the car got that hot. I always leave my (base trim) LCD in "gauge mode" and I was sitting in traffic at the time that it cut out.

Because of this situation, I was watching the temps and they were normal, at least as far as cylinder head temps; ~210 give or take. Still, it's a good thought.

As for the failed update, you may be onto something there with the changed gear ratio and their software not taking the Ford Performance Calibration into account. It seems like they need to figure that out though!

I called to make an appointment about the problem and the service department guy was able to look into the diagnostic data from my ECU though the Ford software which is both creepy and interesting... in any case, it turns out that there are several other fault codes that aren't visible through the tuning pad. One of which is a "torque calculation error" and I'm not sure how that does or does not relate.

 

[AvalancheSVT]

PP GT's dont' have shutters? interesting.

 

[K4fxd]

One of which is a "torque calculation error" and I'm not sure how that does or does not relate.

That code would cause the wrench light. I'd re-flash your ford performance tune. It probably got corrupted when the dealer tried to flash it. From now on tell them not to flash as it has a tune. You should also put duct tape on the OBD plug with the word "NO" showing.


If you want the software fix from the dealer you will have to flash it back to stock while in the shop bay, let them update then re-flash the performance tune. Pain in the ass.

 

[MRGTX]

That code would cause the wrench light. I'd re-flash your ford performance tune. It probably got corrupted when the dealer tried to flash it. From now on tell them not to flash as it has a tune. You should also put duct tape on the OBD plug with the word "NO" showing.


If you want the software fix from the dealer you will have to flash it back to stock while in the shop bay, let them update then re-flash the performance tune. Pain in the ass.

Good point. Thanks for this suggestion!

I don't think they wiped out the performance tune because the car didn't go totally nuts...as it does when the tune isn't there to account for the 4.09 final drive ratio. But reflashing the performance tune certainly wouldn't hurt.

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