Engine coolant over temperature & service engine soon warnings pop on

[BUCKYBRONCO2021]

Also disregard the cylinder 3 misfire. Thats totally unrelated to these issues. They snapped the bolt that holds the coil in when they were putting the motor back together and crossthreaded it. Im in the process of fixing that but it popped out while driving. Its a problem for sure but its not related.

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[Ducati1098]

Let me start by just saying i cant thank you enough. I literally breathed a sign of relief just and valudation that im not imagining this.

Wow thats more info than i have gotten from the dealer since i brought the truck in.

Just to give you some run down:

6/27/25 i brought it in for the engine valve recall. It got a new motor put in and i got the truck back 8/20/25 with 35592 miles on it. Have had the problem since then

So based on that i seems like all the shutter codes started after the engine was replaced. What do you think is causing those codes?

No problem.
You either have a wiring concern to the shutters, or faulty shutters. Unfortunately that’s really the extent I can say without having the vehicle to do testing.

The easiest thing you could do is simply check the connectors.

No idea if they did anything with the shutters during the engine removal. You really don’t need to, but every technician is different on how the do a repair. I know some that would just quickly pull the whole front end off when doing an engine replacement to give themselves more room to work near the front of the engine and make it easier to pull out.

Can’t say whether they did this or not though. It’s possible it’s unrelated, but certainly a coincidence.

 

[BUCKYBRONCO2021]

No problem.
You either have a wiring concern to the shutters, or faulty shutters. Unfortunately that’s really the extent I can say without having the vehicle to do testing.

The easiest thing you could do is simply check the connectors.

No idea if they did anything with the shutters during the engine removal. You really don’t need to, but every technician is different on how the do a repair. I know some that would just quickly pull the whole front end off when doing an engine replacement to give themselves more room to work near the front of the engine and make it easier to pull out.

Can’t say whether they did this or not though. It’s possible it’s unrelated, but certainly a coincidence.

yeah looks like they didnt take the front end off but i wouldnt put it past them not plugging something back in as i must have plugged back in 4-6 connections that were not fully seated and one hose that looked to be an evap hose that wasnt even connected. Again thank you very much for the help. Im armed with information and can now plead my case much better than i would have been able to. Im very glad i tagged you on that post lol!

 

[Ducati1098]

yeah looks like they didnt take the front end off but i wouldnt put it past them not plugging something back in as i must have plugged back in 4-6 connections that were not fully seated and one hose that looked to be an evap hose that wasnt even connected. Again thank you very much for the help. Im armed with information and can now plead my case much better than i would have been able to. Im very glad i tagged you on that post lol!

You’re very welcome.

Based on that picture alone, and considering the codes didn’t start until a few weeks after you already got it back, I’m going to guess that this was an unrelated issue to what they did and just poor luck that you had another problem. But either way, at least you have a direction to go now.

 

[BUCKYBRONCO2021]

You’re very welcome.

Based on that picture alone, and considering the codes didn’t start until a few weeks after you already got it back, I’m going to guess that this was an unrelated issue to what they did and just poor luck that you had another problem. But either way, at least you have a direction to go now.

So, update:

They mysteriously found the codes and according to them "did a pinpoint test and there was resistance in the wiring over 20ohms and the active grill shutters also work on the same network as all oil and coolant electrics called the LIN network. As per ford testing the recommended fix is to replace the full assembly. (active grill shutters top and bottom and the motor). "

So they changed all that and said it was all good to go (I'll spare everyone the details of what got messed up in repairing that).

I was told that all was good and the temp was great. Picked it up yesterday at 5:30Pm paid $922 and returned it at 6:30PM because the temp went up to 241 and it flashed the engine coolant over temperature warning and service vehicle soon warning.

They said it has a new code and its a performance code. The service person said the tech is stumped and reached out to Ford Engineering and are waiting on a response. They also said it could be the battery junction box. which sounds odd but i really don't know. Thankfully I'm in a loaner but this has been quite a roller coaster. I did the math and I've owned the truck for 111 days and its been at the dealer for 59 total days so far. Sucks cause i love this truck but man does it have some issues. Hopefully they figure it out. The saga continues lol.

Thanks again for the help with the codes cause i would have got no traction if i hadn't sent them proof i knew what was going on.

 

[Q1svt]

@BUCKYBRONCO2021

WOW what a journey…. Sorry to see that happening to anyone.
Very glad to see people like @Ducati1098 sharing his experience and knowledge.

So they changed all that and said it was all good to go (I'll spare everyone the details of what got messed up in repairing that).

Unless you don’t want to be that public, please share so others learn and know how to fight back

 

[BUCKYBRONCO2021]

@BUCKYBRONCO2021

WOW what a journey…. Sorry to see that happening to anyone.
Very glad to see people like @Ducati1098 sharing his experience and knowledge.



Unless you don’t want to be that public, please share so others learn and know how to fight back

Oh I dont mind it being public its just like stupid tech specific issues so i didnt want the whole post to be my gripes. Just part of it i guess lol.

For example: The covered the hood prop with the radiator/fan shroud cover. When i asked them about it he said he did that cause i installed hood struts. They scratched a few things and it was all smudged up. Not the end of the world but having a truck there that long and so involved as this one you would think they would have went out of their way to do the right thing. And this is all not including the mess with the engine install. Best advice i can give is to go in prepared as possible and inspect and check everything before and after to drop it off.

And i second the kudos to @Ducati1098 hes was a lifesaver with his knowledge and willingness to help. If he lives in or near new york or ever comes this way I'll buy him a steak.

 

[Brian_B]

There were some issues with the under hood fuse box not being torqued down and having intermittent connections for the fuses. Also some with loose ground points under the hood.

So that’s a possibility

 

[Ducati1098]

So, update:

They mysteriously found the codes and according to them "did a pinpoint test and there was resistance in the wiring over 20ohms and the active grill shutters also work on the same network as all oil and coolant electrics called the LIN network. As per ford testing the recommended fix is to replace the full assembly. (active grill shutters top and bottom and the motor). "

So they changed all that and said it was all good to go (I'll spare everyone the details of what got messed up in repairing that).

I was told that all was good and the temp was great. Picked it up yesterday at 5:30Pm paid $922 and returned it at 6:30PM because the temp went up to 241 and it flashed the engine coolant over temperature warning and service vehicle soon warning.

They said it has a new code and its a performance code. The service person said the tech is stumped and reached out to Ford Engineering and are waiting on a response. They also said it could be the battery junction box. which sounds odd but i really don't know. Thankfully I'm in a loaner but this has been quite a roller coaster. I did the math and I've owned the truck for 111 days and its been at the dealer for 59 total days so far. Sucks cause i love this truck but man does it have some issues. Hopefully they figure it out. The saga continues lol.

Thanks again for the help with the codes cause i would have got no traction if i hadn't sent them proof i knew what was going on.

Glad to hear they at least fixed the one issue. Sorry to hear the overheating is still an ongoing problem though. Looks like it's still related to the shutters probably. Hopefully they get it figured out soon

 

[BUCKYBRONCO2021]

Update: So the truck is still at the dealership. Its been there since i don't even remember its all blurred together honestly.

I'll condense this crap down as much as i can. The tech thinks its the smart junction box but the ford engineer that came on site (allegedly several times) says they need to keep changing the shutters until they get one that works and if they don't get one at some point they will then give approval to change the smart junction box. at this point today they have tried 5 brand new active grill shutters and they said all are bad (this is what they are telling me so if it sounds retarded it isn't me). They have two more coming in today. I said to them this sounds crazy and doesn't make sense. i also see the truck hasn't been moved or started for two weeks and it is in their lot but they said they don't need to start it and the grill and headlight are off and the are plugging in the shutters and testing the ohms. i share this here cause it just sounds so ridiculous to write all that. I wonder if ford monitors these post, if this shutter issue is a real thing or why ford engineers would ok the purchase of at least 7 brand new active grill shutters before they say hey maybe its not the shutters maybe the issue is more upstream. I'm confused, or rather still confused.

@Ducati1098 does any of this make sense? I feel you have a properly ohm'ed out bullshit detector lol

 

[Ducati1098]

Update: So the truck is still at the dealership. Its been there since i don't even remember its all blurred together honestly.

I'll condense this crap down as much as i can. The tech thinks its the smart junction box but the ford engineer that came on site (allegedly several times) says they need to keep changing the shutters until they get one that works and if they don't get one at some point they will then give approval to change the smart junction box. at this point today they have tried 5 brand new active grill shutters and they said all are bad (this is what they are telling me so if it sounds retarded it isn't me). They have two more coming in today. I said to them this sounds crazy and doesn't make sense. i also see the truck hasn't been moved or started for two weeks and it is in their lot but they said they don't need to start it and the grill and headlight are off and the are plugging in the shutters and testing the ohms. i share this here cause it just sounds so ridiculous to write all that. I wonder if ford monitors these post, if this shutter issue is a real thing or why ford engineers would ok the purchase of at least 7 brand new active grill shutters before they say hey maybe its not the shutters maybe the issue is more upstream. I'm confused, or rather still confused.

@Ducati1098 does any of this make sense? I feel you have a properly ohm'ed out bullshit detector lol

lol oh man. Well I can tell you with 100% certainty that I would never try that many shutters to attempt to fix the same issue. I also don't understand why they cant seem to figure out whether it is the actual shutters or potentially a different issue like the junction box. This should be a pretty straight forward pinpoint test to follow

The most logical thing to do IMO, would be to simply take a known good, working one off of a used bronco on the lot if possible. That will obviously rule out something right away.

Blows my mind that they've tried that many different shutters and are still trying them.
I have no knowledge of a common issue with the replacement shutters. I suppose it's possible, but very unlikely with that many "bad" ones.

 

[BroncoChallenger]

Your service department, I'm sorry to say, seems to be filled with parts changers, not service techs...and this Ford Engineer who came out doesn't seem very bright either.

There would be NO reason to replace the shutters that many times, when testing them independently (out of the vehicle) would tell you if they were good or not. From there it would be checking the wires to wherever they terminate, and checking fuse boxes and stuff...as Ducati said, it's a pinpoint test, you test from A to B then from B to C and so on until you find where the problem is.

I like my service department, they seem to have some pretty good techs who actually know a few things...but when that changes, my loyalty to them will absolutely stop. Sounds like when they finally fix your Bronco, you may want to consider the same.

 

[BUCKYBRONCO2021]

lol oh man. Well I can tell you with 100% certainty that I would never try that many shutters to attempt to fix the same issue. I also don't understand why they cant seem to figure out whether it is the actual shutters or potentially a different issue like the junction box. This should be a pretty straight forward pinpoint test to follow

The most logical thing to do IMO, would be to simply take a known good, working one off of a used bronco on the lot if possible. That will obviously rule out something right away.

Blows my mind that they've tried that many different shutters and are still trying them.
I have no knowledge of a common issue with the replacement shutters. I suppose it's possible, but very unlikely with that many "bad" ones.

Whats funny is, i actually mentioned to the service rep yesterday to pull one off of a new vehicle to check it and she said "They cant do that because they are serialized." That was me suggesting it as a layperson but it seems like that was a good idea if you are suggesting something similar. I'm also a cost benefit guy. to me it seems like it is costing more money to order, ship, and try all of these shutters to finally say, hey maybe it isn't this than to change the other part. now all of these are opened, used and they don't know if they were the problem or not. After two i would have said ok it isn't this part its something else. And, this is assuming that everyone is being 100% honest which i know they must be, just like i trust the government and also believe everything on the internet lol. i'll stop there before i get political lol.

 

[BUCKYBRONCO2021]

Your service department, I'm sorry to say, seems to be filled with parts changers, not service techs...and this Ford Engineer who came out doesn't seem very bright either.

There would be NO reason to replace the shutters that many times, when testing them independently (out of the vehicle) would tell you if they were good or not. From there it would be checking the wires to wherever they terminate, and checking fuse boxes and stuff...as Ducati said, it's a pinpoint test, you test from A to B then from B to C and so on until you find where the problem is.

I like my service department, they seem to have some pretty good techs who actually know a few things...but when that changes, my loyalty to them will absolutely stop. Sounds like when they finally fix your Bronco, you may want to consider the same.

Agreed. i will not be using this dealership service dept after this. i originally went there with no problems for the valve recall and they put a new engine in. Since then, mucho problemos. i know what the common denominator is but no one else will touch this vehicle with their hex on it. I have to get past this then i can move on.

 

[Ducati1098]

Whats funny is, i actually mentioned to the service rep yesterday to pull one off of a new vehicle to check it and she said "They cant do that because they are serialized." That was me suggesting it as a layperson but it seems like that was a good idea if you are suggesting something similar. I'm also a cost benefit guy. to me it seems like it is costing more money to order, ship, and try all of these shutters to finally say, hey maybe it isn't this than to change the other part. now all of these are opened, used and they don't know if they were the problem or not. After two i would have said ok it isn't this part its something else. And, this is assuming that everyone is being 100% honest which i know they must be, just like i trust the government and also believe everything on the internet lol. i'll stop there before i get political lol.

LOL serialized? That's a straight up lie. But most service writers have no idea what they're actually talking about.
I hate to throw other technicians under a bus, because sometimes you do run into some crazy problems that don't make sense, but in this case I think the FSE is at more at fault for even telling them to continue getting more shutter assemblies until they receive a new one. That just seems ridiculous.
Anyway, wish I could be more help, but hopefully they'll figure it out soon.

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