TCU/Modem issue redux

SpaceLeftBlank

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I’m posting this here in case it helps anyone because other posts here on the subject were helpful to me solving this, but not fully accurate for my situation.

Yesterday I tried to start my climate remotely with no luck (which was extra unfortunate because it’s about ten million degrees out which made the inside of my car about twenty million degrees). Didn’t think anything of it until I got home and realized Fordpass, Ford.com, etc, thought my car was still at work and that my SoC was the same as when I left, and BlueCruise didn’t work (bummer since I had a LONG drive) and so on. Some internet searching told me that the TCU/modem was probably the culprit. The double-secret diagnostic screen was acting like it couldn’t get info from the TCU and the outside world was disconnected, and the connectivity menu in the (not-top-secret) settings was blank.

Many people say the solution is either to pull the negative-terminal connection to the 12V battery or to pull a couple of specific fuses. Since the fuses are easier to get to than the 12V, I decide to try that. Here’s where the “not quite accurate” comes in—a lot of people say the fuse trick doesn’t help, and that was the case for me—at first. Most posts online say to pull fuses 11 and 19. But the problem is that the relevant fuses apparently have different numbers in different model years, which I realized when I went back to look at the posts and what the numbers were supposed to correspond to, which then led me to check my fuse chart again. The important thing is to pull the fuse for the TCU (Telematics Control Unit) and the fuse for the Gateway Module. I have a 2023 GT, and in mine, the TCU fuse really is 11, but the Gateway Module in my 23 is 21 (both 19 and 21, in my car, are incidentally 7.5A fuses). So then I pulled 21 (11 and 19 were already out because I decided to try again).

I put all the fuses back in a minute or two later and that worked. Although everything was sluggish at first because it had apparently reset a bunch of stuff that needed to provision in the background. But now my car talks to the outside world again and all the diagnostics act like the TCU exists again. I *think* most of the people who said 11 and 19 have 2021s. But if you need to try this, find your model’s manual online and check the fuse chart to see where those two fuses are really located.
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NY_Cade69

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Good Info!
You might want to link to this or duplicate it in the other threads to make it easier for others to search for... :D
 
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SpaceLeftBlank

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Good Info!
You might want to link to this or duplicate it in the other threads to make it easier for others to search for... :D
I think maybe I’ll do that. I considered doing that originally, but people in forums sometimes get cranky about zombie posts on old threads.
 

4-Mustangs

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How do you get to the double secret diagnostics screen?
 


MikeC

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I think maybe I’ll do that. I considered doing that originally, but people in forums sometimes get cranky about zombie posts on old threads.
Please if you have time to do it, please do (f the zombies 😀). This is such a brilliant forum and it has helped me fix stuff myself without having to pay huge amounts of money to the dealer. Currently I have the ’Door Malfunction, service required’ message, which I am getting used to the work around (i.e. no auto hand brake, not in park message etc etc), and once again I have mastered my hill starts by having to manually apply and release the handbrake (brings back great memories of my 1983 2.8 injection Capri….what a brilliant car). On that note if you have a magic fix for the ‘Door Malfunction’ thing please let me know. Once again, thank you so much for your original post. If we are ever in Muskegon again I’ll nip over and buy you a beer.
 
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SpaceLeftBlank

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How do you get to the double secret diagnostics screen?
On the steering wheel, hold down the volume control and the arrow pointing left until a little car icon pops up.
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