Telematics Control Unit Died

[davidlgibbs]

My 2021 F-250 6.7L Tremor lost WiFi connectivity recently. I subscribe to the AT&T unlimited data hotspot that's built into the car, and only recently noticed that my phone was no longer connecting. After a bunch of diagnostics, attempted resetting of the system and even reviewing the TCU module settings in FORScan, I finally took it to the dealer. Dealer diagnosed the TCU module as dead, and has no estimate for when they can get one from Ford.

Does anyone here work at a dealership or for anyone who might have the actual Ford PN for the TCU module for my truck? I was going to see if there was any way to source it elsewhere, and have even been looking for totaled F-250 Lariats with the electronics package which would match my TCU. This also affects the FordPass app's ability to connect with the truck. Ford can't reach my truck remotely because the cellular modem is either in or controlled by the TCU. Can't get a lot of information - anyone with knowledge of this issue I'd be really happy to learn what you know.

 

[gommer]

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Maybe?

Per this page:

https://www.justanswer.com/ford/inrep-2019-ford-f250-tcu-telematic-control-module-fuse-location.html

Looks like it'd be easy enough to get to and get the number off of.

 

[TomcatF14]

My 2021 F-250 6.7L Tremor lost WiFi connectivity recently. I subscribe to the AT&T unlimited data hotspot that's built into the car, and only recently noticed that my phone was no longer connecting. After a bunch of diagnostics, attempted resetting of the system and even reviewing the TCU module settings in FORScan, I finally took it to the dealer. Dealer diagnosed the TCU module as dead, and has no estimate for when they can get one from Ford.

Does anyone here work at a dealership or for anyone who might have the actual Ford PN for the TCU module for my truck? I was going to see if there was any way to source it elsewhere, and have even been looking for totaled F-250 Lariats with the electronics package which would match my TCU. This also affects the FordPass app's ability to connect with the truck. Ford can't reach my truck remotely because the cellular modem is either in or controlled by the TCU. Can't get a lot of information - anyone with knowledge of this issue I'd be really happy to learn what you know.

Any luck with the dealer getting the part or sourcing a TCU yourself? In a similar boat. Dealer and FordPass folks flicking the booger on what’s actually wrong with my FordPass. There appears to be a lack of knowledge within my dealership about what part of the modem talks to FordPass. And an ability to diagnose and fix.

 

[davidlgibbs]

Good Morning,

I apologize as I meant to post a follow-up. The dealer who was such a pain completely failed to assist with this. I called another dealership in the area, took it in the following day for them to diagnose the TCU as being defective, then they immediately ordered a new one. It took 3-4 weeks to arrive, but the moment it did they called, scheduled my appointment for the next day and replaced it. It works flawlessly now. Finally all is back to normal. I was never able to find the part number to attempt to source one, but I think I would have been inviting more problems had I been able to do so.

 

[SJK]

Good Morning,

I apologize as I meant to post a follow-up. The dealer who was such a pain completely failed to assist with this. I called another dealership in the area, took it in the following day for them to diagnose the TCU as being defective, then they immediately ordered a new one. It took 3-4 weeks to arrive, but the moment it did they called, scheduled my appointment for the next day and replaced it. It works flawlessly now. Finally all is back to normal. I was never able to find the part number to attempt to source one, but I think I would have been inviting more problems had I been able to do so.

Hi,
Just out of curiosity, do you know where the TCU is located on the vehicle?

 

[TomcatF14]

Good Morning,

I apologize as I meant to post a follow-up. The dealer who was such a pain completely failed to assist with this. I called another dealership in the area, took it in the following day for them to diagnose the TCU as being defective, then they immediately ordered a new one. It took 3-4 weeks to arrive, but the moment it did they called, scheduled my appointment for the next day and replaced it. It works flawlessly now. Finally all is back to normal. I was never able to find the part number to attempt to source one, but I think I would have been inviting more problems had I been able to do so.

Mine goes in next week. Part supposedly came in on the truck yesterday. They finally relented and realized it’s the TCU and not my FordPass account.

TCU is located on the rear cab wall. Drop the single rear seat back. Pull the two push pins then pull the fiber felt away. Bolted to the wall

 

[Cglenn]

Curiously what symptoms did you have? My truck now has no gps signal

 

[davidlgibbs]

Curiously what symptoms did you have? My truck now has no gps signal

I actually don't have a clue. I knew it was the TCU after some research. My GPS wasn't affected, it was the cellular modem - I subscribe to AT&T vehicle WiFi (based on cellular), and I lost all connectivity. The modem wouldn't respond to resets or any other programming options on the Sync3, and my dealer confirmed that the unit was dead. The TCU is a Telematics Control Unit so I'm not sure if it includes GPS or not. Once I got to the right dealer, they were very helpful in figuring out what was wrong.

I believe the GPS antenna is one of the two "bumps" on the back of the cab roof. Did either of them get hit or damaged?

 

[TomcatF14]

Curiously what symptoms did you have? My truck now has no gps signal

For me it was specifically the FordPass app. Do not have a hotspot. GPS works fine. Wi-Fi connects to my phone. Connects to my home Wi-Fi. FordPass hasn’t worked for me in over a year. Last OTA update was last Nov. FordPass folks say the two are separate Dealer tried a refresh. Didnt work. Next is new TCU which apparently is the part that controls FordPass connectivity.

A little interweb research turns up a lot of articles circa Spring 2021. Mine was built Feb 21. Maybe a bad batch? We’ll see.

 

[davidlgibbs]

For me it was specifically the FordPass app. Do not have a hotspot. GPS works fine. Wi-Fi connects to my phone. Connects to my home Wi-Fi. FordPass hasn’t worked for me in over a year. Last OTA update was last Nov. FordPass folks say the two are separate Dealer tried a refresh. Didnt work. Next is new TCU which apparently is the part that controls FordPass connectivity.

A little interweb research turns up a lot of articles circa Spring 2021. Mine was built Feb 21. Maybe a bad batch? We’ll see.

I thought you were having GPS issues with the Sync3 - this makes more sense. Yes, FordPass is entirely dependent upon the cellular modem in the TCU. Whether you have the hotspot or not, FordPass has to communicate with the truck, and does so via cellular networks. My guess is that they're correct - it's a bad TCU. One of the many issues I had when it went bad is that my truck showed up in the FordPass app as being at a place I parked it at just before it croaked. Never moved. So your GPS is probably still okay, it's just that the truck cannot communicate with FordPass servers to relay that information. I took delivery of my truck in December 2020, so if there is a batch of bad TCUs, it stretches back much further than Spring 2021.

 

[TomcatF14]

Replaced the TCU/Modem and FordPass works again. Other than FordPass not working another indicator was a blank screen when selecting Vehicle Hotspot. Don’t have a hotspot but the menu wouldn’t even populate. Now it’s going through OTA updates.

FYI the TCU is located behind passenger side rear seat above the bottle jack.

 

[davidlgibbs]

Thank you for the information. I actually assumed it was somewhere under the dash. Much easier to access back there. Glad it worked for you. I was so stoked when it all started working again. I hate having things not working on the truck. A little too OCD about these things.

 

[SFDOC]

Replaced the TCU/Modem and FordPass works again. Other than FordPass not working another indicator was a blank screen when selecting Vehicle Hotspot. Don’t have a hotspot but the menu wouldn’t even populate. Now it’s going through OTA updates.

FYI the TCU is located behind passenger side rear seat above the bottle jack.

Did this fix your issue completely? I am having the same issue. Dealer keeps telling me its Ford Pass. Ford Pass Says take it to the dealer. I have the same exact truck (Except mine is black) the paid ATT service does not work. Ford Pass Will not even activate any longer. No ESN# shows for the Onboard Modem (TCU). I am sick of dealing with Dealers. Much less 5 days to diagnose it. No loaner vehicle. I want to get the part my self. I have the part number.

 

[davidlgibbs]

Did this fix your issue completely? I am having the same issue. Dealer keeps telling me its Ford Pass. Ford Pass Says take it to the dealer. I have the same exact truck (Except mine is black) the paid ATT service does not work. Ford Pass Will not even activate any longer. No ESN# shows for the Onboard Modem (TCU). I am sick of dealing with Dealers. Much less 5 days to diagnose it. No loaner vehicle. I want to get the part my self. I have the part number.

Fully resolved the issue. I don't know if the part can be "just replaced," as I imagine there is some programming to tie the truck to the new ESN and model in the TCU, which in turn ties it to FordPass. But, the dealer did replace just the TCU (and it notes some programming), and the problem was fully solved. I saw the same issues you did - no ESN in the head unit, FordPass would not work at all, no internet on the WiFi network in the truck, and a few other quirks. Sounds like your modem is dead like mine was, and replacement is the only fix I'm aware of.

 

[TomcatF14]

Did this fix your issue completely? I am having the same issue. Dealer keeps telling me its Ford Pass. Ford Pass Says take it to the dealer. I have the same exact truck (Except mine is black) the paid ATT service does not work. Ford Pass Will not even activate any longer. No ESN# shows for the Onboard Modem (TCU). I am sick of dealing with Dealers. Much less 5 days to diagnose it. No loaner vehicle. I want to get the part my self. I have the part number.

Yes. Has worked since TCU change.

 

[BCandia]

Mine crapped out. Thanks to this post I located it and it appears the company that installed my subwoofer unscrewed it to get the sub in and didn't re-secure it. I can only assume it's been shaken to all hell since it was not secured.