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DIY Fix for no LTE/WiFi connectivity bug

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Cabonzhp

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Cars
Lucid Air Pure
Hi all. My 24 Air Pure recently decided to stop connecting to LTE and WiFi. There are a few reported instances of this on the forum. No amount of software reboots can fix this, and all users that have posted about this had to bring their car in for service to address this. After dealing with this for a few days, and the service only offering to see the car in ~3 weeks, I found a simple solution myself.

I read about a report or two that the technician fixed this super quickly after crawling in the back seat. Here is the solution you can try yourself if you face this issue.

Fold down both back seats. Peel up the carpeted Velcro flap connecting the bottom of the folded part of the seat to the trunk. Underneath this you’ll see a module labeled TCU. Reach down and unplug the main connector (the only one with multiple wires). Wait a few seconds and replug. After a few minutes LTE and WiFi should return.

Since this is what dealers are clearly doing and users on the forum aren’t reporting the issue coming back, this should be a safe try.

I’ve also seen documentation claiming a slightly different location for the TCU (towards the passenger side of this same area but on the wheel well).
 
This is the correct way to reset the TCU. I would just like to reiterate that Lucid absolutely does not recommend you do this yourself, at present, and would absolutely say that you have service do this instead.

I have no dog in the fight, just wanted to be super clear about it.

But yes, this is how service resets the TCU.
 
I too discovered this resolution and it does indeed work; however, as a Borski said you should at least let Lucid look at the vehicle and make sure it is a software issue that they can track. I have had my car in to service 3 times for this issue (approximately 1/month). All 3 times they designated it as a software issue, but like Cabonzhp I did contact service and they couldn't see me for a few weeks. This was unacceptable so I took it into my own hands knowing approximately where to find the TCU.

My service report stated that the vehicle would not connect with the LDS tool and a hard reset was performed. In addition, they also mentioned that this is a known concern and the fix is in development and will be released at a future undetermined date. Again unacceptable to me, but glad I know how to resolve it myself.

1735820815240.webp
 
I do agree that general consumers shouldn’t typically take fixes into their own hands, and as I’m an Electrical Systems Engineer with history in hybrid and EV vehicles, I sure bet they will be a bit confused by the telemetry they receive of this unit coming back online by itself.

Nearly all devices need to be sequenced down correctly to power off, but with a 12V device and the state it was in and having the information to go on, it was worth a try
 
Cabonzhp said:
I do agree that general consumers shouldn’t typically take fixes into their own hands, and as I’m an Electrical Systems Engineer with history in hybrid and EV vehicles, I sure bet they will be a bit confused by the telemetry they receive of this unit coming back online by itself.

Nearly all devices need to be sequenced down correctly to power off, but with a 12V device and the state it was in and having the information to go on, it was worth a try
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It's nice to have this documented for when cars are out of warranty and the issue occurs. I would be angry that I had to spend the time to get the car to the dealer and pay whatever it costs for someone to unplug/re-plug it in again. Thanks!
 
Funny thing, there were virtually identical posts for DIY-resets a couple years ago concerning our Volvo EV's TCAM module, which furnishes the same functions as Lucid's TCU module. It was made by Continental GmbH and resisted attempts at a soft reset. Could it be the same supplier?
 
DeaneG said:
Funny thing, there were virtually identical posts for DIY-resets a couple years ago concerning our Volvo EV's TCAM module, which furnishes the same functions as Lucid's TCU module. It was made by Continental GmbH and resisted attempts at a soft reset. Could it be the same supplier?
Click to expand...
While that’s possible, it’s likely that this is fixable through controls programming and they did not include power cycling this device in the typical soft reset bracket. Assuming their electrical architecture allows, they should be able to implement a fix that identifies the issue and power cycles the device on its own.
 
Mirage said:
I too discovered this resolution and it does indeed work; however, as a Borski said you should at least let Lucid look at the vehicle and make sure it is a software issue that they can track. I have had my car in to service 3 times for this issue (approximately 1/month). All 3 times they designated it as a software issue, but like Cabonzhp I did contact service and they couldn't see me for a few weeks. This was unacceptable so I took it into my own hands knowing approximately where to find the TCU.

My service report stated that the vehicle would not connect with the LDS tool and a hard reset was performed. In addition, they also mentioned that this is a known concern and the fix is in development and will be released at a future undetermined date. Again unacceptable to me, but glad I know how to resolve it myself.

View attachment 25612
Click to expand...
What exactly are you disconnecting here and reconnecting? Running into the same issue and called into service and they’re supposed to call me back and dreading the idea of going to service for this as it’s FAR from my house
 
You’re unplugging CAN and power from the device, causing it to reboot. This works because the soft resets don’t power cycle the device.
 
I just had my TCU reset for the second time in slightly more than 3 months of owning this wonderful car.

The service rep said that the next OTA —coming in the next several weeks— will give Lucid service the ability to reset the TCU remotely.

Anyone else hear this?
 
Istealrx said:
What exactly are you disconnecting here and reconnecting? Running into the same issue and called into service and they’re supposed to call me back and dreading the idea of going to service for this as it’s FAR from my house
Click to expand...
If you look at the image above and are facing the device in the car. The harness on the drivers side is what you unplug. It's the only one with multiple wires and wire tape on it. The other wires look like ethernet or other custom cables.
1735851757835.webp
 
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I found this but seems hard to unplug. Do you have to remove the device to unplug that cable or are you able to get it out. Was afraid to pull too hard and wasn’t sure if there was a latch that needed to be pressed to get this unplugged. Otherwise I guess I’ll remove the nuts if needed.
 
mjdavis328 said:
I found this but seems hard to unplug. Do you have to remove the device to unplug that cable or are you able to get it out. Was afraid to pull too hard and wasn’t sure if there was a latch that needed to be pressed to get this unplugged. Otherwise I guess I’ll remove the nuts if needed.
Click to expand...
Please do not unplug anything if you are not comfortable with the risk and/or do not know what you are doing.

This is, at present, still something that Lucid requires service to do, not the consumer.

We, the forum, the moderators, and everyone else here assume no risk whatsoever for the results of anything you choose to do with this information.

(That said, it just unplugs and there is a normal clip on the cable/housing - you should not need to remove any screws or nuts. The other cables are more difficult; there is a clip, but first you have to pull back the red tab, and *then* press the clip down. You should have absolutely no reason to unplug any of the other cables at all.)

Again, YMMV and proceed at your own risk. If this voids your warranty, nobody here can and/or will do anything about it for you.

Just covering our bases, as nobody likes fighting lawsuits, no matter how frivolous. <3

(And as @segbrk once said: “borski, I feel misled. The TCU is easy to get to… if your body is shaped like a C and your fingers are 16 inches long…”)
 
Welp, tcu froze again for me and I’m supposed to get a replacement. Today marks 1 month of ownership lol
 
great info. can't believe I'm back to resetting TCUs! My prior car was a polestar, released in 2021 and I got mine in 2022. Among the most annoying of bugs was the TCAM (coms module) needing to be reset, essentially this same problem. in the early days, when the TCAM went out, it would take out GPS and all data connectivity (like this same issue). they eventually split up some of the coms so that when the TCAM went out, it would allow the data to still connect and just the GPS would be lost. They then made it self-healing so when it went out, it would figure it out and reset as needed, even while driving (took about 5 mins for the full reset including reconnection). The fix before that happened was a 12V battery disconnect under the hood and also pull the backup battery in the truck, then put everything back together. took about 15 mins with some practice and a little kit I kept in the frunk (12 or 14mm socket for the battery etc). Would have thought that 3 years in on the Lucid they would have been as far along on this as Polestar! Guess not but hopefully soon!
 
newlucidguy said:
Would have thought that 3 years in on the Lucid they would have been as far along on this as Polestar! Guess not but hopefully soon!
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To be fair it hasn't been nearly as problematic as you describe to warrant so much fixing :p
As far as I'm aware, the most recent update broke something in some small number of cars. Otherwise I've barely seen any reports of TCU issues in the past.
 
segbrk said:
To be fair it hasn't been nearly as problematic as you describe to warrant so much fixing :p
As far as I'm aware, the most recent update broke something in some small number of cars. Otherwise I've barely seen any reports of TCU issues in the past.
Click to expand...
That's great. I'm less than one month in and needed a reset. Glad it's not a frequent occurrence.
 
Oh, also, kudos to whomever did the physical design on the TCU unit, as well as the wiring harness to / from. Really nice. And, conference inspiring.
 
newlucidguy said:
great info. can't believe I'm back to resetting TCUs! My prior car was a polestar, released in 2021 and I got mine in 2022. Among the most annoying of bugs was the TCAM (coms module) needing to be reset, essentially this same problem. in the early days, when the TCAM went out, it would take out GPS and all data connectivity (like this same issue). they eventually split up some of the coms so that when the TCAM went out, it would allow the data to still connect and just the GPS would be lost. They then made it self-healing so when it went out, it would figure it out and reset as needed, even while driving (took about 5 mins for the full reset including reconnection). The fix before that happened was a 12V battery disconnect under the hood and also pull the backup battery in the truck, then put everything back together. took about 15 mins with some practice and a little kit I kept in the frunk (12 or 14mm socket for the battery etc). Would have thought that 3 years in on the Lucid they would have been as far along on this as Polestar! Guess not but hopefully soon!
Click to expand...
How many times have you had to reset your TCU? I have owned my Touring for two years and the TCU froze once. Service came and actually pulled data from the TCU for engineering before resetting. It's my understanding that Polestar TCAM resets were more frequent.
 
MorganB said:
How many times have you had to reset your TCU? I have owned my Touring for two years and the TCU froze once. Service came and actually pulled data from the TCU for engineering before resetting. It's my understanding that Polestar TCAM resets were more frequent.
Click to expand...
just once in less than 4 weeks of ownership (1 week I was away, so 3 weeks of driving). I'll call service if it happens again. so for me, it's a little frequent in terms of length of time of ownership. yes back in the early days, the polestar TCAM resets were very frequent across the fleet. I myself only had maybe 2-3 that I had to do with battery pull, say in the first few months of ownership. but, in the 3 years, I noticed that it would periodically reset itself once they added that healing capability .. sometimes under some very strange conditions. for example., when I would drive into and then out of manhattan, there was something that would cause it to freeze on my way out, kind of regularly .. almost some type of network condition or cell tower handoff -- that was really really odd and I suspect very difficult to figure out. anyway it's especially bothersome on a trip so at least I am glad I know how if needed and it's super simple and no tools needed either. I do marvel at the engineering and assembly of the lucid. in polestar's case, it would have knock-on effects such as limiting the charge amperage until it was reset. I am hoping lucid started with a cleaner code base than what I envisioned the polestar code to be (as they have a hard time getting out of their own way on introduction of defects into the code). can't say how happy I am driving this lucid, what a treat.
 
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