DIY Fix for no LTE/WiFi connectivity bug

[Cabonzhp]

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).

 

[borski]

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.

 

[Mirage]

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.

 

[Cabonzhp]

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

 

[Shuasha]

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

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!

 

[DeaneG]

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?

 

[Cabonzhp]

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?

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.

 

[Istealrx]

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

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

 

[Cabonzhp]

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.

 

[LuHart]

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?

 

[Mirage]

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

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.