2018 Model 3 Modem Issues

[Xebec]

Looking for advice.

A few weeks ago my cellular modem stopped working for about 3 full days. Service mode would show “unknown error” / “health check fail” after it was unable to complete the modem health check. I tried rebooting, and even took a software update with no change. (Ironically this first outage started right after the G5 geomagnetic storm).

After scheduling a service appointment, the modem started working again, and after about 4 days of working, I cancelled my appointment. The modem was good for about 2 weeks and then decided to stop working for another 2 days. Same error and conditions.

In both cases, I took the car on one hour+ drives and the modem stayed non working during those times. (i.e. car didn’t just sit in garage). I’ve got another appointment for next week, but the modem has been working again for a full week.

Does Tesla have access to additional logs that I might not see in Service mode to help with diagnosis? I’d prefer not to pay for replacement when it won’t be clear if that fixes the issue long term. Any other recommendations?

Thanks!

 

[jjrandorin]

Does Tesla have access to additional logs that I might not see in Service mode to help with diagnosis? I’d prefer not to pay for replacement when it won’t be clear if that fixes the issue long term. Any other recommendations?

I dont know if they have any additional logs or not, but Tesla service on their vehicles is VERY VERY largely predicated on "replace parts". They dont "fix" a part, they "replace" a part.

So, I would expect them to either replace your modem, or replace whatever other part might be impacted if their troubleshooting tells them to.

 

[Tronguy]

Um. First off, a bad modem on a six year old car isn't exactly unexpected; over a large enough population of modems, it's a gimmie that there'll be a certain failure rate and it's possible that the die just came up snake eyes for you.

Second, my old Chief Petty Office from the Navy once said to us trainees, "90% of your problems are going to be in the wires." Over the decades since then, I've found him to be right. There is an antenna and connectors on the modem; let a little corrosion get in there and things will get worse, not better. So the old, "Unplug it, then plug it back in" procedure isn't exactly a bad idea: Wiping the contacts back and forth can sometimes Fix Things. Frankly, I'm not exactly sure where the Modem lives in the 2018 Tesla, but an eyeball check might be worth the bother. If you can figure out how to get to it and its antenna.

Third. Um. At this time, in this place, we got 4G-LTE and 5G. I'm pretty sure that a cellular telephone site can be 4G, 5G, or 3G (hard to find that last), but it can't do different ones on the same band and cell site. So.. it could be that AT&T, the cellular provider, is retiring some 4G sites for 5G service. If that's the issue, it could be that. Along these lines, then: Is the problem at one location, or is it all over the place?

 

[Xebec]

Um. First off, a bad modem on a six year old car isn't exactly unexpected; over a large enough population of modems, it's a gimmie that there'll be a certain failure rate and it's possible that the die just came up snake eyes for you.

Second, my old Chief Petty Office from the Navy once said to us trainees, "90% of your problems are going to be in the wires." Over the decades since then, I've found him to be right. There is an antenna and connectors on the modem; let a little corrosion get in there and things will get worse, not better. So the old, "Unplug it, then plug it back in" procedure isn't exactly a bad idea: Wiping the contacts back and forth can sometimes Fix Things. Frankly, I'm not exactly sure where the Modem lives in the 2018 Tesla, but an eyeball check might be worth the bother. If you can figure out how to get to it and its antenna.

Third. Um. At this time, in this place, we got 4G-LTE and 5G. I'm pretty sure that a cellular telephone site can be 4G, 5G, or 3G (hard to find that last), but it can't do different ones on the same band and cell site. So.. it could be that AT&T, the cellular provider, is retiring some 4G sites for 5G service. If that's the issue, it could be that. Along these lines, then: Is the problem at one location, or is it all over the place?

Thanks. I'm in agreement here - not upset about it breaking after 6 years. I have looked into reseating the modem myself but it involves disconnecting the HV battery. Some may laugh but for now I feel it's best to leave that system alone..