SyncUp & Drive kills batteries/alternator

I recently added the SyncUP & Drive device to my account - we are long-time T-Mobile customers and have not had any problems whatsoever besides this to date. My son was getting his license and I wanted to be able to monitor his driving. The SyncUP device worked like a charm for the first week or two, until the battery started dying nearly every night. This battery had been replaced less than 6 months prior, so there should not have been an issue. I was going on a trip, so I decided to let him drive my SUV while I was out of town since he was having problems with the battery and I wanted him in a more reliable vehicle. I also have a new battery in my vehicle, about one year old and also had my alternator replaced between 2-3 years ago. Well, when I was on my trip my battery started dying and then after a couple of days my son had the vehicle completely stall on him while driving. This device not only killed my battery, but my alternator! Fortunately, the batteries were both still under warranty but my alternator cost me a pretty penny. These devices sound absolutely amazing for teen drivers but they are most definitely too good to be true!


Best answer by tmo_amanda 22 June 2018, 19:38

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did anyone got help from tmoible? i am having the similiar issue with my battery. The syncup drive shows offline and the battery dies more often in my nissan rouge. I never had this problem. My car even starts acting weird while driving. I am scared to drive car in this condition.  but reading this thread, i came to know it is because of the syncup drive. i unplugged the syncup drive, after coming here and seeing other people had the same issues. How can we make tmobile pay for this damage? 

I’ve had this problem twice but not with T-Mobile, it was with the Verizon Hum. I figured out what the fix is. After you drive your vehicle, make sure to TURN WIFI OFF from the app!! The wifi staying on constantly will slowly kill your battery. It’s fine driving with the wifi on, but if you know your vehicle will be parked for over an hour or two, just turn off wifi to be on the safe side. Once I did that with the Hum, I didn’t have anymore problems. I just got my Syncup today and I’m following that same rule as I did with the Hum. Hope this helps. 

Userlevel 4

Hey there!

Just wanted to check in and see if you were able to fine a ticket like Amanda suggested!


Why is there no reply from tmobile? I too had big electrical problems and I am scared to let my 16 year old daughter drive with something that is not tested enough. If I don't get an answer from tmobile I will raise hell on social media.

I have been thinking of getting some thing like this for my truck. Reading these responses brings back memory of a PANIC I had, the truck had lost the belt at night (the alt., power steering, water pump belt). After the belt was replaced, there was little charging, noted as the voltage was at the nominal 12.8V. So there was a nail biting trip back 230 miles worth. With some research, I found that the vehicle was smarter than the driver, there is a charge control on the negative cable, to extend battery life.  So during the day time driving the voltage is kept about the 12.8V, but most of the time at night (or with headlights on) voltage does go up to 14V, presumably for the 14V headlights, or when the battery is cool and needs charging.

Now for the 'kills the battery' it would be possible to drain a battery through that connection, but it would take some time.  The OBDII line that powers the plug has a 15A fuse, so current high enough to over power a 150A alternator, that does not figure.

This fact finding will apply to most all GM vehicles. 

It's December 2021 and this is apparently an ongoing issue.  I received to back to back low battery warning just now and the first about 12 hours ago.  I'm pulling it out of the car and returning it and canceling service on the device.  It should have been fixed 2 years ago when these reports started coming in. 

I got the Syncup in September. First issue, major lag time of the tracking feature. It's about 10 minutes off, not helpful. Kept sending alerts even when my car was off. In November my car started dying and my first thought was to remove the only added feature, the sync up. Car didn't die again. Plugged the syncup back in, car was dead by morning. Tried this a few more times to be certain and every time yielded the same results. Eventually caused me to replace my alternate and battery. 

Spoke to tmobile about it twice. The first time I was told I they would remove it from my account no problem. Next bill came up and the sync up was still on my bill. This time supervisor William told me he didn't believe the sync up caused any damage to my car when I was requesting an email to communicate with someone regarding the damage to my vehicle. William the supervisor refused to give me a contact email. Then transferred me without me even aware he was transferring me to David the manager. David also refused to give me an email point of contact regarding my concerns. David also stated that he didn't believe the sync up caused any issues to my car. This is an ongoing issue that tmobile refuses to acknowledge. I have already contacted my lawyer and everyone in this thread should a well. 

I just received this in the mail and will be returning it promptly. Not only does it seem to wreak havoc on cars, t-mobile seems to continue to ignore this issue over the past couple of years.

My syncup stopped working.!!!!

Went to one of the tmobile service stores.. said i have old sim, and replaced it.. Did not help.. I want to cancel the service.. as paying 10$ a month for nothing.. tried with website .. no such option.. tried email.. no such thing.. tried chat.. well it’s after hours. Well im workng too on working hours.. at&t took nice care of me with chat at 9 pm.. was nice if tmobile could too…..

I will definitely be returning it today after 10 times calling tmobile finally got someone to send me the return package to my email what did the syncup device do to your vehicle..

I just purchased  the syncup drive is it safe to use I have a new car 2021 kia forte can someone please give me some information on it

At your own risk and don't trust what t mobile says.  My mechanic says it almost fried my cars power management system.  I ripped mine out.  Plus you'll get very anoid at the constant notices when someone is using the car and it dawned on us we were now open to having our car hacked.  if you're in your 14 days, get rid of it while you can. It's a gimmick and dosnt do anything your phone in your pocket can't do except kill your car battery and power management for me a $1200 part.  RUN AWAY!

Rodgerinmichigan how do I contact t-mobile to send it back I'm new to this I just received the syncup yesterday and do I get my money back. 

Call customer service to lock in your intent to return.  You'll likely have quicker service if you can get to a t mobile store.  If not, good luck on waiting for a mailer.  We've already several mailers behind and waiting over 6 months on a mail return.  I recommend changing providers.  That's what we are getting ready to do.

I don't have phone service with them just got internet service with them..


I too, had issue with this device.  This device killed my battery.  My car stalled on the freeway and i was lucky to be able to pull to the shoulder.  Very scary.  This device is NOT safe and should NOT be promoted by TMobile.

would this have anything to do with the car recall airbags etc.  that's strange

Roderinmichigan t-mobile full of bs I called the nearest store told me I had to call customer service to return the device back

Hello: like others on this thread, my son’s car battery died. The alternator and battery needed to be replaced. 24 hours later the new battery died. The mechanic said it’s the SyncUp Drive to blame.

I just got the SyncUp drive on Wednesday for my 2019 Volkswagen Passat. That same night, I drove from less than 20 miles and noticed a skip when accelerating, but didn't think nothing of it. On Friday, driving home from LA to San Bernardino, the car jerked when I accelerated, but again, I didn't think nothing of it. Today, Saturday, I drove back to LA and my EPC light came on, then my engine light. I just got a new battery and and new fuses in May, I shouldn't be having any problems. Now, I'm pretty sure I will have to use the 100 mile towing that came with the device and pay for repairs that I can't afford. HELP T-MOBILE! 


So here’s my full on rant/review of this 7000T1 device. I’ll be sure to keep it short and too the point. After going back and forth for my months about T-Mobiles SyncUP and Drive device. I finally decided to just go ahead and order it - I was initially interested in getting the device because of the ability to have In-Car wifi and all of the functions it could offer. So I clicked on the Vehicle Compatibility Link and entered the details for my 2014 Maserati Quattroporte GTS and even though ALL the functions of the 7000T1 weren’t available for my car enough of them were for me to proceed with placing my order. My device arrived yesterday 7/23/22 and I followed all the prompts to activate the device in addition to going on a 20 minute drive so it could read and sync with my car. I will say that I was very disappointed in the performance and abilities of the device to say the least during that timeframe and here’s why. 

  • There is several minutes lag in time before it updates my cars physical location within the app. For the first 5 mins It was showing me in a completely different state 
  • Within the “my car profile the Horsepower, Engine Type and Odometer Value are unavailable. My cars fuel grade is Premium and not Regular as the app has it listed. 
  • Within the Fuel menu window my fuel level jumped around from 1/2 a tank to 1/4 a tank of gas even though it is almost on a full tank of gas. 
  • My Cars Engine Health status windows reads “Unfortunately, this information is unavailable right now” I even performed a factory reset by pushing in the reset button on the side of device. 
  • The Battery Heath a feature that wasn’t even compatible with my car according to the website seems to be compatible after all so I guess that’s a bonus that I don’t need. 
  • Several Times throughout the night after getting back from my drive I got multiple notifications from the app that there was a disturbance with my car that was locked and parked in the middle of my 2 car attached garage with nothing in there but trash cans and some yard equipment. Not to mention that it doesn’t even state in the notification what type of disturbance is occurring. 


Other than those above mentioned complaints the wifi works as it should although it’s not 5G. If I’ve got unlimited data on all my other lines why is only given a 2GB data cap before reduced speeds? I definitely will be returning this device since I’m well within my 14 day return window and my certainly will be doing a little more research into other devices that are similar to this that actually works as it should. I personal think that T-Mobile should do some extensive testing against all makes and models of cars that this device is states it’s compatible with before stating that the device will have certain features and functionality that it doesn’t.



A Loyal 5 Year Customer w/ 6 lines of services not including this one. 

Houston, Texas. 





My battery has died twice since I got this device within a week. Coincidence? Don’t think so, the battery is less than a year old. Today, the car started losing power on the highway, and eventually died on the exit ramp while showing the battery warning light. Luckily, it turned back on and the battery light disappeared; but the car had little power. Called AAA, they said the battery was fine and that it was the alternator (aside from the battery not receiving a good charge and trying to provide power to make up for the failing alternator). Car is now at Audi and it sounds like this darn device is going to cost me around a $1,000 in repairs. To make it worse, and I’ll admit it’s pretty funny, the device says my battery is healthy and shows good amps even when the battery died a few days ago and I had to get it jump started, and today when the battery icon turned on and the car was clearly struggling. T-Mobile probably won’t care, I’ll call in the morning; but if you don’t want to risk damaging your car do not get one of these. Just suck it up and pay the premium for your car’s built in wireless service or use your phone as a hotspot. If you want to spy on your teen driver (not why I got this) just stick an AirTag or Tile into the car, or have a pro install a good dashcam (some offer 4G/LTE, not aware of 5G). 

Userlevel 3

Hey, @hjchase1​! 

Welcome to our Support Community! Gosh, that's not a great first experience for your son especially since he's just getting on the road. It doesn't put your family in a great position either with this happening to two vehicles from the sounds of it. I listed next steps in a different thread you commented on: SyncUp Issues​. Please follow those steps to get a ticket filed so our Engineers can figure out why this is happening.

Userlevel 4

Just checking in again on the ticket possibility! 😊


I just added a syncup drive to my 2017 Honda CRV two weeks ago.  Car is less than a year old.  It has worked with no issue for the past two weeks, but last night it killed the battery in my car.  Prior to this, there was an anomolie seen where the device kept saying it was offline and then the battery went dead.  after the anomolie, the care did start and I was able to drive to my next destination, but after two hours of being stopped at that desitnation, the car was dead, but the syncup drive was actually online again.

I believe the dead battery was caused by either the unit staying on, or it causing something else in the car to stay on.

I have removed the syncup drive and the battery has been fine..

I also got the sync up Drive and it was put in my vehicle on Monday so it's been less than a week and I noticed the lights flickering on my dashboard in my speedometer needle and RPM needle. I assumed it was the sync up system trying to check my car system, I'm not sure? It didn't happen all the time but periodically while I'm driving and woke up this morning and there's absolutely nothing working on my car no lights absolutely nothing it's the completely dead my battery is less than a year old so now I have to try to tow the vehicle and I attempted to use the synced up roadside assistance after 3 phone calls and two of them being hung up on what they found is that the device doesn't start with the normal numbers and they can't find me in their system either so now I have to figure out how to get my car towed and figure out what's going on with it the device is still attached but it says it's offline. I'm not sure what's going on but I'm not really thrilled. I love the idea of the fact that the device lets me see what's going on with my car but these other problems are less than ideal and couldn't come at a worse time.