SyncUp & Drive kills batteries/alternator

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.

We had the same issue. I got the Sync-up when they first came out. Had minor issues all along but didn't make the connection that it was this device. My husband was driving my daughters car when it completely shut down on him while driving. He managed to get to the dealership and they told us to never use it, that they cause tons of issues. We didn't use it for 4-months but am trying it again til we find something similar (she doesn't drive far so we feel "okay" using It for the short, local drives).

Good morning,

I am currently posting on this thread due to the fact that, I have purchased two sync drive devices in the past year. I added them to my BMW and Honda, Originally my concern was the notifications of disturbances were really slow. Then this past year soon after i connected the device to my BMW my vehicle died on me and would not turn on, my alternator and battery died, i did not think anything of it. I traded my BMW in for a Toyota highlander that same week of the malfunction. At this point friends and family suggested it might be the Sync drive, I looked past the comments. Sure enough this past December my Honda civic began to have electrical problems starting my vehicle, battery was recently new, and i also had to replace my alternator and starter at the same time. I have been maintaining my vehicle well, and this was unfortunate. The reason why i am writing this comment due to the fact that my vehicle needs to be inspected by today, and sure enough when i take it to the Inspection location they are unable to initiate the inspection due to my car not being able to turn on unless the Sync drive is connected. I contacted the T mobile support number and no one has answers for me, at this point I have lost my patience and am frustrated being that i have been paying for this service and devices and both of my cars that i utilized these devices on, have had issues that are in fact costly. I really need answers, I looked past all the trouble shooting aspects of the device being that i can live with minor, but having my second vehicle die on me this is outrageous and i refused to let this go without any answered or clarity.  

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 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..