• Welcome to N-cars.net - the largest Hyundai N car forum. Check out the model specific sections below and scroll down for country specific forums. Check out the i30 N Bible Here!

Fastback TPMS sensors gone haywire. Wat do

Legit

New Member
#1
Hello people o/ hate to be "that" guy but like the title says I've had sensor related issues for a few months now (car's a 2k19 fastback n)

Every time I start the car there's that "pressure too low" warning on the front wheels (either left or right, it changes). Went to the dealership with it, they did some stuff and changed the sensors.

Not even 2 weeks later, same problem. Here's where it gets weird.

I went back to the dealership (again), they did a test drive, erased the tire pressure warning via computer (as the wheel pressure was just fine) and handed me the keys. I got back in the car, started and driven it not even 100 meters and it popped again, had to drive back to the dealership...again. At this point they were scratching their heads, so they erased it again (lol).

Had a few weeks of no nasty warning then I had to change the wheels completely (winter tires now bois). As soon as the winter tires were on, guess what happened? that damned light mocked me again by existing.
At this point the front desk lady offered me a coffee as soon as she saw me and the mechanic actually hoped that I had some different problem. Anyway, they changed the sensors again and it almost did the trick.

Had 1 month of no warning light bliss, until yesterday.

Now I'm not one to be easily pissed off but I think I hit my limit. Don't get me wrong the car is a dream but small stuff like this makes me wanna microwave hamsters and eat kittens, alive.

Now my main reason for making this thread, aside from getting this off my chest. Did you guys have sensor related problems? is this a thing? how can I get rid of it? Do I need to sacrifice my firstborn to the Korean Gods of Vroom Vrooms?

oh and shoutout to all Baden-Württemberg jungs o/
Landkreis VS
 

BadShadd

Well-Known Member
#4
Just before I switched to my winter tires in Oct, I saw the sensor light come on a few times. I was able to add air / remove air to where I wanted it & the error would go away for a time. Every time the temps dropped to single digits, I would see the error.
 

PeterP

Active Member
#7
I havent seen the pressure light come on in ages on mine (im diligent in always keeping them at what they should be) :O is it possible that it's not the sensors themselves but the system that gets that information? Idk how our TPMS is set up though so im just guessing here.
 

Nomad17

Active Member
#9
I second Peters suggestion. If the error changes from wheel to wheel, and returns after replacing the sensors it's likely not the sensors themselves but perhaps the receiver or "brains" of the system. But is it always one of the front wheels, if so have they ever been rotated to the rear and does the error follow?
 

PeterP

Active Member
#10
I second Peters suggestion. If the error changes from wheel to wheel, and returns after replacing the sensors it's likely not the sensors themselves but perhaps the receiver or "brains" of the system. But is it always one of the front wheels, if so have they ever been rotated to the rear and does the error follow?
That's an interesting assumption! :D If the error follows when you swap the tyres front to back and it will pop up on the fronts again it's definitely not the sensors in themselves.
 

Legit

New Member
#11
I second Peters suggestion. If the error changes from wheel to wheel, and returns after replacing the sensors it's likely not the sensors themselves but perhaps the receiver or "brains" of the system. But is it always one of the front wheels, if so have they ever been rotated to the rear and does the error follow?
That's a good idea but rotating them to rear won't make a difference seeing as I already tried with completely different wheels (summer and winter ones)

Have you over inflated them, driven for a bit, and then taken them back down to the correct pressure?
That's the first thing I did before the first sensor change. No luck.

Maybe my car has "brain" damage and constantly sees some sensor fuckery where it ain't. What can I do in this case? Diagnose and reset?
 

R Veloster N

Well-Known Member
#12
https://www.lesschwab.com/article/tpms-light-coming-on-in-cold-weather-heres-why.html

https://auto.howstuffworks.com/car-...ire-pressure-light-come-on-when-it-s-cold.htm

If it's flashing then the TPMS is not being read by the ECU. On our Audi TTRS when it happened we were told to drive for around 10-15 miles and it would go out.

It can also be a bad TPMS as well. Generally it will be the watch battery in the TPMS. Cold weather kills them.
NOTE: The only other thing I can think of is check and see if the space saver spare has a TPMS? Some do some don't. If the spare does, the ECU maybe reading a low or malfunctioning TPMS on the spare. Air it up to over spec and see if it stops the issue.
 
Last edited:
#13
My car went crazy after I asked the dealer to swap wheels from to rear to the front as rears were fine but front 3mm tread depth. Drove out of dealership and bing light came on. The service manager played with the pressures. I got half way home and bing light on again so had to stop at another dealership on route home.
The car needs the pressure correct when the tyres are cold. The TPMS system knows the tyres are hot and adjusts itself to stop the low pressure light coming on. Car needs about 5 miles to relearn pressures after light has been on.
I also had this when I had a heavier load in the boot / rear and didn't increase the pressure.
Do you have 18 inch or 19 inch alloys? 2.5bar front might be too low for 19 inch and might cause a code / light on dash. The sensors are very sensitive and only a TPMS tool can calibrate or reset them apparently. Dealership also said cold weather can cause issues so slightly higher pressure needed.
Also my hand book says pressure same for 18inch normal or heavier load which can't be right ??
19 inch says increase pressure for heavier loads.
225/40 18 (2.5bar front or 36 psi & 2.3 bar or 33 psi rear)
235 35 19 (2.6 bar or 38 psi & 2.4 bar or 35psi) Normal load in car BUT (2.9bar or 43 psi front and 2.7 bar and 39 psi rear) for heavier loads.
Altitude also a factor as higher up from sea level lower outside pressure atmospheric.
Hope this helps. :)
 
#15
My car went crazy after I asked the dealer to swap wheels from to rear to the front as rears were fine but front 3mm tread depth. Drove out of dealership and bing light came on. The service manager played with the pressures. I got half way home and bing light on again so had to stop at another dealership on route home.
The car needs the pressure correct when the tyres are cold. The TPMS system knows the tyres are hot and adjusts itself to stop the low pressure light coming on. Car needs about 5 miles to relearn pressures after light has been on.
I also had this when I had a heavier load in the boot / rear and didn't increase the pressure.
Do you have 18 inch or 19 inch alloys? 2.5bar front might be too low for 19 inch and might cause a code / light on dash. The sensors are very sensitive and only a TPMS tool can calibrate or reset them apparently. Dealership also said cold weather can cause issues so slightly higher pressure needed.
Also my hand book says pressure same for 18inch normal or heavier load which can't be right ??
19 inch says increase pressure for heavier loads.
225/40 18 (2.5bar front or 36 psi & 2.3 bar or 33 psi rear)
235 35 19 (2.6 bar or 38 psi & 2.4 bar or 35psi) Normal load in car BUT (2.9bar or 43 psi front and 2.7 bar and 39 psi rear) for heavier loads.
Altitude also a factor as higher up from sea level lower outside pressure atmospheric.
Hope this helps. :)
I have 18 inch now (winter tires) and I've played with tire pressure before. By playing I mean giving it +/- 0.2 and driving around. No luck so far :( I'm at 700'ish meters so it shouldn't be that seeing as other N car owners whom I've talked to had no problems whatsoever.

I'll just bother the dealership 'til someone figures out something

oh and bonus car pic for no reason at all.

 
#16
Are you using own pressure meter or garages? If garage try another one just to be sure the gauge isn't wrong. If 19 inch alloys I would try 2.8 bar front and 2.6 bar rear. Dealer said Cold climate can cause tpms errors so try the higher pressures and drive the car for 5 miles (8 to 10 kM) and car should learn new values. Then turn ignition off leave for 1 hour and try driving again.
Hope you sort it.
 

Top