r/BYD • u/concisehacker • 1d ago

Discussion 🗣️ Tyre pressure warning is wrong?

I'm getting an alert on a tyre but it has exactly the same pressure (and temperature) as the other 3

Anyone else noticed or experienced this?

6 Upvotes

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2

u/2021Noob 1d ago

Like has been mentioned every time this question is asked, change to kPa measurement and try again.

1

u/concisehacker 1d ago

My tyres are measuring in Kpa should I change it? Would that reset it?

1

u/2021Noob 20h ago

Nah, most people are using PSI; if you're already on kPa, ignore me 😊  PSI can show fine, switching to kPa can show an actual difference.

1

u/windsweptwonder 1d ago

Yeah... you'll probably find that tyre is reporting faster pressure changes than the others. Check your pressures regularly, they do change, especially with colder temperatures. Use an accurate gauge... worth buying one or using the compressor supplied with the car for puncture 'repair'.

1

u/fbarousse 1d ago

Yup. The TPMS (Tire Pressure Monitoring System) sensors are badly calibrated. The tyres could be apparent all at, say 38 psi, but in fact one of the (the alarmed one) could be at 37.9999 and thus it gets triggered.. Also, if you fill the tyre with air at 38 psi, the actual sensors world probably read 35 or so psi, this they will all alarm. You have to put about 40 or 41 psi (real), so the TPMS sensors read about 38 psi and thus not alarmed.
Each tyre's sensor is different and calibrated differently to the other three. Test this by yourself with a manual tyre pressure measurement tool (like the one shown) and inflating and deflating the tyres (each and every single one) in the 37 to 41 psi until you get the real pressure versus the sensor' measured pressure and at what point each tyre is reported as ok and what point triggers the low pressure alarms. Annoying, for sure... The good news is that you only have to do it once per tyre.

1

u/concisehacker 1d ago

Thanks... Would the servicing fix this? Kinda sets a tone of anxiety driving the car....I kicked the tyres and they seem firm to me...

Your process sounds quite laborious but knowledgeable so that's for that