Hashtag TPMS Issue

Everything was fine right up until the weather got cold. That’s what everyone had the same question.

The Car Claims A Tyre Is Low But It’s Not

You get in your car and you are bombarded with tyre pressure warnings. 1 under the speedo display…

…1 on the speedo…

…1 on the head up display…

…and 1 on the main screen.

Because 4 visual warnings aren’t enough, the voice who lives in the car will verbally tell you that one of the tyres is low.

If more than 1 of the tyres is low, it comes up with “tyre status is abnormal” in red.

What can we possibly do to fix it?

Pump The Tyres Up?

You’d think so wouldn’t you but no. My passenger rear tyre was claiming it was low at 29psi, so I put a pump on it and tried to pump it up to 36psi.

However…

…the pump claimed it was already at 36psi.

Hysteresis

This is nothing to do with womb removal. Hysteresis is a data lag and that’s exactly what we are seeing.

Battery Saving

The tyre pressure sensors have a battery inside them. They communicate with the car using RF. If they transmitted continuously, the battery wouldn’t last a year. So when the car is stationary, the sensors reduce their transmissions to once every 6 hours. Now you have to combine that information with physics.

Air Pressure Vs Temperature

To put it simply, cold air is smaller than warm air. So, over night when it’s cold, the air in your tyres shrinks and the car takes a reading. But by the time you actually get in the car to use it, the temperature has gone up a bit but the sensor hasn’t sent any new data.

To make the sensors send new info, you need to drive. Also, driving will increase the temperature in the tyres and therefore increase the pressure.

What’s The Fix?

Presuming there’s more than 26psi, just drive. The car will eventually update the display with the correct pressures.

The Car Software Is Shit

For example. The pressure was claiming to be low, so I just drove the car. However, even when the pressure in the affected wheel was the same as the others, it was still showing in yellow where the others with similar or lower pressures were apparently OK!

But, a little more driving and suddenly, everything was fine.

Conclusion

As long as there’s some air in there, just drive and it’ll sort itself out. You can try increasing the pressure in your tyres if you want but they are probably already much higher than displayed.

Always inflate tyres when they are cold.