tyre pressure warning system

[Toyota question]

Toyota Yaris Cross Feb 2022 model. We had a slow puncture and the local ATS garage had to take off the rear offside wheel to check and repair it. They also checked all four tyres and inflated them to the correct pressures. Since then the TPWS has not functioned correctly. The orange warning light stayed on with tyre pressures showing --.-, so, following handbook instructions and an excellent You tude video, I went through the re-set procedure two or three times, drove the car for 10 miles or so at varying speeds but still the dashboard display only shows --.- for each tyre. How can I get the system back to showing the individual tyre pressures?

[Bper]

Hi Phil,If prior to the wheel being removed the TPWS was working fine then it would indicate that the removal of the wheel caused a problem. I would double check that every step in the reset process was followed exactly. When you pressed the TPWS reset button, the ignition should have been on, and you should have seen the warning light flash. That flash indicates it’s in learning mode. After the reset, try driving a bit longer at a steady speed sometimes the system needs around 20 miles of driving to fully recalibrate and pick up each tyre pressure.

Since the ATS garage removed the wheel, it’s likely that one of the sensors might have been slightly disturbed. It's worth asking them to recheck that each sensor is securely mounted and that the sensor batteries are good. 👍

[G L J]

I was wondering if the batteries in the sensor are replaceable ? 

Asking as my Yaris is now over 4 years old and  the batteries will die at some point.

[Mojo1010]

TPMS sensors run on batteries that can last anywhere from 5-10 years. Sensor Battery life will depend on how much driving you do over time and the conditions that you drive in.

Have read that most sensors are sealed so cannot replace just the Battery. My last car was 7 years old with just 51k miles, Battery was fine. Some members with higher mileage can chip in if/when they had to  replace.

Cyker ordered a set from Mazda due to it being cheaper than toyota. 

[Cyker]

Sorry, just a minor correction but I didn't order them, just noted they were cheaper (Toyota dealer quoted me over £70 each but Mazda listed a set of 4 for something like £143 - Don't know if that's still the case though as that was 3 years ago!).

My 17"s are sitting sans-valves at the moment as I just had the original sensors moved to the 15" rims (I really should do something with them as they still have practically unused factory tyres on them!)

1 hour ago, G L J said:

I was wondering if the batteries in the sensor are replaceable ? 

Asking as my Yaris is now over 4 years old and  the batteries will die at some point.

Annoyingly, the short answer is no.

The long answer is yes, but it's a massive PITA - The sensors use standard lithium coin cells (Usually CR2032s I think), and would be easy to change... BUT, for reasons (Claimed to make it vibration-proof and air-tightness) the coin cells are soldered into the TPMS sensor and the whole thing is sealed with potting compound.

You can replace the coin cell by digging out all the potting compound, desoldering the coin cell, soldering in a new one then re-potting the sensor, and it would be much cheaper, but it's a messy fiddly PITA and the chances of breaking it when digging out the potting compound is very high.

They should last 10-ish years give or take a few though so don't worry about it, should have ages left on them. Maybe set aside some money for it in anticipation!

 

As for the display only showing ---, you probably just have to drive it more until it finishes recalibrating itself. When I had my 15s fitted I'd driven for maybe 45 minutes and had just gotten home and parked before it started beeping that one side was only 20psi!  (Good job Hills! )