... due to battery failure. Sorry for alarmist subject title, but I only just learnt that the TPWS sensors have non-replaceable batteries that have a life of 5 to 10 years. So on my Prius made in 2016 I suspect that one has come to the end of it's life (I have had the warning light come on and off a couple of times this week, checking tyre pressures manually shows nothing seriously wrong with the tyres). I've looked at local tyre shops and most now offer a TPMS service - i.e. check whether the sensors are working, and offer replacements (but at prices they don't publish - I guess they stock a range of units for different cars). In the UK a TPWS fault is an MOT failure, and as all new cars appear to have TPWS this will become a standard service item (additional cost) for all owners of older cars. Regards, John
You can buy a new sensor and replace it, you can open the old sensor and replace the battery, or you can pay for the service of replacing the sensor by other specialists. Everything depends on your desire and time.
Doing nothing is an option, at least till you’re in need of new tires. Unless you’re obligated to have functional sensors, car needs it to pass some inspection. Be extra vigilant regarding tire pressures. That’s basically how it was, 15~20 years ago. just editorial: the acronym is TPMS, Tire Pressure Monitoring System.
Thanks! Yes same as it was for me 6 years ago, when I was driving a Mk 3 Prius with out TPMS. Sorry about the TPWS, got 'Warning' stuck in my mind rather than 'Monitoring', partly due to this: Train Protection & Warning System - Wikipedia Regards, John
Indeed. But just to rewind a bit, I have a Prius Mk 4 (in UK Business Edition spec with 15" wheels, sat nav, heated seats etc.). AFAIK the TPMS only shows 'there is a problem', not which wheel has a problem. So unless I go and buy a £200 scan tool I don't think I can find out which sensor has failed - please correct me if there is a OBD tool that can do same for less. Then having worked out which wheel, I don't have any means of removing a tyre - so this fault would be beyond most DIYers. Regards, John PS went on 3 short drives today (each 5-10 miles), no warnings. I think the warning only comes on during a longer drive, I've yet to book car in for a check.
Techstream allows you to both program and view sensor data. A little logic and it won't be difficult to determine which sensor has a low battery.
Autel sells tools which directly communicate via rf at each wheel. In addition they can read and write a sensor's serial number into the vehicles's tpms computer. They are several hundred dollars. Many small tire shops around here have them along with all the big chains. However all you need is an obd2 scanner that can read the pressures. You then reduce pressures one tire at a time to determine each sensor's location. Techstream and better scanners have a battery "over or less" field in addition to pressure and temperature. Apparently the "less" voltage bit is transmitted. In this capture, taken before changing id3 and id4, I first determined location by reducing pressure while monitoring. In this case id4 tpms battery sensor showed "less" voltage prior to changing it. The Autel tool below ($190 US) allows rf checks and obd2 read writes The Autel tool works on all standard sensors. Standard sensors have a unique serial number assigned at the factory which is then needed by the TPMS car computer. Aftermarket 315 mhz Toyota sensors for $40 a set work fine. An independent tire shop can install four sensors for $60. So there is really no excuse for allowing your family to drive on tires with 18 psi with resulting blowout or ruined tire potential. Finally the above Autel tool allows use of a special Autel MX sensor that can be configured to match your existing sensor ids. This capability would allow winter wheels to be the same ids as your summer set, resulting in no loss of tpms when switching to and from winter wheels.
I thought the TPMS sensors had a piezoelectric element in them to give the sensor power when subject to road vibration. AKA no battery to die.
No they have batteries. There is a movement sensor to wake them up to maximize battery life from eight to ten years. They will wake up and transmit even when parked on a loss of air pressure or when polled by a system. Honda and a few others have no tpms sensors but calculate a loss of pressure based on tire rotation differences between tires. They use the abs speed sensors. It is simple but has no psi reporting capability.
Toyota also uses this method to calculate the difference in tire pressure drop. What is surprising is that when they supply the same car model to Europe or the American continent, they equip it with TPMS sensors, but for their market, they do not install TPMS sensors.
There are many different devices on the market that can be installed in tires. Visualization of values either on an additional screen or on monitor panels installed in the car.
Yes recent cars display pressures and have built in abilities to recognize and configure new tpms sensor ids.
Thanks for the replies, yes Gen 4 owners are stuck with old tech which is harder to diagnose. Regards, John
