Quote:
Originally Posted by xyzzy
I like the technology used in other manufacturers that use the ABS system for TPMS, it doesn't check the actual pressures in the tires, but uses the rotational speed differences in the tires - seems like quite a simple system to just set the rotational speed range that's allowed and if one or more tires goes outside of that range, turn on a MIL.
Battery operated TPMS sensors are so old school - just like the 4Runner.
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You have that a bit backwards, the old school method of indirectly measuring tire pressure via the wheel speed sensors came first. Toyota implemented that system on early Highlander, Sienna, and I want to say Avalon/Camry? (we don't get a lot of those out here so I could be wrong). It was a clever way to save money and complexity, but it came with a lot of caveats.
-Rotating tires and not recalibrating the system would set the light..
- The tires wearing too much between calibrations would set the light
-Different tires/brands would set the light (i.e. changing only your two front tires or replacing one due to a nail) with no real way to calibrate it properly. I've had to chase my tail on that a few times...
-Temperature affecting the tire rubber could cause it to set the light because it affects the diameter somewhat.
In tire sensors were the best improvement to that system, they also were legally mandated in the US in all models starting in '07 IIRC. The newest version Toyota uses (which other brands have used for a few years now) uses the combination of the TPMS sensor itself and the ABS wheel speeds to figure out which tire is located where (no need for a silly tire dance Ala GM!)
I'm ambivalent about TPMS systems myself. When I threw new wheels and tires on my 4th gen I bought aftermarket Pacific sensors (same brand Toyota uses) my old ones worked fine after over 10yrs and 100k. I'm not sure what the actual life span is for these things, but it seems like with good habits and care 10yr/100k should be easy for them. The batteries drain quicker if you're always driving around with the low pressure light on or flashing as the system ups the frequency it will ping the sensors, also the sensor with a low pressure will ping much more often until the pressure is corrected. That combined with techs/people not paying attention when they change tires results in a lot of dead/damaged sensors (rather glad Toyota finally is switching to sacrificial stems so the sensor is more likely to survive).
All that being said, if you're being a responsible owner and checking/adjusting your pressures once or twice a month and/or around large temperature swings then a TPMS system is just redundant. So I get why some people want to save some future maintenance costs and just disable the system.
Neat way to turn the light off, though make sure you mention it to the tech so they don't end up chasing it as a problem! Lol
