TPMS improvement for vehicles with only a light

I thought I'd pass this along for anyone who has a vehicle with a single TPMS (tire pressure measurement system) indicator on their dash. This won't work for every such vehicle, but it worked for our 2012 Highlander.

I had been using a separate TPMS with the sensors that screw on the valve stems. The problem with those is that they cause an imbalance that's noticeable at highway speeds. I also had a separate display that was limited in setting alarms for low pressure.

I was replacing the stereo head unit in the vehicle with a double-DIN aftermarket unit with a touch screen (Pioneer AVH-W4400NEX) and noticed a port on the head unit labeled "iDataLink". After researching it, I came across this very handy device:

iDataLine Maestro RR: http://maestro.idatalink.com/

If the head unit supports the iDataLink protocol, this device can read various diagnostic data from the OBDII port on the vehicle and translate it into a human friendly format in association with the head unit. It turns out that the tire pressure sensor readings are available on the OBDII port's K-Line in our Highlander and other Toyotas, so I now can display the readings from each tire individually, i.e. no more guessing as to which tire is low.

It requires a setup process by which you deflate each tire in turn, according to a prompt on the screen, to get the Maestro RR device to associate the sensor IDs with tire locations on the vehicle. As it learns each location, it will "tap" the horn to let you know to go to the next tire. After I finished setting that up, I re-inflated the tires back to factory recommendations. The device assumes that any additional ID is associated with the spare, so I didn't need to remove the spare.

I still had a low tire light, which I was then able to associate with the spare being low by 5 pounds. We had a sudden cold snap come through, so I wasn't surprised.

You can check the iDataLink Maestro website to see what capabilities the Maestro RR supports for your vehicle. In many cases, it will replace the factory radio with no loss of functionality. For example, if you set environmental controls via the touch screen on your factory radio, the Maestro RR will likely carry that capability over to the aftermarket head unit. The Maestro RR also translates steering wheel controls to a format the head unit can use for appropriate functions.

I will still use the old aftermarket TPMS for the R-Pod tires for lack of a better option, but I'll be able to put it away during non-towing use.

This one:

https://smile.amazon.com/gp/product/B072NC2753/

It's really designed for a truck with dual tires in the rear, so I had to be creative. I use the front sensors on the R-Pod and the two sets of rear ones were on the TV because the front sensors have one alarm threshold setting and the rear sensors have another.