TPMS & MPG Observations - 2010 RXh
 

Before our road trip to Kentucky and back this past weekend, I had the right rear tire replaced due to a screw in the corner of the tread face. I also had the tire shop push all four of my tires up to 45 psi so I could finally determine which of the four pressure readouts on the dash were for each tire.

MPG observations:
On the trip up, I kept the tires at 45 psi for the first tank of fuel and drove at 78 mph on cruise. I averaged 26.5 mpg which was a pleasant surprise, being a full 1 mpg higher than when I last went to south Alabama and the tires were at 35 psi. I then dropped the tires to 34 psi, still running 78 mph, and the fuel economy dropped to about 25 mpg which is close to what I got on the earlier trip to southern AL. Coming home, I dropped the cruise to 74 mph and my mileage went back up to 26.4 mpg.

TPMS Observations:

Dash cluster readout and corresponding tire position is as follows:

34 34 34 34 <<<<< Tire Pressure Values
A B C D <<<<< Designated readout position on display
RR RF LF LR <<<<< Actual Tire Position on Vehicle


If you mentally envision the vehicle as a trapezoid from the rear, the orientation makes good sense.

Pete, rotate the tires and you'll be BADC ;)
Or CDAB if you rotate diagonally
When I put my winter set on, still get readouts in the garage from the tires in the basement.

Talk about a bubble-burster! You mean that the engineers at Lexus chose to not keep the tire positions fixed on the TPMS? From the little reading I've done, I thought that the indications were simply unidentified, and not that they actually moved around. Is there no way to do a reset on the TPMS to keep it position-friendly?

Pete, the sequence is based on the sensors. Once you figure out the tire it corresponds to in the display, you'll be set. And since there is no diagonal rotation, that should make it easier to keep track. I won't mention how much I enjoy the tire pressure and location display on the '16 RXh ;)

The individual TPMS sensors could be de-registered and re-registered, but that would be a pain, and also I've heard others say that the position on the display is random each time, in order of each sensors first transmit cycle after the vehicle is turned on.

Impressive. I wonder if those who consider themselves susceptible to radio energy headaches know that on a daily drive they pass hundreds, maybe thousands of radio transmitters.