I just swapped my summer tires back onto my IS and despite following the reset procedure in the manual the pressures are not being detected. The light flashes 3 times then nothing happens even after waiting. It just shows no pressure on any of my tires.

 

turn off your car and start your car and check again, it's there

 

I did that already. It still doesn't show anything. I've tried resetting this multiple times and it never picks up the tire pressure. These are stock sensors in stock tires.

 

have you drove the car for a bit ? do you get any warning light ? put psi to 40 for now and drive for couple miles

 

i don't get it why you reset them while they were OEM ? did you know your TMPS system can hold 2 set of tires ?

 

Yes I'm aware that it holds two sets but it didn't pick up the old tires when I put them back on. Which is why I'm in my current predicament.

 

i see, drive the car for bit and see, my issue was similar, i turned off the car and started the car and its back to normal, i just change brand new set of tires.

 

Hard reset? Unplug negative of battery for 5-10 mins.

 

Pretty sure our cars do not store two sets of tpms - only one. When I put my summer wheels back on I had to reprogram my tpms with my Quickset tool.

 

I was told by Toyota that the computer does store two sets of settings.

 

The 2IS had the capacity to store TPMS codes for 8 wheels, and the driver could select which set was currently on the vehicle by way of a dash mounted switch.
The 3IS does not have the capacity to store 8 codes, only 4. The switch that's in the same spot as the 2IS switch is the ODO/dimmer adjustment now.
It may just be an initialization issue that you are having...to complete initialization, confirm the tires are set to the recommended pressure, that all sensors are registered to the vehicle (we'll assume they are), and drive the vehicle at 23mph or more for 20 minutes or more.
Considering that you will have to slow down or stop for traffic lights, it may take a little longer than 20 minutes.
If the light is still on after 20 minutes (or so) of driving, then something is definitely wrong with the system...possibly a sensor, but more likely a trouble coded stored in the TPMS system preventing the system from initializing.

 

All 4 tires show --- how do I get it to reset and read tire pressure?

 

If you just started the vehicle and the tire pressures read "------", and you are sure the pressures are fine and the sensors are all registered to the vehicle, then just drive the car.
It's quite common when you start the vehicle the pressures are "------", once you start driving they will start to show.
If they don't show after 20 minutes of driving, then there is an issue, and your TPMS light will be on. Usually it will take a minute or less for them to show once everything is fine.
I'm assuming your dash reading is "-------" and the TPMS light is NOT on at this time.

 

Everything you said is correct, except I never did see a reading, but what I need to verify now is does it take 20mins after every startup to register. The TPMS light never came on so the next time I'm driving for more than 20mins i will check.

 

I had all tires show with no pressures after I reprogrammed my summer tpms sensors because I forgot to reset the tpms in the car. Once I did that everything showed up like it should.