Well, I tried google search and one suggestion was to push SET 3 times to register the sensors. It did not work.
Note: the following is the procedure for Toyota vehicles with non self learning TPMS systems. The C-HR system may be self learning although the online owner's manual suggests not.
www.tochr.net
If the C-HR system is indeed self learning, then some of what I have written below may not apply.
Normally the warning light should not on before one presses the button; else you may lock up the TPMS ECU and need to pay someone to unlock it.
To get the warning light to go off after changing tires with new/different sensors, you have to first register the new sensor codes using a proper scan tool via the OBD2 port. Then drive around the block for about 30 seconds and the light will go out if there are no faults.
To calibrate the warning system, you have to continuously hold the reset button long enough for the warning light to come on and flash 3 times before the light goes out. The car should be running but not moving when you do this.
When you press the button, this tells the TPMS ECU that whatever the current tire pressure is according to the most recent radio wave data transmission from the sensors, in the future the warning system will trigger the dashboard light if one or more tires have their pressure fall below 75% of the value at the time the button was pressed.
A tire with a pressure initially at 32 psi would trigger the system if its pressure were to fall below 24 psi. If you want to be warned sooner, you could over-inflate your tires to say 36 psi, press the button to force an alarm at 27 psi, and then deflate your tires back to 32 psi.
Remember that in summer, when tire run at high speed they naturally increase in pressure. In winter during a cold spell, the tire pressure will drop. Given these wide seasonal fluctuations in tire pressure, the 75% rule seems to be an attempt to avoid false positive alarms.
