Tire Pressure Monitoring System - TPMS

[gatzdon]

The full size spare on a Highlander has a TPMS in it and it most definitely will trigger the alarm if the pressure in it falls below the limit. The system is designed to read input from ALL wheels so that you don't end up with a flat/deflated spare when you need it most.

Peter

I cannot speak about all vehicles with absolute certainty, but on my '12 Explorer and most vehicles in general, the TPMS sensors do not start transmitting until the vehicle is travelling fast enough (about 20mph). This is to preserve battery life. The sensor has a switch that requires a minimum centrifugal force to close the switch and turn on the sensor.

That said, I can see all sensors and sensor values on my '12 Ex using Forscan Lite. There are only four sensor inputs for the four wheels. Forscan Lite would be a quick and easy way to see which sensor is reporting a fault or low pressure. The sensor location in the TPMS is dependent on the four sensors being trained in the correct order at your last tire rotation.

Faults that don't stay with a single sensor are indicative of RF interference.

 

[peterk9]

I cannot speak about all vehicles with absolute certainty, but on my '12 Explorer and most vehicles in general, the TPMS sensors do not start transmitting until the vehicle is travelling fast enough (about 20mph). This is to preserve battery life. The sensor has a switch that requires a minimum centrifugal force to close the switch and turn on the sensor.

That said, I can see all sensors and sensor values on my '12 Ex using Forscan Lite. There are only four sensor inputs for the four wheels. Forscan Lite would be a quick and easy way to see which sensor is reporting a fault or low pressure. The sensor location in the TPMS is dependent on the four sensors being trained in the correct order at your last tire rotation.

Faults that don't stay with a single sensor are indicative of RF interference.

When I was active in the Toyota forum there were several instances where a TPMS fault was indicated and was traced back to the spare.

Peter

 

[gatzdon]

When I was active in the Toyota forum there were several instances where a TPMS fault was indicated and was traced back to the spare.

Peter

If the spare tire is on our Explorers, you will get a TPMS fault because it won't see one of the sensors (the tire that's not on the vehicle).

But you did get me to search and I see that there are more expensive bi-directional TPMS systems that would allow for the ability to monitor the spare tire (the vehicle sends a signal to wake up the sensor to get a reading).

I couldn't find any specific vehicles that have this. As far as I know, our sensors are one way and don't start broadcasting the pressure until you are going more than 20mph.

In the TPMS module, using Forscan Lite, I only see sensors for the four corners of the vehicle.

 

[peterk9]

If the spare tire is on our Explorers, you will get a TPMS fault because it won't see one of the sensors (the tire that's not on the vehicle).

But you did get me to search and I see that there are more expensive bi-directional TPMS systems that would allow for the ability to monitor the spare tire (the vehicle sends a signal to wake up the sensor to get a reading).

I couldn't find any specific vehicles that have this. As far as I know, our sensors are one way and don't start broadcasting the pressure until you are going more than 20mph.

In the TPMS module, using Forscan Lite, I only see sensors for the four corners of the vehicle.

Our spares do not have sensors and are designed for short trips only. From what I've read here, the spare usually is inflated with a higher PSI. Of course that doesn't guaranty it won't lose air, or worse yet, go flat when it's needed.

Peter

 

[expoman55]

Do I remember somewhere in the threads( I tried search ) that on the 2015 although it is not displayed the low tire or tire pressures/data are maintained in the computer and Forscan logs

 

[thefranchise713]

^ Yes, in FORScan you will need to query the BCM, there are PIDs that correspond to each sensor.