"Car status" psi -- ?

[DrManhattan]

just got my S true detective searching but nada. On my steering wheel controls if I select car status, it lists all the tire psi as --. Is it possible to get a tire pressure readout somehow?

 

[pdxrajiv]

As you start to drive, the "--" would be replaced with the actual value.
I presume this is because the measurement is not useful/reliable until the vehicle is in motion (guess:due to the position of the sensor?).

 

[DrManhattan]

I guess that makes sense. I have only checked it while parked. Anyone know how accurate it is?

 

[mikeash]

It seems to match the readings I get from my tire pump. And when I get it back from Tesla service, the readings exactly match the spec. So I'd guess it's pretty close.

I believe the reason they don't read while parked is because the sensors only activate when there's motion. They're battery-powered and it's not very convenient to replace the batteries, so they sleep when still in order to reduce power consumption. Leave the screen up when you start driving, and you should see numbers pop on within a couple tenths of a mile.

 

[travwill]

Seems very accurate overall - you'll see variations when temp changes, etc.

TPMS sensors use centrifugal force like all others really so needs to move a while to get a reading.

 

[GaryREM]

Seems very accurate overall - you'll see variations when temp changes, etc.

TPMS sensors use centrifugal force like all others really so needs to move a while to get a reading.

Just to be clear, I assume you are saying the sensors use centrifugal force to operate a switch or have an accelerometer to tell the sensor the car is moving to save batteries as @mikeash indicated.

 

[DrManhattan]

Got it to work after driving. Works perfectly I love it! 45psi all the way around!

 

[dhanson865]

As you start to drive, the "--" would be replaced with the actual value.
I presume this is because the measurement is not useful/reliable until the vehicle is in motion (guess:due to the position of the sensor?).

It's to save the batteries in the sensors. They go to sleep any time the car stops moving and wake up when in motion.

Going to sleep they can last 4-12 years, if they stayed on all the time with the current design you'd have to replace them yearly.

Changing TPMS Sensor Batteries