TPMS Questions

[Cut-Throat]

I did do a search on this forum to try and understand how the TPMS system works on a Genesis. I also read the manual. It seems that it works different than the TPMS system on my Lexus. I asked my dealer a couple questions on how to 're-calibrate' the system and here is how he responded. I was wondering if this sounds correct to others?

1. The “TPMS” light will only come on if there is a problem with the sensor, the low pressure light which is the deflating tire, and exclamation point can come on when there is a difference of as little as 3-5 psi between tires (not if they are all 3-5 below). I am not aware of a setting like a thermostat in your house when it kicks the heat/ac on at a certain number that applies to the TPMS system- I believe it just senses the difference between the tires.
2. The only way I have seen to recalibrate is to fill the tires to the proper pressure and with in a short time the system will “learn” that everything is ok and turn itself off.

 

[Mark_888]

Don't understand your question. If the light comes on, you have to put the proper amount of air in the tire(s) and then it generally takes at least several mintues of driving before the light will go off.

The trip point PSI is not user adjustable, if that is what you mean.

 

[Cut-Throat]

The trip point PSI is not user adjustable, if that is what you mean.

Yes, that is what I mean. I am trying to figure out what pressure the TPMS is set for and if it is not user adjustable, then I assume that the dealer has to adjust it.

Example - Say the TPMS is set for 33 psi. At what pressure would a low pressure warning light come on? Let's say the warning comes on at 31 psi. If I want to drive at 30 psi, how would the TPMS get set to 30 psi?

 

[ctrcbob]

It is my understanding that there is no pressure setting that can be reset in each TPMS unit.

The only setting would be to sync with the receiving units in each corner of the car. This is why your dealer must re-sync new TPMS sending units when you install different winter tires/wheels.

As for the pressure difference, I is also my understanding that the TPMS does not give a warning until the pressure goes down below 7 or 8 lbs from the 33 lb preset.

I could be wrong on the above.

In my case, last December, I left sunny and warm Florida, headed to Roswell. I stayed one night in Bridgeport TX and in the morning, the air temperature was around 25F. The next morning, in Roswell, the air temperature was 11F. In neither case did my TPMS light come on. (Most of my time in Roswell, the temps were around 25F every morning).

 

[Mark_888]

Yes, that is what I mean. I am trying to figure out what pressure the TPMS is set for and if it is not user adjustable, then I assume that the dealer has to adjust it.

Example - Say the TPMS is set for 33 psi. At what pressure would a low pressure warning light come on? Let's say the warning comes on at 31 psi. If I want to drive at 30 psi, how would the TPMS get set to 30 psi?

I don't think they are adjustable at all and they are not nearly as accurate as you are assuming.

I keep my tires at 31 PSI (cold tire pressure) and I only had trouble with the warning light one time when it got really cold (according to the laws of chemistry, PSI drops by about one PSI for each 10 F drop in temperature below 70 F). I would "estimate" that the warning light comes on at about 26 PSI (maybe lower), but again these are not percison instruments.

 

[Cut-Throat]

I don't think they are adjustable at all and they are not nearly as accurate as you are assuming.

I keep my tires at 31 PSI (cold tire pressure) and I only had trouble with the warning light one time when it got really cold (according to the laws of chemistry, PSI drops by about one PSI for each 10 F drop in temperature below 70 F). I would "estimate" that the warning light comes on at about 26 PSI (maybe lower), but again these are not percison instruments.

The way the TPMS system works in my Lexus GS350 is the following:

1.) You set the air pressure in the tires that you desire.
2.) Press a button inside the cabin that 'calibrates' the TPMS based on what pressure each tire is currently at.

3.) If any tire drops 10% from the calibration, the TPMS warning light will indicate a low tire.


I am just trying to understand how the Genesis System worked. I was surprised that it works differently.

 

[Mark_888]

There may be some similarities, but on the Genesis:

1. Calibrattion of the receiving unit is a service item, and not user adjustable from inside the cabin that I know of,
2. The level at which the warning light comes on is probably at least 20% below 33 PSI (in my experience).

 

[jgruggiero]

I did do a search on this forum to try and understand how the TPMS system works on a Genesis. I also read the manual. It seems that it works different than the TPMS system on my Lexus. I asked my dealer a couple questions on how to 're-calibrate' the system and here is how he responded. I was wondering if this sounds correct to others?

1. The “TPMS” light will only come on if there is a problem with the sensor, the low pressure light which is the deflating tire, and exclamation point can come on when there is a difference of as little as 3-5 psi between tires (not if they are all 3-5 below). I am not aware of a setting like a thermostat in your house when it kicks the heat/ac on at a certain number that applies to the TPMS system- I believe it just senses the difference between the tires.
2. The only way I have seen to recalibrate is to fill the tires to the proper pressure and with in a short time the system will “learn” that everything is ok and turn itself off.

I have a 2017 G80. During an 11-degree day in a hospital parking lot near some ambulances, when I restarted the vehicle, I got a CHECK TPMS display with both the tire symbol and the triangle fault display. I checked the tire pressures, and they were all good. This fault and message do not prevent you from driving the car but make sure you have proper air pressure. Also, while you can switch the screen to show other functions such as speed or mileage, the fault message will come on every time you restart the car. I checked the owner's manual and as is now typical it says to bring it to the dealer. As my warranty has just expired, I did not want to take it in as I had a bad experience with my Tucson with the dealer. I searched the internet for some suggestions, but nothing was directly applicable to my fault display and indicated a number of possible issues such as FM radio interference (possible the ambulances transmitting), a bad tire sensor or sensor battery, 3 other type sensors that transmit and receive to the tires, the computer board, frozen tire sensors, multiple low-pressure readings etc. Some suggestions were disconnecting the battery and let the residual current drain, using a magnet on the tire stems, driving at a high speed for 10 miles to reset the system and turning the car on and off without actually starting it and reducing the tire pressure and refilling the tires. I waited for a warmer day, and I tried them pretty much in the above order. Nothing worked but I then unscrewed the valve stem core and deflated all 4 tires to zero pounds. I then turned the car on (not just accessory) without stating it and then reinstalled the valve stem core and reinflated to the recommended setting. I then started the car; the fault lights were still on, and I was dismayed but I drove it to see what would happen as you normally have to drive half mile or less for the tire pressure display to read the tires. Low and behold, the faults cleared, and I saved a bit of money.