So I did a little studying on the TPMS and there are two types, the cheap and the expensive. Now Im sure we have the expensive type, but still....

So I check TPMS and have 32psi. This is cold in the garage. When I check with a real digital gauge I have 36psi. I know that we should have 36psi cold so I guess I am good, but just wondering if there is a "warm-up" time for the TPMS to give a correct reading. I am aware that the tire warms, air warms, pressue increases. But I am talking about the actual system. My guess is yes, but wonder what you think.

 

No warm up required. Get a OEM type, generic ones do not work properly. Also there is a calibration procedure that needs to be done after one is changed.

 

I guess the question is why is it off by ~4psi then?

 

Need to use the OEM part.

 

I guess there needs to be some more clarification. No parts have been changed.

TPMS says 32psi cold
Tire pressure gauge says 36 psi cold
TMPS says 36psi once the car is warmed up/driven around.

So to me it seems there is a warm-up period for the TPMS system. Such as- an acurate reading is not available until x miles have been driven.

Oh yeah, the two type are direct and indirect. I'm calling the dealer too.

 

So I got the TPMS up to 35psi on the way home and the reading with a real gauge says 38psi. So it seems my TPMS is about 3-4 psi off. I dont think resetting it will do anygood either since that looks like a learning mode so the system knows what sensors are on what tires and has nothing to do with the actual psi of the tires.

Hmmmmm.....

 

well the reading will change when you drive it cause tires warm up and the psi will rise, and reseting dosent do crap we had that done on are grand prix and it still miss reads.

 

Tpms is tire pressure monitering system, hand held gauge is one in my hand that I put on the tire stem to take the reading.

The difference is 3-4psi cold/hot or whatever. I guess this is difficult to explain, I am not talking difference in temperature vs psi, I am talking about how it is messured hand guage vs tpms system. I have 3 different handheld gauges and they all show the same, so the tpms is off most likely.

Pete, you said there is a calibration, does it calibrate the system? Or are you just talking about telling the system which sensor is on what tire, that can be done from the dash. Oh yeah and the dealer tried to tell me about the temp vs psi, I was like duh. I guess I will just deal with it, but it is the little thing that always bother me the most.

 

I have the same problem with my TPMS, it is higher than my manual gauge reading by about 2 or 3 psi

 

Mine does the same. I switched to Nitrogen with 36 psi and when its cold its reads 29-31. It goes up to 36-37 after about an hour. I was told that Nitrogen wouldn't change that much, so I am wandering the same about the TPMS. I keep getting an email from Onstar that says I need air in my tires but I have 36 psi. I don't get it.