My 997 C4 has OEM TMPS and it always seems to be off. I checked it w/ my pressure gauge and is running recommended pressure, 37F & 44R. Tires are wheels are OEM Rims and 19" Michelins. However, the digital readout in my car is always 4psi lower than what is measured. HOw accurate are those?!

Has anyone experience this?

 

Mine is just about dead-on with my Longacre liquid filled pressure gauge. What type are you using?

 

I find mine to be spot on even when I had a leak- I would fill it up and sure it enough when it leaked it was dead on... Have you tried resetting it

 

Mine is also about 3 lbs lower than actual.

Regards,
Frank A.

 

Do you usually drive your car w/ its maximum load of 4 people and luggage to require 37/44PSI?

The recommended pressure for your car w/ normal load is 33/39PSI...

 

What is normal tire pressure for 19" wheels? I have an 09 997.2 with 19" S wheels. I usually go 36/42.............i am 6'1, 230 lbs...................

 

Up to 2 people and light luggage - 997.2: 34/40PSI cold.

 

I noticed mine are not 100% accurate either.. just go off of the tire gauge. I will say that what the TMPS does well is let you know when when you start losing air. I've had it warn me of low tire pressure twice and both times I had nails in the tire.

 

My 997.1 was about 3 lbs off but my 997.2 is right on.

 

I have the OEM TMPS, and it's usually 3-4psi lower than what my tire gauge says. Im running the recommended specs, 37F & 44R. This is a good setup for 2 passengers, no luggage. Ride is good and performance is not compromised. For track setup, I tend to run 3-4 psi higher. Ive tried to run 3-4 lower as wel, but the car seems loose. Since the rims are 19" and the tires do not have much thickness, Im skeptical in going anything lower than 37/44psi. Thanks for all the inputs.

 

You are running way too high pressures, but hey... whatever pleases you. Your car pressures are 33/39 PSI cold. You say the car is loose... upping pressures, yeah, it will do that.