I just measured (and topped up / deflated) with an Accu-Gage analog pressure gauge to 36 PSI front / 39 PSI rear, +/- 0.5 PSI. After a 10-minute drive, the Fill menu continues to insist I should "Top Off -3 PSI" despite the regular tire pressure window showing 35 front (both) and 38 rear (both). So the warning light doesn't match the car's own estimation of current air pressure. And neither the warning message nor the tire pressure display are particularly accurate.

I guess I will have to take her in just to figure out why the tire warning light is on. One of the front tires was a few pounds light before I started. I wonder if the warning light, despite telling me the rear passenger tire is low, really was obtaining the low signal from the passenger front tire. I'm assuming they use wireless to communicate with the car's computer. Maybe someone accidentally cross-strapped the passenger front tire sensor with the passenger rear tire pressure receiver?

 

TPS can be problematic on all cars
Note that in the set up u can choose heavy load

Sometimes I have to play with that....
I use 35 front, 38 rear
Good luck

 

...a little annoying, but doesn't sound like a serious problem so long as you continue to do physical monitoring regularly. Hope it gets straightened out for you!

 

My right front tire pressure sensor just started to consistently show 2 psi below the actual value when cold. Once warmed up, it is correct again. So far no error message yet.

 

I had this happen today after I swapped my summer wheels for my winter wheels. I entered the correct tire size and type "18" winters" and it took driving a few miles before the tire pressures were displayed. It read 29psi front and 33psi rear and gave me the -6 psi warning message. I measured the pressure with my gauge and it read 32 front and 36 rear. I will check it again tomorrow and see if after driving awhile the sensors read correctly or not.

 

I've never had this on the Mcan but did have it happen for the first time in 8 years with my 911 just last week . I was baffled by it because the computer stated the pressure was fine yet the actual tire read -4 . It reset after i shut off the car and restarted it.

 

My TPMS is saying that the rear passenger tire needs air.(-4). When i check it with a gauge it tells me it is around 39 PSI. Right where it should be. The annoying thing is that i cannot get the warning light to turn off. Is there a way to manually reset the TPMS system to recalibrate all tires?

 

... Is there a way to manually reset the TPMS system to recalibrate all tires?

Yes. Per my Dealer when I had issues, to reset just change the settings to a wrong tire size & type. Example, if you have 19" Summer, part load, change to 20" winter full load. Then change it back to the correct values. This forces the TPMS to reset.

 

I have had it happen a couple times during the change in the seasons, I just let a couple pounds of air out of all 4 tires and then reinflated them back to spec. The warning light cleared.

 

Just figured out if your warning light is on but tires read good with gaugejust go through the set up again on the display and it should clear warning light

 

If this persists, I'd get it dealt with. I had a similar issue on another car I have, and decided to wait. The dealer was never able to resolve it, and by the time they had tried 3 or 4 times, it was out of warranty and I got stuck with it like that forever.

 

I can't recall if I posted this, but the problem needed some miles to correct. Apparently the computer is looking at a moving average so it takes some time to clear. I think I just needed to drive more than 15 minutes on it for the warning to disappear.

 

I just started having this problem yesterday during heavy rain storm. Gauge reads normal pressure, but warning light says 3 lbs low. I even added extra air and check with an analog gauge. Car now says 3 lbs more than it should, but it still gives warning and recommends adding additional 3 lbs. Problem intermittently clears with driving, but then comes back again.

 

Did you ever manage to resolve this problem? I have exactly the same problem which started during heavy rain and driving through a 30 yards stretch of standing water about 6" deep. The warning appeared right after that saying add +3 bar to the right front tyre. That was 5 days ago and the warning has appeared again 3 times since. Actual pressures of all wheels are fine. I will take it into the Porsche workshop if it continues to persist.

 

Anybody having issues with the Tire pressure monitoring system. This thing is driving me crazy. It always gives me a warning saying tires are under inflated. I just put air in the darn things. I feel it's off 2-4 psi. So temporarily I over inflated the tires to 38 front and 40 rear to alleviate the issue. Unfortunately closest P dealer is 250 miles away. Any thoughts?

 

I have not experienced any accurate pressure monitoring system yet. All of them are off by a few pounds. I use my gauge to check the pressure as I always do. I do not experience any warning like you described.

 

by default TPMS is set to full load. If you like me am running with the partial load pressure you might want to change to that setting on the PCM to avoid low pressure warnings.

 

The other thing that I have found helps with these TPM systems -- I've had them on five vehicles between mine and my spouse's now -- is using nitrogen rather than ordinary air.

 

Don't forget to "reset" the TPMS to your new inflation, or it will reference the wrong numbers to determine the warning.

 

Last time I had a warning, it was a nail in my tire!

 

Make sure you have an accurate manual digital tire pressure gage.
The recommended CTP #s are for 68 degrees F. You must make adjustments for hotter temps.

For every 10 degree increase in ambient temp tire pressure increases ~ 2%

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=73


So, figure out whether you want full load vs. part load to be your CTP based on your tire size; 18,19,20 or 21 & make adjustments based on true ambient temp where you are. Adjust TP to this pressure after car was sitting overnight. (You can use the supplied compressor if need be)

Now RESET your TPMS. Easy, just change settings & then change it back.

For ex. I have 19" Summer tires & part load. To reset I change to 20" All Season full load. Then I change it back to what I really have/want.

Now see how your TPMS acts over the next few days. If still way off, just use your tire gage every month & wait till next service to take it to Porsche.

Do not over inflate. Buying a new digital TP gage is cheaper than prematurely replacing tires!

 

My tpms works as designed. I keep my 19's at max load pressure. When I had a piece of metal gash the sidewall ,it was crazy watching the pressure go down so quickly.

 

Thanks to all who replied. Great information.

 

Mine's jacked up. It's properly inflated, but warning is still going off. It's a relatively new issue, so it may be my sensor is bad. Will have dealer check when I bring in for service

 

My former X5's TPMS was the most temperamental thing I'd ever experienced. Once winter came around, it would always show a warning, every morning. Real PIA. Then, when I had a nail in the tire and it was down 12 psi, no warning. Go figure.

As for the Macan, never a problem. When I had a nail, I also watched the pressure going down steadily. Oh, the horror.

 

So what is ideal full load pressure for 20" summer tires on a 2017 GTS? One of my rear tires showed as -9 psi on my TPMS after only 10 days and 700km on the car. I added air but am concerned as the car is so new...

 

What does your manual State? Keep in mind CTP values are supposed to be @ 68 degrees. If warmer, you must adjust according to that article I linked. How many miles on the car/tire has absolutely nothing to do with what the CTP is or s/b.

 

So I was messing around with the TPMS today and now it keeps showing that it's learning no matter how much I drive over 15mph what the heck happened?

Sent from my Nexus 6P using Tapatalk

 

I just posted on a separate thread but I was messing w/ the TPMS this morning and it was "learning" but did not stop I still have the warning light and on the PCM it's showing that it's still learning. Parked the car, car pooled to work, got back and started up the car again and warning light still on. Selected 20" A/S tires went through the steps and still learning. What the heck happened here

 

1) using a manual digital tire gauge, put in the correct CTP.
2) reset the TPMS. To reset, choose wrong/different settings, back out of that screen with "OK" or "enter" & then... change back to correct. For you... choose 18 or 19" Summer Tires. Then, whatever reading it gives you, go back & change it to the correct 20" A/S.

If that doesn't work, call & ask dealer & maybe they have a different procedure to reset or will have you bring it in.

 

the tpms setting also has a check box of "full load". I did not check off on this box.

My 21 summer is set at 34F/36R right now. No issue or warning. I believe recommended / factory setting is 36F/39R. Way too bouncy for me on rough roads.

 

the tpms setting also has a check box of "full load". I did not check off on this box....

If Full load box is unchecked, that means "part load"
I know it is stupid. For a car this expensive they couldn't have added a box explicitly labeled "part load?"