OnStar diagnostic question
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Joined: Feb 2017
Posts: 78
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From: Grand Rapids Michigan
OnStar diagnostic question
Hey friends!
On Tuesday I drove the Vette to take my daughter to piano lessons. While driving I accidentally changed the menu and made it to my tire pressure which read 31 in each tire.
Fast forward to last night when I received my OnStar diagnostic report. It told me that I had 27 PSI in each tire and they all need air. I haven't gone out to check, but is this normal that the OnStar reads differently than the car?
Thanks in advance!
On Tuesday I drove the Vette to take my daughter to piano lessons. While driving I accidentally changed the menu and made it to my tire pressure which read 31 in each tire.
Fast forward to last night when I received my OnStar diagnostic report. It told me that I had 27 PSI in each tire and they all need air. I haven't gone out to check, but is this normal that the OnStar reads differently than the car?
Thanks in advance!
Le Mans Master
Joined: Nov 2015
Posts: 7,382
Likes: 3,501
From: Lake Havasu City Arizona
When you looked at the DIC and saw 31 in your tires they were probably heated up somewhat from driving. When OnStar ran the diagnostics your car was probably not driven for a while and they were cold.
Last edited by joemessman; Mar 24, 2017 at 11:23 AM.
but you still need air. 27 is too low. What does a hand-held gauge say?
Le Mans Master
Joined: Aug 2015
Posts: 6,884
Likes: 2,887
From: Toronto
Are these the OEM sensors? My winter wheels have aftermarket sensors. If I don't drive within 24 hours they go into sleep mode. When I start the car they show 26psi until I drive for a few seconds. My OEMs don't do that.
Melting Slicks
Joined: Jan 2017
Posts: 2,982
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From: Georgetown CA
2018 Corvette of Year Finalist
2017 C7 of Year Finalist
I've found that the Onstar web page shows the monthly report that is issued, so it's not live data. But the app on my phone when you refresh it is live from what I recall.
Team Owner
Joined: Apr 2013
Posts: 26,247
Likes: 4,363
From: Chirper Island
The data on the phone app is taken from sometime when the car was last run (during the last ignition cycle).
The app says so, so I'm assuming that it is from the moment the car was shut down, and every time i've tracked the data, it appears that this is so. Miles, range, OLM, etc seem to always line up. Obviously PSI won't, because the tires cool down before next ignition cycle.
The app says so, so I'm assuming that it is from the moment the car was shut down, and every time i've tracked the data, it appears that this is so. Miles, range, OLM, etc seem to always line up. Obviously PSI won't, because the tires cool down before next ignition cycle.
