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Recently, with the cold weather , I had to add about five PSI air to each tire to bring them up to the recommended 38 PSI. *

this morning my Cheviot is consistently reporting front tire is down to 33 psi.
But when I check it with two actual real physical tire pressure gauge is it shows to be about 38..As I expected.

So my questions are:
Has anyone else run into anything like this?
Any explanations?
Any solutions?

If it’s a bad sensor, think Chevy will cover it? ( I’m well within my three-year 36,000 mile warranty.)

Alex
* P.S., It strike me as somewhat surprising that although all four tires were down to 33 psi nothing in the Bolt ever popped up to alert me to that AFAIK. I only noticed it when I deliberately change driver information display to show the tires.
 

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TPMS sensors have accelerometers in them and only regularly broadcast pressure data (usually once per minute) when the vehicle is moving faster than 15mph. When the car is stationary, TPMS sensors only broadcast once every 12 hours (approximately). I'm pulling this from memory because TPMS sensors behave slightly differently depending on the manufacturer.

So maybe this is your scenario...

You parked your car with 33 PSI in each tire.
You added 5 PSI to each tire...but you didn't drive the car after that.
You check the Chevrolet app later and it still shows 33 PSI in each tire.

The app is just showing the most recent pressure readings the computer received from the TPMS sensors the last time they were broadcasting (in this case...the last time the car was moving).

If you had driven the car for a few minutes after you inflated the tires, the pressure readings would have updated in the vehicle computer and the app. If you had let the car sit long enough, eventually the TPMS sensors would have sent a current pressure reading and everything would look OK.
 

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Its normal for your tires to drop air as soon as we start getting cold days, it just happens.
They drop about 5 lbs, and if you were not paying attention to the air pressures more than one tire could put the yellow light on.
 

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Get a copy of the OPEL EV owners manual on line and look up the various tire pressures. There are various recommendations for different situations, comfort, eco and fully loaded. Same tires same rims, go figure. Remember 1 pound for every 10 degree either way. Get a good racing quality air guage (don't drop it), check it out once a week and between drastic changes in the weather.
 

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Recently, with the cold weather , I had to add about five PSI air to each tire to bring them up to the recommended 38 PSI. *

this morning my Cheviot is consistently reporting front tire is down to 33 psi.
But when I check it with two actual real physical tire pressure gauge is it shows to be about 38..As I expected.

So my questions are:
Has anyone else run into anything like this?
Any explanations?
Any solutions?

If it’s a bad sensor, think Chevy will cover it? ( I’m well within my three-year 36,000 mile warranty.)

Alex
* P.S., It strike me as somewhat surprising that although all four tires were down to 33 psi nothing in the Bolt ever popped up to alert me to that AFAIK. I only noticed it when I deliberately change driver information display to show the tires.
I had a similar problem that was due to a tire rotation and failure to synchronize the tire sensors to their new positions.
 

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Mine are almost good. Maybe 1 psi outside the true value.
I would not worry about it too much... but you may give it a try.

Also, I would check your gauge. Is it correct?
Mine, although expensive, it was off by 5 psi and my tires were always way overinflated. Since then I validate/calibrate gauges in the lab.
 
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* P.S., It strike me as somewhat surprising that although all four tires were down to 33 psi nothing in the Bolt ever popped up to alert me to that AFAIK. I only noticed it when I deliberately change driver information display to show the tires.
33 is not "low" as far as the Bolt is concerned. I can't remember exactly when it actually reports low pressure since it doesn't happen much, but I think it's when the tire is 30 or less.
 

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33 is not "low" as far as the Bolt is concerned. I can't remember exactly when it actually reports low pressure since it doesn't happen much, but I think it's when the tire is 30 or less.
Sounds about right. Mine sometimes register as 33 (38 is recommended and where I try to keep them), but the dash warning doesn't come on until somewhere around 30 - 32 if I remember.
 

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TPMS sensors have accelerometers in them and only regularly broadcast pressure data (usually once per minute) when the vehicle is moving faster than 15mph. When the car is stationary, TPMS sensors only broadcast once every 12 hours (approximately). I'm pulling this from memory because TPMS sensors behave slightly differently depending on the manufacturer.

So maybe this is your scenario...

You parked your car with 33 PSI in each tire.
You added 5 PSI to each tire...but you didn't drive the car after that.
You check the Chevrolet app later and it still shows 33 PSI in each tire.

The app is just showing the most recent pressure readings the computer received from the TPMS sensors the last time they were broadcasting (in this case...the last time the car was moving).

If you had driven the car for a few minutes after you inflated the tires, the pressure readings would have updated in the vehicle computer and the app. If you had let the car sit long enough, eventually the TPMS sensors would have sent a current pressure reading and everything would look OK.
I'm thinking based on my experience, this is not quite how Chevrolet sensors work. The Bolt is my third Chevy in a row where I actually use the TPMS when adding air, instead of a gauge. And I'm doing this fairly often, especially since I use snow tires on separate rims. It often takes several seconds, but the TPMS always shows the change in pressure while the car is stationary, and I'm putting air in the tires. I also periodically check with an old fashioned gauge to verify TPMS accuracy.

Perhaps because I have the car ON while doing this, it updates in real time. However, if one uses a tire pressure gauge and adds air while the car is OFF, it doesn't update until after being driven. Certainly the app isn't going to show any change right away if the car is OFF while adding air.

So in retrospect, your analysis is probably correct. However, if one has the car ON while adding air, that is the one exception in which it will update in real time, and without driving the car.
 

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Drove this AM and all 4 tires were reading 36. Just drove out for a bit and an alert came up for one tire at 16 psi on boot up. All 4 tires look the same. Weird.
 

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There is one other scenario where a TPMS sensor transmits data whether the car is moving or not: a sudden pressure loss

If you let 3 PSI out of a tire in something like 10 seconds, the TPMS sensor interprets that as a problem and will broadcast data immediately. I’m not exactly sure how a sensor reacts if you add pressure in a short period of time?!? :unsure:

I don’t think I’ve ever seen that scenario discussed in any TPMS literature. I wouldn’t be surprised if a sensor does broadcast based on any sudden pressure change (down or up). I may have to try that experiment myself. But my compressor is so small it takes about 1 minute to increase my Bolt tire by 1 PSI...LOL. :)
 

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Recently, with the cold weather , I had to add about five PSI air to each tire to bring them up to the recommended 38 PSI. *

this morning my Cheviot is consistently reporting front tire is down to 33 psi.
But when I check it with two actual real physical tire pressure gauge is it shows to be about 38..As I expected.

So my questions are:
Has anyone else run into anything like this?
Any explanations?
Any solutions?

If it’s a bad sensor, think Chevy will cover it? ( I’m well within my three-year 36,000 mile warranty.)

Alex
* P.S., It strike me as somewhat surprising that although all four tires were down to 33 psi nothing in the Bolt ever popped up to alert me to that AFAIK. I only noticed it when I deliberately change driver information display to show the tires.
The warning light does not come on until the tires are more than 5 psi lower than what is called for. So any lower, and the light would have come on.
Have your tires ever been rotated? If they have, the monitor needs to be relearned in order to know which tire is in which position. So you might have a different tire that is slightly low.
The sensors in the tires are not completely perfect. A variance of up to 2-3 PSI is still considered "normal".
If the sensor is legitimately bad, it IS covered by the bumper to bumper warranty.
 

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Onstar questioned my tire pressure being low. I think it was 35 or so.

One reason I still use nitrogen, helps a bit to stabilize the pressures.
Bought a digital gauge finally because every one I had read differently.

The TPMS sensors can go bad. On my BMW there was a way to calibrate them to read correctly on dash. I'd suspect that GM also has that feature.

Always test cold and that is relative to season. Cold in my summer may be 80 degrees and winter maybe 25.
 
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