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Unable to put correct PSI on my tires


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I have a 2020 Sierra Denali and for the last couple days I’ve been unable to put my tires at the sticker door that said that is 35/36psi.

 

All my tires was showing 31, 32, 30, and I decided to put some air because seems was low, on the driver side now shows 36 and 37 that shows is on range, but in the passenger side front shows 27 and rear 39, in front I added 4psi to at least move to 31, and from the rear I removed 4psi to be on 35, but still not showing that, I know that take sometimes or many miles to update.

 

What I’m doing wrong? Maybe the pump I'm using is not the correct one, for example when I put the 4psi in front on my pump measure was showing 37 when I started and 41psi when I finished and in the car still shows 27psi. Never happened to me this before in any of my other cars.

 

Any idea on what I’m doing wrong?

 

Note I live in Massachusetts and its 36 Fahrenheit.

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What type of pump are you using? I had two that were ok for awhile. Then went wonky. I now use a dedicated digital tire gage and I have a small compressor in my garage. I've noticed to that those TPMS sensors don't always register the pressure just after adding air. 

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When I put air the first time I used the compressor from y garage then after that I was using my ryobi portable cordless inflator that have a digital reader for the psi.

When I look to the tire front one doesn’t seems to be like 27psi, so maybe my ryobi is ok when said it have 41.

 

I’ll try one more time putting air but this time I’ll be using my garage compresor with the digital reading again and I’ll be putting 35 in front and back from the passenger side.

 

Thanks

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I removed some air and in my ryobi I left on 35psi on the front.

 

I got a new gauge and that one measure the same as my ryobi on the front 34.5

 

So I know the psi on the tire seems to be ok, I’ll measure again tomorrow as I was driving and maybe affect.

 

On the rear I removed some air and left in 35, on that one in the car now show 34, so seems ok.

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Add air and check with a separate tire pressure gauge.  Cheap ones can be off by a pound or two.  Also, Air expands and contracts based on temperature.  If you put air in at 3pm, then check it at 8am in Massachusetts, it will read low because of the temp swing.  35PSI at 70 degrees is always going to read lower at 40 degrees.  Watch how the pressure rises when you drive.  Your tires heat up, and the pressure goes up.

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I measured today with 42 Fahrenheit outside and all my tires with exception of passenger rear was in 35psi, the rear passenger side was on 25psi. I used a hand gauge I got it last night.

 

In the dash all said are around 34 with the exception of passenger front that still said low showing 24psi.

 

That makes me wonder if the readings are inverted somehow as per my manual reading the rear is the one that should be showing low as per my manual measure have 24 the same amount it show low for the front in the dash.

 

That is something that can happen that is not showing the measurements in the correct tire position on the dash?

 

I’ll put some air to the passenger rear to see if the lower in the dash increase.


Can someone recommend a quality Hand Gauge Tire Reader, I have another cars that will be convenient to have one.

 

Thanks

 

Edited by jabe
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If you or someone rotated the tires and didn't re-pair them with the truck, they will show in the wrong location. When you rotate tires with TPMS it only knows where they were when they were last paired. When rotated, you need to pair them to the truck again in the new locations. It used to be you could do the procedure without a special tool, then GM got stupid. You can buy a dual frequency TMPMS sensor pairing tool for like $10 online. If you have a 2020, then go into the tire PSI screen and press and hold the "enter" button until you hear the horn honk and the left front marker light comes on. It will then guide you around the truck to re learn the sensor position with the tool.

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2 Things:

1: the tpms sensors read absolute pressure (they don't have a way of comparing to actual outside air pressure) so they can be off from the reading on a good tire pressure gauge. Elevation can really mess with the readings. Some high end cars do adjust for atmospheric pressure in the BCM but Chev/GMCs don't.

2: The computer won't adjust pressure you see until you drive the vehicle. Most TPMS sensors need to get to about 40 mph to see the change. This is done so when the car/truck is parked the sensors go to sleep and don't kill the internal battery.

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On 2/22/2024 at 5:15 PM, GETGONE said:

If you or someone rotated the tires and didn't re-pair them with the truck, they will show in the wrong location. When you rotate tires with TPMS it only knows where they were when they were last paired. When rotated, you need to pair them to the truck again in the new locations. It used to be you could do the procedure without a special tool, then GM got stupid. You can buy a dual frequency TMPMS sensor pairing tool for like $10 online. If you have a 2020, then go into the tire PSI screen and press and hold the "enter" button until you hear the horn honk and the left front marker light comes on. It will then guide you around the truck to re learn the sensor position with the tool.

I only had this car for a couple months, but the dealer installed new tires so maybe they forget to re-pair 

 

I checked those reset re-pair and maybe I’ll get one just to have around as it’s cheap.

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On 2/22/2024 at 8:02 PM, Jay P said:

2 Things:

1: the tpms sensors read absolute pressure (they don't have a way of comparing to actual outside air pressure) so they can be off from the reading on a good tire pressure gauge. Elevation can really mess with the readings. Some high end cars do adjust for atmospheric pressure in the BCM but Chev/GMCs don't.

2: The computer won't adjust pressure you see until you drive the vehicle. Most TPMS sensors need to get to about 40 mph to see the change. This is done so when the car/truck is parked the sensors go to sleep and don't kill the internal battery.

So far seems the psi I put it’s the same as it’s shown at the dash, as I put with my ryobi 35 and my hand gauge measure the same 

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I added air until 35 psi to the passenger rear and now at the dash it shows 32, at least is not alerting me about low air anymore, I ll leave that way for a couple days and if need will put some more.

 

Thanks everyone for the help on this, seems the issue is they are not showing in the correct order, so some re-pair will be needed

 

Thanks

IMG_4324.jpeg

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This is one of my pet peeves - when a service center doesn't re-pair the sensors after rotating the tires.  I guess they figure that most people will not notice.  It really upsets me when a dealer does it.  I don't go back to any place that does that to me.  Unfortunately that means that so far three nearby establishments are off my list, one of which is the dealer I purchased the truck from.  I wrote a letter to the dealer and it was ignored, making me even more satisfied with my decision to never go there again.

 

Buy a pairing tool.  They're not too expensive.  Nice to have around just in case.

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