TPMS strange behavior

[allagaroo]

I'm getting peculiar readings from the TPMS.

I put air in the tires to raise pressure from 33 PSI to 35 PSI. According to the car system I was showing 40 in the LR. I checked it with my tire gauge and it was 34/35 like all my tires. The next day I showed 40 in my RF and all the other tires were OK. Now its the RR that shows 40 and the other tires are OK. Is there a reset or anything I can do about this?

 

[DRS]

Just to back you up.. One quick question.. You measure the tire pressure manually immediately after stopping? I too see the changing pressures. They go up as they should when driving, then drop back down on the display after it sets in shade for a short time. I thought that matched the normal "cold pressure" that goes up while driving for all cars. Maybe not.

 

[Boulderado]

I'm getting peculiar readings from the TPMS.

I put air in the tires to raise pressure from 33 PSI to 35 PSI. According to the car system I was showing 40 in the LR. I checked it with my tire gauge and it was 34/35 like all my tires. The next day I showed 40 in my RF and all the other tires were OK. Now its the RR that shows 40 and the other tires are OK. Is there a reset or anything I can do about this?

TPMS indeed seems unreliable. I went to a gas station and adjusted the pressure to 36 PSI for all four wheels (I know 33 PSI is recommended but it was a warm afternoon and tires were warmed up too). TPMS showed 31 PSI for all four wheels immediately after. The next morning, cold reading was 29 PSI for all four wheels.

 

[JimB47]

What type of tire gauge are you using? I use an Accutire digital gauge and my tire pressures are within 1psi of the TPMS when measured cold before driving. If I use a stick gauge they vary by 3-4psi. Pressures on the TPMS will increase by 2-3psi while driving.

You could be seeing some inaccuracy in the gauge along with a TPMS that is only accuate to +/- 1psi.

http://www.amazon.com/dp/B00080QHMM...hvptwo=&hvqmt=b&hvdev=t&ref=pd_sl_zdrzhnuyq_b

 

[Boulderado]

What type of tire gauge are you using? I use an Accutire digital gauge and my tire pressures are within 1psi of the TPMS when measured cold before driving. If I use a stick gauge they vary by 3-4psi. Pressures on the TPMS will increase by 2-3psi while driving.

You could be seeing some inaccuracy in the gauge along with a TPMS that is only accuate to +/- 1psi.

http://www.amazon.com/dp/B00080QHMM...hvptwo=&hvqmt=b&hvdev=t&ref=pd_sl_zdrzhnuyq_b

Oh it was just the regular stick gauge in the gas station so then maybe it is just a digital vs analog difference? I wonder which one is more accurate...

 

[C-130Geek]

To an extent with either digital or analog you get what you pay for. I just check my tires with 3 analog gauges I had because of discrepancies in TPMS. One of the gauges just went in the trash, 4-6 psi error with other two and TPMS. Generally a smaller range gauge will give a more accurate reading as will reading in the mid range of an analog. I use 0-60 for car, 0-20 for lawn equipment. I have a 0-150 but would never trust it for my car. It's not unusual for my TPMS to read 3-5 higher when driving.

 

[amartz]

Oh it was just the regular stick gauge in the gas station so then maybe it is just a digital vs analog difference? I wonder which one is more accurate...

Those are notoriously unreliable. I'd use either digital, or a good quality dial-style pressure gage.