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Discussion Starter #1
So I noticed when I got my car the front right tire was always 1 psi below the other ones. I thought maybe it was the location, today I got a tire rotation and put the front to the rear. That same tire still is 1 psi below the other ones. It goes up along with the other as I drive but it's always 1 psi below or so. Do you know if it's normal? Are the tire sensors accurate? Do you guys have all your tire pressure readings the same for each tire?

How likely is it that I have a leak? It goes up I believe the same when the other goes up but it's 1 psi below for some reason.
 

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So I noticed when I got my car the front right tire was always 1 psi below the other ones. I thought maybe it was the location, today I got a tire rotation and put the front to the rear. That same tire still is 1 psi below the other ones. It goes up along with the other as I drive but it's always 1 psi below or so. Do you know if it's normal? Are the tire sensors accurate? Do you guys have all your tire pressure readings the same for each tire?

How likely is it that I have a leak? It goes up I believe the same when the other goes up but it's 1 psi below for some reason.
The Challenger is my first car with TPMS (ignoring my brief 4 weeks with my 2008 Cayman S -- taken out by run amuck '89 Volvo). The tire pressures were off some when I picked up the car. The dealer employee said the differences were due to uneven tire heating due to the lack of sufficent drive time so something to that effect.

I do recall from my brief time with my Cayman S there is some truth to this so I didn't think about it.

But it bothered me. I got out my tire pressure gauge -- a dial gauge that "remembers" the reading so if one blinks he doesn't miss it -- and found the tire pressures were wrong. I set them.

Then at some point commanded the TPMS system to perform a reset. I think. That is I recall doing this with my new JCW -- oh the pain of having to learn two new vehicles -- but I think I also did it with the Challenger. (I'd go out and check to see if this is possible but the car is going through a software upgrade and I don't want to inadvertently interrupt/interfere with that by unlockig the car and starting the engine.)

If I did then the TPMS system measured the tire pressures as i drove the car. The readings began to look a lot more reasonable/better. Still some differences though.

During another round of settng the tire pressures I paid closer attention to the gage needle. I then noticed I had kind of been sloppy. The gauge was reflecting what the TPMS system was reporting. The 2nd go around I was more careful and more precise.

And now tire pressures cold -- after several hours of non-use and out of direct sunlight -- actually after the car has sat overnight -- read the same. Under way they pretty much all change together although some times one tire or both tires on one or the other side may differ by a a degree or two. Normal.
 

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Discussion Starter #3
where are the tire sensors located? are they attached to the tires/wheels? so if you rotate the tires the sensor moves with the tire?
 

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I have attached a picture.
Thanks! If the tire pressure for the same sensor attached to the tire consistently reads just 1 psi below, and decreases/increases pressure at the same rate as the other tires, it's likely not a small puncture right? I've had punctured tires but it would lose pressure way quicker. Might just be a sensor issue? It probably isn't location and how hot that area gets because I just rotated it from front to rear.
 

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It's like mine too. My front right tire is always 1 PSI less even if I have rotated the tires. However, as long as it's range of +2 to -2 PSIs compares to the other tires' PSIs, and it will be fine. I wouldn't be concerned about it.

If it's a small puncture then it'd be flattened your tire in a couple of hours or so.
 

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thanks! if the tire pressure for the same sensor attached to the tire consistently reads just 1psi below, and decreases/increases pressure at the same rate as the other tires; it's likely not a small puncture right? i've had punctured tires but it would lose pressure way quicker. might just be a sensor issue? it probably isn't location and how hot that area gets cuz i just rotated it from front to rear
Have you checked/set the tire pressures with an accurate tire pressure gauge? If so and if the car's TPMS offers a "reset" function have you tried this? This what I went through to get the tires first all set to the correct tire pressure and then get the TPMS to report the correct tire pressures. If one is "good" with the tire pressure gauge he should get the tire pressures to within 1/2 PSI.
 

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Discussion Starter #9
Have you checked/set the tire pressures with an accurate tire pressure gauge? If so and if the car's TPMS offers a "reset" function have you tried this? This what I went through to get the tires first all set to the correct tire pressure and then get the TPMS to report the correct tire pressures. If one is "good" with the tire pressure gauge he should get the tire pressures to within 1/2 PSI.
i've never tried resetting it, don't know if my scatpack has that option to reset. i'll have to take a look at the manual.

If you determine that your TPMS sensor is bad, just replace it. You can get a Redi-Sensor , that does not have to be programmed, for only $29.

https://www.blazenauto.com/store/8a-15706571-B00CBQFE8Y-VDO_SE10004A_REDI_Sensor_43392_MHz_TPMS_Sensor.html
i'm still under warranty 3000 miles. if it's faulty, dodge will cover the replacement right?
 

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If you had a leak it does stay at any given off amount, it goes down until flat. A hot tire is 3-4 pounds more than a not driven tire. As long as mine are within a pound of where I want them it’s good by me. Just drive the car and enjoy it.
 

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Have you checked/set the tire pressures with an accurate tire pressure gauge?
This!

You'll never know if your individual TPMS readings are correct without checking them against a good gauge - and that doesn't mean the $10 gauge you got at your local parts place. You should really invest in something like this if you're going to take your car to the track:

Longacre Semi-Pro Digital Tire Pressure Gauge 53003
 

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I'm confused.
OP seems a bit confused whether it's sensor problems and/or a slow leak problem.

First off, if there is some concern of a slow leak use a gauge to make sure that all 4 tires have the same pressure. Best if done when tires are cold or after 3 hours of not being used. Then check the pressure again, a day or so later at the same temperature. They should be the same. Even if the gauge is not that precise, it should be reliable enough to insure repeatability. Don't get the tire sensor involved in determining if you have a slow leak.

Then if you feel the sensors don't agree with your actual tire pressures, you can pursue trying to determine if you gauge is accurate. Although many gauges don't offer an accuracy statement, +/-2% is reasonable in my mind. In fact I see that Moroso 89560 is calibrated for accuracy within 2%.

In any case, I doubt very much if you'd be able to get a dealer to change out sensors under your warranty if the sensors vary slightly from your gauge. Whatever gauge you buy.
 

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I have owned several expensive and inexpensive digital tire pressure gauges. They were all +/- .5 or 1 PSI accuracy and undependable as well. The digital gauges went in the garbage can long ago, now I use the stick gauge my Dad gave me almost 50 years ago. It is easy to get within .5 PSI with that gauge. I have no idea if they make stick gauges that accurate today. I know the ones sold in the parts store where I work are neither accurate or dependable.

The TPMS in my Ram reports exactly the same pressure as the stick gauge while the TPMS in the Scat Pack reports approximately 3 PSI higher. When I asked the dealer if they could adjust the TPMS read out on the Scat Pack they looked at me like I was crazy. So I adjust tire pressure with the stick gauge then monitor it for consistency with the TPMS.
 

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I have owned several expensive and inexpensive digital tire pressure gauges. They were all +/- .5 or 1 PSI accuracy and undependable as well. The digital gauges went in the garbage can long ago, now I use the stick gauge my Dad gave me almost 50 years ago. It is easy to get within .5 PSI with that gauge. I have no idea if they make stick gauges that accurate today. I know the ones sold in the parts store where I work are neither accurate or dependable.

The TPMS in my Ram reports exactly the same pressure as the stick gauge while the TPMS in the Scat Pack reports approximately 3 PSI higher. When I asked the dealer if they could adjust the TPMS read out on the Scat Pack they looked at me like I was crazy. So I adjust tire pressure with the stick gauge then monitor it for consistency with the TPMS.
Interesting post!
My experience with stick gauges has always been bad. Usually way off. Until recently however, when I got a free one that was being given away as promotional gifts with the vendors name on it. I was very surprised to find that this free stick gauge was right on the money when compared to my proven accurate analog dial gauge.
It's common for my TPMS's, in 2 different cars, to be off by 1 psi from one to another.
 

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Actually I don't like the fact that we have to have TPMS. They're fine if you like to have them to give you a heads up that you may have a slow leak and haven't noticed it but don't make them a requirement to get a safety sticker.
On the other hand, I'm sure that there's an accuracy tolerance they are required to meet, similar to speedometers.

Edit: Just researched the Federal regs on TPMS and here's my take on it.
They are required to give you a warning(not necessarily the pressure values) whenever one or more of the 4 tires are 25% (or less) below the car mfrs recommended pressure setting. The system is required to activate when the pressure falls no more then 1 psi below that 25% set point. (within 20 minutes of its occurrence.)
So I guess this is no accuracy requirements for the pressure values displayed. Also, I did not find any reference to actual accuracy requirements of the sensors themselves.
 

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My expensive digital gauge was 4-5 psi off so in the trash it went. My $2.00 stick gauge is dead nuts on. No need to spend big money on one.
 

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My expensive digital gauge was 4-5 psi off so in the trash it went. My $2.00 stick gauge is dead nuts on. No need to spend big money on one.
Exactly.

Use accurate gauge to inflate the tires and use TPMS to monitor them. If the tires are set to 32PSI and TPMS indicates all tires are 35PSI, no problem. If one indicates 30PSI at a later date then there is a problem with that tire and TPMS has done its job.
 
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