TPMS Woes

[mgroeger]

TPMS is one of the few new fangled features I enjoy.

Honest question; why would wheel offset impact the effective radio transmission? Is the antenna on the sensor's transmitter directional and narrow beam? That seems unlikely, but I guess it could be the case.

When you consider that the sensor is sitting inside a belted tire that is almost, but not quite, a Faraday cage, It is amazing that the transmitters work at all.

I don't know the engineering behind the radio transmission but I know that the sensor needs to be relatively close and a wheel with a deep enough backspace and/or offset can move the sensor out of range. As a gross example think of your spare, your spare is far enough away as to not be picked up by the readers on the rear axle.

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[Yellow Cake Kid]

I guess I thought the spare was ignored because each sensor has a designated ID number, and the spare doesn't rotate.

 

[mgroeger]

If that were the case two Jeeps parked right next to each other would read each others sensors. I've seen the Jeep read sensors without rotation (spinning) of the tire.

 

[Yellow Cake Kid]

The idea is that the vehicle only pays attention to the transmissions of the sensors that have the recognized ID info.

All the other EMR is disregarded.

 

[mgroeger]

The idea is that the vehicle only pays attention to the transmissions of the sensors that have the recognized ID info.

All the other EMR is disregarded.

I can take my wife's wheels and stick them on my Jeep or any other JL or JK and the TPMS reader in those Jeeps will immediately pick up the sensors. That works IF you are using the Schrader sensor I mention above.

Sensors don't need to be paired or married to a vehicle, they just simply emit a signal and if close enough to the sensor on the Jeep reading them, will be picked up.

 

[WranglerMan]

Well I had the four rolling tires rotated and figured I may have trouble with them since they were all moved to a different location but after a 10 minute drive they all updated with pressures going up, actually they never dropped out even after the rotation so the only one thats the problem child is the spare hanging on the back, after my last rotation it dropped out and never came back so I rotated it back to the spare spot and for the most part they all have been working but do OCCASIONALLY drop out but only for about 10-15 mins and then come back and then it may be months before they go out again so for now just going to keep the spare where it’s at and rotate every 5k miles and when the tires need replacing will address the sensor issue then unless the just go out and stay out.

I have no issue getting a tazer or similar and turning it off and go back to what we did in the old days of checking pressure with a gage which I have one in very vehicle

 

[Yellow Cake Kid]

...Sensors....

I'm just trying to learn by asking questions.

This pdf evokes a few:

https://www.schradertpms.com/sites/default/files/2020-05/OER vs EZ Sell Sheet 052020_0.pdf

 

[Chocolate Thunder]

Different wheels impact the sensors because if they’re wider, larger diameter, or have more negative offset the sensor pushed is farther away from the receiver and it may not pick up the signal from the sensor as well.

 

[Yellow Cake Kid]

This page has a document: "TPMS Best Practices" that also mentions learning.

https://www.tpmsacademy.com/en-US/Download.aspx

 

[mgroeger]

Different wheels impact the sensors because if they’re wider, larger diameter, or have more negative offset they sensor pushed is farther away from the receiver and it may not pick up the signal from the sensor as well.

I'll let you take over from here, I'm done going down this rabbit hole... lol.

 

[Yellow Cake Kid]

Different wheels impact the sensors because if they’re wider, larger diameter, or have more negative offset they sensor pushed is farther away from the receiver and it may not pick up the signal from the sensor as well.

I can understand why that would seem to make sense, but having some personal experience in the field of wireless transmission this explanation seems less likely than several other possible factors.

As far as I can tell, the JLs have a single Tire Pressure Monitoring Module stuck up in a wheel well and all the transmitters in the stock wheels can get the signal to it despite all the reflections, interference, and EMI.

It seems that when a single wheel is problematic it is more likely that a battery is going bad in the transmitter, or perhaps the sensor was damaged during service.

Like I say, I am just trying to learn about TPMS implementation, and that is because I am about to get some new rims and tires and would like to preserve the function of my TPMS system.

Thank you.

 

[Chocolate Thunder]

Ok. I got nothing else. Good luck.

 

[WranglerMan]

I want to thank all you more experienced Jeepers, you guys have way more knowledge than me and ultimately it comes down to what @mgroeger advised I need to decide how important the TPMS system is to me and if it’s not important and gives me trouble then turn it off or get new sensors and move on.

I was advised by the tech at DT that Method advised they had others that have had issues with other wheels they sell, not sure why as several have stated it’s a radio frequency that should be picked up by the receivers mounted but when we venture away from what FCA designed it’s all a crap shoot and we hope that we can get what we want without headaches but sometimes that does not happen and we have to try different things and rely on those that have tested different things to give us insite.

I would like to rotate my spare as I paid for the tire but for now I thing I may act like I have a spare delete and pretend it’s not there as the ones that are currently on my axles all work and I have no headaches....at least for now.

Im sure if I have a flat I will know it and don’t need a dash display to tell me, I also and don’t laugh check my pressures with a old fashion gage at least once a week prior to cleaning my Jeep up but then I check oil level along with brake fluid, coolant and PS fluid....I’m a tad OCD and that may be a big part of the problem

 

[Goin2drt]

Wow that sure did go down the rabbit hole. Lots of wrong information. Anyone need help just PM me and I can help. Not going to type a big long dissertation on TPMS but I know a thing or two. Been selling them for about 12 years. Here to help and here to give out a forum discount. Cheers to all and all a good night.

 

[JayJay]

Wow that sure did go down the rabbit hole. Lots of wrong information. Anyone need help just PM me and I can help. Not going to type a big long dissertation on TPMS but I know a thing or two.

How's about answering one question if you don't mind? How many TPMS receivers does the wrangler have? One, three, four? I seem to remember reading that it was three as strange as that may sound.

Thanks,
Johnny

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