TPMS Woes

[Goin2drt]

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

We were told one from our Jeep contact but that would be a better question for a FCA person. All cars are different. Some mount the one sensor in an awkward spot with a different distance to each wheel so that is how they tell which wheel. Others back in the day used to have an antenna at each corner to get the signal.

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[WranglerMan]

We were told one from our Jeep contact but that would be a better question for a FCA person. All cars are different. Some mount the one sensor in an awkward spot with a different distance to each wheel so that is how they tell which wheel. Others back in the day used to have an antenna at each corner to get the signal.

I thought I remember reading either here or somewhere else that their are two receiver modules on the JL but I have nothing to prove that, I have looked under mine before when on a lift and saw nothing marked as a tire sensor but then I doubt they would clearly mark them

 

[Goin2drt]

I thought I remember reading either here or somewhere else that their are two receiver modules on the JL but I have nothing to prove that, I have looked under mine before when on a lift and saw nothing marked as a tire sensor but then I doubt they would clearly mark them

Very well could be. We do not do anything with that as when that is the issue the person needs to take it to the dealer to fix. That is not a TPMS sensor issue then at that point. Those components rarely go bad. Some of the older Porsches and Bentley's they seem to see issues.

 

[Yellow Cake Kid]

Jeep's wiring diagrams show one. MOPAR part listings mention one. A Schrader patent I read last night describes the use of one.

I would love to see the real life Jeep service manual, but I don't have convenient access to it. I'll bet it says "one".

I feel like I am supposed to apologize for being interested in this subject, but I do find it interesting.

Reading through the Schrader website last night I found two things.

1) The TPMS industry struggles to encourage acceptance of TPMS. It has been an uphill battle to persuade both technicians and customers to embrace the technology.

2) The tech training emphasizes correct positioning of a Schrader TPMS sensor, but sadly the publicly available training does not elaborate on why the positioning is so critical. Schrader offers a variety of sensor mounts to help achieve proper positioning in differing circumstances. The training for shop floor installers formalizes the basic techniques for mounting the sensor in the prescribed position, and explains how to dismount and mount the tire without disturbing the position or damaging the sensor.

I did not find any mention of tire thickness or rubber mass causing issues in any of the Schrader tech info I read.

Any mention of aftermarket wheels concerned making decisions about positioning the sensor properly with regards to the circumstances of valve hole alignment and inner rim geometry. I think it is safe to assume that OEM manufacturers get full support from their vendor when planning for the coordination of the geometry of the wheel cross section with the positioning requirements of the sensor. I imagine there are aftermarket wheel manufacturers that have less interest in, or capability for learning about the details and implementing appropriate designs.

I did find that Schrader sells TPMS sensors, that seem remarkably similar to what we use in our Jeeps, for use in commercial heavy equipment where wheels and tires are much more massive than what we use on our "crawlers".

Schrader has a chart that shows their experience with battery life. Lifetime of servcie varies widely. They described a spike in failure at 75,000 miles, but also found a significant number of failures occur well below that threshold. Meanwhile some installs last well beyond 75,000 miles. The point to take away from their data is that a battery can fail at just about any time.


I also looked up some patents for Vehicle wheel auto-location and found that Schrader owns a technology that employs a phase angle detection system.

This is where it got interesting.

The phase angle detection system is remarkably sophisticated and complicated. This subject may seem deep in the rabbit hole when the internet already knows why TPMS is problematic with aftermarket products, but it only takes a couple seconds to consider the premise of phase angle detection and why, or at least when, proper sensor positioning could be crucial to such a system.

Food for thought.

A more basic need for proper positioning is related to the use of an accelerometer to start and pause the function of the sensor. It is designed to be placed in a particular orientation and to "float" away from the surface of the rim.

I wonder how many shop floor techs know if or why the sensor positioning is important for a particular application?

I wonder how likely it is that a good enough 'cause it works some of the time procedure might introduce confusion and misunderstanding to the experience of wage earners that have plenty of things to do besides learning about a technology that is forced upon them?

Crazy times.

Speaking only for myself, when I get my new wheels and tires I will buy a box of doughnuts for the installers and insist on the brand new Schrader OE parts for the wheels. I will endeavor to encourage the installers to consider sensor placement a priority. If my choice of wheel presents some sort of challenge regarding placement I will ask them to select the appropriate mounting solutions. If there is a problem with the TPMS I will ask them to double check that the sensors are placed correctly and were not damaged when they were installed.

It seems as if there is reason to believe that TPMS sensors should work.

Thank you for the impetus to learn more about these ideas.

 

[mgroeger]

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.

Uh oh, don't let the admins see you are giving out discounts because before you know it you will be forced into paying to be on the forum as a sponsor.

 

[wolf]

Will there ever be some way to adjust your tire pressure threshold with out something stuck in or a programmer? It seems to me there has to be a way to adjust your tire pressure threshold yourself up or down. FCA is a real pita.

 

[Stuckinthesand]

How does the JL/JLU know which tire/rim/wheel is where .....

Well, there are 3 sensors on the chassis that monitor the 4 TPMS Sensors found on the 4 tire (rim) positions.

Info from the 3 chassis sensors is transmitted to the Wireless Control Module. There is no need for a 4th chassis sensor as the computer uses the process of elimination to determine the fourth tire location.

Yes, your JLU/JL knows exactly which rim is where, within seconds of a tire rotation for example. Yes, It's all done automatically.

There is a TPMS sensor in the factory mounted spare but it is not read by a chassis sensor/ considered by the computer until it is placed in one of the 4 tire positions.

 

[Yellow Cake Kid]

The internet has done it again.

 

[DavidArmen]

OMG THANK YOU!
No Joke. I have my TPMS turned off with my Tazer and every time I start the Jeep after everything is up and running a get one final "ding". I always look at the dash and there is nothing, it's always bothered my like what the heck is the Jeep trying to tell me... lol. I wonder if that's what the ding is?

My new wheels and tires don’t have TPMS. I turned off the TPMS light with the Tazer. I get the “ding” as well. Just another sound I associate with the start up routine.

My JLUR is fully stock and I’m running my stock KO2s (with factory TPMS) at 37psi so I don’t get any tire pressure warnings at all but I also get one ding when I turn on the ignition before starting the engine. I don’t think it has anything to do with TPMS but I’m also curious what it’s trying to say, if anything ?

 

[WranglerMan]

My JLUR is fully stock and I’m running my stock KO2s (with factory TPMS) at 37psi so I don’t get any tire pressure warnings at all but I also get one ding when I turn on the ignition before starting the engine. I don’t think it has anything to do with TPMS but I’m also curious what it’s trying to say, if anything ?

If there is nothing in the message center on the EVIC and no idiot light and pressures are all updating I would have not idea

 

[mgroeger]

My JLUR is fully stock and I’m running my stock KO2s (with factory TPMS) at 37psi so I don’t get any tire pressure warnings at all but I also get one ding when I turn on the ignition before starting the engine. I don’t think it has anything to do with TPMS but I’m also curious what it’s trying to say, if anything ?

One ding is normal. The ding I am referring to (and the others with the Tazer tweaking the TPMS I believe) is one final ding after everything is completely up and running.

 

[wtodd]

Be careful about Discount Tire. I like the guys I deal with there a lot but...

They put Nitto 37s on my Fifteen52s and installed sensors. When I mounted the wheels (right before a trip), the sensors weren't recognized by the Jeep so I turned TPMS off (via Tazer).

When I was eventually able to go back, over a couple of different visits, I was told:
* Their programmer/device can't read the sensors through the big tires(!!).
* The programmer/device CAN read them but none of the five are responding.
* They'd order OEM parts to replace the dual-frequency sensors they'd installed.
* The "other" programmer/device can read the sensors & they're FINE.

After that last, I left TPMS on for a while just in case but eventually turned it off.

I guess I ought to re-engage this but after reading this thread I may just leave it alone.

 

[WranglerMan]

@wtodd its funny you mention that, when they scanned all (5) the spare on the back and the rear driver side did not get picked up by their handheld scanner but the driver rear was reading and updating in the Jeep, I did have the tires rotated but did not rotate the spare into the mix and all (4) updated so I will just leave as is now and when they go out I will more than likely go with OBD JSCAN to turn it off as it’s more cost effective than the Tazer.

I carry a tire gage in all my vehicles and I know when I have a flat, when I air down on the sand when I air back up I always use a tire gage anyway, really just tired of the whole TPMS thing, nice convenience but kinda like the ESS battery issue just a PITA....

 

[onepluto]

One ping, one ping only. I just did the Tazer update and started getting that random ping, I think it's the cruise control activating but that's just the last screen that pops up.

 

[Chocolate Thunder]

From the factory the warning light comes on at 29 PSI(?) and won’t turn off until you’ve inflated to at least 36 PSI.

When adjusting the TPMS value with the Tazer, what are you actually adjusting? The pressure at which the system warns you of low tire pressure, or the value to which you have to inflate to get it to remove the warning?

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