I posted this in another thread.......feel free to try it out, I'd LOVE to know!!

I'm guessing this is BS, but I read some jeep owner claiming if you have good pressure when you turn the ign off, as long as the sensors are not close enough to be read, the computer will not notify you of anything after restarting. He put normal stems on, moved the sensors far away, and had NO alarm from the 'puter. I don't believe it, but just reporting what I read! No light, no nothin'....and supposedly had been that way for many miles.....?

 

After the chime and the light at start up will the chime continue as you are driving or only at start up?

I really don't want to mess with the sensors but if the thing ins dinging at me all the time then I will use them.

 

I put Cragar Soft 8s on and I had heard the stock sensors would not fit so I did not switch them over. Here is what happens.

At first the light didn't come on as if the sensors were there. Then after a week it realized they were not there and started reporting a problem. The alarm dings a few times when I start and the light stays on while driving. Once in a while, like every 10 min or so a single ding might happen but I really don't notice it. The only real downside is that when a warning light is illuminated on the dast, you cannot dim it at all! So its BRIGHT! Not just the warning light but that whole little section around it with the Gear Display and Odometer.

Ok, heres the funny part. After a few weeks the sensor must have though "aw whatever" and turned off! It didn't report a problem anymore. I was excited. But then a few weeks later it came back. So I don't know how the computer determines when sensors are there or not, but most of the time it appears as though the computer knows they are gone and reports a fault. But its just not that annoying to me.

As for fixes like putting the sensors far away or in a baggy in the cab.... none of that works. The only solution is put Chrysler style sensors on the wheels.

 

Ok, Don't bash me if you think this is a silly idea.

A friend of mine sugested that we buy some heavy 4" PVC tubing and cut it about 6-10 inches long Drill 5 holes in it and install the TPM sensors in it. Then cap both ends of the PVC pipe. Air it up to 32 psi and stick it in the back, under the seat, or strap it under the Jeep.

At 32 psi there is realy no danger at all. I have PVC pipe feeding all the air supply at my shop and it is always at 100-130 psi.

What do you all think about that?

 

The sensors don't have batteries in them they need to spin for power. That is why you have to drive up to 15 miles to register a fault.

 

Most of the newest sensors actually have a lithium battery rated at about 10 years life. Centrifugal force activates a more "real-time" transmission of the pressure signal. At rest, the sensors enter a sleep-mode to preserve battery life. At this point, they send a signal roughly every 30-60 minutes.
As far as keeping them away... These sensors can transmit at a surprising distance (I've tested them at up to 75 feet). You can build a tube to maintain the pressure to "fool" the system. BE EXTREMELY CAREFUL. Even 35 psi inside a tube 3 inches in diameter can be powerful if the end cap separates. I know because I was a dumb ass and found out the hard way.
The government meant well with this system, but most of the people in the automotive field (including technicians) don't understand how it works.
...and by the way- Hello All. I read this forum daily and appreciate everyone's advice/input/opinions/humor.

 

Nothing silly about that. Seems like a good idea to me.

 

I'd like to see someone try it, but the sensors have accelerometers in them that detect the wheel spinning. When the wheel begins spinning, they begin transmitting their pressures. They also transmit when it's not spinning, but less frequently. One of the bits in the transmitted message to the ECU indicates that the accelerometer is detecting spinning. I think the Jeep ECU might get suspicious if the Jeep is moving but none of the TPMS sensors are reporting spinning. Give it a try though and let us know what you find out.

That would be great if it were true, but it's not. Each sensor has a battery sealed within it. The electronics are designed such that the battery is expected to last from three to seven years. Here's a PDF link to the operational description of the sensors filed with the FCC. Page 2 describes how the sensors behave when the vehicle is moving vs stationary, page 3 is a block diagram showing the battery, and page 4 lists the power source as a battery.

https://gullfoss2.fcc.gov/prod/oet/f...ive_or_pdf=pdf

Because of transmission collisions and other noise in the 315MHz unlicensed spectrum, transmissions from the tire sensors to the ECU are not guaranteed to make it to the ECU. 15 miles / 15 minutes is listed in the manual as the worst-case time you should expect to wait for at least one transmission from each of the sensors to get to the ECU. Under normal circumstances, the response is typically much better. My TPMS usually reports normal conditions as soon as I start the Jeep after airing back up.

-Glen

 

Let me add to the mix here...

What if you are driving down the highway and you pick up a vehicles TPMS sensors that is near you after you have the lower psi reflash. Does that screw with the ECM?

Is there a ECM controller you can buy to adjust for tires, lift, Stability control, TPMS, gears, etc. pretty much all functions of the computer.

 

If trying the pressurized tube with the sensors all in it, I would put it under the Jeep somewhere...not so much for safety, but just so it never gets in the way.

also, anyone know how the sensor actually senses the pressure? If it's some type of mechanical action, like a spring loaded plunger or something. Maybe remove the valve stem, put in some epoxy, reinstall the valve stem, quickly reinflate, then let the epoxy set it...permanently?

Just a thought....don't try it....I have no idea if it's even mechanical