Low Tire Pressure Sensor II

Low Tire Pressure Sensor REVISITED!

by Scott Fabre

Last Update: 10/07/2006

This is an important update. This more common failure mode is very easy to fix!

To begin with, notice the white powdery substance in the plastic sensor housing. This is pulverized black plastic. Note the scored or scraped pattern.	This is the top of the power generating unit. It is a plastic housing with a metal cube in the middle. The metal cube is attached to a peizo cell. This cube is intended to vibrate between the two black plastic retainers as you drive..
The problem occurs when the metal cube moves far enough down between the two black retainers to make contact with the outer housing (see photo 1) to touch.	When the metal cube touches the outer housing (photo 1) then the movement is restricted resulting in a failure to build enough stored energy in the cap to send the RF signal. The above photo shows the part that rubs on the right. The part on the left does not touch.
Above you can see that one side of the metal cube does not touch.	Here is a good shot of the top which clearly shows that part was rubbing.
Again another shot of the top showing the part that rubs.

My theory is that the leads of the peizo cell (if not soldered snuggly) will stretch. Or the retaining sides rub against the housing which wares them down. The net result is the same. Eventually the metal cube sticks against the outer housing.

The fix is simply to unsolder the cube leads, snug them up making sure the cube does not protrude past the side retainers. You may also choose to use a small grinder to grind off a small part of the metal cube that is touching. That's it.

If you do this be very careful not to damage any of the circuit. But more importantly when you remove the whole black plastic sensor from the metal band that holds it to the wheel be very careful bending the metal tab that holds the sensor in place.

Bend it just enough to clear the tab. Do not bend the band itself. Just the little tab on the band. Also, I used a bit of loctite on the screw that holds the band in place just to make sure it does not loosen up.

STANDARD DISCLAIMER: Be aware you do all work at your own risk. I make to claims that any of the above is safe to do. You are on your own.


	Disclaimer: Repairs and techniques are reported here by amateurs and professionals as an informational opinion service only and should not be attempted by other than factory trained and certified technicians. The ZR1 Net does not recommend anyone doing these procedures and is not responsible for any adverse outcome. Factory repair manuals should always be used and followed to the letter in conjunction with any repair or maintenance performed. All cautions and warnings that appear in the factory manuals apply here as well. As recommended in all service manuals, proper eye and body protection as well as proper tools must be used for any maintenance performed by individuals. Working on automobiles is dangerous and could result in personal and/or property injury. If you do not have the proper tools or know-how, you should not do any of these procedures, but have a qualified technician perform the work.

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