finally made some progress with custom TPMS setup

[V]

well, i have put this project on the back burner but today i finally got to take the first main step.... disecting a factory Tire Pressure Monitoring Sensor.

I thank sweetbmxrider for providing me the sensor.

For my project i need to know how the typical TPM sensor works, how its powered and such. It wasnt easy to tear apart but definately worth it, and has now provided me with an idea on how to modify future sensors to work outside of a moving tire and to be ignition activated.

I found it interesting that the sensor actually uses the valve stem as the antenna to transmit. The cylinder in the center sticking up off the circuit board is the inertia switch and it is all powered by a simple 3v battery.
The molded in casing was a pain to remove, but like i said, this one was just to see how one works and location/size of the components.
This one proves my idea should work so the next step is to actually cut up a CTS-V specific TPM sensor. That will be to verify exact location of the same components, and then a second CTS-V sensor will be modded and "hopefully" remain functional. Once tested and confirmed it works, 3 others will be modded and added into a pressurized container and wired up to an ignition/battery source coming from the car.

For those of you who are completely lost, the purpose is to run 4 sensors to trick the car thinking the tires are at specific stock pressure levels, but the sensors will be mounted in the trunk or somewhere...
This allows lowering tire pressure under 24psi AND still be able to turn off stability control, something the TPMS overrides.
Also you can run a set of tires swapped on for drag racing or autocross without having to have sensors in those tires as well.

Here are some pics of the carnage...


http://i32.photobucket.com/albums/d50/SmokingSS/TPMS/1.jpg
http://i32.photobucket.com/albums/d50/SmokingSS/TPMS/2.jpg
http://i32.photobucket.com/albums/d50/SmokingSS/TPMS/3.jpg
http://i32.photobucket.com/albums/d50/SmokingSS/TPMS/4.jpg
http://i32.photobucket.com/albums/d50/SmokingSS/TPMS/5.jpg
http://i32.photobucket.com/albums/d50/SmokingSS/TPMS/6.jpg
http://i32.photobucket.com/albums/d50/SmokingSS/TPMS/7.jpg
http://i32.photobucket.com/albums/d50/SmokingSS/TPMS/8.jpg
http://i32.photobucket.com/albums/d50/SmokingSS/TPMS/9.jpg
http://i32.photobucket.com/albums/d50/SmokingSS/TPMS/10.jpg
http://i32.photobucket.com/albums/d50/SmokingSS/TPMS/11.jpg
http://i32.photobucket.com/albums/d50/SmokingSS/TPMS/12.jpg
http://i32.photobucket.com/albums/d50/SmokingSS/TPMS/13.jpg
http://i32.photobucket.com/albums/d50/SmokingSS/TPMS/14.jpg
http://i32.photobucket.com/albums/d50/SmokingSS/TPMS/15.jpg
http://i32.photobucket.com/albums/d50/SmokingSS/TPMS/16.jpg





oh and to give you an overall idea how the final ones will be modded, heres a quick picture i drew up..
The battery will be cut out and power wires hooked up( 12v car battery will be reduced to 3v source for sensors.
sensor will be drilled right over the Inertia sensor terminals on the board and two wires soldered on, they will then run to a relay controlled by the cars ignition circuit. So when you turn the ignition on, the sensors also turn on.

http://i32.photobucket.com/albums/d50/SmokingSS/TPMS/17.png
http://i32.photobucket.com/albums/d50/SmokingSS/TPMS/18.png

[mtg6486]

instead of going through all this work (which will be cool if you can make it work) is there a way to just tune it out in the cars computer?

[V]

instead of going through all this work (which will be cool if you can make it work) is there a way to just tune it out in the cars computer?

Possibly, but only with a GM TECH 2 tool(3-4,000 bucks). Even with one, it hasn't been confirmed that its possible. It also would be illegal on the federal level for any dealer to do it.

In the 7 years since the car came out, no one has come forward saying they have bypassed the system or turned it off.

[sweetbmxrider]

i needed that back.......:lol:

glad you made some headway with it. i had another i was going to send to you but i think it got tossed. i might have a broken hyundai one if you want it? this one came off of a chevy truck.

[V]

i needed that back.......:lol:

glad you made some headway with it. i had another i was going to send to you but i think it got tossed. i might have a broken hyundai one if you want it? this one came off of a chevy truck.


im sure with a lil duct tape itll still work haha

nah i shouldn't need any more.

the next ones i get need to be for a 04-05 CTS.
One of those will be cut up like this one, like i said to verify all components are in the same location, and then the second one will have just the battery removed and be drilled in order to tap into the interia switch. That second one will then be tested to see if the computer will recognize it. If so, ill keep it wired in my car for a few days to verfiy itll keep putting out readings at all different speeds etc, and not go into sleep mode when i dont want it to. Finally if that works, itll get put in a pressurized container and then tested for a few weeks. before i buy 3 others and make a full set.(im also working on the possibility of removing the pressure sensor all together and having it put out a fixed 32psi reading)

Once i have a functioning TPMS bypass kit for myself , ill make a 2 or 3 more and try to sell them at cost, or maybe just loan them out to be tested by others. In the end, I hope to be able to make a complete CTS-V retail kit for under $200 with custom order for other makes/models. (a bmw emulator kit sells for $289)