How to remove the valve stem on TPMS valves?

[mkb]

I have TPMS tire valves on my 07 Grand Prix. One is leaking air. I tried to remove it with a regular valve stem tool, and it doesn't work. On further inspection, it looks like maybe it have a slot for straight blade screw driver... if a press the valve stem down the screw driver could go in the slot. I tried this but it doesn't seem to work.
What's the trick?

These TPMS valve have been a pain. I had one break off last summer. Now this.

Thanks.

 

[TheOtherNick]

Are you talking about the core? Or the whole sensor?
The whole unit has to be removed with the tire off.
The core just comes out like normal.

 

[Deimos]

the valve is pulled through and bolted on inside with screw if rubber and bolted from outside if metal.

 

[mkb]

Are you talking about the core? Or the whole sensor?

I should have made that clear. I'm talking about the valve stem core.
It doesn't come out of the valve body with a standard valve core tool.

 

[corsagtp]

If the core isn't coming out with a regular valve stem tool it's because the core has corroded, possibly because you have a metal cap and valve stems with sensors aren't supposed to have them for this very reason and you will have to replace the special valve stem for your car

 

[Omen87]

I used to work at a tire shop, and the same thing happened to several cars I worked on. They would run a TPMS car without valve stem caps and eventually the core would corrode into the stem of the sensor. Then when you go to turn it out with the core tool, it just shears the core off in the stem and presto! They just spent $100+ for a new sensor from the dealer!