I first enter my 2009 chevy hhr lt and start it up. The TPMS warning light blinks for a min and then stay constant lit. None of my sensors are reading any pressure. Just dashes. Tried to do the relearn procedure. The LF tire horn chirp in seconds, but after decreasing/increasing for the RF Tire, no sound at all. What may the problem be or am I doing somthing wrong?

 

Did it used to work? If it did, what happened just before it stopped. Follow the procedure exactly as the Owner Manual says; if you need one an online version is available from a link in my sig.

Sounds like you are probably doing it right, but check.