I have owned 5 hhr's. I bought some TPMS sensors w/ rubber valve stems off ebay. I was getting new tires for the front so I took 2 sensors with me to have them installed while changing the tires. I drop the tires and wheels off, because I dont have time to wait and I dont trust that the lugnuts were torqued properly and I redo it anyway. The guy calls and says that my valve stems did not seal up so he installed walmarts TPMS w/ valve stem and charged me $30 each for the sensors. I get home and mic the ebay valve stems vs. a brand new schrader valve stem and sure enough the ebay valve stem is almost 1mm smaller in diameter. I go to program all the sensors using the key fob method and a orange EL-50448 and the first wheel (Driver's Front), this is the walmart sensor and of course it does not work with the key fob. Both back sensors previously worked. Now I try to program the Driver's rear first and it work, but when I move to the Passenger Rear it does not work. Yes I know I am going out of order, but I am just verifying that the rear work and the Passenger rear now does not work. I take it to walmart, since they will have to reprogram everything anyway and they tell me that the passenger rear is defective. I had no issues with the passenger rear until I went to program them. I always find it most difficult to program the passenger rear on ALL of my HHR's. Why is this? Do you think that the passenger rear is too far from the BCM and the signal is not strong enough?

 

No, because the signal doesn’t come from the BCM.
Donbrew can educate you on TPMS. He has the experience.

 

If the first (LF) does not program none will. The RCDLR is what is being matched, think BlueTooth
The first one you set is put into the LF slot. The second one goes into the RF. The third goes into RR. The fourth goes into LR.
When you started with LR first it is now registered as LF. etc. Whatever was last in line thinks it is LR.

When you program you are telling the RCDLR where the sensor is located.

I don't know why they didn't just unscrew your supplied sensor from the stem and screw it back on a new stem.

 

I’ve never been a fan of any aftermarket sensors, the adage you get what you pay for , comes to mind.
I just order 4 at a time by GM part number and they last 5 to 8 years.