So I had my left rear sensor reading bad. I replaced it with a compatible one from discount tire and the tire pressure will not show up in the system when checking. But the tire pressure light doesn't come on. Any help with this would be great. I've tried resetting it but still no resolve.

 

Go back to Discount Tire and have them reprogram it. I had the same issue when I put my summer wheels back on a couple of weeks ago. After I performed the swap procedure with my Alteq tool I had no pressures, but no tpms light. Once I redid it and reset the tpms on the car the problem resolved.

 

What exactly do they need to do because I have had them reset it 3 times and they continue to follow whatever instructions show up on their tool but it still does not engage?

 

Maybe they don't have what is necessary to reprogram if they aren't connecting to your OBD port. My Quickset tool actually programs the sensors into the ECU each time I change tires.
You may need the dealer to reprogram them to the car for you (at a price, I'm sure).

I bought a new set of summer tires and sensors from Tire Discounters, not Discount Tire last year and I believe they actually programmed the TPMS to the car. Maybe you can call around to different shops and see who can "reprogram" them.

 

Mostly due to sensor placement when they program it.

I found out the the correct order is (to read the IDs with the tool before programming):
Rear left
Front left
Rear Right
Front right

I had this exact same problem with my cloned sensors, and when I swapped my left wheels (one is slightly bent and was causing steering shake), I started having the pressures register in the dash.

Another thing you might try is to drive couple miles, then hold the reset button under the dash without turning the car off. They sometimes take a lil while to register.

 

I've literally driven the car for about 200 miles and also I have seen then send it to the computer using the ODB2...maybe it is that they did not scan them in that order you stated above...

 

I'd had them try it. I spent last winter with no pressures registered in the dash thinking it was the cloned sensors thaweren't 100% compatible... I was wrong!

Before that, try doing couple miles and hold the reset button before shutting the car off, it might work.

 

Some basic TPMS operation guidelines for Toyota/Lexus vehicles:

• When a defective sensor(s) is replaced, the sensor code needs to be removed from the ECU and the new sensor code programmed to the ECU
• Most of the vehicles can only hold 4 sensor codes at a time (some models are capable of holding 8 sensor codes...summer set and winter set)
• Toyota/Lexus vehicles will "search" for TMPS readings for approx. 20 minutes of continuous driving after the vehicle has been started...after approx. 20 minutes, if there is an issue, the TPMS warning light will illuminate
  Up until that 20 minutes threshold, the TPMS warning light will likely staff off