TPMS and how NOT to work on them

I had my wifes car show that the TPMS was showing an error. I read the 4 TPMS sensors on the 2009 Prius and it showed RF and LR are not transmitting. The LF and RR work and read fine . I bought two TPMS sensors off eBAY. The car needed some tires so I went to Wallymart and asked if they would replace the two dead TPMS sensor but they said it was a dealer only work. Okay..I ordered 4 tires to be put on. I get the Prius back and my wife and her sone take off to Paris for a month..They are out of my hair..or what hair I have left...ANYWAYS....I replace the RF and LR TPMS. I use the scan tool and see that I have to have the car relearn the values and upload them to the ECM. I did..and I followed the procedure but the TPMS lite is still on..even the manual reset on the bottom dash is not working..it won't clear...WHATS GOING ON??
Okay its back to basics again...my scanner keeps the previous values to I start over again. I scan the RF and LR and they show output..I scanned the two TPMS I bought on eBAY so I knew they work. I scan the LF and RR tires....and their DEAD! They were alive before the tire change...Now I know..those yoyos changed the tire and had the tire sweep over the sensor and damaged them...Both of them! Since the car had the TPMS sensor light on..those tire jockeys didn't see anything different...as the indicator light just refers to a malfunction not how many. So NOW I see the BIG PICTURE! I can't erase any faults because I had assumed the TPMS sensor that were good were still Good but not anymore...LOL! I order some on eBAY for $65 OEM Toys TPMS. They better be genuine and not chinese fake boxs reprinted to OEM likeness....Also in changing out the two dead TPMS sensors originally....besure NOT to unscrew the hex nut all the way as I thought the valve stem threads were part of the valve stem seating process..no no no...its not... I ended dismounting the tire off the rim and fished the dead TPMS out..although I tried to think of a way to get it out with tire bead off rim...no can do.
I have a tire machine so no big deal. The other tire..just break the bead down. Get some 2x4s to wedge in., Use a tie wrap and put it on the body of the TPMS so that if it falls...you have the end of the tie wrap to get it out..probably better if you use two tie wraps..Anyways..thats the Situation for today... Will update when I get the TPMS in the mail on the...21st

 

Yeah I have a Tire Machine but I use that term very loosely LOL! Its a Harbor Freight model but it works well considering the price. I have it stored away usually as I have a medium height two post hoist as well. Danmar Max Jax. I usually unbolt one hoist cylinder to bolt in the Tire machine so its steady. NOW because I am lazy I bought a Bead Breaker from Harbor Freight so I can swap out the TPMS sensors. I only had to do two so I went ahead..well as you can see...I dropped the first one into the tire LOL! THATS why I ended using the tire machine to dismount the bead and get the TPMS..next one I got the gist... I used a tie wrap to secure the TPMS sensor so ieven if it falls in I still have it tethered. Actually the best tool is to get a valve stem cable tool which screws onto the valve stem with about 10 in cable hooked to it. You can get them on eBAY for $5 or less if they are China. The bead breaker machine works well if your going to swap out TPMS and dont' screw up and drop it in the tire...I tried to think of anyway to NOT use the tire machine but...its one of those..I could dismount the tire and get it by that time my gears in the brain were trying to find a solution!!

 

Alright Finished the Prius and here is some insights that YOU don't have to go through. Although I bought four OEM genuine Toy TPMS units from eBAY for $65 I only used two to replace the dead ones. I used my AUTEL TS501 to do the diagnosis and programming...which since even as I am a professional fleet mechanic I normally do not do these repairs when I was working. Like anything else...when you are retired technology in the field can pass you buy if your not on the pulse of whats going on. So anyways..I am a fast learner so here we go.
I scan all the TPMS units..they all scan and are good. I write the scan codes because I want to verify that the scanned codes are the ones being written into the ECM as genuine and accurate. In this case I am replacing dead one so it doesn't matter on two of them but its a procedural that cannot be skipped in case so you don't waste time. I plug in the OBD2 and I go to the menu which shows me which TPMS signals are valid. Mine says all four where as before it was 2 only. I go to the ECM menu which shows me the codes of the TPMS it has in its memory and there are 2 correct and 2 incorrect. Okay..I go to relearn menu and proceed with writing over the ECM codes with the NEW codes that I scanned previously. It writes and is successful....I check the ECM codes to what I wrote previously to verify its write. Okay all four mirror what I wrote on my piece of paper...should have used my cellphone eh? Oh well. anyways all four tires are inflated to 35 PSI.
I have erased all codes relating to TPMS faults from before and I still have no faults. The TPMS symbol went from blinking to steady on.
Meaning.....that its LOW on air....this is where you have to know the low threshhold of what the TPMS system wants as far as the lowest it will allow before it lights the TPMS lite on the dash. I go for a test drive but the dash light stays on. Puzzling..as in some cases it may take 19 minutes for it to relearn the new repairs...I tried the incar TPMS reset procedure but failed to clear the light. I check some things on the internet in regards to Prius TPMS Pressure thresholds. seems around 35-42 psi is the range. Screw it I opt for the 40 psi median value.
I air up the tires and going for a test drive..I back out of my driveway - around 60 ft..and the Dash Light went off. Well there it is...The wifes 09 prius is done..my more primitive 04 is a lot simpler with no TPMS. LOL! All in all it was a tech challenge and also some frustration.

 

I am using the Autel TS501 which has a signal pickup so it detects the info from a good TPMS sensor. I just point to the valve stem and it picks up and stores those codes for writing later to the ECM or ECU. Yeah but your right...after 10 years those original TPMS sensor are about done and are on OVERTIME! Overtime for FAIL!