Using two TPMS systems

[skloon]

I know I should get one with 6 sensors but can get a deal on two 4 sensor systems with the valve cap type sensors can I use the two in one vehicle or are the sensors the same and it will wreak havoc ? I would assume they are different so that you don't get the information from a vehicle you are parked beside but want to know before I do something stupid again

[Rickf1985]

Good question, never really thought about it. I would assume they are like padlocks and there are a set number of frequencies sent out to each area of the country. But what happens when you end up next to the guy that got the same frequency on the highway? I went into a Lowes to get some keyed alike padlocks. Well, being a locksmith the first thing I look for is the key code. There were five packs of four locks each in the same box that ALL had the same key code! 20 locks in one display that all used the same key, how is that for local neighborhood security? Luckily I needed 12 of them.
I guess the same could happen with TPMS. When I think about it those sets are expandable just by adding more sensors and letting the unit see them. I wonder if they work on Bluetooth? People steal the sensors all the time.

[Sasquatch]

TPMS sensors send out packets of data every "X" minutes.  The first pid in the packet is a unique ID serial number.  The rest of the pids are pressures, temperatures, battery status and duplicates in case of a failed transmission.  The receiver will pick up all transmissions on the given frequency, then compare the received serial numbers to the numbers it has on file.  If there is a match, then it displays the data for that given sensor.  If the SN is not recognized it is disregarded.

Now, this is how proper commercial systems work.  I have no idea how the cheap Chinese crap systems work.  I have never heard a good report from those systems.  Many people took a look at the price of our system (using SmarTire and Valor transmitters) and decided to buy cheap knockoffs.  Of the reports I heard, none were good.

[HamRad Mobile]

Good morning, Skloon; 

     If your cost for two (2) of the same TPMS with four (4) sensors each, is less than the cost of a TPMS kit with six (6) sensors, then go for it.  You can always use one of the two "extra" sensors on the spare tire also.  And you will have a complete spare monitor display system if anything happens to the first one of them. 

      Wish I had seen a deal like that. 

          Enjoy; 

          Ralph 
          Latte Land, Washington