08 Extra wheels & TPMS
 

I have an 08 and want to get a set of snow tires on steel wheels for the snowy weather we are having. Since a set of 4 TPMS sensors will cost a little over $300.oo, I would like to not get them. I realize that the TPMS system light will be ON for the time that the OEM tires/wheels are sitting in my garage, and I am OK with that. My question is: Will the TPMS system light go out when I re-install the OEM tires in the Spring?
I am hoping that the computer will remember the OEM sensor serial numbers for the 5 months that I don't have them on the car.

I understand your situation as I have grappled with it as well. Even if you buy 4 new sensors for the take-off rims, you still will have to visit the dealership to have the sensor ID codes re-registered every time you swap tire sets (twice a year). I think some tire shops can do this for you, but my tire vendor is an older fellow challenged by TPMS technology. He claims Hyundais are the most difficult to reprogram. He's a very good tire man but I also know he does his accounting on the back of used envelopes. I've delayed buying any snow tires and rims until I sort this out locally.

Regardless, I've read most, if not all, of the TSBs regarding the TPMS system. Once a wheel sensor is registered with the car's systems using the TPMS-Exciter scantool, the sensor ID remains in static memory. I think your plan will work. Of course, you can always load the Elantra up with the original tires and rims so that the car thinks they are still mounted. Passengers?, you didn't say anything about having passengers...

Ken99,
Thanks for the reply. I think I'm going to buy the snows without the sensors. If the TPMS receiver "forgets" the sensor IDs, I'll have to get them re-registered in the Springtime when I put the OEM wheels back on.
If the static memory holds the IDs for the few months, I'll post that result too.
BTW, the sensors will only transmit when 1) they are excited by a scan tool, or 2) they are being spun (as in on a rotating wheel). It turns out that they have accerelometers in them that turn them on when the wheel starts turning.

I did not know this. Thanks for sharing. But what keeps the TPMS system from triggering if the car is sitting still? Hmmm.

If the sensor is stationary (not rotating) for more than 10 minutes, it goes into "sleep" mode to conserve battery power. I got this info from the shop manual. The manual does not describe what happens if there are NO sensors for a couple of months (my original inquiry).
BTW, I was talking to the local parts guy and he showed me a sensor. The battery appears to be potted in....meaning not user replaceable.
I didn't find any "expected battery life" info, but I suspect that after a couple of years, I'll have to replace the whole set. There is a DTC for Low Sensor Battery, so you'll get a warning of some sort.

Yes, I've seen these too. They was a set sitting on the parts counter when I purchased oil filters last. Supposedly, the batteries are good for 5 years. The system was deployed on the NF model in late 2005. Might be interesting to see when folks start writing threads about dead TPMS sensor battery codes. Keep us posted on your experiment.

Results
 

I got new snows & wheels without sensors and installed them on Feb 4th. After about a mile of driving, the TPMS light came on, which was expected. Because it's on the right hand side of the panel, it wasn't an annoyance. The car has been driven every day since then. Yesterday (Mar 17th), I put the OEM tires & wheels (with sensors) back on. I drove about 1/4 mile at about 30 mph and the TPMS light went out.
Conclusion: The TPMS receiver/computer does retain the sensor IDs when non-sensored wheels are installed....at least for 1-1/2 months.

Great, this is good information for know. Thanks for sharing the experiment.

Anti-lock brakes
 

Are the sensors used as a part of the anti-lock braking and electronic stability systems? Thet are on some vehicles, but how about the Elantras, specifically the Touring?

The TPMS sensors are not used as part of the ABS/TCS/ESC systems. There are other wheel sensors for that.