Have a 2004 SL500 that gives me a warning every time I start up of tire pressure warning and it needs to be re-activated. Does anyone know how to reset or do I need an OBD tool to do it.

 

There are no tools required to reset the TPMS system uses the scroll buttons on the steering wheel .. Check the Air pressure before performing any reset.

 

I've had the same problem since I bought my Sl new in 2004. Even the service center could not get it to work right. Now I"m told the batteries need replaced in each wheel. There seems to be no way to disable this feature and it is a pain. Sorry I can't help other than to say your not alone.

 

2004 S500..... I also had problems with the TPS
The dealer I bought the car from had replaced the Control unit AND the batteries in each wheel. After doing so I was told the batteries are typically good for about 5 years. A month later I got low pressure warning......checked the tires and it was correct. HOWEVER...I over pressurized the tire in question thinking it may be a slow leak (I didn't have the time to "take it in)....then got the warning once again!!!.......off to dealer and was told the TPS will register a HIGH pressure setting warning also!
- just a little more info

 

I also can not get the TPMS to work, keep getting an ?"Not Operational?" fault. The sensors in all tires are new. when I reset I drive for 10 minutes at a steady speed and the same fault comes back ?"?" any ideas ???

 

if you have a light indicating the problem and not a read out on a screen, I cut a nicely shaped piece of black tape and covered the light on my 320. check the air yourself like we used to.