rb23lb

Every 2 weeks my tire sensor goes off...Always the same tire... the rear driver's side tire... the pressure goes from about 40 psi where I leave it after filling, all the way down to 26 or 27 psi once after 2 weeks when the tire monitor trips...

Do I have a Bad Valve or a bad Tire????

I am sure if I bring it in, they will say i have a bad tire and that i ran over something so I have to pay for it out of warranty...

But if it takes two weeks after correcting the pressure and resetting the sensors, does it really mean the tire is bad??

seems more like a faulty valve stem if you ask me...


what do you all think???

thanks in advance for responses...!

jo17jC230

Check the tire, you may have a slow leak from running over a nail or something. Those can be patched up at any tire store or repair shop.

Baron Samedi

It's easy to replace the valve stem core yourself to check. Just go to the local auto supply and buy a packet of cores (it should also come with a removal tool). The cores just screw in and out (but when removing the core, keep your head to the side in case the tool slips off it. You don't want the core shooting out under pressure and lodging itself in your eye). You'll lose some pressure removing/replacing the cores, but just do the job where you have access to compressed air and you'll be good to go.

Having said all this, my bet is on a nail/screw in the tire.

delirium

I thought our TPMS only has one sensor in one wheel???

Baron Samedi

That's correct. One sensor per wheel in the US.

jrct9454

To clarify, each wheel has its own sensor, attached to the valve inside the wheel.

Also, be aware that on another thread, at least one W204 owner has the dealer admitting that there may be a systemic problem with the TPMS, with some revised parts coming somewhere down the line.

We've had no problems, so far, at 6000 miles and 8 months.