Just started getting the Check Tire Pressure in the display yesterday. Checked tires with air gauge, all fine. TPMS reset doesn't seem to work. I reset yesterday, used the car today to work - got the message again - checked good with tire gauge, reset again, got the message again on the way home from work.

What I do not understand is after the reset, the system does not repeat the message again during my drive home. Does it only report the message once for each engine start, and the reset stops the message from re-appearing until the next engine start? I tried resetting the TPMS on both warm tires, and cold tires, makes no difference.

I've read some threads here, it sounds like I would be getting different messages if a sensor wasn't functional at all, and the "run flat" icon on the dash would be illuminating, neither of which are happening.

Any ideas? Should the car be stationary when I do this, or should I be moving?

Possible bad battery in the TPMS sensor.

They could have invested a little more time in this TPMS system to show the reading at each wheel, so you could know where to look. I knows its a federally mandated system, but the implementation leaves alot to be desired, it just doesn't give any specific information about what its reading.

+1 - I agree... My wife's '07 Tahoe has it... Really helpful.

Why not drop by the dealer and ask these questions?

The dealer is in the opposite direction from where I travel to work. I can email them questions however.

The manual doesn't specify any particular discipline to resetting the system. This should be simple, but its not working out that way. I may have to deflate the tires a few PSI, reset tpms to that level, then reflate the tires to the spec to see if the system still reads them as low. That should prove whether its a misreading sensor or not.

I had this same problem and I had to take it to the dealer. Apparently they can recalibrate the sensors to become less sensitive to air pressure changes caused by the temperature. Your sensors are probably too sensitive right now. You will have to take it to the dealer.

My came on couple of times and each time after I fill it back up to correct pressure it goes away. I agree the system stinks in that it does not tell you anything like which one is low on pressure. My wife's Acura shows you all the tire pressure so you know which one is low on air.

If you are sure all your pressure is correct, you should go to the dealership and see what's going on. You may have a bad sensor. I know once I fill the tire with the issue, the message goes away immediately.

I was able to successfully reset mine twice this winter while driving. I ended up adding an extra PSI or two of air to mine to stop it from triggering the warning light.

Are you getting the yellow tire icon or is your main center gauge turning red with a warning message?

When I had this happen to me, it was a slow leak in one of my tires, so first check your tires.

Indeed, today it did not come up with the message - but the temperature was near 40 today, I think that's why. It's going to be below 20 later this week, so that should be a good test to confirm its temperature related.

also you can make sure all your stem are tighten at the sensor.

btw, i found my sensor cracked into two pieces inside the passenger rear wheel. not covered by warranty apparently. dealer wants $230 just for one sensor. I'll probably go to my parts guy at another dealer just to get the parts and have it done outside the dealer.

Buy the same unit from Tire Rack for about $70. I did.

Why wouldn't it be covered by the warranty?

So if you buy it from tire rack instead, who installs it? You have to dismount the tire from the wheel to install it, right?

If the sensor has to be bought by the owner, there is no point in paying dealer prices for it. Yes, the tire has to be at least partially dismounted because the sensor pulls out from inside.

Since the car in question has had the wheels and tires changed, the person who mounted the tires damaged the sensor and it finally let go. I know all about this scenario because it happened to me. When the dealer's tire guy mounted my Tire Rack Bridgestones on my 18s which I bought from them for installation before delivery, he broke the sensor off which fell in to the wheel. Since the dealer employee did the damage, they took care of it. Warranty didn't come into it.

I looked it up. dealer charges ridiculous labor. retail on the sensor's about $100 at parts dept. another guy on the forum has a spare one. i'll just get it from him. $73, not bad. probably similar price for me if i go to my parts hook up at another dealership.

but still a ****ty quality part that would break that easily.

how do you reset when it already states "inoperable" I followed the steps but there is section that supposed to say ok for reset, but mine does not give that option. Thanks in advance.

I have a 2003 SL500 - TPM doesn't work - it wants to measure pressure SEPARATELY on each of the four tires. Uses batteries that die after four years. Big Brother therefore expects me to have all four tires removed (no big thrill for the tires) and then spend $300 or $350 EACH to replace the sensors, PLUS cost of "resetting" them. My car had this as an OPTION, and I couldn't care less whether I have it or not, but the dealer says it cannot "legally" kill or dismantle the option. I guess the sensors are each little radio transmitters that send info to the dashboard on EACH tire to advise the current pressure. What a great help! Just a message saying check presure would be good enoughh. Checking tire pressure by yourself takes only minutes, not $1,500. As a side note, my wife has a Lexus, tire pressure monitors cost only $15 per wheel to replace.

The 2012 C350 shows the pressure at each tire on the center screen between speedo and tach. This picture and specific pressure readings is a new feature for 2012 C class; it's also on a relative's new 2012 M class.

I'm glad they improved the system for the 2012 to show which tire is low. That will help. I went through a bad period there with my TPMS system, including having one that fell into the tire and was making a howling noise while rotating in there. But its been OK lately. The system also seems to be less flaky with Michelin tires than the OE Contis, which were horrible tires. My car has 72K miles now.

Take a breath. New sensors for your car should be less than $100 each (check Tirerack.com) and there is no resetting per each but just the system which is done by you. I paid about 70 bucks each but that was in 12/07. You will have to pay for installation which means dismounting the tires.

The 2010-2011-2012 model years all have individual PSI readings in the cluster, only the 08-09 dont show individual settings. To those of you having intermittent issues its the sensor itself doing its job, if you read a cold tire at 35 psi it will reach 39/40 warm so when u do a reset at lets say 35 psi, a cold day will have u around 31 and will trigger a warning. The proper way to do a reset is to use an accurate guage, not a gas station air machine, and put whatever PSI u like into the tires. Then do a reset and lock in that PSI into the system. Now go back and add 2-3 PSI w the guage and u are all set for a few months, this should be done every 3 months or at least seasonally. If after doing this u have a message, guage each tire individually. If one is a 2 or more PSI off u have a leak somewhere....

If you have a 2012 C Class, go to page 321 of the owners' manual. Tells you how to reset monitor so it doesn't keep bothering you with message an/or illuminated tire symbol in the tach display. P.S.: After researching and driving a fair amount we set front tires on our C350 at 30, rears at 32 (when cold, of course). This is the same setting we had on our 2008 C350 with same size wheels and tires. Makes for a much more comfortable ride but still is responsive. Haven't noticed a decrease in gas mileage. Of course, if car is fully loaded with hefty passengers and cinderblocks in the trunk, you should increase the pressure. Unless you live where the streets and highways are like glass (e.g., Germany) the levels shown on the gas flap or driver's door pillar are ridiculous. I've conformed this with very experienced Mercedes techs as well. Enjoy your 2012 c class!

I lot of people have trouble with dead or low batteries at the 5 year point.

My SL shows pressure of the 4 separate tires. One would think they could have put this on all models. When batteries started to fail on it, I had the dealer turn TPMS off in star. I have a $5 pressure gage that works just fine. I am not sure what year the actual mandate came out (06 maybe), but MB will turn the system off in any car earlier than the actual mandate year.