MarylandGLK250B

All of a sudden I am getting a TPMS warning when I start up, even though the display (correctly) indicates that each tire is fully inflated. I press "OK" on the steering wheel control to eliminate the warning.

What gives and how do I eliminate this needless warning?

ygmn

NEed to reset the TPMS for what is your normal pressure.

Check manual out... It explains better then I could...

as TPMS wanr you when tire air pressure drops a certain amount from the RESET value...

so if the reset value is 50PSI lets say and you are running at 36 it will warn you all the time even though tires are fine.

Kind of dumb but that is how they do it... I just want to know if they lose pressure fast or drop below min tire pressure

andreigbs

Resetting the “correct” values is what’s needed. The manual describes this process.

It’s also possible the batteries in the sensors are getting weak. But do the reset first.

MarylandGLK250B

Thanks. I get the reset. My question is why the warning in the first place? My four tires are always at 40, well above the threshold for TPMS warning. Now I am warned (my two front readings are in yellow) even though the indicated tire pressures are still 40. I checked with a gauge and they are indeed at 40.

PS I've had the car since new, have never changed the factory settings, and just got the warning for the very first time this week.

So why did the TPMS warning go off in the first place? Or should I just reset and not ask questions?

ygmn

What were they reset to?

Maybe 44? then warning would make sense.

Reset and then see what happens over next few weeks.

MarylandGLK250B

They were set to factory specs: 33 front, 35 rear.

ygmn

how do you know that?

MarylandGLK250B

Haha, you're right. I don't literally know what the settings were.

Here's what I do know: I've driven the car for 5 years and 75K miles, the settings have never changed, and the warning just came on this week even though the tire pressure has remained constant at 40.

So again, the puzzle: why suddenly a warning?

ygmn

5 years??
maybe TPMS battery is dieing or system is failing?

again try a reset and see what happens

Mmr1

If reset doesn’t work it’s possible it’s the battery