tire pressure
 

The tire pressure monitor system has a malfunction. And just after the extended warranty. the vehicle: 2014 E350 4 matic.
First it showed one tire under inflated. I clicked 'ok' on steering wheel. then a couple days later another tire, and than all four tires. The tire icon shows up in display. Now every time soon after I drive the heads up display will show all tires.
Can I reset the program by removing and replacing the fuse or some other nontechnical fix, or will I be at the mercy of my dealer over charging me for a similar procedure?

Stupid question maybe but did you check and adjust the pressure to spec?

tire pressure
 

yes sir, many times. Don't drive it very often, once or twice a week. I will give it another try though. can't hurt. What I will do is deflate each tire a lot, then inflate to proper pressure. May possible 'reset" the valves? Who knows.

Don't know what year & model you are talking about but most that have TPM systems (such as my 2008 E320) have a function available on your dash monitor to reset the TPM after adjusting pressures. The system then looks for deviations from that reset value.

Check your owner's manual for the procedure.

I would take it to an indie mechanic, or even a tire store, since they can probably tell you if it is just weak batteries in the sensors or something else.

Most tire stores should be able to try a relearn on the system and scan your sensors to make sure they're all working. Batteries failing in the sensors is not that uncommon as you approach around the 5 year of age mark.

TPM
 

rocky raccoon,
I will check owners manual. I played around with heads up display but could not find anything. car is 2014 e350 4 matic.

mpolli & Smeans92, That will be my nest option after trying rocky raccoon's idea.

Been busy cooking 600 # of shrimp today for our local KC shrimp boil this Friday.
Thanks for all suggestions. I do appreciate them

Make sure you adjust the pressure(s) to the spec shown on the fuel filler door. Read the label carefully as some models require different pressures front vs. rear, max vs. min load, different size options, etc..........These are the values the TPC control unit is looking for.

This may sound like a really stupid suggestion, but have you tried a different tire pressure gauge?

Here's why I bring it up as a suggestion:

A few years back I had a similar issue with my Honda (it'll complain if it's even 1PSI low). I verified that all 4 tires were at 32PSI with my gauge and just ignored the TPS warning thinking I had a bad battery (Honda doesn't tell you which wheel has a problem).

Flash forward several months later, I got a new tire pressure gauge, digital this time, and decided to compare the two. Lo and behold, the digital read out at 29PSI while the mechanical "stick" type said 32. Inflated tires until the digital said 32 and guess what....light went out. The mechanical gauge went in the trash.

What, no calibration traceable to NIST standards? No " For reference only" sticker on the gauge? The metrology dept isn't doing their job. :(

When your ass is smarter than your mouth, it's better to keep them both shut.

My point of the story was to share something that actually happened and was caused by picky electronics in a vehicle and an instrument that had a skewed reading. They're 50¢ at the hardware store and I have a good half dozen around the house and shop. I don't have space in my life for one that isn't even close.

Oh come on, I was just funnin. I figured you would get the NIST and " For Reference Only " from having to deal with that at work. At my work everyone hides when metrology comes around to locate every piece of equipment as even for reference items need a new sticker.

Diseasel 300, I have both digital and stick, but both are very old. Just wish they still made the inline gage on the air hose that was at gas stations back in the 60's.I have a 60gal air compressor and that would maybe make it easier to get the correct psi. But the problem seemed to correct itself by my deflating the tires way down to around 19-20 psi, let them set for 1 day, and then inflating them to stated on the fuel filler door as suggested by ILUVMLS.

You can get a tire chuck / gauge combo. It fills when you squeeze the valve and checks pressure when you let go.

Here is one, it can likely be gotten through a dealer for less. Manufacturers tend to keep pricing high to prevent undercutting dealers. There are other brands of gauges as well.

Longacre Quick Fill Tire Pressure Gauge 52009

I had exactly same thing on my 2015 ML350. Seems the tire store aired my tires to 45/48 per the door sticker (another story) and reset the pressure monitor system to that baseline. I let them down to 36 psi when I got home, and started getting the light and messages shortly after.
Check the manual, page 304 I think, on my 2015. Wife has the car, so I can't check exact procedure; but basically use the steering wheel controls and go "right" to "settings" then "down" to pressures, then look for a sign asking if you want to use current pressures as the reference setting and click "yes"

Something like that.

Mercedes tire pressure labels are really confusing:
The door sticker references the absolute max setting: only for traveling over 100 MPH, with maximum cargo, and maximum trailer weight. (45/48 for my ML350). Totally insane for normal driving conditions.
The fuel door indicates std pressures for normal load/speed (32 for mine)
and to add pressure for higher load or speed. I've found the 32 psi rides nice and soft and mushy, and really wears the side tread. 35-36 cold seems to be a good compromise for my vehicle and driving scenarios.