PrestonXavier

Hey guys - Looking for some help as recently my tire pressure notification has been advising that the pressures are too high. I've never added or removed air since purchasing the car but somehow it goes up to 39 and even 40 psi after driving. I took out some air yesterday and the pressure now goes up to 36 psi but is at 30 psi when its cold.

Any idea whats going on?

alexasa

iTrader: (1)

tire pressure will raise with heat in the tire. So when you cold start it should be lower and as you drive it should raise up and then may fluctuate 1 PSI up or down while at temp.

that's not enough air for the OEM 19's, IMO.

mo11

it was most likely reset and activated with low air pressures.... and air was added without resetting the values. Try letting the car cool down. Put some air, with a tire pressure gauge, use the stock values on the gas cap cover depending on how much load you normally drive with. Reset and activate the monitoring system. If it still shows an error after, go back to the dealership.

'Hope this helps!

Bibenstein

The recommended tire gauge pressure is shown on the sill inside the driver's door. My C450 recommends 40 psig cold. Of course, tires can expand/contract depending on weather and use so it's not unusual to see the pressure rise or fall.

I have seen my tires run up to 45 - 46 psig at highway speeds in hot weather, good tires are designed to take that.

Gungaslow

Actually the tire pressure is listed on the inside of the fuel door.. the max inflation is listed on the driver door..

Extreme Dimensions

That makes sense, if you are in a desert where climate change is extreme from day to night, a few PSI change would occur.

PrestonXavier

the issue is that the car keeps throwing off signs to check the tire pressure. That cant be normal.

AMG_FVR

After you set your tires you have to reset the tire pressure monitor system through the menu.

alexasa

iTrader: (1)

If you do this and still have problems, then you actually have problems.

At that road, go to your dealer.

Vipershade

For even wear (unloaded) on 19" wheels, your pressures should be in the 38-40 range for fronts and 30-32 rears... which is slightly off the three person R19 guide numbers (front 36 and rear 32).

DeusExMachina

It happened to me as well. Easy fix: go to any gas station or shop and make sure the psi is right. Then, reset and load the new readings as default. Worked for me. My readings went crazy when I had the car impounded for excessive speed. The ****ers lifted it on a ramp but when unloading they dropped it a little bit heavy

z28lt1

I will say, the Tire Pressure warning system on this car does seem to have issues. I've had multiple occasions where the pressure warning comes on, because one tire dropped a single PSI, and then it remains on no matter what happened to the pressures (I fill, they go up because of temperature, etc.)

Been driving me crazy. However, as noted, the fix is to set the temperatures properly (cold) and then reset the system on the information display. Unfortunately, I seem to have to do this several times a year.