user 69696969

I rotated the tires and of course my air pump blew up after putting air in the first tire. I know MB recommends 29 lbs in the front and 34 in the back. So I drove the car for a few days with 29 lbs in 3 out of 4 tires. The system alerted me via the ! tire signal and a text warning of impending doom. So I have now corrected the tire pressure to 29 fronts and 34 rears and although it no longer gives me the text warning, the signal light is still on.


Is this a reset issue? I have to reset the service indicator anyway, I am wondering if that process will also reset the tire warning or is there a separate process or separate issue?

marc hanna

There is a reset just for the TPMS in the instrument cluster. Just browse through the menus until you find it.

user 69696969

So I guess my next question is if that is normal? I other vehicles when I corrected the air pressure the light went off. I gave this one several days of my wife driving to and from work and its still on even though the other indicator shut off. I will reset both either way. thanks

marc hanna

It does recalibrate when it resets, so that might be why the light hasn't gone out.

user 69696969

reset it is. thanks

user 69696969

So today the tire pressure light came back on. It was pouring so I couldnt check the tire pressure. I am wondering if its marginal. It calls for 29 in the front and 34 in the back or 34 and 36 if fully loaded. So do people really change pressure if they load the car?

So when hot and cold the pressure goes up and down. Just how sensitive is the gauge?

josworth

Our 2006 doesn't have TPMS. But it does use vehicle sensors to sense if it is "leaning" and prompts you to check tires.

For reference, I keep ours at 34lbs year round and at all 4 wheels.

My Honda has TPMS, and with the first cold day, my tire warning went off. I had to add air to all 4 tires to get up to the 34lbs I run in that as well.

The door sticker BTW is cold pressure....

user 69696969

They seem fine. I am guessing 29 is the minimum for the sensor. If I filled with nitro maybe 29 will hold better. I am thinking I will just add a few to the fronts. This only started when I rotated the tires and put the pressure at 29 for the fronts. I am thinking the fronts were higher then 29 or my gauges are slighty off. The problem is I dont have a pump. I will fill it this week.

Thanks for the help

marc hanna

Also remember that the pressure gage you used when you filled your tires might not be that accurate. It's not uncommon for them to off by 5 psi or more. You may also have a slight air leak in the valve stem.

user 69696969

I said as much in the last post. The computer in the mb could also be off. I have 2 different gauges and when I filled the tires I used a gas station to fill and theirs was digital and equal to my gauge.

I just think the gauge is tripped at 28 ot 27 psi and being that its been cold and raining I may have set the gauge when it was 90 out or after driving. So 29 is probably not ideal without nitro. Which if you rotate and try and keep 29-34 would be a pain. Unless I was going to briing it to a pro or dealer everytime I rotate.

I think 34 around sounds good. Maybe 32 - 34.

marc hanna

Sorry, I obviously didn't read your post carefully. You're safe to give it a couple extra pounds in each tire. Then reset the runflat in the instrument cluster again.

marc hanna

. . . or if that still doesn't work, try putting a couple extra pounds in after you reset the indicator.

user 69696969

Thats the plan. I will take it up to the gas station when I go to Scouts tonight. I am going to start with 32 in the fronts and see if that cures it.

user 69696969

I am not sure where I got my info, but its not 29-34, its 30-34. So if I had 29 or 28 it was tripping the light. I am thinking I checked the door, but the numbers in the gas tank show 30. I stopped at the gas station and put some air in. Not sure how much because it was raining and dark. User error on this one.