Tire Pressure Monitoring System Questions
Thread Starter
MBWorld Fanatic!
Joined: Mar 2004
Posts: 5,017
Likes: 16
From: Ft. Lauderdale Area, USA
2015 ML 350
Tire Pressure Monitoring System Questions
My car has this option.
Where exactly are the "pressure sensing devices" located within the tire? Are they part of the metal valve stem? Or are they a device strapped around the hub of the wheel?
Why must they occaisionally be "reset" (Activated, to use the Manual's jargon)to read the tire pressures? Other than when you rotate wheels on a car to a different location I can't see any reason to reset them.
If you don't reset (activate) them, is the pressure displayed on the dash the current pressure or is it the tire pressure from when you last "activated" the TP system?
No Salesman or SA seem to have the answers...
Where exactly are the "pressure sensing devices" located within the tire? Are they part of the metal valve stem? Or are they a device strapped around the hub of the wheel?
Why must they occaisionally be "reset" (Activated, to use the Manual's jargon)to read the tire pressures? Other than when you rotate wheels on a car to a different location I can't see any reason to reset them.
If you don't reset (activate) them, is the pressure displayed on the dash the current pressure or is it the tire pressure from when you last "activated" the TP system?
No Salesman or SA seem to have the answers...
Member
Joined: Sep 2004
Posts: 85
Likes: 0
From: Bucks, PA
2003 E500 Sport, 2004 E500 Wagon
It is a sensor in or attached to the valve stem with the receiver anntenas in the wheel housing. Check out the "325 HO TPC" Training manual, you can find links to the manuals in other posts. It details everything including reasons for activation. I had to do an activation after resetting pressures in my wife's car. The dealer had delivered 4lbs high in the front and 6lbs high in the rear!
“Activation” Notes
Activation means:
– Clearing old tire pressure specifications from TPC memory
– Storing new tire pressure specification values for each wheel
Activation is performed when:
– setting a different inflation pressure base-line value
– cluster says to “Re-activate TPC”
– tires are rotated
– winter tires are mounted
– a wheel sensor has been replaced
– the TPC control module has been replaced
– a TPC fault code has been erased
Activation is initiated using steering wheel & ICM buttons and completed by driving
the vehicle
“Activation” Notes
Activation means:
– Clearing old tire pressure specifications from TPC memory
– Storing new tire pressure specification values for each wheel
Activation is performed when:
– setting a different inflation pressure base-line value
– cluster says to “Re-activate TPC”
– tires are rotated
– winter tires are mounted
– a wheel sensor has been replaced
– the TPC control module has been replaced
– a TPC fault code has been erased
Activation is initiated using steering wheel & ICM buttons and completed by driving
the vehicle
Senior Member
Joined: Jan 2002
Posts: 429
Likes: 1
From: New York Area
'14 E350 wagon; BMW G12 (2020) G01 (2019)
I tend to adjust my tire pressure a couple of times a year -- when the weather turns dramatically colder or warmer, as that affects the cold tire pressure. Then I reset the sensors too. Also if you rotate your tires, the sensors should be reset. As noted in the earlier post, the sensor is part of the valve stem assembly. I have an extra wheel and tire (too long a story) and I was able to get a pressure sensor from Tire Rack for the extra wheel.
Thread Starter
MBWorld Fanatic!
Joined: Mar 2004
Posts: 5,017
Likes: 16
From: Ft. Lauderdale Area, USA
2015 ML 350
Originally Posted by Benz-E-r
It is a sensor in or attached to the valve stem with the receiver anntenas in the wheel housing. Check out the "325 HO TPC" Training manual, you can find links to the manuals in other posts. It details everything including reasons for activation. I had to do an activation after resetting pressures in my wife's car. The dealer had delivered 4lbs high in the front and 6lbs high in the rear!
“Activation” Notes
Activation means:
– Clearing old tire pressure specifications from TPC memory
– Storing new tire pressure specification values for each wheel
Activation is performed when:
– setting a different inflation pressure base-line value
– cluster says to “Re-activate TPC”
– tires are rotated
– winter tires are mounted
– a wheel sensor has been replaced
– the TPC control module has been replaced
– a TPC fault code has been erased
Activation is initiated using steering wheel & ICM buttons and completed by driving
the vehicle
“Activation” Notes
Activation means:
– Clearing old tire pressure specifications from TPC memory
– Storing new tire pressure specification values for each wheel
Activation is performed when:
– setting a different inflation pressure base-line value
– cluster says to “Re-activate TPC”
– tires are rotated
– winter tires are mounted
– a wheel sensor has been replaced
– the TPC control module has been replaced
– a TPC fault code has been erased
Activation is initiated using steering wheel & ICM buttons and completed by driving
the vehicle
I have noticed that sometimes it takes less time/milage to re-set after re-activation. I can't figure out how it knows when enough is enough... but oh well, Its working properly because the dash display did turn all red one day when I picked up a screw.
Thanks !!
Last edited by Barry45RPM; Feb 10, 2006 at 05:29 PM.
