Brake change sensor

drvai · 04-01-2009, 03:33 PM

How does the computer in the car tell how much brake pads are left.

I have 7k miles and tells me it still has 20k to go.

How reliable is this? I don´t want to be overdue and destroy my rotors.

lucid · 04-01-2009, 07:17 PM

It is most likely using accelerometer data to estimate pad wear. If you wear your pads beyond their operational threshold, a second system will be triggered--the physical pad wear sensor--and the red "brake" light that comes on when you turn on the ignition will not go away after your start the car. There is no reason to be concerned since you will get a warning either way before you reach some kind of critical state.

Big Windy · 04-01-2009, 07:31 PM

Quote:

Originally Posted by lucid

It is most likely using accelerometer data to estimate pad wear. If you wear your pads beyond their operational threshold, a second system will be triggered--the physical pad wear sensor--and the red "brake" light that comes on when you turn on the ignition will not go away after your start the car. There is no reason to be concerned since you will get a warning either way before you reach some kind of critical state.

a bit OT, but have you ever noticed that the "brake" light initially comes on as yellow, then switches to red? i wonder if there is some type of brake diagnostic that occurs at startup. anyone???

lucid · 04-01-2009, 07:49 PM

Quote:

Originally Posted by Big Windy

a bit OT, but have you ever noticed that the "brake" light initially comes on as yellow, then switches to red? i wonder if there is some type of brake diagnostic that occurs at startup. anyone???

maybe fluid pressure? i don't know...

Big Windy · 04-01-2009, 07:57 PM

Quote:

Originally Posted by lucid

maybe fluid pressure? i don't know...

south will know!

lucid · 04-01-2009, 08:31 PM

Quote:

Originally Posted by Big Windy

south will know!

yes, south to the rescue!!!

JJM335 · 04-01-2009, 08:39 PM

There is a wear sensor on both front and the passenger rear brake callipers. It is a simple fuse-like device that breaks when the pad is worn causing the warning light. The mileage in the BC is just an estimate.

04-01-2009, 03:33 PM	#1
drvai Major 135 Rep 1,274 Posts Drives: E92 M3 AW Join Date: Dec 2007 Location: FL iTrader: (0)	Brake change sensor How does the computer in the car tell how much brake pads are left. I have 7k miles and tells me it still has 20k to go. How reliable is this? I don´t want to be overdue and destroy my rotors.
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04-01-2009, 07:17 PM	#2
lucid Major General 374 Rep 8,033 Posts Drives: E30 M3; Expedition Join Date: Apr 2007 Location: USA iTrader: (0)	It is most likely using accelerometer data to estimate pad wear. If you wear your pads beyond their operational threshold, a second system will be triggered--the physical pad wear sensor--and the red "brake" light that comes on when you turn on the ignition will not go away after your start the car. There is no reason to be concerned since you will get a warning either way before you reach some kind of critical state. __________________
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04-01-2009, 08:39 PM	#7
JJM335 Second Lieutenant 7 Rep 229 Posts Drives: 2008 E92 M3 Join Date: May 2007 Location: GA iTrader: (0) Garage List 2008 E92 M3 [0.00]	There is a wear sensor on both front and the passenger rear brake callipers. It is a simple fuse-like device that breaks when the pad is worn causing the warning light. The mileage in the BC is just an estimate.
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