BRAKE Warning Light - BMW 3-Series (E90 E92) Forum

sle39lvr · 02-23-2013, 12:29 AM

I replaced my brake pads and rotors. However I did not replace the brake sensors. Brakes were worn out but didn't have any brake warning lights on prior to the replacement.

After the replacement, I didn't get any lights on till reset the CBS system. Used the directions posted here. Soon as I did the reset for the front, I got the "BRAKE" light on.

Is this because I didn't replace the sensors?

idrift4wd · 02-23-2013, 02:00 AM

Replace Your Sensors....

Crewchief05 · 02-23-2013, 02:09 AM

I thought the sensors were the yellow light?

sle39lvr · 02-23-2013, 02:12 AM

Quote:

Originally Posted by idrift4wd

Replace Your Sensors....

I guess that's what I have left to do. Sensors could be replaced without taking apart the calipers? Can I just pull them out?

idrift4wd · 02-23-2013, 02:35 AM

Quote:

Originally Posted by sle39lvr

I guess that's what I have left to do. Sensors could be replaced without taking apart the calipers? Can I just pull them out?

yup! just pull off and push on. fronts are easy just follow to the black box open and replace. the rears are a bit tougher as you will need to unscrew 4-6 8mm bolts to undo the wheel well lining. because the case is behind it. just follow sensors and route them back to exactly where they were before. reset and enjoy no more brake light. process shouldnt take more then 30 minutes as lifting the car and taking off wheel might take the longest.

sle39lvr · 02-23-2013, 11:51 AM

Thanks for the replies. I ordered two new sensors. Meanwhile, I head if you cut the sensor head out and tape the ends, the light should go away.

idrift4wd · 02-23-2013, 12:17 PM

Quote:

Originally Posted by sle39lvr

Thanks for the replies. I ordered two new sensors. Meanwhile, I head if you cut the sensor head out and tape the ends, the light should go away.

yeah, you can also not connect the sensor to pad at all and tuck it away. never get the light again, but you'll have to manually check. which i dont recommend.

sle39lvr · 02-23-2013, 12:43 PM

Quote:

Originally Posted by idrift4wd

yeah, you can also not connect the sensor to pad at all and tuck it away. never get the light again, but you'll have to manually check. which i dont recommend.

But what exactly causing the computer to make the BRAKE light go on then? How does the computer know if its a new sensor (for it to turn it back off)?

VTECaddict · 02-23-2013, 01:32 PM

The sensor works by wearing out fine wires to increase resistance. More resistance means its more worn.

The car expects minimal resistance (new sensor) when you reset it. If it detects a worn sensor when you reset, it will throw out the red service warnings.

sle39lvr · 02-23-2013, 01:47 PM

Quote:

Originally Posted by VTECaddict

The sensor works by wearing out fine wires to increase resistance. More resistance means its more worn.

The car expects minimal resistance (new sensor) when you reset it. If it detects a worn sensor when you reset, it will throw out the red service warnings.

Nicely explained!

sle39lvr · 02-28-2013, 12:20 PM

I cut the wire to each sensor. Taped the edges. Reset the computer again, NO LUCK! Light still stays on.

02-23-2013, 12:29 AM	#1
sle39lvr First Lieutenant Drives: 08 328i Join Date: Aug 2011 Location: United States Posts: 351 iTrader: (2)	BRAKE Warning Light I replaced my brake pads and rotors. However I did not replace the brake sensors. Brakes were worn out but didn't have any brake warning lights on prior to the replacement. After the replacement, I didn't get any lights on till reset the CBS system. Used the directions posted here. Soon as I did the reset for the front, I got the "BRAKE" light on. Is this because I didn't replace the sensors?
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02-23-2013, 01:32 PM	#9
VTECaddict Where'd my VTEC go? Drives: 06 330i 6MT Join Date: Mar 2009 Location: Orange County, CA Posts: 4,037 iTrader: (3)	The sensor works by wearing out fine wires to increase resistance. More resistance means its more worn. The car expects minimal resistance (new sensor) when you reset it. If it detects a worn sensor when you reset, it will throw out the red service warnings. __________________ AW/Terra \| ZSP \| ZPP \| ZCW \| iDrive \| CA Mods: KW V2 \| OEM Blacklines \| M-tech rear \| custom dual exhaust \| M3 steering wheel \| BMW SSK \| ZHP shift knob \| BMW Performance rep spoiler Varrstoen ES1 19x9.5+20 Front, 19x11+25 rear

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02-23-2013, 02:00 AM	#2
idrift4wd Colonel Drives: Three Hundred and Thirty Five Join Date: Jul 2010 Location: Yonkers NY Posts: 2,510 iTrader: (0) Garage List 2007 BMW [3.25]	Replace Your Sensors....

02-23-2013, 02:09 AM	#3
Crewchief05 SBD Drives: 335i e90 Join Date: Dec 2012 Location: Arkansas Posts: 250 iTrader: (0) Garage List 08 335i [0.00]	I thought the sensors were the yellow light?

02-23-2013, 11:51 AM	#6
sle39lvr First Lieutenant Drives: 08 328i Join Date: Aug 2011 Location: United States Posts: 351 iTrader: (2)	Thanks for the replies. I ordered two new sensors. Meanwhile, I head if you cut the sensor head out and tape the ends, the light should go away.

02-28-2013, 12:20 PM	#11
sle39lvr First Lieutenant Drives: 08 328i Join Date: Aug 2011 Location: United States Posts: 351 iTrader: (2)	I cut the wire to each sensor. Taped the edges. Reset the computer again, NO LUCK! Light still stays on.