Do I have a failing wheel speed sensor?

surge98 · 02-04-2020, 08:27 AM

I have a 2010 128i with almost 100,000 miles. I've started to see the dynamic stability control symbol (yellow !) flash during normal driving on dry, smooth road surfaces. It seems to happen mostly on side streets and while driving at lower speeds, it's not unusual to see it flash four or five times in the course of two miles of city driving. I don't feel anything happening when the light flashes, and the car is not throwing any fault codes. My best guess is that one of my wheel speed sensors is on the way out. Is there anything else that could be causing this, and is there any point in having it looked at until it starts throwing a code? Thanks.

dtla1 · 02-04-2020, 11:49 AM

Have you ever had the battery replaced?
Sometimes weird error codes/lights happen with a dying/dead battery.

surge98 · 02-04-2020, 11:53 AM

Quote:

Originally Posted by dtla1

Have you ever had the battery replaced?
Sometimes weird error codes/lights happen with a dying/dead battery.

Yes, the battery was replaced at a dealership one year ago.

dtla1 · 02-04-2020, 01:48 PM

Then it's likely it may be a wheel speed sensor. Any chance you have something to read the error codes off the car?

Also, wheel speed sensors are relatively cheap and easy to install FYI.
You could try cleaning it/the area around as an easy step as well.

Ric in RVA · 02-04-2020, 01:58 PM

Pull and clean.

Clean sensor tip and trigger wheel as well.

Very easy to replace.

Mine have always been rears that failed.

surge98 · 02-04-2020, 02:02 PM

I have a Foxwell NT510, but the car is not currently throwing any fault codes. I've only used the NT510 to read codes, I'm not very familiar with the live data capabilities. I'm not sure if that would show me which sensor is activating the stability control.

m_thompson · 02-05-2020, 07:27 AM

Mine did the same thing. It did have a code that said the left rear sensor was intermittent. Without a code you won't know which sensor is causing the trouble.

The tone wheel on the axle was rusty and the end of the sensor had an accumulation of rust. I cleaned the tone wheel and the end of the sensor, and put a 1mm washer under the sensor so it would not hit the tone wheel. It had been working OK for about 6 months.

1mang · 02-24-2020, 02:41 PM

I have a similar issue but only when taking certain tight/angular corners at a fast pace. I have brake light, traction control light, and ABS light all turn on yellow. After driving normal or on a straight line for awhile, eventually those lights turn off. The code is stored in the ECU but will not throw a check engine light. It turns out its my driver side wheel speed sensor when I run via Carly app. Eventually I'll replace the sensor since its most likely failing.

surge98 · 02-25-2020, 07:34 AM

I thought I'd update this, just in case someone has the same issue in the future. After a month of the DSC randomly activating during normal driving, the ABS and DSC lights finally went on. It happened when the cruise control was on, it would shut off on its own and I would turn it back on. After the third time it shut off, the lights came on immediately. They turned off the next time I started the car and didn't come back on.

Fortunately, I pulled the codes while the ABS light was still on and got P1505 and P15C9. P1505 is for the idle air control, which this car doesn't have. I assume it's just a nonsense code triggered by the wheel speed sensor. P15C9 is the right rear sensor. I replaced it a week ago and the problem has not come back.

One more thing I should mention for owners of manual transmission cars, a bad wheel speed sensor will deactivate your start off assistant feature, so the car will roll backwards when starting off on a hill. After 10 years of driving this car, it's easy to get lazy with your starts and forget what it was like to drive a manual without this feature. So be careful not to roll backwards at an inopportune time.

m_thompson · 02-25-2020, 07:35 AM

Quote:

Originally Posted by 1mang

Eventually I'll replace the sensor since its most likely failing.

Maybe not. You could have rust on the sensor and tone ring.

1mang · 03-04-2020, 02:02 PM

Quote:

Originally Posted by m_thompson

Maybe not. You could have rust on the sensor and tone ring.

I haven't had a chance to clean it yet but are you still on the original? I notice you are on 2009 model.

m_thompson · 03-05-2020, 07:28 AM

Quote:

Originally Posted by 1mang

I haven't had a chance to clean it yet but are you still on the original? I notice you are on 2009 model.

All of the sensors are original. The left rear had rust particles on it from the tone ring, and showed scrapes where the rusty tone ring touched the sensor. I cleaned the rust from the tone ring and coated it with a rust preventative. I put a small washer over the mounting screw to space it away from the tone ring. It has been code free for many months.

1mang · 04-10-2020, 05:01 PM

Quote:

Originally Posted by m_thompson

All of the sensors are original. The left rear had rust particles on it from the tone ring, and showed scrapes where the rusty tone ring touched the sensor. I cleaned the rust from the tone ring and coated it with a rust preventative. I put a small washer over the mounting screw to space it away from the tone ring. It has been code free for many months.

I have the trifecta lights on consistently now. I did change my brake lines, CDV delete, and brake reservoir. I bleed clutch using a pressure bleeder and then brakes using speed bleeder valves. I also inspected and cleaned the rear driver and passenger side speed sensors. They had some gunk on it but everything looks in order.

The car drives fine. Nothing unusual aside from those lights and no traction control and ABS. I checked all ABS/DSC fuses and they were fine. I also unplug and plugged the ABS module from this youtube video (

). This worked for a little bit where the lights would turn off. Then during same driving session, it would come back again and stay on.

The code via Carly remains the same at 005DA0. This is "speed sensor, rear electronically defective / speed sensor front electronically defective right..."
I ordered replacement parts from FCP Euro so hopefully this would fix it. I really do not want to deal with ABS module....

1mang · 04-13-2020, 11:15 AM

Problem fixed. It was the sensors after all. Replaced rear driver side and front passenger side. The lights went out and did not come back after a long drive. Traction control kicks in as normal now.

02-04-2020, 08:27 AM	#1
surge98 Private 37 Rep 65 Posts Drives: 2021 BMW m240i Join Date: Aug 2019 Location: Pittsburgh, PA iTrader: (0)	Do I have a failing wheel speed sensor? I have a 2010 128i with almost 100,000 miles. I've started to see the dynamic stability control symbol (yellow !) flash during normal driving on dry, smooth road surfaces. It seems to happen mostly on side streets and while driving at lower speeds, it's not unusual to see it flash four or five times in the course of two miles of city driving. I don't feel anything happening when the light flashes, and the car is not throwing any fault codes. My best guess is that one of my wheel speed sensors is on the way out. Is there anything else that could be causing this, and is there any point in having it looked at until it starts throwing a code? Thanks.
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02-04-2020, 11:49 AM	#2
dtla1 Colonel 828 Rep 2,232 Posts Drives: 2011 135i, Space Grey Join Date: Apr 2014 Location: Silicon Valley iTrader: (2)	Have you ever had the battery replaced? Sometimes weird error codes/lights happen with a dying/dead battery.
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02-04-2020, 01:48 PM	#4
dtla1 Colonel 828 Rep 2,232 Posts Drives: 2011 135i, Space Grey Join Date: Apr 2014 Location: Silicon Valley iTrader: (2)	Then it's likely it may be a wheel speed sensor. Any chance you have something to read the error codes off the car? Also, wheel speed sensors are relatively cheap and easy to install FYI. You could try cleaning it/the area around as an easy step as well.
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02-04-2020, 01:58 PM	#5
Ric in RVA Bergspyder 1466 Rep 1,212 Posts Drives: '11 BMW 128i Sport 6mt Join Date: Oct 2015 Location: Richmond VA iTrader: (1)	Pull and clean. Clean sensor tip and trigger wheel as well. Very easy to replace. Mine have always been rears that failed. __________________ Ric in RVA 2011 128i 6 MT Sport, 2009 Cayman 987.2, 2011 528i N52, 2018 F150 Platinum
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02-04-2020, 02:02 PM	#6
surge98 Private 37 Rep 65 Posts Drives: 2021 BMW m240i Join Date: Aug 2019 Location: Pittsburgh, PA iTrader: (0)	I have a Foxwell NT510, but the car is not currently throwing any fault codes. I've only used the NT510 to read codes, I'm not very familiar with the live data capabilities. I'm not sure if that would show me which sensor is activating the stability control.
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02-05-2020, 07:27 AM	#7
m_thompson Major 133 Rep 1,416 Posts Drives: M-Sport 128i, 328xi, 3.0CS Join Date: Jun 2008 Location: New England, USA iTrader: (0) Garage List 2009 128i [0.00] 1972 3.0CS [10.00]	Mine did the same thing. It did have a code that said the left rear sensor was intermittent. Without a code you won't know which sensor is causing the trouble. The tone wheel on the axle was rusty and the end of the sensor had an accumulation of rust. I cleaned the tone wheel and the end of the sensor, and put a 1mm washer under the sensor so it would not hit the tone wheel. It had been working OK for about 6 months. __________________ '09 128i - Black Sapphire Metallic\Coral Red\Glacier Silver\N51 DISA\6MT\Navigation\Premium\M-Sport\Heated seats\Xenon\Headlights\iPod\Smartphone\Euro Delivery
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02-24-2020, 02:41 PM	#8
1mang Private First Class 36 Rep 127 Posts Drives: 135i Join Date: Jun 2014 Location: Bay Area, CA iTrader: (0)	I have a similar issue but only when taking certain tight/angular corners at a fast pace. I have brake light, traction control light, and ABS light all turn on yellow. After driving normal or on a straight line for awhile, eventually those lights turn off. The code is stored in the ECU but will not throw a check engine light. It turns out its my driver side wheel speed sensor when I run via Carly app. Eventually I'll replace the sensor since its most likely failing.
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02-25-2020, 07:34 AM	#9
surge98 Private 37 Rep 65 Posts Drives: 2021 BMW m240i Join Date: Aug 2019 Location: Pittsburgh, PA iTrader: (0)	I thought I'd update this, just in case someone has the same issue in the future. After a month of the DSC randomly activating during normal driving, the ABS and DSC lights finally went on. It happened when the cruise control was on, it would shut off on its own and I would turn it back on. After the third time it shut off, the lights came on immediately. They turned off the next time I started the car and didn't come back on. Fortunately, I pulled the codes while the ABS light was still on and got P1505 and P15C9. P1505 is for the idle air control, which this car doesn't have. I assume it's just a nonsense code triggered by the wheel speed sensor. P15C9 is the right rear sensor. I replaced it a week ago and the problem has not come back. One more thing I should mention for owners of manual transmission cars, a bad wheel speed sensor will deactivate your start off assistant feature, so the car will roll backwards when starting off on a hill. After 10 years of driving this car, it's easy to get lazy with your starts and forget what it was like to drive a manual without this feature. So be careful not to roll backwards at an inopportune time.
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04-13-2020, 11:15 AM	#14
1mang Private First Class 36 Rep 127 Posts Drives: 135i Join Date: Jun 2014 Location: Bay Area, CA iTrader: (0)	Problem fixed. It was the sensors after all. Replaced rear driver side and front passenger side. The lights went out and did not come back after a long drive. Traction control kicks in as normal now.
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