General E46 Forum
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|11-28-2007, 05:33 PM||#1|
Join Date: Mar 2005
My Ride: 2007 335 CIC
Wheel speed sensor
2001 325 cic
120,000 + miles
I had some issues with my car starting last week which appeared to be fuel which I believe it was and adding fuel it did start, but when I got the car running the speedometer, mpg gauge and cruise control will not work. My fuel gauge is at a 1/4 tank and at times will go to empty (with reserve light on) back to a 1/4 tank in a matter of a few seconds. On top of that my ABS, DSC, Brake and service engine soon lights all are on. I took it to Auto Zone and the code check showed a speed sensor malfunction.
Is this something easy to repair and how do I tell which one it is?
If I do have to take it in can anyone recommend a good private mechanic in the Washington DC/ Maryland area other then VOB$$$$$$$ dealership?
Thanks for everyones help the last time.
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|11-29-2007, 11:08 AM||#2|
Join Date: Aug 2003
My Ride: 2001330Ci
The sensors are accessible from the back side of the wheels. Each is held in by a single allen head bolt. The hard part is getting the sensor out after removing the bolt. But, before trying to remove one or all sensors, use a ohm meter to check the resistance of each sensor. The bad one will be either open (infinite resistance) or a short (no resistance). Each sensor's wiring connector attaches to the chassis wiring harness in a little black box in the wheel well. Open the box, disconnect the sensor's connector and check the resistance. The bad sensor's reading will be significantly different that the other three.
Also, how old is your battery? From the symptoms you provided you may have a battery that's about to go out. BMW electronic systems are notorious for being sensitive to low voltages.
|08-12-2008, 12:39 PM||#4|
Join Date: Feb 2008
Location: Columbus, OHIO USA
My Ride: 2001 330i
what about cleaning the sensors? is that a good idea? how is that done?
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- David Rockefeller, Memoirs, page 405
|05-16-2010, 03:24 AM||#6|
Join Date: Jun 2009
Location: Dubai / UAE
My Ride: BMW 330i 2001
Hoop you are all fine,
Today I had a problem with my car (330i 2001) I was driving in normal speed 80 km and every thing was ok and I switched On the lights the I founded that the speedometer is crossing 120 to the maximum of the meter but my speed is less than 80kmh, can you please advice why the meter is reading more than my actual speed and what I have to do to check it , please advice ,
|08-17-2011, 07:33 AM||#8|
Join Date: Aug 2011
Location: North andover, MA
My Ride: 330i
Brake and DSC lights coming on occasionally on 2003 330i
I am also having the problem where the brake and DSC warning lights are
coming on occasionally. Once they come on I can turn the ignition off and
then start the car again these lights will go off. Last week though they came
on and no matter what I did they stayed on and lasted like that for a whole
week. When these lights come on everything else in the car like the
speedometer, cruise control still continues to work. This weekend I decided to
take a look at all four speed sensors. Jacked up the car and once you remove
the wheel from the car you can readily see the black colored speed sensor
cable. At one end of the cable you will find the sensor attached to the wheel
shaft with a 5mm hex screw. The other end of the cable ends up at a black
box underneath the body close by the jack attachment location.
Removing the hex screw was somewhat difficult, you can spray some WD40 on and near the screw head for an hour or so to let it soak before you start.
Also make sure the hex wrench is all the way into the screw head or you could end up stripping the head if not careful. Try to go back and forth like unscrew two turns and back one turn to get the screw to loosen up.
What I found was that all four speed sensors were a little dirty but nothing
that should have prevented them from doing their proper function. I cleaned
them up good anyway. Something else that I found is interesting, you should
be able to see the toothed pattern on the rear wheels the speed sensor
uses to measure the speed and they should be nice and clean for proper functionality. On the front wheels however you cannot see these toothed
pattern but you can poke your pinky finger (if it is small enough) through
the hole and "feel" the toothed pattern as you spin the rotor.
When I removed my finger from the hole I found my finger with a black
greasy residue. I had to use three Qtip (both ends) before they were coming out clean. Make sure you spin the Qtip as you spin the rotor to get the most
use out of the Qtip. I am pretty sure this black greasy residue was
preventing the speed sensor from properly registering the speed (RPM).
The car is now back to normal with over 100 miles since the cleaning job and
no more intermittent brake or DSC showing up. So cleaning just the sensor
may not correct your problem completely, also clean the toothed pattern on
the shaft as well if you find them dirty. Luckily on my car the dirty pattern was on a front wheel where I was able to rotate the rotor to clean it. If the
rear wheel pattern was dirty it would be much more difficult to rotate the
shaft. I have taken some pictures of the looks and location of these sensors
on a 2003 330i and hope you will find them helpful.
lights coming on
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