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BMW – ABS / ASC / DSC Warning Light and Inoperative Speedometer – E39 5-series 528i 540i etc

May 27, 2010

Q
car year: 1999
car model: 528i Wagon
I JUST REPLACED MY REAR BRAKE PADS AND ROTORS. PRIOR TO DOING THAT I HAD ALL SORTS OF WARNING LIGHTS ON THE DASH. THE COMPUTER SAID FAULTY SPEED SENSOR. THE SPEEDO ACTED UP JUST PRIOR TO THE BRAKE JOB. I REPLACED BOTH REAR SPEED SENSORS. THE COMPUTER IS STILL TELLING ME THAT THE RIGHT SENSOR IS FAULTY. I ALSO HAVE ALL THE DASH WARNING LIGHTS STILL ON. WHAT DO I CHECK NEXT ON THE RIGHT SIDE? SHOULD I REPLACE THE FRONT SENSORS OUT OF PRICIPLE. FRONT PADS AND ROTORS WERE REPLACED LAST FALL. I WOULD LOVE TO GET THE ABS AND TRACTION CONTROLL BACK WORKING.

A
Let’s see if I understand correctly; You have the ABS and the traction control (ASC / DSC/ ASC+T, etc) lights on and you have replaced both rear ABS wheel speed sensors (correct?). Additionally, the speedometer was not functioning. Since you did not mention that the speedometer is still not functioning, after replacing both rear sensors, I will assume that replacing the rear sensors did cure the speedometer fault (?). On the E39 chassis (5-series 97-03) , the left-rear wheel speed sensor feeds the speedometer. Therefore, if the speedometer is working, the left rear sensor should be OK.

What type of tool are you using that will read the ABS fault codes?  And, you are saying that the code still reads as the right-rear sensor?

Click below for ABS sensors:

8 Comments
  1. Gordon replied:

    THANK YOU FOR THE RESPONSE. I AM NOT SURE WHAT TYPE OF DEVISE IS BEING USED TO READ THE CODES. I HAD THE WORK DONE AT A LOCAL SERVICE SHOP THAT WORKS ON BMW. THEY SAID THAT “THE COMPUTER” WAS SHOWING THAT THE RIGHT REAR SENSOR WAS STILL BAD. TIME PERMITTING, THEY WERE GOING TO TRY TO TRACE THE WIRES FROM THE REAR TO THE CONTROL? DEVICE IN THE FRONT. I HAVE FORGOTTEN WHAT THEY CALLED THE DEVICE IN THE FRONT.

    SINCE I CONTACTED YOU, THE WARNING LIGHTS HAVE GONE OFF AND BACK ON SEVERAL TIMES ONLY LEAVING THE CHECK ENGINE LIGHT ON. I HAVE A SIMPLE TESTER TO SEE WHAT THE ENGINE LIGHT IS SAYING BUT AT THE MOMENT I DO NOT HAVE IT AS I LOANED IT OUT. AT THE MOMENT THE WARNING LIGHTS ARE OUT. A SHORT?

    • If the fault code is being read properly and is indeed saying that the right rear sensor is at fault, and it has been replaced, the next stage would be to check the wiring through the chassis, for that sensor. The ABS control unit is the heart and control of the ABS and traction control systems. Before replacing any wires, you should inspect the wiring from the sensor plug and also check the toothed gear-wheel that is on the end of the axle. This is what the sensor reads as the wheel turns. Additionally, it is possible that you have a faulty new sensor at the right rear. If you swap the left and right rear sensors and the fault still comes up for the right side, then the wiring or the toothed wheel are likely at fault. If the fault changes to the left side, then the sensor is at fault (and the speedometer would likely not work). I’ll also ask the obvious here ….. Are the warning lights still on and is the technician clearing the fault codes after each attempt at repair?

      The CHECK ENGINE light will not have anything to do with the ABS system. If the CHECK ENGINE light is coming on, there is a fault code being stored in the engine management system. You can use your code reader tool for this.

  2. BeachGal permalink

    I’m experencing the same brake ABS/speedometer and cruise control doesn’t work either in a 1998 BMW 528i. If I lived nearby, I’d bring it to Otto’s shop. But, I am in need of a good recommendation of a place to take my car to for the repair. Anyone have any recommendations for a BMW shop in the NJ Shore area?

    • We do not have a specific shop recommendation for you, but it is likely that the left rear wheel speed sensor is faulty (since the speedometer and cruise control do not work).

  3. Nilson DeJesus permalink

    Hi, im having a similar problem, my 98 540i has the DSC light on (triangle on dash) the tranny is in limp mode and the speedometer goes up to 20 only, replaced the battery cause it needed, i even replaced the speed sensor unit (the one under drivers seat that controls speedometer and DSC) also swaped the abs sensors to make sure wasnt that, i read alot problem with the abs module, but most of them have the brake light and DSC light on, on mine its only the yellow triangle on, no speedo and tranny on limp mode. I have the bmw compatible scanner 1.3.6 i will try to get the codes. Please help me out

    • At this point, I would say that you do need to read the fault codes for the ABS/DSC system. It’s likely that the fault is in the control unit, but before replacing it, you should see what the fault codes are.

  4. Sean Ferrin permalink

    I just experienced my Speedo dying on my 03 525i, but I do not have the ABS or DSC light on, just a dead speedo. Would that also be the left rear wheel speed sensor?

    • If the left-rear wheel speed sensor were faulty, you would also have an ABS fault warning. Since you do not have the ABS warning, we would think that your speedometer fault may be within the instrument cluster. We do not have any specific DIY diagnostics that you can apply in order to make a determination on a fault within the cluster.

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