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Old 09-17-2010, 06:59 PM
jeffstri jeffstri is offline
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Location: CT
 
Join Date: Sep 2010
Posts: 45
Mein Auto: 740il
This is my first post here. I apologize for it's length and I hope it's taken in the spirit intended (intended to be helpful).

I have a '01 e38 (740il) which has the same ABS/DSC system that many of your e39s have (DSC5.7). I found this thread searching for some insight into my ABS problem: the dreaded brake light trifecta with fault codes that I haven't seen reported here (more about that another time.)

I've perused the entire thread twice and one observation I'd like to make is that there seems to be a misunderstanding of what fault codes mean and how they should be used. Fault codes are not intended to be diagnoses. Whatever scan tool you use, a fault code(s) rarely leads to a solution without more testing. I suspect that the misunderstanding comes in part from the way consumer scan tools such as the OBD scanners Autozone uses, the Peake tool, and Carsoft are marketed.

To give an analogy that's meaningful to me, given my healthcare background, a fault code is like an abnormal blood test result. For example, an abnormally increased white blood cell count (a "fault code") suggests an infection (although it could be caused by other things, and even be "normal"), but it doesn't tell you anything about the site of the infection (e.g., lungs, abdomen, etc) or the organism that has caused the infection, both of which are necessary to treat the infection properly. More information and tests are needed.

Similarly, a wheel sensor fault is not intended to mean that the sensor itself is defective and should be replaced without further testing. It means that the control unit (the DSC module) that monitors the sensor is reporting that it had faulty (or no) communication with the sensor. If the fault code text from a scan tool such as Carsoft is overly specific (e.g., the wiring is faulty), that's probably inaccurate and misleading, and not the same fault description that BMW would use .

The software a BMW dealer uses to read fault codes (INPA, GT1/DIS) also allows measurements (e.g., brake pressure) and activation of various components (e.g., ABS solenoids, pre-charge pump). DIS also provides diagnostic algorithms and tests for translating fault codes into a diagnoses. Modules can be calibrated, coded, and programmed with DIS, SSS/Progman and NCS Expert. WDS provides wiring diagrams, pictures of component locations, module pinouts, and electrical troubleshooting procedures.

INPA, DIS, SSS/Progman and NCS Expert can be be found on the internet, along with excellent instructions for installation and use (http://forums.bimmerforums.com/forum...play.php?f=233). All you need is a computer (preferably a laptop) and a diagnostic interface/cable set; I use an "INPA/Edaibas" set that I bought from China on ebay for about $35. WDS can be accessed directly online http://www.bmw-planet.com/diagrams/r...9new/index.htm)

All the above is a preamble to defending the process that agent15 went through and the likelihood that he has in fact solved his problem. What he did was entirely consistent to what is recommended in the WDS:



It's also important to note that reliance on the diode/resistance tests advocated in this thread would probably have indicated his wheel sensor was not the problem and may have led to unnecessary repair/replacement of his DSC module.

Last edited by jeffstri; 09-17-2010 at 07:15 PM.
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