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  • DSC light has come on and remains on

    Just got back from getting a MOT for my MC and on the way back the DSC light came on of its own accord. Pressing the DSC switch doesn't do anything. Restarting the engine doesn't knock the DSC light off and neither does removing the DSC/ABS fuses or disconnecting the battery for a while.

    I suspect a wheel speed sensor might be the problem so I'll take a look at those as the first stage.

    Has anyone else had this problem and what was the fix?
    /// Exdos ///
    "Men who try the impossible and fail spectacularly are infinitely superior to those who reach for nothing and succeed" --Napoleon Bonapart

  • #2
    Hi! Yes I would look at ABS sensor too if it has been stood for a while as they are major input for the system BUT is the ABS light not on also? If there is a sensor fault then that should trigger too.

    Other potential reason is steering sensor?

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    • #3
      Originally posted by c_w View Post
      Hi! Yes I would look at ABS sensor too if it has been stood for a while as they are major input for the system BUT is the ABS light not on also? If there is a sensor fault then that should trigger too.

      Other potential reason is steering sensor?
      Hi Chris,

      Only the DSC light comes on permanently with no other warning lights. The car drives fine and shows no signs of triggering braking or cutting engine power. It's as if I'd switched the DSC off.

      I've just been watching a few Youtube vids on the BMW ABS sensors and it looks easy enough to examine them, so I'll check them all tomorrow as my starting point.

      Thanks for your help.
      /// Exdos ///
      "Men who try the impossible and fail spectacularly are infinitely superior to those who reach for nothing and succeed" --Napoleon Bonapart

      Comment


      • #4
        Worth a quick look;

        https://www.z3mcoupe.com/forum/showt...Steering+angle

        Comment


        • #5
          Originally posted by Jon_Bmw View Post
          Jon,

          Thanks for that. I've got a datalogger/scanner that works with the OBD socket under the steering wheel, but I'm afraid it doesn't read chassis codes, so I'm working a bit in the dark without taking the car to a garage.

          Where is the steering angle sensor located? I'll take a look at that.
          /// Exdos ///
          "Men who try the impossible and fail spectacularly are infinitely superior to those who reach for nothing and succeed" --Napoleon Bonapart

          Comment


          • #6
            Unfortunately the OBD2 port in the passenger compartment is mainly useless! My car is a March 2002 build and it has very limited functionality.

            I have a b cables scanner(eBay) but I haven't actually used that on the coupe yet. You would need the round connector adapter. I used an autologic (expensive) from work using the round connector to reset the steering angle sensor. Remember mine was an intermittent fault that occurred after I removed 18" wheels and returned to 17" with spacers. I guess I threw the alignment very very slightly off with those changes.

            Because I did a reset of the dead ahead position I didn't have to swap sensors I never needed to find it. Logic would say it's on the steering column somewhere.

            As yours appears to be a hard fault it is possible it is one of the control units for the dsc.

            Comment


            • #7
              I've just been watching a couple of videos of steering angle sensors on different BMWs and one sensor required 8 hours labour because the whole dash and steering column needs to be removed, whilst the other just needed the airbag and steering wheel to be removed to access the part.

              I suppose it'll be easiest to put the car into my Indy and get the codes read so that the repair gets a direction from the outset rather than me messing about in the dark.

              In the past I have adjusted the geometry but never had the steering angle reset and driven plenty with it since.
              Last edited by exdos; 02-08-2018, 09:17 PM.
              /// Exdos ///
              "Men who try the impossible and fail spectacularly are infinitely superior to those who reach for nothing and succeed" --Napoleon Bonapart

              Comment


              • #8
                I think that is probably the best bet.

                From reading your previous posts you seem like someone who doesn't mind getting his hands dirty and getting involved in fixing stuff. If that is the case and you know how to use a laptop, then I would recommend this;

                https://www.ebay.co.uk/itm/BMW-Diagn...oAAOSw-3FZD4bI

                The software installation is pretty easy. My logic is that most places will charge you between £30-75 to do a code read for you. That has paid for the cable.

                I would say it gets a lot more complicated if you end up needed to code a new module. I nearly shit myself coding an airbag module on my 760, mainly due to worry of either the airbag going off in my face or the entire car not working again! But reading codes is fairly straight forward, and you have the ability to reset them if remedial work is required.

                Note - I bought the "silver" cable from eBay as this allows you to use it on post 2007 vehicles as well. Its another £15 I think?

                Comment


                • #9
                  I think from my previous research that the M versions of the Z3 only got the Teves MK 20 DSC III. If you have a quick look everything seems to point that after 09/2000 everything Z3/E46 based should be on MK 60, but I don't think it got carried over to the M coupes probably because of the low build numbers and the cost to change couldn't be justified.

                  Here is some information on the various different E46/Z3 traction control systems.

                  https://www.bimmerforums.com/forum/s...tandalone-info

                  (click number 9 of useful links)


                  It lists all of the control modules and sensors, unfortunately their locations will be wrong as it is based around an e46 I think.

                  Comment


                  • #10
                    Originally posted by Jon_Bmw View Post
                    I think that is probably the best bet.

                    From reading your previous posts you seem like someone who doesn't mind getting his hands dirty and getting involved in fixing stuff. If that is the case and you know how to use a laptop, then I would recommend this;

                    https://www.ebay.co.uk/itm/BMW-Diagn...oAAOSw-3FZD4bI

                    The software installation is pretty easy. My logic is that most places will charge you between £30-75 to do a code read for you. That has paid for the cable.

                    I would say it gets a lot more complicated if you end up needed to code a new module. I nearly shit myself coding an airbag module on my 760, mainly due to worry of either the airbag going off in my face or the entire car not working again! But reading codes is fairly straight forward, and you have the ability to reset them if remedial work is required.

                    Note - I bought the "silver" cable from eBay as this allows you to use it on post 2007 vehicles as well. Its another £15 I think?
                    Jon,

                    You're right, I quite enjoy a bit of spannering from time to time but you can have too much of a good thing!

                    My only problem with INPA is that I'm a Mac user and don't have a PC but I'll have to source an old laptop and get kitted out.

                    I've removed the left side wheel speed sensors, which both look OK and cleaned them up. The car's only done 36k miles and been garaged kept all its life so I don't really expect to find an obviously bad one.
                    /// Exdos ///
                    "Men who try the impossible and fail spectacularly are infinitely superior to those who reach for nothing and succeed" --Napoleon Bonapart

                    Comment


                    • #11
                      Yes I feel your pain, with a young child now my spanning/tinkering hours are severely limited! The enthusiasm is going.

                      A really quick check you can do with most ABS sensors is to check the resistance across them. You don't even need to remove the sensors, simply unplug them and stick an ohm meter across them. From memory you should be looking for about 0.8-1.2Kohms (google this as a electrics aren't really my thing!). If any are open circuit then they are dead.

                      I would be surprised if any were dead or else you ABS light would be on as well. I always start on the LHS of the vehicle as this side gets the crud off the side of the road flung at it.

                      Is the car dry stored as some Z3 owners suffer water ingress that ends up in the foot well where I think the YAW and acceleration sensors are. Given the weather we have had recently I doubt this is the issue either.

                      Comment


                      • #12
                        Problem is I'm getting old and crawling around on floors isn't as easy as it used to be and I maintain a few vehicles and a couple of go-karts so the novelty has long-since worn off!

                        I've had my MC since 2003 and used it loads in the first few years but I'm afraid because of low mileage S54 MCs increasing in value so much, it's become a garage queen and only done 400miles in the last 4 years. I've examined all the wheel sensors and they are in top shape. The car is immaculate and clean inside and out and is bone dry.

                        I now need to dig deeper. I've ordered a cable and INPA and I'll find a PC somewhere and my next move will be to run that.

                        Whilst researching the problem I came across this thread: https://www.e90post.com/forums/showthread.php?t=545976
                        The second post is interesting, so I've checked the ABS fuse box and found that my MC has exactly the same part number Blue Relay, so I'll probably give that a try after scanning the ECU. Another post in that thread says that the Porsche 944 had a similar DME relay issue. So perhaps that might prove to be the problem?
                        /// Exdos ///
                        "Men who try the impossible and fail spectacularly are infinitely superior to those who reach for nothing and succeed" --Napoleon Bonapart

                        Comment


                        • #13
                          If you don’t have the ABS light on it’s not going to be a faulty wheel speed sensor.
                          Your fault is within the DSC part of the system, steering angle, yaw sensor etc
                          If you have had the tacking done recently or someone has realigned the steering wheel the steering angle sensor needs recalibrating.
                          Personally I think your wasting your time guessing what the fault could be, & May cause more problems disturbing sensors that have been there for 15 years plus, it needs the memory reading with proper BMW software.

                          Comment


                          • #14
                            Originally posted by Walk View Post
                            If you don’t have the ABS light on it’s not going to be a faulty wheel speed sensor.
                            Your fault is within the DSC part of the system, steering angle, yaw sensor etc
                            If you have had the tacking done recently or someone has realigned the steering wheel the steering angle sensor needs recalibrating.
                            Personally I think your wasting your time guessing what the fault could be, & May cause more problems disturbing sensors that have been there for 15 years plus, it needs the memory reading with proper BMW software.

                            As I said, the car has only done 400 miles over the last 4 years, but I do to take the car out for a 10 mile run to get the oil to temperature every 2-3 weeks and switch everything in the dash to keep everything working and I've maintained the car, to avoid problems from lack of use. The geometry hasn't been adjusted for several years so this problem has come out of the blue. The car hasn't been neglected or just left alone.

                            Once I get the INPA running I should be pointed in the right direction.
                            /// Exdos ///
                            "Men who try the impossible and fail spectacularly are infinitely superior to those who reach for nothing and succeed" --Napoleon Bonapart

                            Comment


                            • #15
                              If your getting software I’d suggest ISTA, that’s the newer BMW diagnostic software, or even the older version that was used when these cars were new DIS.
                              It will show guided fault finding, telling you exactly what to check & what to replace. Also has the facility to calibrate steering angle sensor.

                              Comment

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