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  #1  
Old 02-08-2018, 04:10 PM
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Default 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?
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Old 02-08-2018, 07:30 PM
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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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Old 02-08-2018, 07:38 PM
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Quote:
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.
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Old 02-08-2018, 08:36 PM
Jon_Bmw Jon_Bmw is offline
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Worth a quick look;

https://www.z3mcoupe.com/forum/showt...Steering+angle
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Old 02-08-2018, 08:46 PM
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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.
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Old 02-08-2018, 09:08 PM
Jon_Bmw Jon_Bmw is offline
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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.
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Old 02-08-2018, 09:14 PM
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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.
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Last edited by exdos; 02-08-2018 at 09:17 PM.
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Old 03-08-2018, 07:05 AM
Jon_Bmw Jon_Bmw is offline
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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?
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Old 03-08-2018, 07:51 AM
Jon_Bmw Jon_Bmw is offline
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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.
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Old 03-08-2018, 12:37 PM
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Quote:
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.
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