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RAD 330i
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67 Posts
Discussion Starter #1
After being gone for a month I startede up my wifes 2001 Z3 Coupe and the DSC Light came on after a couple of seconds. Stopped the car and turned it off. Started again and the same thing. Now it is on immeditaly and stays on. No BRAKE light though.

Thinking I just needed the codes read I took it to my indie who has the Auto Engenuity software. This could not see the DSC controller but the Steering Subsystem showed the Steering Angle Sensor reading -1024. The Weel speed sensors were 0 and 0.3 but did not change when a wheel was turned.

As far as I can tell ABS is still working (if I slam on the brakes on dirt they pulse and the car stops straight). I think this tells me that the control module is OK as both DSC and ABS are in the same module.

So I suspect the Steering Angle Sensor and my questions to the experts are these:
1. How can I confirm this diagnosis
2. Is this an easy DIY and is there one I can follow.
3. If I do DIY it seems that the new one will need to be calibrated; can only the dealer do this? If they are going to rape me for that should I just have them do the whole thing?

Any comments are apprectiated.
 

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Registered
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1,578 Posts
To replace the DSC sensor is a DIY but you then need to get it re-configured/setup buy a shop the the correct software.
 

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RAD 330i
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67 Posts
Discussion Starter #4
Result

Well I didn't get much help here but I'll post the results in the hope it may help others.
I decided to take the car in to a specialist shop (not the dealer) and have them check it out. They called back and said that it looked like the DSC module was at fault and recommended replacing it for around $1200. After some talking and probing with their manager we discovered the following.
1. They tested the steering angle sensor (SAS) and found that it was fine but they could not see the module from the scan tool. There is no fault code for a Control Module failure.
2. They recalibrated the SAS and it appeared OK and the DSC light went out.
After we talked awhile we concluded that the most likely explanation was that the SAS indicated a fault when I first started the car after a month away and the system voltage was low.
Once the DSC module sees a sensor fault it will not respond to queries from the scan tools and may look like it is faulty.
After recalibrating the SAS the light is off and all is working fine.
If they had replaced the module, or the sensor and recalibrated it would have looked like it fixed the problem, but simple recalibrating the SAS may be all that is needed.

Bottom Line: If your DSC light comes on don't replace anything until you try recalibrating the sensors and you may save a lot of money.
 

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Investigative Tinkerer
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5,011 Posts
I think you could've found the problem immediately with better diagnostic software. I have the AutoEnginuity, and there were numerous times that it didn't connect to everything on the cars I had it hooked too (but *sometimes* it would...). I'm now using AutoLogics, and it sees everything (everytime) and does everything short of handing me the tools. There is no comparison in price though, and for what it costs, the AE is better than nothing.

Edit: when I see cars that haven't had the codes cleared for a *long* time, there're a ton of them, eventually I'll get to the screen that displays a low voltage fault, and then it all makes sense. Nowadays, I know to look for a period of low voltage before I take many of the DTCs serious.
 

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19,585 Miles
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11,141 Posts
I think you could've found the problem immediately with better diagnostic software. I have the AutoEnginuity, and there were numerous times that it didn't connect to everything on the cars I had it hooked too (but *sometimes* it would...). I'm now using AutoLogics, and it sees everything (everytime) and does everything short of handing me the tools. There is no comparison in price though, and for what it costs, the AE is better than nothing.

Edit: when I see cars that haven't had the codes cleared for a *long* time, there're a ton of them, eventually I'll get to the screen that displays a low voltage fault, and then it all makes sense. Nowadays, I know to look for a period of low voltage before I take many of the DTCs serious.
AutoEnginuity doesn't connect consistently. Actually it connects rarely.
I'm going to try and see what they can do.

Doesn't appear that AutoLogic covers the newer Z4's.

Bavarian Technic used to work with Z4 and E36 but not anymore.
Supposedly will fix it but not yet.
 

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RAD 330i
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67 Posts
Discussion Starter #7
Diagnosis

I agree about the AutoEngenuity software but the last shop claims to have the latest and greatest tools (better than the dealer?) and their first response was still to replace the module.
I think the point is that it is easier to diagnose a bad module and sell you a new one than to dig a little deeper.
 

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Equine 1/4 miler ancestor
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1,687 Posts
I had an angle sensor error, and fixed by the recalibration. That worked for a year, then the angle sensor couldn't be fixed by recalibration and had to be replaced.
 
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