DSC light permanently on (code 163)

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trotter
Joined: Fri 08 May, 2015 23:00
Posts: 5

  Z3 roadster 3.0i
Location: Lancs

DSC light permanently on (code 163)

Post by trotter » Wed 11 Apr, 2018 15:39

Hi,
I would be grateful for any advice regarding a DSC error code on my Z3 3.0i ( WBACN52020LJ ). A couple of months ago the DSC light came on permanently and INPA shows an error code 163 "Lateral acceleration Sensor electrical failure". I'm unable to clear the code, it immediately comes back on.
I've replaced the acceleration sensor with an "alleged" good one and there is no difference, it also shows the same fault if no sensor is connected. The sensor is the vertical one under the passenger seat (drivers seat if left hand drive). I disconnected the other (yaw?) sensor to prove and this produced a 161 code, so I'm pretty sure I'm dealing with the correct sensor. The car is an E36 yet the sensor is marked as E46 and has obviously been changed changed previously. Is this a common failure?

I've tried to configure the (new) sensor using another program (Tool32) but this too reports a problem with the sensor. There are 3 connections to the sensor, power, earth & signal and it looks like the DSC unit is expecting a 1.7V on the signal wire to make it happy that the car is level. Does anyone know which connection is which? I was thinking of connecting a 1.5V AA battery to the signal wire to see if it would register.

At the moment I have either (1) a faulty sensor :? (2) faulty wiring :( (3) faulty DSC unit :x

I would really appreciate any suggestions from you guys on how to move forward with this......The Z3's currently SORNed and the MOTs due next month!

Many thanks, Phil
Last edited by trotter on Wed 18 Apr, 2018 09:48, edited 1 time in total.

therealdb1
Joined: Tue 25 Jun, 2013 22:47
Posts: 263

  Z3 roadster 2.0

Re: DSC light permanently on (code 163)

Post by therealdb1 » Wed 11 Apr, 2018 22:53

It could be that you need to zero the replacement sensor. If you have a diagnostic package like INPA you should be able to see the live output from the sensor which will vary if you leave it connected electrically but move it around. It will also show you if the output is within expected parameters. If it is not then that is why you get the error code.
It could also be that the "known good" one is faulty but then you will be able to check with INPA. It will also give you a clue if there is a wiring problem too which is sounding likely if taking the sensor out makes no difference.
I think that I would get a multimeter on the wires and check that there is a supply and earth which is actually at earth and not floating. If that is ok then I would rather temporarily fit a potentiometer in place of the sensor and move the wiper either side of the centre point to replicate the sensor. I think this is safer than introducing a separate battery which has the potential cause damage to the DSC control unit if you are unlucky.

trotter
Joined: Fri 08 May, 2015 23:00
Posts: 5

  Z3 roadster 3.0i
Location: Lancs

Re: DSC light permanently on (code 163)

Post by trotter » Sat 14 Apr, 2018 06:44

Hi therealb1,

Many thanks for your response.

I can't see any live output from the sensor as the DSC is reporting an electrical failure. I've used INPA and Tool32 (along with google translate :oops: ) but I'm unable to get any response from the sensor.....apart from the error code.
Good idea re multimeter but I don't know which wires are supplying voltage,earth and signal. I'm also unsure whether the voltage is supposed to be 12V or 5V as I suspect that the power is fed from the DSC unit itself.
I take your point about using a potentiometer instead of a battery but I don't have one. :? ****EDIT I've just looked on Ebay, is this the sort of thing I could use? https://www.ebay.co.uk/itm/16mm-Potenti ... SwHHFY92Cz ****

Does anyone have a DSC_46 wiring diagram that shows wire colours, designations and terminal connection numbers? :(

Many thanks, Phil
Last edited by trotter on Fri 20 Apr, 2018 08:13, edited 1 time in total.

therealdb1
Joined: Tue 25 Jun, 2013 22:47
Posts: 263

  Z3 roadster 2.0

Re: DSC light permanently on (code 163)

Post by therealdb1 » Sat 14 Apr, 2018 23:23

Hi Phil,
Yes that potentiometer is the sort of thing I had in mind. I am a bit confused as to the value of it though. Might be worth looking at Maplin (30p for a 10 kOhm linear) or an alternative electronics supplier.
I had a quick flick through some wiring diagrams and it appears that supply goes to pin 3, pin 2 is ground and pin 1 is the signal. Check the order on the connector though as it could be that supply and ground are the outer pins.
The wiring colours threw me though as they are stated as follows:
Pin 1 - Blue / white / yellow
Pin 2 - Brown / black / white
Pin 3 - Black / red / white
I don't know if that is combinations that have been used over time but you normally only have a single colour or a trace not two traces. Have a look and see what you have. You should not harm anything if you are only connecting a voltmeter anyway.
It does not say if it is 12v or 5v but the sensor does derive its power directly from the DSC module so it could be either but if you have neither of these then that could be your problem.
Best of luck!

Bumpa
Joined: Fri 23 Jun, 2017 21:31
Posts: 44

  Z3 roadster 2.2i

Re: DSC light permanently on (code 163)

Post by Bumpa » Sun 15 Apr, 2018 14:18

My garage changed that sensor on my 2002 2.2 litre after the old one was flooded by rain water, and the light stayed on with the new one fitted. They found that it needed to be calibrated so that it read zero when the car was stationary. I'm afraid I don't know how that was done.

trotter
Joined: Fri 08 May, 2015 23:00
Posts: 5

  Z3 roadster 3.0i
Location: Lancs

Re: DSC light permanently on (code 163)

Post by trotter » Wed 18 Apr, 2018 10:12

Thanks again for the replies...

I have a Blue/white/yellow on one of the outer pins, a brown/black/white on the middle pin and a black/red?/white on the other outer pin. I can't see the actual designation on the connector but my eyesight isn't what it used to be :oops: (The extra trace colour is widely spaced around the other 2 colours. I'm not explaining myself too well but it's obvious when you see it)
I'm not at home at the moment but will try a multimeter & obtain a potentiometer when I get back next week. In the meantime I'd really appreciate it if anyone could direct me to/ forward a wiring diagram just in case it's the wiring at fault.

Regarding the calibration of the sensor: This can apparently be done with Tool32. It didn't work for me as I can't get any signal from the sensor.
I have a PDF outlining the procedure from another forum but can't upload this here. if anyone needs this please pm me.

Thanks again, Phil

therealdb1
Joined: Tue 25 Jun, 2013 22:47
Posts: 263

  Z3 roadster 2.0

Re: DSC light permanently on (code 163)

Post by therealdb1 » Wed 18 Apr, 2018 17:45

Try here Phil: http://wedophones.com/BMWManualsLead.htm
Their 'BMW Z3 - M Roadster - Z3 - M Coupe Electrical Troubleshooting' download is the same as my Bentley Manual for 2002 MY.
There is some confusion over the set up applicable to your car but going by the wire colours the DSC III appears the most appropriate. You do have to consider it originates in Good Ol' USofA! :D
There is not much to see on the diagram though just three wires going to the control unit. If you do not have the necessary supply at the sensor it suggests a break in the wire somewhere or a duff control unit.

trotter
Joined: Fri 08 May, 2015 23:00
Posts: 5

  Z3 roadster 3.0i
Location: Lancs

Re: DSC light permanently on (code 163)

Post by trotter » Thu 19 Apr, 2018 11:59

Thanks again therealdb1, just what I was looking for.

I'll post a quick update once I (hopefully) get this sorted. :?

Cheers, Phil

SORTED: Checked all wiring for continuity to DSC module (0.2 Ohms on all) and checked voltages at the sensor (4.96V DC). Everything looking OK so I taxed the car on the remaining few days MOT and took it for a run with the replacement sensor fitted.
Light stayed on for around 20 miles of lively driving. Stopped for a coffee and the light went out & stayed out for the rest of the journey. Checked the error codes when I got back and found four code 163's. Cleared the codes and all's been well so far....No further error codes. It looks like the DSC unit calibrates the new sensor dynamically during use and not while the car is stationary. Learned something new again. :rtm: :dunce:

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