Octavia 2 rear parking sensors not working DSG lever fault

[KevinSt]

Hi,

 

I am in need of some assistance. My father and I both own a 2005 2.0TDI Octavia Elegance. His is a DSG and mine a manual. Just recently his rear parking sensors have stopped working completely. No graphic on the radio and no beeping. However the reversing lights work correctly and the LCD in the dash correctly indicates 'R'.

 

I have removed his parking sensor controller from the boot and tested it in mine and it works fine.

 

If I lift the trim around his DSG gear lever and gently pull on the wires from the circuit board along side the lever sometimes the graphic appears on the radio when reverse is engaged.

 

 

My questions are:

 

1. Has anyone else had this fault?
2. What is involved in removing the gear lever and accessing the circuit board?
3. How does the system work, does it communicate with the parking controller over the CAN bus?
4. Does anyone have a circuit diagram that may help to guide me?
5. Why doesn't the parking system work if the reversing lights and the dash LCD are working correctly?

 

Thanks for any assistance.

 

Kevin

Edited 16 November, 2013 by KevinSt

[KevinSt]

I've used the guide on the forum here:

 

http://www.briskoda.net/forums/topic/258617-identify-and-change-a-faulty-rear-parking-sensor-mk2-octavia-updated/

 

to identify which sensors had failed. It was the outer two. I bought two new, pre-painted sensors from eBay (goodparts32) for about £16 each.

 

I have replaced them and I get the clicking sound from them but the radio graphic is still intermittent and there is no beeping.

 

Do I need to clear any stored error codes before it will work correctly?

[JohnFerg]

I have exactly the same issue and questions as Kevin with my 2006 1.9TDI Octavia Elegance Estate DSG.  I can get the sensors to beep and show on the radio by wriggling the gear lever, but as soon as I let go the service disappears - all points to a loose connection or dodgy switch in the area of the gear selector lever.  Like Kevin, I've lifted the lever surround plate and peered into the hole and can see the circuit board.  My Haynes manual covers the rear end (bumper sensors and control unit) but there's no mention, or circuit diagrams, for the gear lever area.

 

Any advice on how to proceed gratefully accepted.

 

John

[KevinSt]

Hi John,

 

I still have not fixed the fault. I am thinking that the gear selector lever probably does work correctly because it interfaces directly onto the CAN bus and if that wasn't working then the reversing light would not work and the gear selection indicator on the dash would not work, both of which do.

 

I have now obtained the circuit diagram for the gear selector and it just shows a single electronic module that connects to the CAN bus.

 

I did wonder whether there was a problem with the radio. I thought that it might be interesting to disconnect the radio and then try the reverse alarm again.

 

Kevin

[JohnFerg]

Thanks for the update.  It's good to know that your circuit diagram indicates a single unit in the area of the gear lever.  It means my fault is almost certainly either a wiring fault connecting the board to the loom, a faulty board, or a problem with the physical connection between the lever and a sensor on or near the board.

 

In my case, I'm pretty sure the fault is in the area of the gear lever as the radio display works when the sensors work - and wriggling the selector lever works both simultaneously.  Over the next few days I'll peer into the area beneath the the gear lever again and let you know what progress,if any, I make.

 

Regards

 

John

[KevinSt]

Reading the manual, the procedure for accessing and changing the selector lever PCB is horrendous, it involves removing the exhaust and undoing things from underneath.

 

I would say that if your reversing light and dash are working reliably then I don't understand how the selector switch module and wiring can be at fault.

 

Unfortunately I don't have access to any CAN bus diagnostic tools.

 

Let me know if you get any further forward.

 

Kevin

[JohnFerg]

Stangely my fault has corrected itself and the parking sensors are working again - I don't know why.  I checked the fuses and switched the the radio option for the PDC on and off and that's about it.  My next stage was to remove the trim around the drivers side of the central consol with a view to gaining access to the circuit board that flanks the bottom of the the DSG lever.  I fear the fault is as a bad connection somewhere and will return in due course.

 

Whilst I await for the fault to return I have established that:

 

a) My Haynes manual has no wiring info for the parking sensors.  The wiring diagram for the audio sysytem does not show a connection for the PDC (perhaps it comes over the CAN Bus).

The reversing lights and parking sensors have separate fuses in the end of facia fuse box.

c)  The manual gearbox versions have a reversing light switch attached to their casing; the DSG appears to have internal switches sending gear selected information to the dashboard via a complex socket, and an internal reversing lights switch.

 

If I make any further progress I'll post in due course.

[KevinSt]

The DSG selector is connected to a control unit on the CAN bus. See the diagrams below:

 

 

 

 

 

[mk2cliffy]

I've got the exact same problem on my 2.0tdi dsg

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[mk2cliffy]

What would you say I need to do to get it sorted?

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[KevinSt]

I had a play with PDC radio settings today and learnt the following:

 

With the car parked just in front of a wall, switching the ignition on, putting the gear selector into reverse does not bring up the graphic on the radio and there is no beeping. Moving the selector back to park results in the graphic of the car appearing for about 1 second but there are no obstacle distance markers, just the outline of the car and no beeping.

 

Selecting mode on the radio with the gear selector in reverse sometimes results in the car graphic and the distance markers appearing for about 1 second but no beeping. Changing the PDC setting to OFF and then back ON makes no difference as does changing the PDC volume.

 

I don't know whether this is of any use to our collective fault finding of this problem.

[JohnFerg]

Kevin,

 

The results from your 'play' with the DSG lever accurately mirror my experience  early this month (April 14).  However, strangely, my fault seems to have rectified itself.  There is not much I can do until it returns and I'm rather inclined to let sleeping dogs lie. 

 

When the fault  returns, as it surely will, it's my intention to investigate the area around the circuit board that flanks the DSG lever.  Thank you for the circuit diagrams - I'm sure they will prove very useful in helping to logically locate the cause of the fault.

 

John

[KevinSt]

Good news, I have fixed it!

 

It would appear that the control unit tests the buzzer before it operates. If the buzzer measures open circuit then it prevents the system from operating. Why can't it just use the graphic with a warning that the buzzer is inoperative?

 

Anyway, I removed the lower trim from the passenger side C pillar and the buzzer was easily accessed. I pulled the plug out of the bottom of the sounder and temporarily plugged in a small speaker that I had. I then tested the parking system and it worked correctly!

 

To remove the old buzzer you have to push out the central part to the plastic rivets from behind and then it all comes off easily. The part number is 8E0 919 279 and they are about £12 on eBay from Europe. I'll check the main dealer locally before ordering online.

 

Kevin

[JohnFerg]

Congratulations - excellent news, and thanks for sharing the solution.  What clever lateral thinking made you investigate the buzzer?  I must admit that it is the very last place I would have looked for a fault.  Well done!

 

John

[KevinSt]

I'm afraid that I cannot claim credit, my dad had the fault codes read and it indicated a fault with the warning buzzer. When he told me that was the fault code I found it hard to believe that the control unit would actually make any kind of measurement to check the buzzer. I was very sceptical right up to the point where I connected another speaker and tested it.

 

I suspect that if anyone else has the same problem, simply connecting any loudspeaker or headphones to the connector in the C pillar would suffice to fool the controller. It probably only looks for a resistance of about 4 - 30 ohms.

[mk2cliffy]

I've got the same problem. I take it the pillars are a, b, and c starting from the front of the car?

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[adamal]

Double post sorry.

[adamal]

I think you mean B pillar for the speaker don't you? Well solved though.

And yes its a, b, c, d from the front to back.

Adam

[KevinSt]

Yes, it was the B pillar, the one by the left elbow of the passenger. Unfortunately I cannot see a method of editing and correcting my earlier post.

 

Just for interest, the price at the main dealer was £18. I see the same part is used on everything from VW to Lamborghini.

[mk2cliffy]

Is it just a simple case of pulling th plastic trim back at the bottom? What does the part actually look like? Thanks

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[adamal]

Its one of these:

http://www.carsystems.pl/vw-pdc-buzzer-8e0919279,id472.html

The trim is a little fiddly and you may need to remove the bits over the door sills first. But essentially it all clips in. Try and avoid taking it all off to the top, as it gets fiddly putting it all back together around the seat belt aperture at the top.

Adam

[Norco]

Good find

 

I would imagine lack of a buzzer would make the screen inoperable so as not to let drivers put the car in reverse and see the screen on then reverse into something due to the lack of a beep. 

 

[KevinSt]

In reply to mk2cliffy, I removed the top B pillar trim first by gently levering out the bottom sides before pulling the top out horizontally.

 

Once that was out of the way, I removed the bottom trim by pulling the top section off horizontally and then pulled it upward to release the bottom clips.

 

The tricky bit was removing the plastic rivets from the buzzer. I just pushed them out from the back. You could push them in but you might loose them inside the pillar.

[KevinSt]

Here are some diagrams of the trim and buzzer:

 

https://drive.google.com/folderview?id=0B6ytVYfsfAiNUWs3RWhRUjYwd0k&usp=sharing

 

The part number for the buzzer is 8E0 919 279, main dealer price £20, eBay price £10.