PDC / reversing sensors stopped working (2010 FL RS)

[Binary]

Hi all,
I'm wondering if anyone can share experience / advise on fixing the reversing sensors on my 2010 vRS. I have searched and read around the site (and other sites) as much as I could so apologies if this has been covered already and feel free to point me elsewhere.
A month ago I noticed that the PDC was intermittently not working - i.e. when I put the car in reverse the radio would continue to play and the PDC display would not come up, or would pop up very briefly and then disappear. My wife also noticed this when she backed in to a concrete wall in an underground carpark (damage to be repaired after I get the sensors working!)

I had a fiddle around, reset the PDC settings via the cluster, etc. It continued working for another week or so but has since deteriorated in reliability to where it doesn't ever work now - the Bolero display doesn't respond at all to the car going in to reverse.
I have done the ticking test on all four (rear) sensors and all are ticking away happily, so I believe the sensors are OK. When I go in to the vehicle settings via the console, occasionally the "Assistant" menu for PDC settings doesn't exist at all, other times it does. When it does exist, the PDC volume and frequency are set to "4" and cannot be changed (it always resets to 4). Is it likely that the PDC module itself would fail?

I use Volkstech in Melbourne (Heidelberg) for servicing and am planning to take it to them to have a look but they have extended holidays over xmas until the end of Jan, so I've been trying to nut it out myself in the interim.
I suspect I will get stuck quickly without VCDS but if anyone has any ideas or previous fixes that they could offer, many thanks would be returned.

[kamold]

I would have the PDC module checked for fault codes first.
Suspicion would be the PDC module itself, or a cabling/earthing problem to the module.

[Binary]

Thanks kamold. Sounds I'd best wait a few more weeks and get it scanned for codes at Volkstech before I invest in a new PDC module.

[Lams]

yeah it could be an intermittent power issue. We had a mk5 Jetta that had cold start issues, turns out to be the connection between the ECU's fuse and its fuse holder

[putney40]

Have you noticed if the rear speaker/buzzer is working? Test it by walking around the car while in reverse (engine off but ignition on).
My Yeti rear sensors became intermittent and then stopped altogether. Found the little speaker open circuit. The unit is a small speaker like those used in earphones with about 50 ohm impedance. Replacing the speaker restored normal operation. The parking module must sense the current drawn by the speaker and inhibits functions if not within normal range...

[Binary]

Thanks all for the suggestions.

Have you noticed if the rear speaker/buzzer is working? Test it by walking around the car while in reverse (engine off but ignition on).

I had read somewhere that a faulty speaker / buzzer can cause the system to stop working, i.e. the PDC system-check fails and causes the system to become disabled. When I walk around the sensors I cannot hear any beeping or indication that the PDC system is on except the faint ticking from each sensor when I put my ear against them.
Would a scan with VCDS detect a failed buzzer / open circuit on the buzzer circuit? Do you know where the buzzer is located and if I could simply test it by subbing the buzzer for a 50 ohm resistor without causing any harm? Replacement buzzers appear to be available cheaply online, so I'm now hoping its the buzzer!

[putney40]

Would a scan with VCDS detect a failed buzzer / open circuit on the buzzer circuit? Do you know where the buzzer is located and if I could simply test it by subbing the buzzer for a 50 ohm resistor without causing any harm? Replacement buzzers appear to be available cheaply online, so I'm now hoping its the buzzer!

Yes a scan showed an error something like - speaker resistance greater than 50 ohm - which gave me a clue to the specs of the speaker. In the Yeti the speaker is located under the roof lining about 150mm in from the D pillar on the drivers side. To replace it would require pulling all the A, B, C & D pillars covers cabin lights and more, a big job....So instead I mounted the replacement behind the D pillar cover and cut the wires and soldered them to the speaker. The original speaker is still in the car. The controller is mounted behind the cargo bay cover near the taillight. A 47 ohm resistor should be OK as a test to simulate a correct load. As a temporary setup I used an old 8 ohm speaker with a series 39 ohm resistor. It worked but was too quiet. Not sure if the Octavia is the same as the Yeti but likely similar.

[Binary]

Just updating the thread to say a big thank you to putney - I have located the buzzer on the B pillar and stuck a 47 ohm resistor in the connector (in place of the buzzer). The PDC system now works reliably since then. Of course no beeping tones while I just have a resistor in place, but the graphical display works fine, etc. I have ordered a replacement buzzer for around $12 on ebay so hopefully i will have it all fixed within a few weeks for only $12 and a couple of hours troubleshooting.

[H8T0W8]

Binary, did replacing the buzzer solve the issue?

Can you please share your fix as my PDC has just stopped functioning

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