My first post here. I did search the forum for the same problem, but my car's symptoms don't fully match any of the posts I found here.

I have a 2017 Octavia estate, 1.6 diesel, 105,000 miles. It has 4 reversing sensors, no rear camera, no front sensors. A month or 2 ago I got an error on the infotainment screen when engaging reverse: Park Pilot not currently available, which stayed until I pressed OK. Originally I did sometimes still get the reversing "radar" image with the 4 zones on the screen maybe briefly, but that doesn't show now.

I used a Bluetooth ODB scanner, and the error code said centre left sensor faulty. To narrow down, I cleared the error code, re-read codes, none now reported. Then I swapped the suspect sensor for the left sensor, engaged reverse, and the infotainment sytem again said parking error. I re-read the code, and it only said left sensor error, and no report of an error on centre left, so the error had moved with the suspect sensor. I cleared that. Simillarly I swapoed tbe suspect sensor with the one from the centre right position, and the error was now reported only in the centre right position.

I am assuming that the sensors are only powered when reverse is engaged, and checked for a valid output (not stuck fully on or fully off?) at power up.

So as far as I could tell the electronic control unit was good in terms of the ability to read all 4, thus the wiring was good for all 4, 3 sensors were good wherever I connected them, and one particular sensor was bad, wherever I connected it.

I ordered a sensor from ebay, it came in fairly anonymous packaging, I fitted it, and got the same fault on infotainment screen and when reading the code. Again I tried clearing, swapping the new sensor to at least 2 positions, and the error code followed the new sensor position.

So I concluded the new sensor was faulty, sent it back with the above explanation, and got a refund.

And then I ordered another, from a different supplier, it arrived, in a genuine-looking VW Seat Skoda Audi labelled sealed plastic bag, part number 5Q0 919 275 C.

Confidence high, I fitted this new new one, same fault!

It seems a stretch that I received 2 bad new sensors.

Some suggestions here that a low battery can give parking sensor errors. I measured 12.4V battery ignition off, 12.1V ignition on with engine not running, 14.1V engine running, I didn't check the cranking voltage, but it starts very promptly.

11.4V at sensor cable connector (with new sensor not connected) with ignition on engine not running and in reverse, so 0.7V below battery - maybe some voltage loss in however the module switches power to the sensor, but seems a large drop. Even if I wait until the engine is running, thus 14.1V, as soon as I engage reverse, the error comes up.

So options are just sit and cry in the corner with tears of frustration, or seek help from knowledgeable people here, as I can't think what to try next, other than repeating the whole swapping process, expecting the same confusing result. So any clever ideas would be much appreciated. Thanks in advance.

I suggest you buy a sensor from a reputable source not eBay.

BTW the sensors need to be painted to match the bumper.

Thanks for the quick response.

I did think the newest one seemed genuine, based on the packaging, as attached photo. But then a label is trivially easy to fake and apply to some piece of junk.

I am trying to check the original with my bench power supply, and a DVM on the output, but I don't know what the expected output should be, e.g. a variable voltage or a Pulse Width Modulated signal. I might be brave enough to try the same with an old good one and the new allegedly bad one, just to try to understand what is good.

And the new sensor is black all over, same as the so-called "diffuser" it fits into, so I didn't see any need to paint. Or is painting necessary for some reason?