my factory fit rear parking sensors are not working _(octy hacthback).

when i select reverse, i get a longer and louder than normal beep for about 5 seconds. (the normal beep when you engage reverse is a 1 second, relatively quiet beep). both types comes from the same place; the driver's side seat belt, B-pillar.

the sensors do not detect / beep when i reverse currently.

it did seem to work better this morning after a short drive. i selected reverse and it did a normal short, quiet beep, but then almost straight after did a long, loud beep.

so whats wrong? any help appreciated!

(p.s. i have cleaned the sensors up (outside of bumper), as they were averagely dirty, but that has not helped at all.)

Probably one of the 4 sensors has failed. Or at least, that was the problem on my wife's BMW Mini when it had exactly the same symptoms. My Octavia's sensors haven't gone wrong yet! The long beep is just to tell you that it's got a fault and isn't going to work.

If you can get access to VAG COM, then it'll tell you the exact fault.

If you can't, then the sensors actually make a really quiet clicking noise when you're in reverse. Put it in reverse (with ignition on but engine not running, obviously) and then put your ear next to each sensor one at a time. If one of the 4 isn't clicking and the other 3 are, then either that sensor has failed or the wiring to it has. As far as I know you can't easily fix a failed sensor and will have to buy a new one. For the Mini, I ordered one in the right colour and it came pre-painted.

thanks AJB. I tried listening for the clicking but couldn't hear any clicking from any sensors, but there is some road noise and wind outside. How loud is it? Is it hard to hear?

thanks AJB. I tried listening for the clicking but couldn't hear any clicking from any sensors, but there is some road noise and wind outside. How loud is it? Is it hard to hear?

Yes - it's quite hard to hear. The Mini ones were louder than the Skoda ones too. You need to make sure the parking sensor are active (ie reversing lights on), and then there's a really quiet click maybe once a second or so. Road noise or wind noise could easily hide it. I had my ear right next to the sensors on my drive, and then could hear them.

Do you have any kids? Their ears may be a little more sensitive (not that I am suggesting your old!!!), and might be able to hear the clicking a little better.

I use my OEM solution - a towbar

Just thinking about it again, from memory I think it's probably more than one click per second. Maybe more like 3 times per second? That is from memory though...

Test the sensors in turn by bringing something up to each of them with car in reverse. I kindly had the wife to place her hand nearer each sensor, and found the far right sensor knackered. It sometime plays up in rainy weather. I had heard that the module can play up also if you have no sensors working at all, but as mentioned VAGCOM will find this.

AFAIK if one sensor (or the control unit obviously) fails, then the whole lot stops working.

So I get no beeps when anything goes near any sensor, which doesn't help diagnose which is at fault.

I have a 3rd party vag com lead on its way to me, so I can fault code read it and hopefully get a clue as to what has happened.

there is a small scuff in the dirt on the rear bumper, on the right hand (offside) corner, which is pretty close to the rear right sensor. i think someone parking may have touched it. not even hard to affect the paint, but maybe enough to jig a wire loose or break the sensor.

how can i get access to the sensors without removing the bumper? So that I can jiggle the wires?

and where is the control unit box? I know its in the boot somewhere!

AFAIK if one sensor (or the control unit obviously) fails, then the whole lot stops working.

This was definitely true on the Mini - they all stopped working, and it didn't beep at all (apart from the long initial "I'm broken" beep). But the 3 good ones did carry on clicking.

I have a 3rd party vag com lead on its way to me, so I can fault code read it and hopefully get a clue as to what has happened.

That should do the trick.

how can i get access to the sensors without removing the bumper? So that I can jiggle the wires?

I think the outer ones you can maybe just reach up behind the bumper, but I've got a feeling the inner ones are a bumper off job.

and where is the control unit box? I know its in the boot somewhere!

It's behind the carpet on the left hand side, near the CD changer. It's nearer the front of the car than the CD changer - possibly tucked up near the back of the wheel arch somewhere I think. It's quite a small box, if I remember correctly.

well having just got my VAG COM lead, predictably the system has started working again after a short drive last night!

So, clearly it must be a loose wire somewhere, which when I have managed to bump back into place.

Will try the lead on the car and see which place the wire was loose hopefully.

It looks like I can remove 5 torx screws underneath the bumper to get enough access to get a hand in. In the boot, where the boot lock catch is, there is a plastic panel above the bumper where some big black wires go. I think if i removed that trim I could fiddle with the wires going into the bumper from there too.

Will update on a conclusion if I find one!

With the Mini, it was a faulty sensor (when I swapped the one that wasn't clicking with another one, the not-clicking moved with the sensor). But it was intermittent. One day it would be broken, the next day it'd work.

Hopefully it'll turn out to just be a dodgy connection, but don't rule out the sensor just because it's started working again.

Following with interest, my newly acquired 05 Octy 2L TDI DSG Elegance has random parking assist behavour. Thanks guys.

As a side note (slightly OT), When I adjust my Right hand mirror the Left adjusts too - Was told by the garage this is normal... anyone know is that the case?

I miss the Fabia vRS tho...

EDIT: I finally got my hands on the User manual and answered my own question - yes that;s how the mirrors work.

I do have broken park assist tho... booked in for assesment. Ta everyone.

Edited 17 April, 200917 yr by rosss