Identify and change a faulty Rear Parking Sensor - MK2 Octavia - UPDATED

[octavia5]

A guide to help identify and replace a faulty Rear Parking Sensor

If a sensor fails you will only get a 3 second ’squeal’ when you select reverse and there will normally be no display on the radio or beeps as you reverse – so be careful reversing if you have become reliant on the sensors.

If you have access to VCDS or someone with it then you can run a scan and the fault code should identify the failed sensor. If you do not have access to VCDS then follow the steps below to identify the failed sensor.

For Mk2 Octavias 2005-2009 the replacement part number on the Sensor is '7H0 919 275' they cost about £125 from a dealer plus fitting charge which could include removing the bumper at great cost - but I bought mine from Ebay and fitted it myself. I bought mine from this post but it will have expired by now, probably relisted though

http://www.ebay.co.u...984.m1423.l2661

Seller is 'goodparts32' in Poland price was just under £33 delivered. Be careful when buying from Ebay as there are several sellers selling sensors with different part numbers and these are not alternative replacements for the Octavia and will not fit the standard sensor housing – later Octavias MAY also have different sensors in which case you need to remove the sensor and check the part number on the connector housing before ordering a replacement.

EDIT.. I was unlucky and had a second Sensor go. I bought the replacement from Ebay seller 'CARBOXPARTS' a UK seller for £22.99. Quick delivery

http://www.ebay.co.uk/itm/200764285553?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

You could also try breakers or check the Biskoda Car Parts for sale section. Usual care if buying from a breakers. If you buy a standard Black Sensor and have to paint it remember to use only enough light sprays to get a colour coating, too much paint can ruin the sensor or cause it to misbehave.

1. Working sensors do emit a faint clicking noise - You do not have to start the car to check this, just turn the ignition on and select reverse gear. The clicking is very faint so cup your hand around each sensor and place you ear against your cupped hand and wait for a quiet break in any traffic. VCDS had identified my failed sensor correctly but several people have reported that their sensors appear to have been reversed so VCDS identified the wrong sensor.

2. Once you have identified which sensor it is you should obtain a replacement. To replace it you will need to undo the bumper under-tray (the black under trim - 4 plastic screws with 3mm hex heads) and wedge it down so you can get your arm under the inside of the bumper The two centre sensors are relatively easy to access, the outer ones not so - especially the one by the exhaust, you may need to drop the exhaust pipe to ease access. A powerful torch will be handy to shine up under the bumper to help see what you are doing.

3. The Sensors are fitted into an outer carrier or housing (the outer circle when looking at the sensor from the back of the car) The sensor has to be removed with the carrier as you can not release the clip to release the sensor from it with the sensor in place. You will need to wiggle the sensor assemble sideways and up / down until the adhesive holding the assembly on breaks free - this should not damage the bumper even though you may have to use some force. It might help to have a second person pushing the sensor from the outside. The carrier has two side wings, which has the adhesive holding the assembly to the bumper.

4. My Sensor wiring harness was clipped into the rear of the bumper - inside the Black Plastic trim - and this meant that the cable was too short to allow the sensor assembly to drop far enough for me to access the connector on the rear of the sensor and disconnect it. I could not release the clips to get more slack in the harness but noticed that the harness itself was simply tied to the clips with black tape, so very carefully I cut the tape to free the harness. This gave me enough slack to drop the sensor to a point where I could unclip the connector. If you need to cut the tape to free the harness this must be done very very carefully so as not to cut into the harness itself - get a good light on to the area to be cut and use a thin bladed sharp knife (I used a thin bladed craft knife with a longish handle) cut along the clip where the tape is wrapped around it, do not cut along the harness itself. If you cut the wires in the harness you will have a serious problem and probably need to take the bumper off to repair or replace the harness.

5. With the sensor and its housing removed simply unclip the sensor from its housing and fit the new sensor into the housing

6. It is a good idea to check that the new sensor works before refitting permanently, this can be done by simply connecting the new sensor to the harness and letting it 'dangle' behind the bumper. Then turn on the ignition and select reverse - if the sensor is working the radio display will show the reversing sensor diagram and be screaming as if you about to reverse into something. If selecting reverse still gives the 3 second 'error' beep then recheck the harness connection and carefully check where you cut the harness free in step 4. If you get the correct display on the radio go to step 7.

6a. If you still have the 3 second error beep then you have either selected the wrong sensor as faulty, bought the wrong replacement or have a harness fault. Unclip the new sensor and check that it has the same part number on the cable connector, if so it is unlikely to be faulty if you purchased a new one rather than a used one from a breakers. If in doubt push the replacement sensor back into the bumper and restart this guide from step 1 and hope you do not have a harness fault - if the sensor you identified a faulty (by the lack of clicking) still does not click and the others do then it is probably a harness fault. A new harness is not expensive from the dealers but you will need to remove the bumper to replace it. There is a guide to removing the rear bumper on the site somewhere - search for 'Fitting a Tow Bar' OR TRY THIS LINK: http://octavia-vrs.c.../towbar-install

7. To reattach the housing into the bumper you will need to apply some thin but very sticky double sided tape to the wings on the sensor housing or you could use some UHU type glue to hold the housing in the bumper. I would avoid using epoxy glue as it will make it very difficult to replace the sensor should it fail again in the future. I used a smear of UHU on each wing and this has held in place for 2 weeks now.

[pete h]

thanks very much that was very helpfull.

[Morphim]

Thanks also. This was very helpful, especially the fact that the sensors click when you get close to them; a bit like a spark on a hob ignition. Helped me easily discover which was faulty.

Just as a point of note, I removed the sensors without removing the glued surround. It's a bit fiddly but there are only 2 small clips top & bottom but they aren't that tight. Just takes a bit of blind finger work. Gently pull one away whilst gently pushing the sensor from the outside. This pushes it away just enough to stop the clip from re-engaging, allowing the top one to be disengaged.

Also, I already have a replacement sensor fitted (not by me) with a different part number (7H0 919 275D) which has the same connector but angled. It all fits fine.

Finally, I also removed a working, clicking sensor & tried it in the non working plug, just to check it wasn't the wiring. It clicked fine, so not the wiring

Just to be 100%, I fixed the non working sensor to the working socket. No clicking so it's def the sensor. Best to be sure of everything : )

Cheers

Edited 16 February, 2013 by Morphim

[sadexpunk]

great advice thanks, im gonna have to give this a go as my drivers side sensor has just failed.

thanks a lot

[teledu]

So useful... thanks for the much-appreciated topic.

[tonywoodtw]

Most helpful. TYVM.

[Grumbee]

Great tip about the clicking.... one question though, do they still click after the 3 second beep or is the power shut off when the unit detects a fault?

[Chickenlicker22]

Great tip about the clicking.... one question though, do they still click after the 3 second beep or is the power shut off when the unit detects a fault?

anybody ?

[Guest]

The gooduns still click as long as the ignition is on and reverse gear is selected so you don't need to run round the back to hear which are dud!

[tandk1234]

I found it difficult to hear the sensors clicking (or not) so I found a tack hammer and rested the end of the handle against a sensor and the metal head of the hammer against my ear. Worked a treat, but got some funny looks doing it!

[Guest]

The cardboard inner tube from toilet/kitchen roll makes a good listening device for the sensors if you're hard of hearing or in a noisy environment, doesn't even need to be an empty roll.

[Phil-E]

So a month or so ago I started to get the long beeeep of death!

 

I hooked up VCDS which showed the innner N/S sensor was faulty (confirmed by listening for the clicks- was very audible to me as soon as I got near them).

 

Ordered a replacement part off ebay (not original):

 

http://www.ebay.co.uk/itm/171099063379?_trksid=p2060778.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

 

It came from Poland but postage was super quick.

 

I also bought a can of paint and lacquer from here (they seem to do loads of different colours):

 

http://www.ebay.co.uk/itm/271042417882?_trksid=p2060778.m2749.l2649&var=570109329806&ssPageName=STRK%3AMEBIDX%3AIT

 

This guide was super helpful. Pushed the sensor in while wiggling it around and removed it along with the holder. I could have unclipped with a bit more effort but couldn't be bothered.

 

Phil

[Chickenlickin]

Hi I have the same problem on a 2007 Mk2 1.4 TDI I have just brought 110,000 miles, and I used a car stethoscope but I have no clicking anything else I can check.

I do get the short and then longer tone and the radio does show up for a short while when I first engage reverse 🙁