Parking / Reversing sensor fault ?

[jj9]

Hi, I have factory fitted parking sensors on my 2006 berlingo but they don't work.

When I engage reverse gear nothing happens no beep or anything, the switch to turn the sensors on & off has an indicator light and this just flashes,  reading the handbook it states that if the switch indicator flashes it means there is a problem.

The reversing lights come on when I select reverse gear so the switch must be working.


Any ideas as to where to start with this problem?


I've searched the forum for this problem and although there are a few threads there is no real advice on fixing them.





Thanks. 

[dumdum]

If they are factory fitted then get it plugged in to lexia, it will be able to read the factory parking sensor fault codes and all will be revealed normally

[jj9]

Thanks for your reply.

I haven't got a Lexia so that's not an option at the moment.

I was just wondering if there is a common point that causes problems with the system that someone may know of.

[dumdum]

Yes a sensor is common, but guess work will only get so far, if you want to spend a few quid then buy a sensor and swap em one at a time, not hard and may fix your issue if your lucky, however if your unlucky and have two sensors down it won't help and has now cost you a few quid for potentially the wrong part...

[jj9]

I don't think the system is getting as far as turning the sensors on because I can't hear any sound from them.

On a working sensor you can actually hear it giving off a faint ticking sound if you put your ear next to it, none of them are doing this on my car.

From what I can see the control box is located behind the rear bumper so that will have to come off for a look to see if all is ok, it may just be a bad connection.


Thanks.

[jj9]

I don't think the system is getting as far as turning the sensors on because I can't hear any sound from them....

.... From what I can see the control box is located behind the rear bumper so that will have to come off for a look to see if all is ok, it may just be a bad connection.


Thanks.

A little progress...

When I listened for the sensors ticking the other day I had the car in reverse gear but I only had the ignition on.

Tried today with my mate putting the car in reverse gear with the engine running and I can hear the sensors ticking, so the engine has to be running before the system is engaged  

There are 4 sensors but I can only hear 3 of them ticking, the one on the far N/S has no sound, so I'll have a look at that sensor and make sure the wiring is ok, hope it's just a bad connection.


The control box is located behind the N/S panel in the boot, it's not behind the bumper as I thought.

[jj9]

Ok...
Had a look today, loosened the rear bumper to gain access to the N/S sensor and to check the wiring.

The wiring looked ok so I swapped the far N/S sensor (the one that was making no ticking sound) with the one next to it, this would rule out any wiring problems.

The far N/S sensor made no ticking noise in its new position, the other sensor still made a ticking noise at the far N/S position, so I think it's safe to say the sensor is faulty and not the wiring.

I'll get another sensor and replace the defective one and let you all know how it goes.



Thanks.

[jj9]

Ok...

Problem sorted, reversing sensors fixed and working  


The problem turned out to be two faults, the sensor that wasn't ticking was defective so the new sensor cured that, but also the speaker that makes the beeping noise was defective.

I tried replacing the speaker with a small two inch 4 ohm car speaker, this did make a beeping sound but the beeping was permanent even when NOT in reverse gear!

I then found an old set of headphones which had small speakers in them, so I tried one of these, and low and behold it works fine. I noted that the speaker from the headphones was 30 ohms, so I guess the system must need a speaker with more than 4 ohms!



I hope this helps someone with the same problem at some time  

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