I’ve had the car for about 9 months and always assumed the parking sensors were broken, then come Easter weekend they were reborn!

How they occasionally work.

Putting it in to reverse gives a loud beep every time.

Any ideas were to look for a lose connection or a connections that could be getting damp and cutting the system out given the heat of the weekend.

Mine were always intermittent, the left side becoming oversensitive, sometimes it was better after cleaning, sometimes worse, then I had a Romanian car wash, you know the type that takes 90 seconds with scores of people swarming over the vehicle, they used a really high pressure washer for the traffic film remover and rinse, so powerfull it removed the paint on my towbar shield plate. After that the parking sensors worked perfectly, better then ever before and have remained so for a couple of months now.

 

One of several faults on my car that have miraculously healed up!

My sensors were broken and were doing the same as you have described. I placed the keys in the ignition without starting the car and inspected the sensors. You can tell which one is faulty as they click if you put your ear to them. The one not clicking is the faulty one. I managed to put my hand up under the rear bumper and push out the sensor and could see that the wire has snapped. 

I ended up reconnecting the wires and they now work perfectly 

Whilst here. I’m not sure if it’s an additional upgrade or something but when I reverse no parking sensor indicator appears on the head unit. My old mk2 vrs did this but not my current car ? 

I’ll try the key in and listening.

Does it need to be in revers or is it just keys in no turning and they will click?

in reverse gear, ignition on, engine not running.

Try scanning for fault codes, had to replace my 2 left sensors recently. Works a treat now 

I have just found out when I reverse in my Scout there is no display and no bleeping yet the reversing lights come on, DTC 01543 shows 'parking aid reversing chime' H15 as faulty !

It'll be the separate speaker it uses for the beeps. As it's detected a fault it will have disabled the entire system.

 

Check it and it's wiring then replace if necessary :-)

The "beeper" is behind the L/H "B" pillar trim

Thanks for the info lads, I will have a look to see how I get to it, Is it just a remote speaker or is there some electronics with it ? Doesn't look like I will do it today as I have to work on it outside ! Cheers Stuart

It's just a speaker nothing fancy 

 

Removing – Switch off the ignition and all electrical components. – Remove bottom left trim panel of pillar B →Body Work; Rep. gr.70. – Unplug connector -2-. – Remove button rivets -arrows-.

– Disconnect parking aid warning buzzer -1-.

 

Thanks for that nige, just been firing up an old PC which has elsawin on it and had to do a few updates ! Finally found it in section 94 outside lights etc, and now I am trying to get the printer working ! the troubles I have when you mothball it just to keep it for elsawin info.I wouldnt have thought just the speaker failing would shut down the whole warning system ! but I am about to find out. cheers Stuart

You mentioned on the other thread that you have been towing a caravan recently. If I remember correctly pluging the caravan into the car socket disables the reversing sensors, at least it does on mine, so could the cause be the sensor that detects that the caravan is plugged in has failed?

Thanks for that, yeh I am hoping the boxes are next to each other in the boot, must have a look and see if any fuses have popped, might go down to the caravan and plug it in and see what happens as it normally shows a pic of a trailer, cheers Stuart

There may be a microswitch in the socket that is mechanically activated by the plug body being inserted. if there is then I would check that it has not got gummed up.

I've not seen a microswitch in the parking aid unit, just going to buzz out the wires to the buzzer, just been printing off the wiring connections to each unit so still ongoing ! Cheers Stuart

I have had 13 pin towing sockets with a very crude, unprotected and unreliable contact arrangement inside intended to cut out the vehicles rear fog lamp when the trailer electrics are plugged in, I did a test last night and my current vehicle either doesnt have it or its not been connected because the reversing sensors continue to work when I plug my tester into the towing socket.

 

Does anyone know where to connect a cut out switch that will not throw up faullt codes?

Looking at the OEM wiring diagrams, there is no cut-out switch incorporated in the socket, the "trailer detector control unit" must sense the extra bulbs and switch the car fog lights off and tells the PDC unit that there is a trailer connected via the CANbus system 

 

Also no connection with this problem, but I noticed the OEM wiring doesn't include the ignition switched supply for the caravan fridge (pin 10) ??

 

Edited 28 April, 20197 yr by nige8021

Your correct on the trailer socket as there was no fridge power and no continuous 12v for charging the battery, when mine came fitted from the factory with 3 pins missing so with a brand new car I had to run cables to the fuse box taking off the trim etc. The fog lights on mine are controlled by the extra trailer box 1K0907383E on the canbus. You can buy sockets with a switch to turn off the fog lights and that would probably flag up a bulb out, so you would have to fool the cars ECU by putting a resistor in the fog light feed down to ground. Cheers Stuart

Big thanks to everyone, my middle passenger side sensor isn’t clicking.

Given the magical rebirth over the Easter weekend it may just be a connection or damp so ill have to remove it and test when I get a bit of free time.

Does anyone know if manuals online to make removing the sensor/bumper easier?

Edited 30 April, 20197 yr by mlwilliams

It was the speaker in the trim behind the seat belt on the near side, I tested it first by putting a 47 ohm resistor in series with a 4 ohm speaker and it all started working so then spent £8 on eBay for a replacement.The trim pulls off starting at the top, If I can find time I will post some pics.  The original speaker was 50 ohm and the replacement measured 25 ohms, Cheers Stuart