Parking Sensor Wiring

[DubDriver]

I apologise in advance for raising the subject of parking sensors yet again, but I do not seen to have found a solution to my problem in other posts that I have viewed.

 

My particular problem is that when the sensors are operated i.e. reverse selected or button on dash pressed, there is a short beep followed by a much longer higher pitched beep from the control panel under the passenger seat accompanied by a flashing light on the dash. I have been fortunate that the control panel has not suffered from water ingress, therefore I have had my sons listening to the ticking noises from the sensors.

 

We have determined that the front offside sensor nearest to the number plate is not making a sound. I took off the bumper trim and swopped the two offside sensors round which proved that the sensor is not faulty, so there seems to be something wrong with the wiring. The wiring connection to the sensor is tight with virtually no slack in the loom, however there does not appear to be any damage to the the cable.

 

I would be grateful if anyone can give me any ideas where the loom exits the car at the front and if there are any connectors in the loom that may have got water in them or in fact any places where the cable may have got damaged.

 

I would also like to know if I could take a feed from the adjacent working sensor to solve the problem?

[Mirez]

Ok to start, no you can't splice the wiring from the adjacent sensor. They are all addressed separately by the controller so they don't interfere with each other, wiring them together won't work and could potentially cause damage to the controller. That said they do share common supply and ground lines so you could splice those if you really wanted to.

 

The inner right sensor has three wires, Pins 1 and 3 (Red and Brown) are the supply and ground feeds and the centre pin 2 (blue) is the signal wire. Its reasonably common for the wiring to break at the plug - I would advise you remove the insulation tape back a good 8cm and fully examine the wiring for any breaks. There is a connector in the engine bay, on the left hand side although that

Edited February 2, 2009 by Mirez

[richyrich]

I had exactly the same problem a few years ago - exact same sensor. Found out that when I pushed the sensor fully home the tight wiring loom caused the plug to slightly come off. Cured it then by putting a spot of superglue in the plug before connecting it.

I did a job on my a/c not so long ago and took the whole front bumper off - surprisingly easy, only takes 15-20 mins. When you do that you have to unplug the parking sensor loom and the temperature sensor. This would give you a better look at the wiring loom around the inside of the bumper - up to you!

 

Richard

[DubDriver]

Thanks Mirez and Richyrich for your prompt replies, I will have a closer look at the plug and wiring near to the sensor for fit/damage.

 

That's if it stops snowing sometime soon!!!!!!

[Glen]

Dubdriver, did you get this problem resolved?

 

I have a similar problem which is driving me insane and I could do with the some help from you experts! When selecting reverse, I get either a constant tone or a beeping as if I were approaching an object. This is intermittent but happens more often than not. I have plugged in a restricted version of VAG COM and this indicates that the O/S/F middle sensor next to the number plate is detecting an object as the distance measured is much less than the other sensors. I have swapped the sensors around but the fault still lies with the same sensor. This then led me on to check the wiring loom. With the aid of a wiring diagram, I removed the bumper trim and all the front sensors and removed the wiring loom between the sensors and the connector behind the N/S/F fog light. This was inspected and continuity tested to check for any breaks but all seems OK and all the plugs look clean. I replaced the front loom and tested the whole circuit again between the (disconnected) control unit connectors under the passenger seat and the sensor connectors at the front using both a continuity tester and a megger type insulation tester. All tested out fine. I reconnected the sensors and the control unit but the fault is still there. This lead me to believe that the fault must lie with the control unit as I had tested and eliminated the sensors and the wiring. So I bought a new control unit from VAG parts at a cost of around 80 quid. I plugged it in and guess what? The fault is still there. I am now at a loss as to what else it could be. Having come this far, I really don't want to admit defeat and hand it over to a dealer. Any ideas anyone?