e39 touring parking sensors

[mattycoops43]

Hi

Still chuffed with my E39 tds touring, love the way it drives and it's whooshiness!

I didn't realise it was meant to have parking sensors, but when you put it in reverse (auto) I get a beep for about 10 seconds, that sounds like a parking sensor tone, then it goes off. Nothing to do with anything behind the car changes the sound. The parking sensors in the rear bumper look like they have been taken out and re glued in.

I can get sensors and a sensor ecu cheap enough on fleabay, but I was wondering if anyone knows whether the fact that it makes a noise at all means the ecu is working, and its the sensors? or if I just have to change one thing at a time.

Is it like abs, ie-1 sensor stops working, the whole system is down?

Thanks. I have never had anything to do with these sensors at all.

[andyp]

mine does this when reversing into my drive but its the corner ones picking up the gates as i pass them, so are you saying that there is nothing next to you either

[AndyG]

if you get a single tone when you select reverse then they stop completely then they may just need a proper clean. If they have any dirt build up or even polish on them they'll stop working. So its worth giving them a good clean with something to take the previous polish or grime off, then have another go to see if they work again!

If one sensor goes on the blink then yes they all stop. But you can tell which one is on the blink, you need to listen to each one carefully as they'll emit a noise of sorts (according to google if you do a search).

[B7]

It will be a faulty sensor. You'll see the light on the switch flashing after the tone stops. need to be careful when buying second hand as there are several different types. Check your part number and only by like for like.

If you put your ear very close to them with the car in revrse and the ignition on, NOT STARTED , you should here them ticking. If you find one that isn't, thats yopur faulty one. However, it's not always the case that one stops ticking.

You can have the diagnostics run which will tell you which one it is.

They can also suffer water ingress. And they take forever to dry out! Some say you can offload a full can of WD40 directly into the leans and some will find it's way into the sensor via the back. But I tried it and it didn't work for me.

[mattycoops43]

Thanks guys. Nothing next to me, but I will have another look and see what they are doing. definitely not working as you can be 3" off a wall and nothing.

Will definitely try a good clean, as the car came from the dealer with a really thick wax on the whole thing, if I drive in rain, then park, it is at least 4hrs before the windscreen dries out and you can see all the droplets collecting and the light reflecting funny, so that must be on the sensors as well.