Parking sensor problem e46 Bmw 3 series

Hi all.

I am having some problems with the parking sensors in my car. They have basically stopped working suddenly.

When I put the car into reverse the buzzer sounds continually, as if something was very close to the rear of the car it then stops after a few seconds or if I disengage reverse and re-engage it again, however as I reverse up to an obstacle there is no sound at all from the warning buzzer.

The car is a 2001 318ci and the sensors are oem (presumably factory fitted).

I'm comfortable enough attempting to tackle them myself if someone could point me towards possible causes or solutions to the problem.

Thanks.

nogoodnamesleft

I had this problem on my Passat.

The PDC system works roughly the same in most cars. The PDC system usually consists of 4 sensors connected to a PDC controller usually hidden behind some trim in the boot and a speaker (for the beeps).

When the PDC system is engaged they always perform a self test to ensure every thing is working ok. If a fault is detected it emits a different beep to indicate that it encountered a fault and turns itself off a few seconds later as a safety precaution.

I had VAGCOM and it diagnosed the fault sensor for me. But you can also do a self test. With the car off and in reverse turn the key to ignition, quickly test each sensor at a time by putting your hand over it before it turns itself off to identify which sensor is faulty. You might have to turn the ignition on and off to test each sensor depends on how quick you are!

I couldnt source the sensor anywhere but the main dealer 80euro later :mad:

I came across the PDC sensor for BMWs thou here. reasonable enough although check with BMW Ireland to compare as kufatec are sometimes more expensive. Its a US site but they are based in Germany.

http://kufatec.com/index.php?main_page=product_info&cPath=102&products_id=476

nogoodnamesleft

European Part Price:

http://www.kufatec.de/shop/product_info.php/info/p1105

Slidey

The 5 series lets water into the boot and the control unit is in the footwell.

Have a check and see if there is water in the well, probably not the same but it won't take long to eliminate it either way

Thanks for the reply's I will check out whats suggested when I have a chance.

Captain Slow IRL

Slidey wrote: »

The 5 series lets water into the boot and the control unit is in the footwell.

Have a check and see if there is water in the well, probably not the same but it won't take long to eliminate it either way

I'm pretty sure the module is tucked behind the fuel filler cap - don't think water ingress would be a problem for it.

It sounds like a sensor has failed - you will need someone with diagnostic equipment to check which one. When you find the defective sensor, swap it with another sensor to ensure it's not the wiring that's at fault.

If you want to try popping out the black trim piece with the sensors on it, disconnect each and make sure the connections are nice and clean - use some electrical contact cleaner (or wd40, whichever's handy!) on the plug and sensor to eliminate this as the problem.

the merchant

The PDC in my 02 5 series hasn't worked for the last 18 months. When I saw this thread I decided to have another look this evening to see if I could sort it out for once and for all.

So first thing to check was the sensors. An easy way to do this is... ignition on, into reverse and put your ear up to the sensors. You should hear a clicking noise from each sensor. If there's one or two not clicking, they're probably faulty. In my case none of them were clicking.

I then took a look at the PDC control unit, noticed that there were only two of the three block connectors connected to it, found the stray cable and bingo, back in business.

Actually I think I know what happened. IIRC it stopped working when I replaced the battery so I must have knocked out the connection then.

Owen

+1 on the clicking sound. You should be able to hear the sensors operating correctly.

Voodoomelon

Clicking sound it a good way of diagnosing faulty sensors. Because you are getting the beeping coming from the back of the car, it means one of the rear sensors is faulty, not the front. So stick your ear next to each one and have a listen.

If one is not ticking OR ticking more faintly than the rest, its more than likely faulty. You can pick up PDC sensors on eBay, pulled from other cars for about €30.

TJJP

Likely a sensor, I had the same issue. If any one sensor fails you get the constant sound on engaging reverse. You can swap them out one by one until you solve the issue. I have a few lying around that I didn't need after a repair. PM me if you if you are interested. I can let you have one for €20 (if that's allowed on here).