Rear Parking Sensors are temperamental

[CryptoWhale]

I thought it'd be worth creating a separate thread as this is a completely different issue to my last.

Basically as title says - my rear parking sensors worked fine the other day whilst parking up. Then yesterday in the car park they didn't work. When I got home, I turned the ignition on and put the car in reverse, went behind the car and each sensor worked correctly.

This morning when reversing into a space, they didn't work. Turned the engine off and on, still didn't work, messed around for a few minutes and still nothing. I've just gone back to the car this afternoon and again they didn't work at first. Turned engine off and played around with the ignition and gearstick a few times and low and be hold they started working!!

Is this a common issue or am I just missing something obvious here? :lol: Any ideas why it's so temperamental? :headbang:

Thanks

 

[parabolica]

Common issue. Mine have been intermittent since I bought the car 2 years ago; sometimes they work fine, other times the tone is continuous. I've checked all my sensors and they are fine (last time I checked); I think the PDC control module in the boot is prone to failing. Easy enough to replace and it's a pretty common BMW part but just never got around to it.

 

[CryptoWhale]

Common issue. Mine have been intermittent since I bought the car 2 years ago; sometimes they work fine, other times the tone is continuous. I've checked all my sensors and they are fine (last time I checked); I think the PDC control module in the boot is prone to failing. Easy enough to replace and it's a pretty common BMW part but just never got around to it.

Good to hear that it should be relatively straight forward then. It's not a big deal but it's a nice feature to have when parking up, bit annoying when its temperamental though.

 

[dhobbs]

Mine did the same thing. Tempermental then fine. I cleaned them outside incase there was dirt in them. I reseated the control unit and even had the bumper off and reseated each sensor. Eventually one of them did fail which I replaced and all is fine now.

 

[Wortmanov]

Mine was quite tempramental as well. Of course, it never worked in a tight spot...
Turned out the sensors were fine, but the loom had a break somewhere. Replaced that, haven't had any issues since.

INPA did show an intermittent fault, that's what led me to the cable.

 

[pr117]

Easy to diagnose the one that is going to fail. If system telling it is not working go listen each sensor very closely. The ones that are working correctly make very high frequency clicking sound. The one that does not is probably faulty (or the wire connected to it). Ignition has to be on, engine not running to hear the clicks.