[P-ToK72]

I have an intermittent issue with my Rear Parking Sensors (i think caused by water ingress) that is causing the emergency brake to jam on sometimes when reversing.
I may have caused this by being a little to keen with the jet wash as it appeared to have started around the time a few washes back.

I read online that some people solve it with WD40 and i did this around 2 weeks ago and it did seem to work. However with the current weather and persistent rain the problem is back again.
I figured out that I can turn off the rear emergency brake on idrive which will prevent the unnecessary stopping of the car in reverse however the sensors will still be going bonkers without anything being there to trigger them.

Have any of you guys had this issue with their current or past BMWs?
I'm desperate to solve this but fear that it might need booking in to BMW.

Any advice would really be appreciated with this...

[TuffLittleUnit]

By coincidence, it happened to me in a supermarket carpark at the weekend. Hadn't washed the car for a couple of days and I never use a pressure washer. The car simply wouldn't let me reverse into a parking space with a car on one side and an empty bay on the other - and it was the vacant side the sensors were complaining about. I looked like a right numpty stranded at 45 degrees across the road with that horrific grinding noise from the brakes every time I tried to reverse. I checked multiple times to make sure there wasn't a small child, trolley, box etc behind me.

In the end I pulled forward a little, reversed again with no problem. Not had another occurence since. Just one of those things... it's happened maybe 4 or 5 times in the 20 months I've had the car, usually when it's damp and the car's a bit dirty.

[RichardM]

I experience this occasionally too, it just refuses to let me reverse even though I can see it is clear. I've never thought it was a faulty sensor just a flawed system

[P-ToK72]

Thanks TuffLittleUnit and RichardM

In my instance it seems very coincidental that my sensors started playing up after a wash one weekend and for some time it has been going absolutely mad with the sensors falsely activating, the car braking and that nasty grinding noise you were describing.
I have read that water can ingress into the sensors when using a power washer so i think it might be that.
I am probably going to jinx it here but over the past few days the issue has not been happening but for now the AutoBrake under reversing is switched off.

[Nembus]

Hey all I had this issue for the past two weeks but managed to get a fix where it ceased entirely so far.

1. First you'll need some sort of scanner tool or PC connected to your computer to find out which sensor is the one giving you the issue else you'll be doing the 6 sensors on the entire end of the vehicle(which actually isn't a bad idea).

2. Then you'll need to buy some electronics contact cleaner and protectant, there are a few brands but get something good here, don't think I can post links here. Also a plastic o ring tool/pick.

3. With the o ring tool/pick take out the rubber gasket surrounding the parking sensor, get around the edge and pull it out. Try and be gentle with it. Once the rubber gasket is out, grab your contact cleaner and spray/clean out the void where the gasket was. Do this for all and any sensors you think have an issue. Let everything dry out, follow the directions on the bottle. Wipe everything with a clean microfiber cloth and put the gasket back in and done voila. No more annoying PDC issues fingers crossed. This should work for any PDC sensor if the issue is intermittent. Else you have an actual issue with the sensor where it needs to be replaced.

[P-ToK72]

Originally Posted by Nembus

Hey all I had this issue for the past two weeks but managed to get a fix where it ceased entirely so far.

1. First you'll need some sort of scanner tool or PC connected to your computer to find out which sensor is the one giving you the issue else you'll be doing the 6 sensors on the entire end of the vehicle(which actually isn't a bad idea).

2. Then you'll need to buy some electronics contact cleaner and protectant, there are a few brands but get something good here, don't think I can post links here. Also a plastic o ring tool/pick.

3. With the o ring tool/pick take out the rubber gasket surrounding the parking sensor, get around the edge and pull it out. Try and be gentle with it. Once the rubber gasket is out, grab your contact cleaner and spray/clean out the void where the gasket was. Do this for all and any sensors you think have an issue. Let everything dry out, follow the directions on the bottle. Wipe everything with a clean microfiber cloth and put the gasket back in and done voila. No more annoying PDC issues fingers crossed. This should work for any PDC sensor if the issue is intermittent. Else you have an actual issue with the sensor where it needs to be replaced.

Hi Nembus, that's really good information, thank you. I'll keep this in mind as an option if i continue to have problems.

I would be interested to know what you used in terms of the contact cleaner / protectant. I'll send you a PM if you wouldnt mind letting us know so that i get something along the same lines.

I want to avoid replacing if i can as i know the sensors will cost a fortune and it will inevitably involve removing the rear bumper.

[TuffLittleUnit]

I should add that my previous car (BMW G01 X3) did the same throughout the 3 years I had it. Very infrequent - maybe 2 or 3 times a year.

Personally I'd never turn the feature off because it saved me twice in the X3, once in a fuel station and once in a supermarket car park.

I'd checked behind me properly (camera, mirrors and periphery) on both occassions but as I came to reverse, someone pulled too close on my blind side. The car slammed the anchors on both times ... pretty sure I would have been deemed "at fault".

My view is it's better to have a false positive.

[P-ToK72]

Originally Posted by TuffLittleUnit

I should add that my previous car (BMW G01 X3) did the same throughout the 3 years I had it. Very infrequent - maybe 2 or 3 times a year.

Personally I'd never turn the feature off because it saved me twice in the X3, once in a fuel station and once in a supermarket car park.

I'd checked behind me properly (camera, mirrors and periphery) on both occassions but as I came to reverse, someone pulled too close on my blind side. The car slammed the anchors on both times ... pretty sure I would have been deemed "at fault".

My view is it's better to have a false positive.

Agreed, it's only temporarily turned off until i get this sorted. They false readings are happening so frequently that it's difficult to reverse or park anywhere at the moment.

I picked up some WD40 contact cleaner last night as i was passing Halfords. I'll give that a try with removing the seal as described by Nembus and then maybe see if i can get or borrow a fault reader to see if it brings anything up.

[Nembus]

Originally Posted by P-ToK72

Hi Nembus, that's really good information, thank you. I'll keep this in mind as an option if i continue to have problems.

I would be interested to know what you used in terms of the contact cleaner / protectant. I'll send you a PM if you wouldnt mind letting us know so that i get something along the same lines.

I want to avoid replacing if i can as i know the sensors will cost a fortune and it will inevitably involve removing the rear bumper.

Yeah PM me and i’ll send you the product I used. My fix is still working as of today. I tried the WD40 and it didn’t last very long.

[ianmar90]

When you're disconnecting parking sensors, do you need to disconnect the battery first?

I need to replace some bumper trim so need to remove the bumper and want to make sure i dont cause any issues!

[bmnut]

Originally Posted by ianmar90

When you're disconnecting parking sensors, do you need to disconnect the battery first?

I need to replace some bumper trim so need to remove the bumper and want to make sure i dont cause any issues!

Recently replaced the ‘bugs bunny’ grille on my G22 and just unplugged the sensors then re-connected them without causing any issues at all.

[a.summers86]

Originally Posted by ianmar90

When you're disconnecting parking sensors, do you need to disconnect the battery first?

I need to replace some bumper trim so need to remove the bumper and want to make sure i dont cause any issues!

No need to unplug the battery if you’re removing the bumper and sensor connector.