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Get to your PDC unit (water issue)

E8x 
365K views 342 replies 110 participants last post by  drew_g 
#1 ·
Right, a few people have mentioned of a problem with faulty parking sensors, 'Xmas tree dash', random electrical issues, or their PDC (Parking Distance Control) showing special Icon showing up on your dash when put in reverse, like this:-



The possible cause is that there is water in the PDC holster well & it has got water damage.

This can be caused by:

Changing your rear lights. (Reusing a seal instead of a new one on the lights)

Holes in the side of the car letting water in. (black things which have filters in for air feed inside the car)

If you have this issue, here is a Brief "How To" get to the PDC Module and check for water:

First of all, start by removing the floor carpet which basically lifts and pulls out like so:


Next is to remove the plastic boot strip, located either side is 2 plastic Caps which you can remove with a flat-head screwdriver like so:

Under these caps consists of a Philips Screw.... You know what to do.

Once you have removed the Screws if you look at the bottom of the plastic panel there are 2 plugs, simply Prise them out with a flat-head screwdriver like so:

Then using some pin-nose pliers or another tool, simply pull. They are not attached; they are just plugs to secure it. Like so:

Your side panel will then be accessible more easily like this.


Next is to undo the bolt on the side which attaches some Trim to the hook:

It requires a Torx Screwdriver, but I simply found a long enough Flat-Head screw driver useful.

For more ease you need to remove the plastic panel above which holds your rear speaker in place, I however left it there because it is very fiddly to remove.

I also recommend removing the rear light for more accessibility into the PDC's well.

Now that you remove all the nessicery parts, Simply Pull on the Arch cover, pulling it out from the boot seal and out as far as it will go (don't bend it too much, it is fiberglass.)

The PDC is located down here:


Now..... Model of your car MAY differ; I noticed some of you do not have the Polystyrene Holster for your PDC Module, whereas I do:

Example pictures here:

2009 FL 3-door M-sport Hatchback:

Remy's Pre-FL 5-door M-Sport Hatchback (Notice the water issue she has)


To remove the PDC:

For anybody with a PDC holster like Remy's simply pull the tabs apart either side and pull the PDC out.

For people who have the PDC like mine, the Wire is tacked to the polystyrene, simply Pull on the wire, and then slide the PDC Module out, leaving you with this:


Now if there is water damage, and water in the well, GET IT OUT!!!

Disconnect it, get it in a bag of rice, and leave it in a warm location for 72 Hours (3 days)

Hope this helps you all.

Lee. :D
 
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#252 ·
I replaced PDC unit with a unit with the same part number off ebay but they are still not working. Display warning light now comes on and front sensor button flashes!

I can test the rear sensors by putting my ear to the sensors and can hear all 4 are clicking but how can I test the front sensors?

I know I may also need my new PDC unit coded but wanted to just eliminate a faulty sensor could be causing failure
 
#253 ·
scw02102 said:
useful thread but still havent fixed my issue

My 120d parking sensor errors on the dash and light flashes on the button when I engage reverse. I checked my PDC and was dry but still ordered a new one from ebay that apparently is perfect, the model numbers match perfectly and came from the same 120d as mine.

Plugged in tonight still no luck exactly the same issue.

Any ideas what to test next? I have also listen for the clicking noise on the sensors from the bumper but cant hear anything at all, also I have checked both fuses and both are fine

What next.....????
thanks in advance
Snap. I bought a brand new PDC unit from Cotswold BMW but it didn't fix it. Checked one 5A fuse (behind glove compartment) and it was OK - where is the other? I cleaned all the sensors carefully and then removed the rear bumper and checked and cleaned all the connections. Still nothing.

Strange thing is that sometimes they work for a few seconds before failure and this is why I doubted the fuse.

I've not tried to listen for clicking yet. I'm buying Carly to see if it can help identify the error.
 
#255 ·
Cabbage Patch said:
The PDC in my 2012 F10 520d has gone screwy this week. I'll take a look in the boot for the module but before I do can anyone point me to where it lives in an F10?

Off topic on BabyBMW I know but this forum's much more active than any 5 series one.
Not sure the 5er (at least the F10) has a PDC module:
I looked for a random model and random PDC config, so search for yours within there and you might find different.
 
#260 ·
floydroid said:
scw02102 said:
useful thread but still havent fixed my issue

My 120d parking sensor errors on the dash and light flashes on the button when I engage reverse. I checked my PDC and was dry but still ordered a new one from ebay that apparently is perfect, the model numbers match perfectly and came from the same 120d as mine.

Plugged in tonight still no luck exactly the same issue.

Any ideas what to test next? I have also listen for the clicking noise on the sensors from the bumper but cant hear anything at all, also I have checked both fuses and both are fine

What next.....????
thanks in advance
Snap. I bought a brand new PDC unit from Cotswold BMW but it didn't fix it. Checked one 5A fuse (behind glove compartment) and it was OK - where is the other? I cleaned all the sensors carefully and then removed the rear bumper and checked and cleaned all the connections. Still nothing.

Strange thing is that sometimes they work for a few seconds before failure and this is why I doubted the fuse.

I've not tried to listen for clicking yet. I'm buying Carly to see if it can help identify the error.
Success! Parking sensor system working and no more 'Christmas Tree' warning. I bought a second hand sensor and started replacing each one in a process of elimination. It worked at the third sensor.

So, now that I don't need my brand new Cotswold BMW supplied PDC unit - who wants to make me an offer for it???
 
#261 ·
Hi all - thanks for an extremely useful forum. The parking sensors on my 118d (2010) went wibble a few weeks ago and thanks to this discussion I've found the water issue and a frazzled PDC unit. The bottom 1cm of the circuit board was damaged. I just wanted to let people know an alternative to getting robbed by Main Dealers or buying a potentially dodgy used PDC on eBay. Instead, I sent mine to a place in Sheffield called Nova Electronics and they've managed to repair the board and post it back to me for £55 all-in. I just plugged it back in to check and it works perfectly. I haven't fixed the water issue yet though.... a job for the weekend.

Their website is here:
The service was superb!

Thanks again for the great post Lee.
 
#262 ·
Thanks all for the helpful posts in this forum.
The parking sensors on my 118d hadn't worked since I bought the car 3 years ago, just had the error light on the dash and I've just got round to fixing it.
I initially thought it may be the water issue but on inspecting the PDC module it was bone dry and apart from slight corrosion on 2 pins, it looked fine but I stuck it in rice for a few days anyway. When I put it back in the car it still didn't work.
Next I bought a 2nd hand PDC with the same part number off eBay but it still didn't work.
I then decided to read through the forum properly and saw that I should check that all sensors make a clicking noise when the car in reverse (turn the battery on but not the engine). One of the sensors didn't make any sound and after checking it wasn't the wiring I bought another sensor of ebay. It took 1 minutes to fit, I didn't need to remove the bumper or even jack up the car. Now parking sensors work properly, and my original PDC was fine :).
Thanks guys.
 
#265 ·
Dave 77 said:
Stupid question but does the PDC unit control parking sensors
Yep. PDC module = Park Distance Control module. It does prety much everything associated with the parking sensors:
- it generates the voltages that drive the sensors.
- it processes the return signals from the sensors, to determine the distance each sensor is detecting (on some models, the distance is displayed, or at least an indication of distance (near, nearer, stop you blithering idoit you're about to hit it).
- it generates the output for the human (either through a little speaker in the back, through the head unit and car speakers, or through screen display for models more posh than mine :) ).

Sensors themselves do pretty much nothing but chuck out an RF signal (so weak a thick layer of paint will stop it - I kid you not), and detect any reflected back to pass a signal back to the PDC.
 
#267 ·
Hi all, new to the forum and thanks for the priceless advice given on this issue. Just bought a 2009 1 series and struggling to sort the factory fit rear sensors (no front sensors). I've been through all pages here and unfortunatley nothing has worked. No damp or signs of moisture when removed, ordered and tried a new unit with the exact same part number which again failed to resolve the issue, no signs of poor wiring, and no fault codes or errors with rear lights. I get no sound whatsoever from inside the car or from any of the 4 rear sensors while in reveerse so I am led to believe it's not sensor related, although it's not looking like a module problem unless I have 2 faulty units or the wrong part number! If anyone has any suggested next steps before I give in and get it to the garage it would be much appreciated!

Jay.
 
#268 ·
jay100 said:
Hi all, new to the forum and thanks for the priceless advice given on this issue. Just bought a 2009 1 series and struggling to sort the factory fit rear sensors (no front sensors). I've been through all pages here and unfortunatley nothing has worked. No damp or signs of moisture when removed, ordered and tried a new unit with the exact same part number which again failed to resolve the issue, no signs of poor wiring, and no fault codes or errors with rear lights. I get no sound whatsoever from inside the car or from any of the 4 rear sensors while in reveerse so I am led to believe it's not sensor related, although it's not looking like a module problem unless I have 2 faulty units or the wrong part number! If anyone has any suggested next steps before I give in and get it to the garage it would be much appreciated!

Jay.
Fuse?

If you put your ear up to each sensor, can you hear each clicking?
 
#271 ·
Thanks! So I've checked fuses and all look good. I also testd opening the door with side lights left on with the key removed and the warning beeper sounds fine (presuming this is the same beeper for the rear sensors?), although no sound when testing this with the low beams left on. Except for wiring I'm pretty much out of ideas :cry:
 
#272 ·
Which car and head unit have you got?

Some cars (with Business HU) have a speaker in the rear for the parking beeps, wired directly off the PDC unit (like mine :) ), so other bongs and gongs working would be irrelevent.

Which part number is fitted? Just because you replaced like for like doesnt mean a previous owner didnt attempt to fix a problem and fit the wrong one (we've had folks on this forum do that). If you have the BU PDC and a Pro HU, then the sounds wont work (I've not checked if the wiring is sufficiently different to stop the sensors clicking as well).
 
#273 ·
Cheers, great advice and it's funny you say that as I have just been wondering whether it's the wrong part number! Checked realoem.com and the Bosch part number doesn't seem to appear (mine is 6621-6982402). It's a 2009 1 Series M Sport 120D with factory Business HU. I did read about the speaker being in the back passenger area but not got around to looking for it. So with this info, any ideas how to confirm which part number should be in my car? Or does it need a call to BMW? Also discovered this morning it could be related to the Parrot kit which came with the car?

Thanks all.
 
#274 ·
Update on this one..

-Turns out I am getting clicks from each rear sensor, all 4 working fine
-Confirmed my PDC unit works fine, both tested by unplugging and re-plugging with tests, and confirming part number with BMW
-No separate speaker in my model, just an empty space where it shoud be
-Both rear speakers working fine (presuming this is where the sound would come from?)
-No additional options in HU for PDC
-Disconnected the Parrot handsfree and still no luck
-Fuses all okay

Can anyone suggest what else there is to check, otherwise looking like a trip to the garage :cry:

Is there a diagram of factory fit business radio headunit connections anywhere as there's all sorts going on behind this dash!

Thanks!
 
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