W212 Blind Spot Radar

[Sander1337]

Hi All,

Since recent time I have a weird malfunction on my W212. After driving about 15 minutes on the motorway the car mentions that BLIND SPOT ASSIST IS NOT FUCNTIONING and turns of the system, leaving both mirrors with an orange triangle.

Upon coming home I read the faultcodes and the following came up:

(Translation "Component B29/6 is configured incorrectly")

I checked the cabling of the sensor and found that it looked all good and the sensor was properly connected.

I then proceeded the working of the sensor:

Looking good and the radar sensors seemed to detect objects (my neighbours and my second car) fine. Also when backing up making sure the objects are out of range, it seemed to detect this just fine:

Sensor seems good then. So what has changed in the recent days that might have caused it? The bumper had a respray due to some damage (I assume that wouldn't make a difference).

However, upon inspecting the sensor a little bit better I found that the sensor was fitted like this to the bumper:

The previous owner however insisted the system was always working properly and the owner before him must have mended the blind spot system like this.

Im a little lost as to what my next action would be, would you guys have some recommendations? I was personally thinking of switching the sensors left and right around and test if indeed the sensor is fine, that way I can also visually inspect if there is anything underneath the left radar-holder.

Can I just exchange the sensors (without having to reprogram)?

Looking forward to your reply and insights, would love to have this fixed without buying a new bumper and having that resprayed.

 

[mersum1es]

They should not needed coding IIRC, mine was also giving an similar error and it was corroded connectors... cleaned and since all been good.

Looks like someone have had problems with water ingress and sensor has been tried to seal better... only if there is already some corrosion inside sensor, that may not help (plug can pass some water inside still). It is very hard to see if sensor holder is still intact or has it been broken and repaired by glob of sikaflex.

Because you got your errror in mid of driving, it must be something to do with connection/signals. You are now getting inoperative message right from starting?

 

[Sander1337]

They should not needed coding IIRC, mine was also giving an similar error and it was corroded connectors... cleaned and since all been good.

Looks like someone have had problems with water ingress and sensor has been tried to seal better... only if there is already some corrosion inside sensor, that may not help (plug can pass some water inside still). It is very hard to see if sensor holder is still intact or has it been broken and repaired by glob of sikaflex.

Because you got your errror in mid of driving, it must be something to do with connection/signals. You are now getting inoperative message right from starting?

Hi Mersum1es, thanks for your reply. I already suspected a poor contact but coulnd'nt figure how. Water/corrosion might be a good explanation. Do I fix the connector on the carside or the connector on radar sensor (I presume both), just with a steelbrush gently clean them? After doing this I will try to exchange the sensors from left to right and come back!

You are right I get the errors in mid of driving, never from the start. Given the error I would also assume the issue is with the signal. The interesting fact: even when the system is malfunctioning the sensors are still detecting fine and the picture that I made showing the distance to objects were made with the Blind Spot system malfunctioning. It appears one of the sensors just provides an unexpected value/short circuit and the system shuts down, but does not restart (guess this is just how it is made). Up to the moment I get the error the system works flawlessly on either side and it detects and warns vehicles in my blind spot.

A new used sensor is some 150 euro's so nothing too crazy, but would like to rule out anything other than the sensor before buying one .

PS: the owner before the previous owner had the car maintained at the MB official dealership in Germany, my girlfriend works for Mercedes and I have the complete repair history of the car. 4 years ago there is some mentioning of a control check of the radar driver assistance ("Driver assistance package/radar sensor control unit Software status") module but nothing about the actual work they have done afterwards... Anyway, looks like this was a bodgejob from the MB dealership, one more reason not to go there...

 

[mersum1es]

I just cleaned sensor connector and put some electric corrosion prevention spray. I remember reading whole harness is same crap and Parktronic is included at same harness (not 100% sure). I never tried take whole harness out because I have a trailer hitch and I would need to take bumber out to get harness changed. But if I need some day change radars, I would change whole harness too because some damage already done there.

There is some updated sensors available, Xentry (or WIS) stated that if newer sensors fitted, software update may be needed.

Chinese seems to have clone radars but... I nowadays try avoid anything made in China. Just because.

One trick to avoid moisture problems is drill holes bottom to original radar sensor holder so water can drain out and not keep sensor box floating in its place... of course now in your case that does not matter

 

[Sander1337]

You are right I get the errors in mid of driving, never from the start. Given the error I would also assume the issue is with the signal. The interesting fact: even when the system is malfunctioning the sensors are still detecting fine and the picture that I made showing the distance to objects were made with the Blind Spot system malfunctioning. It appears one of the sensors just provides an unexpected value/short circuit and the system shuts down, but does not restart (guess this is just how it is made). Up to the

I just cleaned sensor connector and put some electric corrosion prevention spray. I remember reading whole harness is same crap and Parktronic is included at same harness (not 100% sure). I never tried take whole harness out because I have a trailer hitch and I would need to take bumber out to get harness changed. But if I need some day change radars, I would change whole harness too because some damage already done there.

There is some updated sensors available, Xentry (or WIS) stated that if newer sensors fitted, software update may be needed.

Chinese seems to have clone radars but... I nowadays try avoid anything made in China. Just because.

One trick to avoid moisture problems is drill holes bottom to original radar sensor holder so water can drain out and not keep sensor box floating in its place... of course now in your case that does not matter

I have just taken the cable out, inspected it but couldn't see anything out of the ordinary/rust and put it back, a test drive later today will determine if it has fixed the issue. In case of corrosion I would say the message would only return after a day or so. The stupid AMG exhaust pipe is really in the way to be able to easily access the sensor and clean out the goo that was holding it in place so will do that over the weekend. Can I just spray the corrosion protection spray in the connector of the radar sensor while it is still attached? Imo it wouldn't damage the sensor or anything but that way I can quickly rule out corrosion on the connector.

I also would not suspect water in the sensor given the way it is mounted but will switched them around anyway.

Previous owner also stated the bumper might be not tied together good, causing the wind to vibrate the bumper causing the sensor to malfunction. Could not see anything out of the ordinary on the bumper fitment, but is this possible?

 

[LostKiwi]

Contact cleaner directly on connections is fine. Don't use WD40 as it causes the silicone seal to swell and you'll never get the connector on again.

 

[Sander1337]

I drained the plug and the sensor connector in contact-cleaner, then removed the goo around my sensor and exchanged left and right, then went for an hour testdrive and happy to report that the malfunction did not appear to come back. Also this morning's 30 minute drive on the motorway didnt cause any malfunctions.

I will know for sure this weekend when I will have a 2 hour drive but things are looking good! will keep you posted!

 

[Sander1337]

Alright, so the sensor threw another error, this time on the right side leading me to the conclusion the sensor itself is toast.

I want to replace it, but I see many variants of this parts which all look alike, does somebody know the OE number? This is the picture of the functioning sensor (which I want a duplicate of ).

I.e. this is PN A0009051300

I see a lot

PN A0009051302

Feels to me as the latter is just a replacement/upgrade/supersession, but is this true, can someone confirm? The latter is a lot cheaper than the first

 

[mersum1es]

I have also found that there are several part number at very different prices... someone claimed those sensors are compatible each other, but I would stick on EPC numbers. I had two different choices, A0009062600 and A0009062000. So here we see mine are totally different than yours. Give in VIN and someone digs part numbers for you.

 

[Sander1337]

I have also found that there are several part number at very different prices... someone claimed those sensors are compatible each other, but I would stick on EPC numbers. I had two different choices, A0009062600 and A0009062000. So here we see mine are totally different than yours. Give in VIN and someone digs part numbers for you.

Thanks for you replY! So good to see that there is so muhc knowledge here
I also have the 2000 on mine (see attached picture), so would the 2600 also work?

WDD2122021A323600

 

[mersum1es]

Thanks for you replY! So good to see that there is so muhc knowledge here
I also have the 2000 on mine (see attached picture), so would the 2600 also work?

WDD2122021A323600

For you car, EPC gives ONLY A 000 906 20 00

 

[Sander1337]

For you car, EPC gives ONLY A 000 906 20 00

Bought a replacement for 180 euro including shipping.

Hopefully this puts the car back in the right order

 

[Cricket1]

When refitting these types of sensors that are exposed to the elements try wrapping in “self amalgamation “ tape. Tape the body prior to fitting,then the electrical connection once fitted. Easy to use,cheap as chips from Screwfix. I’ve just been quoted £500 parts and labour to replace a damaged unit which I suspect is just water ingress, the new unit and wiring will be wrapped I can assure you. Mercedes should sort this weak spot out. My sensor has done 16000 miles but is sadly out of warranty,they are getting the old one back!

 

[sonic]

When refitting these types of sensors that are exposed to the elements try wrapping in “self amalgamation “ tape. Tape the body prior to fitting,then the electrical connection once fitted. Easy to use,cheap as chips from Screwfix. I’ve just been quoted £500 parts and labour to replace a damaged unit which I suspect is just water ingress, the new unit and wiring will be wrapped I can assure you. Mercedes should sort this weak spot out. My sensor has done 16000 miles but is sadly out of warranty,they are getting the old one back!

Good stuff self amalg used it on radio mast cables for years, completely waterproof.

 

[Blobcat]

Good stuff self amalg used it on radio mast cables for years, completely waterproof.

Then a bit of Denso-tape over that
Somewhat challenging to get your hands clean afterwards if you weren’t wearing gloves, but It keeps the weather out.
I wouldn’t recommend Denso-tape for automotive use though

 

[sonic]

Then a bit of Denso-tape over that
Somewhat challenging to get your hands clean afterwards if you weren’t wearing gloves, but It keeps the weather out.
I wouldn’t recommend Denso-tape for automotive use though

Denso was very good but very messy. Defenatly needed gloves!

 

[matthew k]

Contact cleaner directly on connections is fine. Don't use WD40 as it causes the silicone seal to swell and you'll never get the connector on again.

Yeah, bit of a nasty product TBH. I once in my youth got some on a brake caliper, it swelled the seal so much the piston started binding. I also remeber as a child applying it to my bike chain, it attracted grit like fly paper.