al300sd

Hey All, I Have a 2014 facelift E550 i got messages saying blind spot and lane keep assist are disabled. i believe its the rear radar. How can i know for sure (which module is it when i scan) ??? Has anyone replaced these before? Are they interchangeable?


Thanks all

kajtek1

Get a scanner and read what is it.
Lane assist can be dirt on windshield.

Arrie

Does this happen from the start of the car? Does the error clear after you turn it off and re-start?
If above is true you may have a problem with the AUX battery. Lane keep and blind spot assist are separate functions. Lane Keep works from the camera in the windshield and does not use radar sensors so them both going out at the same time is probably something else than the radar sensor. It could be a coincidence that both go out at the same time but not likely. Scanner may be able to tell what the problem is but if it does not then look at the AUX battery condition.

I have a 2010 E550 and I had this same problem when the outside temperature wend down during winter time and the AUX battery got weak. Re-starting the car cleared the errors as the engine after one start fired up easier. The fix was to replace a fist size AUX battery that my car has. Yours is probably different design but these are the same symptoms when the AUX battery goes weak. In my car I also lost the Distronic function when this all happened.

al300sd

The windshield front and back are clean and I do have a scanner however when I look up the left and right radar it tells me it has an error communicating with the ECU so I'm thinking I'm looking in the wrong place. I did take out the sensor to examine it and the sensor was dirty with a slight bit of rust but no bulging.

al300sd

I remember I had this issue a few years ago when the main battery was dying so it would make sense that the auxiliary battery would cause the same issue. I know that there's one in the trunk are there any other ones that I should look into?

kajtek1

Sounds like you found your answer.
I did not have this trouble yet (knock on the wood) but I read that those radars are prone to corrosion damage.

bmwpowere36m3

If the scanner is telling you no communication… then likely the radar sensor/s are dead (under rear bumper). They commonly corrode and the harness does as well.

Clean them up, unplug, look for green crusties.

CaliBenzDriver

No ECU COM'S error does sound like a networking issue more so than anything else.

I can try to have a closer look at that control module if someone WISe would please show us where it is hosted + wiring schematic

I'd guess it is located somewhere near the front... under the dashboard -or footwell side??

My bet is... this safety related module does have professional grade but wiring issues.
My 2x front side RDU sensors invariably report being affected by "external noise" but appear to work.
The crusted rear sensors are on my list to visit with silicone calk before rain contamination sets in.
Let's see how we can sort this out.
👍

++++++++
TOGETHERNESS :
"BlindSpot and LaneKeepAss. disabled".
What do they share that makes them go wonky simultaneously ?

Idklol69

If this has to do with one of the modules near the exhaust, I ran into some issues last week. I didn't get anything was disabled, but while I would drive, I would see a picture of a car on the right side and the car would slow down and sometimes tighten my seatbelt. For your case, I wouldn't know which module it is, left or right. I highly suggest you get under your car, and with your phone + flashlight on, clean each module with a wet paper towel or microfibre cloth with a glove (lots of dirt will fall). After you clean both, maybe spray water on the modules with a hose as I did. I did this knowing water could damage the module, but I thought the module needed replacing anyways, so I took the risk. Everything has been working flawlessly since I cleaned the module.

al300sd

thanks everyone, I pulled one out earlier and cleaned it and put it back, saw a few light rust spots around the white rubber. going to pull the other tomorrow. Checked the batteries both are ok. I do have a code for a bad b7 parking sensor. can that be it?

konigstiger

Swap sensors (same part # for both sides) to see if fault code follows if so and there are no visual problems to sensor, replace it. See attached bulletin.

al300sd

I'm using the mb II
Vin# wddh9bb8ea874513

bmwpowere36m3

That's the rear radar, B29/6 and B29/7 are in the rear bumper.

al300sd

yep looks like it... Does anyone know if they are interchangeable. or do i have to match the part# exactly?

bmwpowere36m3

Interchangeable with what? Their the same part left and right.

The sensor has undergone several revisions over the years... if you want to avoid the possibility of needing to code them, then replace them with the exact same P/N, along with other designators on the sensor (HW and SW). See here: https://mbworld.org/forums/e-class-w...placement.html

al300sd

That's what I was afraid of. I have to purchase a used sensor cross my fingers and hope it lasts.

dave2001auto

Hi Konigstiger,
Geat files you posted.
Without a scanner is there any way to diagnosis if it is a CAN problem or 2 rear sensors?
Both sensors are inoperative and both sides don't detect a car in the rear. Everything else on the car seems to work.
The left driver side under panel was serviced 1 month before blindspot when inoperative (scrapped bottom on parking garage -- too steep between floors).
The sensors looked fairly clean. Sprayed under bumper if dirt between sensor on bummer cover. Wait 3 day to dry area before turning back blindspot assist. Still no go.
Dave
2012 E350 4-matic 4 door.
WDDHF8JB7CA638461

T100T

For what it's worth I got the same message about blind spot disabled, no more red symbols in door mirrors, inspected both units under rear bumper both looked good, no contact corrosion, no bulging. Scanner said it was left unit that was bad. Purchased a used unit from eBay (price seemed high but alternative was a new one from MB and programming), the three numbers on the replacement matched those of bad unit, installed it and it is working fine. Peter

KEY08

^ good job on the fix!

dave2001auto

without the scanner, there was on orange triangle on each side mirror that stayed orange instead of turning red? If so, looks like mbz took away simple diagnostic for diy’ers. Both my mirrors stays orange.
Will salvage on be at end of its life cycle ?

pagerry

@konigstiger The detailed diagrams and information you provide are great… You’ve probably been asked this before, but is there a way that any one of use can access this type data for our MB’s via a website or purchased digital manual on our own? I have a 2015 E400, and would like to get detailed drawings, digitally.

Thanks!

DubVBenz

I had these same errors a couple of days ago and then the car wouldn't start a day later. I had been driving it so infrequently the battery had died. Post charge-up everything returned to normal. I've been driving the diesel to try and save some bucks at the pump...

konigstiger

For part diagrams that I post owners can subscribe to MBUSA (I believe current cost is $75 for 1 year): https://www.startekinfo.com or consider purchasing knock off disk search ebay: “wis epc mercedes”.

Arrie

Hi All,
So, just 2 days ago almost side swiped a truck next to me when changing lanes. Had my blinker on but no warning from blind spot monitor.

The triangle comes on yellow with very slow speed or stopped but it does not come on with someone in blind spot while driving. It does seem to work on the passenger side, i.e. the triangle comes on yellow when someone is in the blind spot but it does not work on the driver's side, which is the more important side due to the mirror being straight glass.

I do not have any error messages or warnings at all. Checking with my iCarsoft MB II does not help at all either so I'm thinking if the sensor simply fell off of the bracket and is pointing in direction it cannot see any vehicles in my blind spot...?

Can I access the sensor without taking the bumper off of the car? konigstiger posted nice documents, as usual, but there is also instructions for removing the bumper.

kajtek1

Don't know if I clicked something wrong, but after long registration process, I come to annual subscription for $921
Daily is $20