Edmundcape

I replaced my auxiliary battery about 2 years ago. Everything worked as expected. About 6 months ago all of the driver assist, PreSafe, blind spot, Lane assist, early brake detection became inoperative. I checked the fuses in the back of my car. All good. I haven't checked the relays but I don't think they are involved. Is there a way to “reboot” the system? I can't believe that it's a malfunctioning sensor that would cause all the features to fail. I had a blind spot assist failure fixed by replacing a sensor, so I'm familiar with that type of problem. That's not what seems to be going on now. Any ideas?

CaliBenzDriver

What year, mileage and engine type is your vehicle?

The issue you're facing is a transient disruption of a few modules hanging at once with a bottleneck situation on CAN-C.

It's hard to say what modules gets crazy first then upsets all the other VIP starved for timely data.
This usually causes amazing delayed banging shifts where tranny works poorly. The standard procedures is to do multiple adaptations with hit/miss success.


The nature of this issue is incremental. The repair is a combination of fixes to remove built-in defects.
1-- Check live voltage
2-- Clean MAIN GND Strap
3-- Clean painted GND posts
4-- Scan the vehicle for recurring DTC's

Good things these modules are able to work in degraded modes under "best-efforts law"
the above work has good secure your car a fix.

Advanced safety features are not simple. You may want to let your honest specialist do what he can do best.

Edmundcape

Thank you for the reply. The car has 190,000 miles on it. It's a 2014, 4matic, regular fuel engine (I.e., not flex).

Your answer makes sense - one subsystem can't find what it needs and somehow prevents others from finding what they need. That said, somewhere, somehow there must be a way to check each feature one by one. E.g, turning off all but one…? Check, repeat on the next?

This type of problem could consume hours of tech time… expensive to have done. That said, I could be convinced if I knew the person truly knew what they were doing.

Arrie

My 2010 E550 AUX battery is located in the end of driver side dash. In your 2014 model I believe it is in the trunk and is a bit bigger battery in physical size.

But, the thing is, my battery has its own fuse that is located right next to the battery so I wonder if there is a fuse for the AUX battery in your car also somewhere close to the battery and could be missed to check?

ygmn

check aux battery; connections and proper battery test

CT.W212

Very interested in how this plays out as I have been dealing with these issues as well.
The vehicle I purchased was in a combined front/rear collision so I am not sure what I am chasing here…I originally replaced my main battery (due to typical battery failure issues) and then shortly after received all the lights & warnings you have listed. I replaced my aux battery and drove the vehicle to clear the codes. All went away. Side note, the aux battery I took out read 12.4V when checked with my multi-meter…anyway, the other day (after about two months with both new batteries) all the warnings began to come back in! I cleared/reset them all with the use of my buddies XTool. I still have a few codes “current & stored” that I cannot clear. Investigating has gotten me to believe my CGW may be the issue…

S-Prihadi

If your Advance Driving Assist includes the rear bumper radar , that thing is known to corrode and shorted.
If it takes down the CAN-BUS channel which are shared by the sister devices , all sister devices will not work too.

Edmundcape

Yup. Brilliant minds think alike... that was one of my first gotos. Perhaps worth checking the voltage when loaded.

Edmundcape

I pretty confident that mine does not include a rear bumper sensor. That said, the problem seemed to happen on a particularly humid/rainy day. So I wonder if a short in any of the sensors might cause all of them to go. That would be a horrible design, but worth my looking into. Thank you for the idea.

Edmundcape

I would like to get my hands on an XTool. I hope the equivalent of the "mother board" did not somehow get damaged (the CGW?). That will be the last step if the problem is not found in the peripherals.

CT.W212

I was also leaning towards the CAN-BUS (still not ruling it out) however when I ran diagnostics through the XTool everything checked out SAT with regards to CAN-BUS. Wondering if could be being masked somehow?