Edmundcape

I have a E350. The blind side assist and lane keep assist functions are inoperative. I've tested the batteries (both hold a charge above 12V without running the engine), wiggled the connections to the rear bumper radar sensors, confirmed no obvious swelling or water damage and finally confirmed that the fuses are ok. I'm sharing this as "same but different" to other people's experience. I have not removed the sensor to clear them. There is some dirt. I just don't know how to remove the sensors without removing the bumper which seems unnecessary. - E

jonUF02

Electrical system problem occurs in severe rain storm, disappears after sitting and car works fine in dry weather... sounds like a water intrusion / short of some electrical component to me. Sorry for your luck, it could definitely be a tough one to track down.

M278

In case anyone is wondering, there is a connector in the trunk for the radar sensors. I disconnected mine to physically isolate the sensors from the CAN. The red/black is +12v from fuse 59, the two green are CAN bus, and the brown is chassis ground.

Leonardick

it sounds familiar to my 2013 E550. I'd the MB of South Orlando replace those sensors for the Distronic, BlindSpot, Lane Keep then 2 days later it rains very heavy and the Blind Spot, Lane Keep inop. Brought them back in, MB of South Orlando said it's all good. 3 weeks later there was heavy rains and it did the same. Brought it back in again spent more than an hour and they can't find anything wrong with it. It NEVER happen before MB of South Orlando replaces those sensors, I have had the car during raining season in Seatle, Houston, Orlando before. I am so tired of bringing the car back for nothing to be done so I guess I have to live with it.

Waterdog3

My 2014 E 350 did very similar. I started the car and pulled away and all of the sudden I got every inoperable message there was. The steering got funny (no power steering at slow speeds) and the transmission would not down shift. I made it to the dealer and they turned it off then on and the check engine light lit up along with everything else. I still have CPO warranty so I left it. I have also had both rear radar sensors replaced in the past 2 months. Not sure if both were replaced or they just got them working each time.
They called the next day for me to pick it up. Said they couldn't find anything wrong with the car. Said they found a software update and it was fine after the update. I doubt that's all that was wrong? I'm waiting for it to happen again.

I also just moved to FL 6 months ago and am wondering if the rains have something to do with it?

mellonc

My two cents: MB should separate primary system and secondary system in its main processing network. Primary being the main drivabiliyt and secondary being accessory functions. the OP should have been at least drive home with such minor function being inoperable.....

ItalianJoe1

There are two networks, one for drivetrain, one for body. The car can be totally dead on the body can and might still start and run if the EIS can see all the Drive Auth system components. It will lose some functions and will be in limp mode, but it will move. It's not possible for a body can issue to shut down the drivetrain can in any normal circumstance.

Maallen40

Hey, you paid 1800 CAD for your rear sensor? Wow...I paid 900$, then two weeks later the right side went bonkers...also 900$.
Just thought I would reply because I saw how much you spent and did a double take.


M

CaliBenzDriver

Yep, indeed these cars are designed with multiple independent networks for safety reasons. So bumpers or mirrors should NEVER bring down the engine or steering...
TEN separate data networks :
LIN signaling: used for alternator control and main battery sensing
CAN-A Telematics: (mBrace, radio ...)
CAN-B Interior: (Doors, Roof, KeylessG, Seats ...) + Rear-SAM
CAN-C Drive train: (only Motor & Gearbox)
CAN-E1 Chassis: (Camera, blind spot, IgnitionSw... ) + Me-SFI
CAN-E2 :
CAN-F Central: (Command ...)
CAN-H VehDynamics: Distronic, BlinSpot...
CAN-I Engine: fuel and Nox
CAN-L Hybrid: electric cars
CGW: Central Gateway by Bosch
FWGW: Chassis Gateway by Lear

No one seems to know exactly what causes OP conditions when the whole car electronics dangerously goes crazy.
The word is " we have never heard of that..." "you are the first one my friend..." poker face complete denial instead of relevant consideration.
From what I gathered out of these situations, there is NO DTC fault or existing TSB pointing towards the root cause.

Something is stressing these networked modules beyond abilities to function.
Examples:
- Many times I unlock my car with the keyless handle, pull open the driver door and then the stupid alarm goes off because it was still armed !! (network delay)
- Some people report the trunk simply opening itself while the car has been parked for many hours (systems normally "sleeping").

Insight share: (see EDIT below)
- Battery Control commands deep discharging: after a while driving around daytime, alternator is commanded to deeply discharge the main battery below 12V
- Central Gateway by Bosch : this core module interconnects all the car networks together. It acts as a data router between buse

- ME-SFI by Bosch runs CAN-C but is also connected directly to CAN-E.
- It's a serious bug if a secondary peripheral module can bring down the main vehicle computer with no early warning !!!!!

EDIT2: Fancy combination of failures
Under voltage system failure is caused by a string of design factors.
Alternator control unable to reliably read BatterySensor from CAN-B goes into limbo law (discharge below 12v at cruising speed, daytime)
Data stream traffic across the CentralGateway bus interconnection is disrupted (signals are delayed through deep stacks)
A sick module on any 1 of 10 buses sends junk signaling

This means many things...
Reduce the number of failed modules to the minimum especially those failed since day-1 at factory production (Benz quality gone wild)
Gateway module faults are sign something is brewing (Ex: U103888: "service manual" + U103812: "service manual")
As it is the car systems have limited fault tolerance and can crash in a hurry without proper warning
BatterySensor LIN bus should get connected directly to engine CAN-C Bus NOT through the Rear-SAM (legacy rear MainBatt)
Bosch should seriously stress test its Gateway design to prevent road kills

Every car used to have either an Alternator Warning Light or a Voltage Dial... Benz too but its dangerously hidden under "Workshop Menu"!

Reward yourself:
Clear all module faults from ANY of your car then observe the engine runs nicer: smoother with low torque, less random missfires
Do NOT zap any adaptations, only the bus faults in this case
The hard faults will come back but until then happy car
Fix them hard faults... now you know why!
Many if not most fuel injection designs are licensed from Bosch. They all share that busy CPU bottleneck.

------------------------------
Drive cautiously knowing you can get limp-mode at freeway speeds with no steering power... luxurious nightmare courtesy of MB.

------------------------------
Edit after the charge system analysis:
- Failed alternator control can lead to deep battery discharging: after a while driving around daytime, car may consistently deeply discharge the main battery below 11.xV instead of floating at 12.6

kajtek1

Just to put some perspective to it >>> MB is famous driving MACHINE.
Electronics are not their specialty and when you follow the list
W123 has electronic tachometers and CC - very common failure
W124 has electronic CC - very common failure
W210 has electronic transmission - very common failure, mainly on connector and then electronic cluster like to loose displays.
Not to mention that MB logistics drove me crazy more than once.
Still early years electronic BMW would put car in limp mode, when door switch malfunction.
So at least MB avoided that glitch.

CaliBenzDriver

Imagine the top grade nightmare for Amazon with the five thousands of delivery vans they bought/leased from Benz

Let's see how fast Amazon switches to a different unrelated brand or stick with the maintenance chaos Benz designed for their commercial vehicles.

We are not alone .... LOL

Mud

Excellent info, thanks for posting it.
Saved for future reference.

kajtek1

I drive with ScanGauge for last 6 months and discharge below 12V never happen.

CaliBenzDriver

Hi Kajtek: I am really happy that your ownership is going smooth. I think you driving diesel car, right?

If you've never witnessed your main battery below 12V while driving daytime, you should be ok.

What explains the difference is the set of options you have may work better.
Do you see any recurring module faults ... ?

CaliBenzDriver

Added EDT2: "Fancy failure" to post #34 - This explains the failures that bring down the Bosch system.

Bottom line: you want the least amount of CAN-Bus faults, as simple as that!

fishymick

@M278 This single post and the pics saved me from a ADD spiral. . .I had so many codes being thrown across every CAN connected module. . .disconnecting the rear sensors isolated it super quick and cleanly - thank you so much!!!