W203fanatic

I am getting a weird rare intermittent issue where I was merging on the highway and all of a sudden got a vibration, CEL for on 1 for second and I tried giving it gas but the car wouldn't accelerate. Had to pull over, restarted the vehicle and issue hasn't come back.

Dealer is not sure, they think its the blind spot sensor, however they work. Saying there is little corrosion there. They aren't 100% sure because there are no active codes. The only code were

The issue with these sensors is they are $3000 CAD total job, and if it doesn't fix it because its something else then im going to be pissed. So before I spend money getting this done I am just wondering if there are reports of these blind spot sensors being able to cause a car to shut off while moving. Been googling for hours and can't find much about this issue.

CaliBenzDriver

Nop!
To cut the chase, you can simply disconnect both of these BlindSpot sensors to rule them out of the loop.

These sensors routinely go bad from moisture entering the unprotected harness connectors. It's super unlikely they are causing your limp mode because they are on a distinct CAN unrelated to ECU/TCU/LPFP powertrain.

Let's simply disconnect them for now to give all chances to the ECU to stop acting up on the open roads.


From there we can consider the laundry list of DTC's you have listed. Realise that almost ALL of these DTC's individually can trigger your limp mode
(BlindSpot is not listed as a fault, correct?)


Root cause: this list of DTC's is consistent with a severe ECU disruption. It's not one bad module, it's a specific VIP collection that went nuts.

You've got the pedal sensor, the noisy fuel pump module, ECU, Cluster, BCM...

70% chance under voltage plays a role in crashing CAN controls as evidenced by:
> U0111 - Lost Coms with Battery Control Module
> U0100 - Lost Coms with ECM/PCMAll of these faults are VIP errors.

What exactly is wrong... perhaps just the noisy wiring near the LPFP crashing SAM Coms related to BCM.

I'd focus on the live Voltage to witness ECU controls ALT without fault for extended period of run time (not just 20mn drive).

This defect may be exacerbated by low MAIN battery, though new Batt is not a fix for it.

Let's try to corner this.

W203fanatic

The car did not enter limp mode however. I gave it gas and it just kept coasting to a stop.

If it was in limp mode wouldn’t I be able to at least keep the car at a certain speed?

The main battery was replaced about 1000km ago with MB battery.

CaliBenzDriver

1- Yes that is textbook limp mode.

2- New OEM battery is great but says nothing about proper starting/running VOLTAGE.
Float and and keep a close eye on ALT output.
Unruly computers can drain the Main drain battery both with engine stopped and while driving.

streborx

Check the battery connections. The tech may have been unable to find a left handed end wrench and never tightened them.

egosnous

I got bad Blind spot assist sensor I guess, becuase it shows the message of “Blind assist inoperative” it was ok, I could live with that. But then I started lose electricity after rains. Sometimes the battery was totally dead, I needed to jump start it. There was a time I saw one of the rear lights buzzing after rain with engine off. only one time not sure if it was real. So obviously something is draining my battery, I suspect it is the bad blind spot assist sensor. Anyway, after a while. I started having this “advanced emergent brake inoperative” message with engine light on from time to time, all in the morning after rain. And every time when I saw this message, I lost power, I gave gas, no acceleration. This scared **** our of me. Luckily I dont use high way anymore after I started to have this issues. So I pulled over, turned off the engine and restarted, then I could drive as usual. After couple of days, the engine light would go off. I suspect this is caused by low battery level. So I got a new battery. Interestingly, I got my auto engine off function back after I got the new battery. That means with low battery, some functions can not operate. So then it rained again, I lost some of the electricity of the battery again, and I lost the auto engine off function again, and after i drive for a while got the battery charged, the auto engine off function would come back. and I experienced this advanced emergent brake inoperative issue again. So I suspect, this is caused by low battery. NowI found the fuse for the blind spot assist sensor and disconnected it, and will wait till next raining days and see if it would save the battery.

streborx

Random, weather dependent anomalies and low battery charge state could be caused by a defective ground connection. Check the cable connecting battery negative terminal to the vehicle's chassis. Make sure the connection is tight and free of corrosion.

egosnous

After I disconnected the fuse for the blind spot detect sensor the battery is never low any more even through several times of long rainfall nights. The advanced emergent brake non operative warning never occurred again. I guess low battery is the cause of this issue that probably why MB didnt do anything about it it’s not the problem of emergent brake system. It makes sense to disconnect gas throttle if a collision is happening. However since it happened to so many customers and the car lose power after the issue. it is very dangerous on the road. They should do something to stop losing power after such electronic glitch.

KanataSteve

I've had bad blind spot sensors, but never had this issue. I had lots of warnings pop up however, traceable to an old worn out main battery. Changed it, solved a lot of issues, but ECO shut off still didn't work, along with occasionally faulty blind spot sensors. I found one thing to check was the secondary battery. Use a voltmeter to check its voltage. Changed that, and poof! All fixed. It's under a cover in the spare tire compartment in my GLK 350, I believe it can be in other places in other cars.

It's easily replaced (lasts 3-5 years), remove the cover, the mounting strap and the vent hose, disconnect the battery (CAREFULLY!), install a new battery, reconnect the wiring (CAREFULLY!), reconnect the vent hose, reinstall the mounting strap and cover. Make sure the mounting strap secures it tightly, don't want it bouncing around leading to early battery death. Absolutely easy to do by yourself and saves a ton of money. Just make sure to get a direct replacement battery with a vent. The vent is used in case the battery ruptures (unlikely) and vents corrosive fumes into your car. Best to put safety over convenience.

Hope this helps.

KanataSteve

I've had bad blind spot sensors, but never had this issue. I had lots of warnings pop up however, traceable to an old worn out main battery. Changed it, solved a lot of issues, but ECO shut off still didn't work, along with occasionally faulty blind spot sensors. I found one thing to check was the secondary battery. Use a voltmeter to check its voltage. Changed that, and poof! All fixed. It's under a cover in the spare tire compartment in my GLK 350, I believe it can be in other places in other cars.

It's easily replaced (lasts 3-5 years), remove the cover, the mounting strap and the vent hose, disconnect the battery (CAREFULLY!), install a new battery, reconnect the wiring (CAREFULLY!), reconnect the vent hose, reinstall the mounting strap and cover. Make sure the mounting strap secures it tightly, don't want it bouncing around leading to early battery death. Absolutely easy to do by yourself and saves a ton of money. Just make sure to get a direct replacement battery with a vent. The vent is used in case the battery ruptures (unlikely) and vents corrosive fumes into your car. Best to put safety over convenience.

Hope this helps.

KanataSteve

By the way, check for corroded connections, seems to be a known issue. Protect connections from moisture.

streborx

One other tip when changing out the battery. Connect a backup power source to the car so that you don't lose all your settings. Noco makes several varieties of battery chargers and power sources, and also has an accessory item that connects the charger/power source to the car via the OBDII connector. Connect this power source before removing the battery and leave it connected until the new battery is installed and connected. I've used this a couple times when replacing batteries, and it saves time having to reprogram stuff such as the radio and reinitializing the windows and sunroof.

There are cheaper ways to do this, but avoid the 9V battery that plugs into a 12V cigarette lighter socket, unless you're sure the socket is active when the ignition is off.

egosnous

Long raining time collision prevention assis plus inoperative every few minutes and lost power.
found this https://www.youcanic.com/wiki/merced...rative-message