Earlier this month, I purchased my EQB 300 and our first trip home was 450+ miles home from the dealership. All went fine on the drive no issues.

6 days later, I had driven not very far, parked went into the store, and when turning back on my car, the titled error appeared on my dash rotating between three messages: (1) "Have High-Voltage System Checked - See Owners Manual" + (2) "Malfunction" (in yellow with gears icon) + (3) "See Operator's Manual" in red text with a battery icon"

Photos: https://imgur.com/gallery/JYZH56h

I got home fine, called my salesman/dealership - he asked for photos, I sent them and he talked to one of his mechanics and they advised to "let the system reset", charge it to 100% and it'll reset overnight. After following those instructions, two of the three messages on my dash disappeared, however, one remained - the Malfunction with gears icon.

The car drove fine, without any issues, and after navigating to the i button on the screen, the message went away for that drive, but then would still pop up anytime I turned on the car.

Has this happened to anyone? I have an appt tomorrow morning. I could have gone in this morning but they didn't have a loaner available, and I need a car having children, but wanted to check to see if anyone else had this issue and if so, what was the resolution.

I did check https://www.mbusa.com/en/recall as well as https://www.nhtsa.gov/recalls but nothing came up when entering my VIN. I did also see this recall: https://theevreport.com/mercedes-ben...tery-fire-risk, and I intend on asking them to make sure my car isn't included in it, as it doesn't say that it is at this time.

I'm happy to provide an update for anyone else that happens to in the future.

 

Hmmm, not common, probably a bad battery or software issue.

 

I'll be curious to see what is found. You don't say if it is used or new...if used, I wouldn't be surprised to find a bad 12 volt battery...that throws all sorts of scary codes that go away with a new 12 volt and software reset. Keep us posted.

 

Bought it brand new, had 33 miles on it when I left the dealership. It's been there a full 24 hours at this point, without an update. To be fair, my service advisor did say that they would "need it a full day (dropped it off at 7:30am) at minimum to do a full inspection as Mercedes orders thorough inspections when cars this new come in requiring service to make sure anything they still have on the lot can be inspected to prevent this from happening going forward." But will update this thread once I hear back.

 

Bought it brand new, had 33 miles on it when I left the dealership. It's been there a full 24 hours at this point, without an update. To be fair, my service advisor did say that they would "need it a full day (dropped it off at 7:30am) at minimum to do a full inspection as Mercedes orders thorough inspections when cars this new come in requiring service to make sure anything they still have on the lot can be inspected to prevent this from happening going forward." But will update this thread once I hear back.

 

Hopefully they figure it out, it must be frustrating.

 

Where do you store/keep the key when you get in to drive? (Hopefully not the front passenger cup holder).

 

in my purse, I never take it out of my bag. Curious though why it doesn’t go in the cup holder? I have a cup phone mount in my driver cup holder then my water tank in the passenger cup.

 

If I am understanding it correctly, I guess you don't want to spill fluids on the key.

 

Actually happened to me once. Background: With a bad battery you place the key there and the RFID allows you to start the EQB even if the key fob battery is dead. But of all the times I left it there with a good battery, one time it would not start ('23 250+ if that matters). Similar warnings can't start, and do not tow. I called AAA waited and waited. Then when he arrived I pulled the key out of the cup holder, and placed it on top of the dash for him to see it is there in the cabin. All errors gone and it started right up!

 

I see, interesting find! Thanks for letting me know.

Unfortunately I dont think that's the case in my scenario as the key never leaves my purse or my crossbody bag when I'm driving. My crossbody is either on me at all times or on the rare occasion I have a purse it's on my passenger seat. Thanks, though! My car is still in the shop and they told me that I won't likely be getting it back until Thursday/Friday this week.

 

FINAL UPDATE (for now) Just got my car back on Wednesday this week. Just finally got the time to update this thread in case it might be helpful for another EQB driver. Notes from the Invoice:

CAUSE: DC/DC COVERT INOP 54720 73
54 ELECTRICAL AND INSTRUMENTS
175 W
1 000-342-97-00 VOLTAGE CONVERTER (N/C)
1 000-989-71-10-09-0109 MB 325.6 G40 (N/C)
ANTI-FREEZE 1 GALLON BASF (N/C)
2 913025-008000-64 NUT (N/C)
NEAL

694 INTERNAL ELECTRICAL FAULT IN THE DC/DC CONVERTER.
Upon inspection, function test and road test was bale to verify a HV malfunction light coming on in the cluster. Connected a battery maintainer, connected xentry and inspected the cluster event log and confirmed all the warning had come on via the log. Performed a quick test and found fault codes in the HV system - N82/9 - Battery Management System (BMS). P0E2F00 Electrical Fuse B for the high voltage has a malfunction. N83/1 - DC/DC converter (DDW).
-P0C3B00 Temperature Sensor A of the DC/DC Converter has a short circuit to positive.
-P0C4000 Temperature Sensor B of the DC/DC Converter has a short circuit to positive.
-P0E5400 Current sensor A of the DC/DC converter has a short circuit to positive.
-P0E9700 Voltage Sensor C of the DC/DC converter has a malfunction.
-U011500 Communication with control unit "Drivetrain" has a malfunction. Performed the xentry guided test and states to check connections and wiring / open a Tips case. Found no newer DCDC sw. Powered down the vehicle. Inspected connections, socket tensions and wiring at the DCDC. Found no malfunction. Inspected the LV wiring harness and found wiring harness routed near the coolant pump M13/5 and coolant hose mounting bracket. Harness making contact against the harness. Drained the coolant system. Removed HV battery coolant pump M13/5 to access affected area of the harness. Removed insulation tape from the harness and inspected wiring for any damage. Found no damage to the cable harness. Insulated the harness and rerouted away from the contact. Opened Tips case 246303628. Uploaded vehicle and test data. Uploaded photos of the harness and contact area. Tips advised to replace the DCDC converter. Deactivated the HV system once again. Disconnected the 12V battery. Removed and replaced the DCDC. Performed programming and teach in. Cleared all codes, refilled coolant. Performed coolant bleeding. Allowed for bus off. Charged the LV and HV batteries and road tested several times. No further fault codes or warning lights returned after repairs. Miles out 694.

 

Glad they fixed it, thanks for posting the work order.

 

Many tanks for sharing this
May I ask whether they charged you on this or its expenses were considered as a part of your warranty?