Hi all,

I’ve had a couple of scary incidents with my 2020 EQC 400 4MATIC (32,000 km). While driving, the car suddenly shows “Battery Malfunction”, slips into neutral, and becomes unresponsive. No warnings beforehand. Restarting the car has fixed the problem as if nothing happened.

Mercedes Dealer Workshop findings:
Apparently the XENTRY logs show high voltage errors, but no faulty components identified - I can't confirm this as I don't know how to read the logs.
They suspected outdated firmware and so went through and updated all the firmware as needed.
They could not reproduce the issue in the workshop.

Latest Incident occurred the day after getting the car back from the workshop.
Happened 30 mins into a normal drive, the car went neutral and flashed 'Battery Malfunction' with no prior warning. I waited 1 minute and restarted the car, everything was fine for the rest of the day.

Logs & Pics:
The workshop was kind enough to share the XENTRY Logs:
https://drive.google.com/file/d/1QH0FJLMgfLkTIMwRUabibQoeCfuhzQq7/view?usp=sharing





Has anyone experienced this “Battery Malfunction” issue or something similar on an EQC or other MB EVs? Any insight appreciated, the local MB dealers don't seem to have a clue unfortunately.

Thanks

 

Since the firmware update didn't resolve it, the problem (U005588 – Bus OFF (CAN Communication Fault) points to an intermittent hardware fault (e.g., wiring, connectors, or a control unit) that's difficult to reproduce in a workshop.
Here’s what I would do:
1. Request Deeper Diagnosis: Push for a thorough hardware investigation focusing on:

• Wiring and Connections: Inspect high-voltage harnesses and connectors.
• Ground Points: Verify system grounds.
• Data Logging: Request on-vehicle data logging to capture the incident's exact parameters.
• Control Unit Testing: If necessary, discuss potential testing or replacement of suspect control units (e.g., Battery Management System, Drivetrain).

2. Check TSBs/Recalls: Inquire about any known service bulletins or recalls for this issue on your EQC model.
3. Document Everything: Maintain meticulous records of all incidents and workshop interactions.

Let us know how it goes.

 

I believe this is not a Battery Malfunction, but it is a drive system malfunction.

Mercedes EVs has a manufacturing deviation with the electric drive module, that results in collant leaking into the motor module causing this issue, which required replacing the motor module