E18
Mercedes-Benz
Master/Slave Load Sharing Communication Error
Wallbox shows E18; charging is blocked; often when multiple Mercedes-Benz wallboxes are installed in a cluster.
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Broken daisy-chain communication cable between wallboxes, Incorrect master/slave configuration, Address conflict in load sharing network, Faulty communication port on one wallbox
How to Fix / Troubleshooting
Safety first: Turn off power to all wallboxes in the cluster before modifying communication wiring.
- Verify topology: Check that the communication cables (e.g., RS-485 or Ethernet) are connected according to the Mercedes-Benz multi-wallbox installation guide.
- Check termination: Ensure that termination resistors or settings are correctly applied at the ends of the bus, if required.
- Confirm roles and addresses: Using the configuration interface, verify that only one wallbox is set as master and that each slave has a unique address.
- Isolate faulty unit: Temporarily disconnect one wallbox at a time from the communication bus to identify if a specific unit is causing E18 for the group.
- Repair or replace: Replace damaged communication cables or repair the communication port on the faulty wallbox as needed.
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Repair Difficulty
Medium
3/5
Required Part
Load Sharing Communication Port / Harness
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