Symptoms

The Powerwall+ / Tesla Solar Inverter is failing the MCI self-test.

Note

If a string displays voltage during the self-tests but is grayed out and displaying 0V after self-tests have completed, there is likely an MCI issue. See MCI Diode Test and Resistance Test (MCI Health Tests) to identify faulty MCI(s).

Confirm MCIs are Functioning as Expected

Confirm the MPPTs are functioning properly:

1. Set the inverter state to DC Only mode.
2. Confirm each string displays the expected voltage as displayed on the planset.

   

3. If a string is not displaying the expected voltage:
   1. Select Stop System on the landing page in Tesla One, then turn Powerwall+ / Tesla Solar Inverter OFF.
   2. Disconnect a functional string (displays the correct voltage and amperage when the system is running) from its MPPT (consider this a functional MPPT).
   3. Disconnect the problematic string from its MPPT, then connect the problematic string to the functional MPPT.
   4. Turn the system back ON and Start System and Enable Solar.
   5. If the problematic string now displays the correct voltage and amperage (while plugged in to the functional MPPT), contact Tesla Support for additional troubleshooting support.
      Note

      Move the string back to its original (presumed faulty) MPPT to confirm that MPPT still does not function. If, upon moving back to the original MPPT, the string displays the correct voltage, the issue is resolved. No additional action is required.
4. If the string does not display the expected voltage while plugged into the new MPPT, see MCI Diode Test and Resistance Test (MCI Health Tests) for instructions to test all MCIs in the failing string. If a faulty MCI is identified, replace it.

If all strings are failing the MCI self-test, contact Install Support for additional troubleshooting support.