Alert: MCI Self-Test Failure

Symptoms

The Powerwall 3 is failing the MCI self-test.

Informational PurposesAn informational icon, calling your attention
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. See Determine True String VOC for instructions to conduct an open air voltage test.
    Informational PurposesAn informational icon, calling your attention
    Note
    Alternatively, select Stop System then Start System, then navigate to the Powerwall 3 device page. It is possible to see VOC during the PV Isolation Self-Test.
  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 3 OFF.
      Warning IconA warning icon, calling your attention to a possibly risky situation
      Warning
      Confirm Powerwall 3 is de-energized before disconnecting or connecting any PV strings.
    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.
    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.
      Informational PurposesAn informational icon, calling your attention
      Note
      Turn Powerwall 3 OFF again and 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.