CP_a009
Tesla
Internal Self‑Test Failure
Wall Connector shows error and app logs CP_a009; no charging current delivered
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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
Control board firmware corruption, Failed relay or contactor driver, Faulty current sensor, Internal power supply fault
How to Fix / Troubleshooting
Safety: Do not open or modify the control board. This is an internal electronics fault.
- Power cycle: Turn off the breaker for at least 2 minutes, then restore power to allow the Wall Connector to perform a fresh self‑test.
- Check environment: Ensure the unit is within Tesla's specified temperature and humidity range and that there is no visible water ingress.
- Verify wiring: Confirm that line and ground connections are correct and tight; incorrect wiring can cause self‑test failures.
- Update firmware (Gen 3): If the Wall Connector is Wi‑Fi connected, ensure it has internet access so it can download the latest firmware automatically.
- If CP_a009 persists: The internal control board assembly is defective. Replacement of the Wall Connector is required.
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Repair Difficulty
Hard
4/5
Required Part
Tesla Wall Connector main control board
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