MyTeslaMate
APP family

APP_w321_bmsMia

Not Available

What does the APP_w321_bmsMia alert mean?

One or more of the messages the Autopilot electronic control unit (ECU) receives periodically from the high voltage battery management system (BMS) ECU is not received, indicating the BMS ECU may be unavailable (MIA).

What you'll see in your Tesla

  • Not Available

What triggers it

One or more of the expected messages from the BMS ECU is not received.

When it clears

The Autopilot ECU starts receiving expected messages from the BMS ECU.

Potential impact

The Autopilot ECU may keep the chassis (CH) bus awake longer than expected to upload telemetry. Autopilot features may be unavailable, or may not function as expected.

Affected models

Cybertruck Model 3 2017-2023 Model 3 2024+ Model S 2012-2020 Model S 2021+ Model X 2015-2020 Model X 2021+ Model Y Model Y 2025+ Semitruck

Track your Tesla's alerts automatically

Alerts like this reach MyTeslaMate through your car's Tesla telemetry API. MyTeslaMate logs every alert your Tesla reports and turns it into readable history and real-time notifications — hosted TeslaMate with no server to run.