BMS-A121
BMS_a121_SW_NVRAM_Config_Error
Also written as BMS_A121 / BMS A121 / BMS_a121_SW_NVRAM_Config_Error / bms_a121_sw_nvram_config_error
Why does the exact Tesla alert ID matter?
Record the exact alert ID, including underscores, suffixes, and companion alerts. Tesla alerts that look similar can point to different modules, timestamps, and service procedures.
What does BMS-A121 mean?
Tesla alert code in the Battery Management System (BMS) module. Indicate that NVRAM data was not initialized because of a config error Indicate that a graceful power off has been activated by the BMS BMS has reduced power for driving due to a fault Indicate that an FEIM test is required but currently blocked by another fault
Original Description
Indicate that NVRAM data was not initialized because of a config error Indicate that a graceful power off has been activated by the BMS BMS has reduced power for driving due to a fault Indicate that an FEIM test is required but currently blocked by another fault
Affected Tesla Models
What You May Notice
- BMS-A121 may appear with another Tesla alert in the Battery Management System (BMS) system.
- The vehicle may limit charging, driving, comfort, or safety features depending on the active alerts.
- The alert may clear after sleep, but recurring alerts should be treated as service-relevant.
How to Diagnose and Resolve
- 1 Reboot the vehicle (hold both scroll wheels for 10 seconds)
- 2 Check the Tesla app for any pending software updates
- 3 Monitor the alert over 1–2 charge cycles; schedule service if it recurs
Severity Notes
BMS-A121 is an Alert in the Battery Management System system. Confirm the vehicle screen and Tesla app show no driving or charging restrictions, and schedule service if the alert returns.