BMS-A178
BMS_a178_SW_Uncontrolled_Regen_PwrB
Also written as BMS_A178 / BMS A178 / BMS_a178_SW_Uncontrolled_Regen_PwrB / bms_a178_sw_uncontrolled_regen_pwrb
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-A178 mean?
Tesla alert code in the Battery Management System (BMS) module. Alert that pyro is being blown for an uncontrolled regen event in track mode A brick has shown 2nd order instability noise BMS detects that one of the DC Link (pack) switches is welded
Original Description
Alert that pyro is being blown for an uncontrolled regen event in track mode A brick has shown 2nd order instability noise BMS detects that one of the DC Link (pack) switches is welded
Affected Tesla Models
What You May Notice
- BMS-A178 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-A178 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.