BMS-A040
BMS_a040_SW_Watch_Dog_HW_Triggered
Also written as BMS_A040 / BMS A040 / BMS_a040_SW_Watch_Dog_HW_Triggered / bms_a040_sw_watch_dog_hw_triggered
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-A040 mean?
Tesla alert code in the Battery Management System (BMS) module. The BMS uses this to indicate the SWT peripheral triggered a watchdog expiration Alert indicating HVP Error/EOUT pin asserted A brick has exceeded the maximum brick voltage BMS detects that the HV battery cannot support sufficient power for driving BMS has detected a memory error
Original Description
The BMS uses this to indicate the SWT peripheral triggered a watchdog expiration Alert indicating HVP Error/EOUT pin asserted A brick has exceeded the maximum brick voltage BMS detects that the HV battery cannot support sufficient power for driving BMS has detected a memory error
Affected Tesla Models
What You May Notice
- BMS-A040 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-A040 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.