BMS_a131 — Bleed FET Failure

Full alert identifier: BMS_a131_Bleed_FET_Failure

Alert description

A bleed Field-Effect Transistor (FET) on the Battery Management Board (BMB) is not operating as designed. This will prevent the battery from balancing the brick by decreasing the brick voltage.

Potential impact

The bleed FET will prevent the battery from properly balancing the brick by bleeding the voltage down. There is a decrease in available energy to the vehicle potentially leading to decreased range.

Set condition

Upon a periodic wake, after an ECU reset, or every 6 hours, the Battery Management System (BMS) will test all bleed switches by switching them on in turn. If the sensed brick voltage does not significantly change, this alert is set.

Clear condition

The bleed test reports sufficient voltage change across each brick.

Signals to check

Open this alert in Service Mode Plus and review the Payload tab. Use the field names below to identify the values shown by your vehicle.

Signal	Unit
Brick ID `BMS_a131_brickID`	—
Delta V `BMS_a131_deltaV`	V
Retry Count `BMS_a131_retryCount`	—

Check other alerts

With Service Mode Plus enabled, open Service Alerts → All. Review the other alerts for clues to the cause of BMS_a131.