VCFRONT_a191 — Exit Drive Low LV Bus Voltage

Full alert identifier: VCFRONT_a191_exitDriveLowLVBusVoltage

Message shown in the car

Electrical system power reduced Vehicle shutting down

Alert description

An issue with the low voltage (LV) electrical system requires the vehicle to come to a stop immediately. The vehicle should enter graceful power-off (GPO) to exit drive, and a separate alert should indicate that condition.

Potential impact

The vehicle will not enter drive. If the vehicle is driving, it will exit drive through graceful power-off (GPO) to come to a stop immediately. A separate alert should be present to indicate the GPO

Set condition

Lead acid: Low voltage (LV) battery voltage below threshold for 3 seconds (3s); transistor gating LV battery connection is open (no current flow); vehicle load shedding is active; or reverse battery transistor issue detected.

Clear condition

Low voltage (LV) battery voltage above threshold; transistor gating LV battery connection is closed; no reverse battery transistor issue detected; vehicle loadshedding is not active.

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
IBS Voltage `VCFRONT_a191_IBSVoltage`	V
LVBMS Voltage `VCFRONT_a191_LVBMSVoltage`	V

Signal	Unit
ECPA State `VCFRONT_a191_ECPAState` 0 OPEN 1 CLOSED 2 INVALID 3 SNA	—
LVBMS Current Target Valid `VCFRONT_a191_LVBMSCurrentTargetValid`	—
Lvbmsmia `VCFRONT_a191_LVBMSMIA`	—
LVBMS Voltage Target Valid `VCFRONT_a191_LVBMSVoltageTargetValid`	—
MOS State `VCFRONT_a191_MOSState` 0 OPEN 1 CLOSED 2 INVALID 3 SNA	—
Not Enough Power For Support `VCFRONT_a191_NotEnoughPowerForSupport`	—
Pcs mia `VCFRONT_a191_PCS_MIA`	—
A 180 DCDC Not Supporting LV Bus `VCFRONT_a191_a180_DCDCNotSupportingLVBus`	—

Show 11 more fields

Signal	Unit
Bms State `VCFRONT_a191_bmsState`	—
Exit Drive Warning Timer Expired `VCFRONT_a191_exitDriveWarningTimerExpired`	—
Frunk Open `VCFRONT_a191_frunkOpen`	—
Hv State `VCFRONT_a191_hvState` 0 DOWN 1 COMING UP 2 GOING DOWN 3 UP FOR DRIVE 4 UP FOR CHARGE 5 UP FOR DC CHARGE 6 UP	—
Reverse Battery E Fuse Fault `VCFRONT_a191_reverseBatteryEFuseFault`	—
Service Mode `VCFRONT_a191_serviceMode`	—
Vehicle Load Shed Active `VCFRONT_a191_vehicleLoadShedActive`	—
Vehicle Load Shed Hv Fault Active `VCFRONT_a191_vehicleLoadShedHvFaultActive`	—
Vehicle Load Shed Post Crash Active `VCFRONT_a191_vehicleLoadShedPostCrashActive`	—
Vehicle Load Shed Stage `VCFRONT_a191_vehicleLoadShedStage` 0 IDLE OR UNDEFINED 1 1 2 2 3 3	—
Vehicle Power State `VCFRONT_a191_vehiclePowerState` 0 OFF 1 CONDITIONING 2 ACCESSORY 3 DRIVE	—

Check other alerts

With Service Mode Plus enabled, open Service Alerts → All. Review the other alerts for clues to the cause of VCFRONT_a191.