Skip to content
Diagnostic tests 2026 firmware

HVBMS read HVC PN

Gen3/tasks/TEST_HVBMS_X_READ-HVC-PN

Model 3 / YModel S / X (2021+)

What this task does

The test reads the High Voltage Contactor (HVC) part number and reports the part number to High Voltage Battery Management System (HVBMS).

Vehicle & firmware coverage

Open a version to see its description, requirements, and input definitions. Hardware configuration and live vehicle checks also determine availability.

Model 3 / Y AMD · Firmware 2026.32.3
Vehicle coverage
2024+ Model 3, 2025+ Model Y, Model Y, Pre-2024 Model 3
Supported connection
Local connection
Vehicle state
Stationary · Parked
Gateway diagnostic level
No specific level listed

Task inputs (0)

No user inputs are listed in this firmware.

Model 3 / Y Intel · Firmware 2026.32.7
Vehicle coverage
Model Y, Pre-2024 Model 3
Supported connection
Local connection
Vehicle state
Stationary · Parked
Gateway diagnostic level
No specific level listed

Task inputs (0)

No user inputs are listed in this firmware.

Model S / X (2021+) AMD · Firmware 2026.20.6.1
Vehicle coverage
2021+ Model S, 2021+ Model X
Supported connection
Local connection
Vehicle state
Stationary · Parked
Gateway diagnostic level
No specific level listed

Task inputs (0)

No user inputs are listed in this firmware.

Related service tasks

Browse all tasks →
Service procedures

Blocked Contactors - Attempt to Clear

Clears open Voltage Sensing Harness (VSH) latch alerts and isolation counters. Resets the High Voltage Processor (HVP) and High Voltage Battery Management System (HVBMS) Electronic Control Units (ECU) in an attempt to clear blocked contactors. Even in the case all internal routines PASS, contactors may still be blocked from closing due to other external conditions.

PROC_HVBMS_X_CLEAR-BLOCKED-CONTACTORS

Model 3 / Y Model S / X (2021+)
Service procedures

Clear HVBMS Open VSH Latch

Clears the Voltage Sense harness (VSH) alert BMS_a119_Fast_Open_Vsh_Detected latch within the HVBMS NVRAM. This routine shall only be executed after installing a new/remanufactured HV battery.

PROC_HVBMS_X_RESET-VSH-FAULT

Model 3 / Y Model S / X (2021+)
Service procedures

HVBMS - Clear Isolation Counters

This routine clears the High Voltage Battery Management System (HVBMS) isolation counters, which clears BMS_a027_SW_Repeated_Isolation_Failure_In_Drive and BMS_a172_SW_Isolation_Failure_In_Drive_Warning alerts. Execute this routine after repairing any isolation issue on the vehicle's High Voltage (HV) system. The HVBMS isolation counters latch the alerts BMS_a027 and BMS_a172 when reaching a certain count threshold.

PROC_HVBMS_X_RESET-ISOLATION-COUNTERS

Model 3 / Y Model S / X (2021+)
Self-tests

HVBMS BMB and VSH Connection Test

This routine checks the HVBMS connections to the Battery Monitoring Board (BMB) and the Voltage Sense Harness (VSH).

TEST-SELF_HVBMS_X_BMB-COMMS-VSH

Model 3 / Y Model S / X (2021+)