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Service procedures 2026 firmware

Thermal Fluid Fill and Drain

ModelSX/tasks/PROC_THC_X_FLUID-FILL-DRAIN

What this task does

Starts or stops the coolant and/or refrigerant fluid fill and drain routine. 'Start' will set the coolant valve to Series mode with the radiator 50% bypassed, chiller valve 50% bypassed, and all coolant pumps off. This routine fully opens the chiller evaporator expansion valve and chiller solenoid (if equipped). It also disables the refrigerant compressor. This routine fails if another routine is already running on the Thermal Controller or if the vehicle is charging or in Drive. 'Stop' will cancel the fluid fill and drain routine and restore normal operation. Stopping this routine will fail if it is already stopped.

Vehicle & firmware coverage

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

Model S / X (legacy) Legacy infotainment · Firmware 2026.14.6
Vehicle coverage
Pre-2021 Model S, Pre-2021 Model X
Supported connection
Local connection
Vehicle state
Stationary · Parked
Gateway diagnostic level
Factory, Service

Procedure notes

System will be inoperable until routine is stopped.

Task inputs (2)

Fluid Fill Target

target · String

Select target to start or stop. Options are coolant, refrigerant, or both.

Firmware default: Both

Options: Coolant, Refrigerant, Both

Action

action · String

Start will position the valves to allow a fill / drain to be performed. Stop will return the valves to normal operation.

Firmware default: Start

Options: Start, Stop

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Service procedures

Coolant Air Purge

Powers the accessory rail and runs HVAC pumps at maximum speed, changing the valve positions. Estimated time to complete is 20 minutes. To exit the routine early, run this routine again with STOP as the input.

PROC_THC_X_COOLANT-AIR-PURGE

Model S / X (legacy)
Service procedures

Louver Calibration

Runs the ModelS front louver calibration after actuator replacement. And returns the calibration status of all four louvers.

PROC_THC_X_LOUVER-CALIBRATION

Model S / X (legacy)
Service procedures

Start Thermal System Test

Start thermal system test. It proceeds for 5 minutes.

PROC_THC_X_THERMAL-TEST-START

Model S / X (legacy)
Service procedures

Start Thermal System Test with Precondition

Start thermal system test with precondition. It preconditions if needed, and then proceeds for 5 minutes to run thermal system test.

PROC_THC_X_THERMAL-TEST-START-PRECONDITION

Model S / X (legacy)