Vehicle Management System (VMS) Module Rebuild and Repair

Tesla Roadster Vehicle Management System — VMS Module Repair & Rebuild

The Vehicle Management System (VMS) stores vehicle logs and monitors, controls, and coordinates key systems, including the PEM, battery temperature management, and HVAC. It also serves as a gateway between the vehicle’s CAN and LIN buses, translating and re-transmitting messages across the networks so the rest of the car can communicate correctly. The VMS is located in the passenger footwell.

Factory behavior — thermal management

• Continuous battery-coolant monitoring. While parked (e.g., during charging), the VMS can initiate cooling via the 12 V controller.
• If battery temperature exceeds limits, the VMS commands the 12 V controller to increase coolant flow, engage the A/C compressor, and open the battery refrigerant solenoid to route refrigerant through the heat exchanger.
• To prevent over-cooling, refrigerant flow is switched off below 46°F (8°C) and will not resume until the temperature rises above 54°F (12°C).
• The normal battery charging temperature range is approximately 37°F (3°C) to 113°F (45°C).
• Priority note: Battery cooling takes precedence over cabin comfort; the VMS can divert cooling away from the cabin when required.

Internal architecture (quick reference)

• CAN–LIN bus interface processor
• Central door locking/alarm inputs processor
• Connector processor
• Central door locking processor
• MCU (microcontroller unit) processor
• Power processor
• Vehicle interface processor

Why the VMS Modules fail

• Heat & vibration: micro-cracked solder joints, oxidized connectors.
• Aged power stages: drifting regulators/electrolytics causing brownouts/resets.
• Interface wear: stressed CAN/LIN transceivers leading to bus faults/timeouts.
• Memory errors: flash/EEPROM wear or corruption affecting logs/config.

Our solution

• Firmware Reload: A Firmware reload may be necessary to restore full functionality
• Reverse-engineered bench harness, full inspection under magnification, ultrasonic clean.
• Component replacement of stressed regulators, capacitors, CAN/LIN transceivers, and reference ICs; precise reflow of cracked joints.
• Connector refurbishment, contact treatment, and targeted strain-relief improvements.
• Validation & burn-in under load: charge/discharge handshakes, contactor logic, SOC/ideal-miles stability, CAN/LIN gateway health, and thermal command outputs.
• Conformal protection plus a concise final test report.

Service & coverage

Available at our Phoenix facility or via ship-in. If you are holding through the next market cycle, we can store your Roadster in a climate-controlled EV Preserve environment.