Tesla vehicles are equipped with on-board diagnostic technology that allows them to provide you real-time on screen alerts if an issue arises during operation. In some cases, these alerts will affect the vehicle’s drivability. 

This article highlights the top 10 most critical drivability alerts your Tesla may display and guides you on how to respond if they appear on your vehicle’s touchscreen.‍

1. BMS-a170 - Acceleration and Top Speed Reduced - Performance May be Restored on Next Drive

This alert triggers when the high-voltage (HV) battery voltage falls too low. Resolving this issue may require an HV battery replacement or diagnostics to identify underlying causes, such as battery imbalance.

In some cases, this alert is triggered when your vehicle’s State-of-Charge is too low. In that instance, charging your vehicle to its designated charging level will resolve the alert. 

This alert may also display on screen as “Acceleration and Top Speed Reduced - Performance May be Restored on Next Drive.” 

2. VCFRONT_a180 - Electrical System Power Reduced - Vehicle May Shut Down Unexpectedly

This alert triggers due to Low-Voltage (12v) or HV battery issues. To resolve the alert, charge or replace the 12v battery. If the alert persists, inspect the HV system and secure diagnostics to identify any further issues.

‍3. VCFRONT_a191 - Electrical System Power Reduced - Vehicle Shutting Down

This alert will appear on screen when the 12v battery has too little power left to continue powering your vehicle. The vehicle will shut down to preserve energy and cannot be driven until this alert is resolved. 

Schedule service to rectify the issue. This may require replacing the 12v battery or further diagnostics to determine the underlying cause of concern.

4. VCFRONT_a192 - Electrical System is Unable to Support All Features - Switching Off Features to Conserve Energy

Caused by major electrical system failure, often related to the 12v or HV batteries, this alert requires immediate service. Service could involve inspecting and/or replacing HV battery contactors, the power conversion system, or the battery management system (BMS). 

5. UI_a006 - Service is Required - Schedule Service

This alert is caused by HV battery degradation or an internal safety lockout due to a detected fault. This alert should be serviced immediately; it may require HV battery pack service and/or replacement, a software update, or recalibration. 

6. BMS_a067 - High Voltage Battery Performance Limited - OK To Drive, Schedule Service Soon

This alert is triggered when your vehicle detects an HV battery condition that is limiting its performance. Your vehicle’s maximum range and power may be reduced until service is performed. 

While your vehicle is safe to drive, you may notice reduced power and/or range. Avoid aggressive acceleration and high-power usage to minimize battery strain. 

This alert can be caused by HV battery voltage imbalances, HV contactor wear, Thermal Management System issues, or software/system communication faults. Seek remote diagnostics to isolate the cause of the alert and develop a plan to rectify the issue. 

7. BMS_a068 - High Voltage Battery Requires Service - Acceleration and Charging Performance Reduced

This alert is caused by an internal condition in the HV battery that is limiting its performance. You may notice reduced acceleration and overall power when driving while this alert is active. 

Possible causes include HV battery voltage imbalance, HV contactor issues, Thermal Management System issues, Cooling System issues, HV battery degradation, and/or software faults. 

To address this alert, schedule remote diagnostics to identify the cause of the issue and develop a plan for repair. 

8. BMS_a079 - Unable to Charge - Maximum Charge Level Reached. Reduced Maximum Charge Level - Schedule Service

This alert requires immediate service. It is triggered when an internal HV battery condition limits the battery charging to 50%. 

BMS_a079 indicates that your Tesla cannot charge because the Battery Management System (BMS) has detected an issue and thus limited the maximum charge level of your HV battery. This could be a sign of battery degradation, voltage imbalances, or a fault in the charging system. 

9. DI_a138 - Front Motor Disabled - OK to Drive - Vehicle power May be limited

This alert means that your front motor is unavailable/unresponsive. Power will be limited as the vehicle must use only the rear motor to drive. 

This alert may be a temporary condition that will resolve by your next drive. However, if the alert persists, you may need service to repair/replace your front drive unit or diagnose underlying issues that may be causing the loss of front motor power. 

10. VCFRONT_a216 - Vehicle May Not Restart - Service is Required

This alert is triggered when your vehicle detects a loss of HV isolation either internal or external to the HV battery pack contactors. 

Isolation is the resistance between high voltage (+ or -) and the vehicle chassis. Normally, your vehicle maintains a high resistance to ensure the safety of the HV battery system. In cases where this resistance drops, you should seek service and remote diagnostics immediately to identify the exact issue and secure repair. 

A loss of isolation can occur via contamination, a physical condition affecting insulation material, or due to moisture.

Conclusion

If your Tesla displays one of these alerts, remain calm. In most cases, it’s safe to continue driving for a short period—but be sure to schedule service promptly to prevent further issues. 

If the vehicle is not drivable, contact roadside assistance immediately. With timely action, many alerts can be resolved quickly and without complication.

For more information, tips, and guides to Tesla ownership, join us on social media: 

‍Instagram, Linkedin, X, Facebook 

‍