The high-voltage battery is the heart of your Tesla Model 3 or Model Y. When it starts degrading — or fails outright — you’ll feel it immediately: reduced range, slower charging, reduced performance, or warning messages in the app. AT Automotive in Sacramento diagnoses and replaces Tesla HV battery packs, with direct experience handling these systems safely and correctly.
Signs Your Tesla HV Battery Needs Attention
Battery degradation is gradual, so many owners don’t notice until it’s significant. The most common signs include noticeable range loss compared to when the car was new, charging that stops short of 100% even when set to charge fully, longer charge times than usual, reduced performance or power limits, and warning messages in the Tesla app or on the touchscreen about battery or charging system issues. If you’re seeing any of these, a battery diagnostic is the right first step.
What We Check First — Battery Diagnostics
Before recommending any replacement, we run a full battery health diagnostic. This includes reading the battery management system (BMS) data, checking cell voltage balance across the pack, reviewing charge and discharge patterns, and assessing overall pack capacity versus the original spec. A lot of shops skip this step and jump straight to replacement — we don’t. Many battery issues come from cell imbalance, cooling problems, or charging behavior that can be addressed without replacing the whole pack.
When Replacement Is Necessary
If the pack has degraded beyond a reasonable threshold, has a failed cell module, or has suffered physical damage, replacement is the right call. We source replacement packs from reputable suppliers — both OEM-equivalent new packs and quality-tested refurbished units — and can discuss the tradeoffs of each. We’re upfront about what each option costs, how long it takes, and what kind of warranty coverage comes with it.
High-Voltage Safety
Tesla HV battery packs operate at 350–400 volts. Working on them safely requires proper HV training, insulated tools, and the right equipment to discharge and isolate the system before any work begins. This is not a job for a general shop that doesn’t regularly work with EVs. Our team works on Tesla and hybrid high-voltage systems regularly — HV safety is part of every job we do.
Which Tesla Models We Service
We service the Tesla Model 3 (Standard Range, Long Range, and Performance) and Model Y (Standard, Long Range, and Performance) for HV battery diagnostics and replacement. If you have a Model S or Model X with battery concerns, contact us — we handle those on a case-by-case basis.
Schedule a Battery Diagnostic in Sacramento
If your Tesla’s range has dropped or you’re seeing battery-related warnings, don’t wait. Battery issues that are caught early are often more manageable — and less expensive. Bring your Model 3 or Model Y to AT Automotive and we’ll give you a straight answer on what’s happening and what your options are.