High-Voltage Battery System Limp Mode (Reduced Power)
The TESLA-BMS_U008 (Tesla Battery Management System (BMS)) EV fault code means: High-Voltage Battery System Limp Mode (Reduced Power). This is a serious severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- expert
- Estimated cost
- Entirely dependent on the root-cause fault, which can range from a 12V battery issue to a high-voltage component repair. Diagnose the underlying alert before estimating.
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Common Symptoms
- Touchscreen reports reduced acceleration or limited power
- A reduced-power or "vehicle needs service" message
- The car drives but will not deliver full power
- Usually appears alongside one or more other high-voltage / BMS alerts
Probable Causes (Ranked by Likelihood)
- A protective limp-mode response to an underlying high-voltage or BMS fault (cell imbalance, thermal, isolation, or contactor issue) Very Likely
- A low-voltage / BMS power-supply problem forcing a protective state Possible
Step-by-Step Diagnostic Procedure
Limp mode is a symptom, not a root cause: the BMS has commanded reduced power to protect the high-voltage system. The fix is to find the alert(s) that triggered it.
Read the full active alert list via the service menu or a tool such as Scan My Tesla, and address the underlying high-voltage/BMS fault rather than the limp-mode message itself.
Because high-voltage diagnosis is involved, this is a Tesla service / qualified EV technician task, not a DIY repair.
Frequently Asked Questions
What does BMS_u008 mean?
It indicates the battery system has entered limp mode -- the BMS has reduced available power to protect the high-voltage system. It is a protective response to another underlying fault, so the real problem is whatever alert triggered it.
Can I drive in Tesla limp mode?
You can usually drive a short distance at reduced power to get somewhere safe, but you should not keep driving on it. Have the underlying high-voltage/BMS alert diagnosed by Tesla service.
Sources
This page is built from documented references. Verify against your own service info before repair work.
- Tesla firmware alert reference (core-hacked/tesla-alerts-dictionary): BMS_u008_limpMode — community-maintained dictionary, not an official manufacturer document
- Tessie Tesla alert statistics — aggregated owner telemetry — evidence of frequency, not of definition
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