Battery Management System — State Transition Condition Not Met
The TESLA-BMS_a071 (Tesla BMS (Battery Management System)) EV fault code means: Battery Management System — State Transition Condition Not Met. This is a moderate severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- easy
- Estimated cost
- DIY fix (navigation preconditioning habit): $0. Coolant top-off with Tesla-spec pink OAT coolant: $20 to $40 in parts. Coolant pump replacement: $300 to $700 at an independent EV shop, $500 to $1,200 at Tesla service. BMS recalibration or software update: typically covered under warranty or $0 to $150 at an independent shop.
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Common Symptoms
- Alert BMS_a071 shown on the touchscreen
- The vehicle may log the alert without any change the driver notices
Probable Causes (Ranked by Likelihood)
- The vehicle reported BMS_a071. Tesla's firmware identifies this alert as "BMS_a071_SW_SM_TransCon_Not_Met" — the battery controller being unable to move into a requested state because some blocking condition is present; the dictionary states this outright. High
Frequently Asked Questions
What does BMS_a071 mean?
Battery Management System — State Transition Condition Not Met. Tesla's firmware identifies it as "BMS_a071_SW_SM_TransCon_Not_Met".
Can a generic OBD2 scanner read this?
No. Tesla alerts are a manufacturer-specific system and appear in no SAE standard, so a generic OBD-II scan tool cannot read or clear them. The alert text on the touchscreen and the Tesla app are the authoritative sources.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
Read the alert text on the touchscreen exactly as shown — Tesla's own wording is more specific than any third-party list, this page included.
Check for a Tesla service bulletin or a pending software update; a number of alerts clear on their own after an over-the-air update.
If the alert persists, request service through the Tesla app. Tesla alerts are not standard OBD-II codes and a generic scan tool will not read or clear them.
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
- Tesla alert dictionary (canonical firmware alert identifiers)community-maintained dictionary, not an official manufacturer document
Commonly Affected Vehicles
- Tesla Model 3 (RWD, Long Range AWD, Performance) -- most commonly reported, large owner base
- Tesla Model Y (LR AWD, Performance) -- shares the same BMS thermal architecture as Model 3
- Tesla Model S (LR, Plaid) -- older 18650 and newer 2170 cell packs both show this alert in cold climates
- Tesla Model X (LR, Plaid) -- larger pack thermal mass means cold-soak recovery takes longer
- Tesla Cybertruck (RWD, AWD, Cyberbeast) -- 800V architecture still subject to BMS_a071 at temperature extremes
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