diff --git a/homeassistant/components/tesla_fleet/__init__.py b/homeassistant/components/tesla_fleet/__init__.py
index bc837aa4cac..ff50a99748e 100644
--- a/homeassistant/components/tesla_fleet/__init__.py
+++ b/homeassistant/components/tesla_fleet/__init__.py
@@ -64,6 +64,15 @@ CONFIG_SCHEMA = cv.config_entry_only_config_schema(DOMAIN)
 async def async_setup_entry(hass: HomeAssistant, entry: TeslaFleetConfigEntry) -> bool:
     """Set up TeslaFleet config."""
 
+    try:
+        implementation = await async_get_config_entry_implementation(hass, entry)
+    except ValueError as e:
+        # Remove invalid implementation from config entry then raise AuthFailed
+        hass.config_entries.async_update_entry(
+            entry, data={"auth_implementation": None}
+        )
+        raise ConfigEntryAuthFailed from e
+
     access_token = entry.data[CONF_TOKEN][CONF_ACCESS_TOKEN]
     session = async_get_clientsession(hass)
 
@@ -71,7 +80,6 @@ async def async_setup_entry(hass: HomeAssistant, entry: TeslaFleetConfigEntry) -
     scopes: list[Scope] = [Scope(s) for s in token["scp"]]
     region: str = token["ou_code"].lower()
 
-    implementation = await async_get_config_entry_implementation(hass, entry)
     oauth_session = OAuth2Session(hass, entry, implementation)
     refresh_lock = asyncio.Lock()
 
diff --git a/tests/components/tesla_fleet/conftest.py b/tests/components/tesla_fleet/conftest.py
index 0dc5d87984f..2396e2a88f3 100644
--- a/tests/components/tesla_fleet/conftest.py
+++ b/tests/components/tesla_fleet/conftest.py
@@ -33,7 +33,9 @@ def mock_expires_at() -> int:
     return time.time() + 3600
 
 
-def create_config_entry(expires_at: int, scopes: list[Scope]) -> MockConfigEntry:
+def create_config_entry(
+    expires_at: int, scopes: list[Scope], implementation: str = DOMAIN
+) -> MockConfigEntry:
     """Create Tesla Fleet entry in Home Assistant."""
     access_token = jwt.encode(
         {
@@ -51,7 +53,7 @@ def create_config_entry(expires_at: int, scopes: list[Scope]) -> MockConfigEntry
         title=UID,
         unique_id=UID,
         data={
-            "auth_implementation": DOMAIN,
+            "auth_implementation": implementation,
             "token": {
                 "status": 0,
                 "userid": UID,
@@ -90,6 +92,12 @@ def readonly_config_entry(expires_at: int) -> MockConfigEntry:
     )
 
 
+@pytest.fixture
+def bad_config_entry(expires_at: int) -> MockConfigEntry:
+    """Create Tesla Fleet entry in Home Assistant."""
+    return create_config_entry(expires_at, SCOPES, "bad")
+
+
 @pytest.fixture(autouse=True)
 def mock_products() -> Generator[AsyncMock]:
     """Mock Tesla Fleet Api products method."""
diff --git a/tests/components/tesla_fleet/test_init.py b/tests/components/tesla_fleet/test_init.py
index 7c17f986663..7e97096e4e8 100644
--- a/tests/components/tesla_fleet/test_init.py
+++ b/tests/components/tesla_fleet/test_init.py
@@ -30,6 +30,7 @@ from homeassistant.components.tesla_fleet.coordinator import (
 from homeassistant.components.tesla_fleet.models import TeslaFleetData
 from homeassistant.config_entries import ConfigEntryState
 from homeassistant.core import HomeAssistant
+from homeassistant.data_entry_flow import FlowResultType
 from homeassistant.helpers import device_registry as dr
 
 from . import setup_platform
@@ -424,3 +425,20 @@ async def test_signing(
     ) as mock_get_private_key:
         await setup_platform(hass, normal_config_entry)
         mock_get_private_key.assert_called_once()
+
+
+async def test_bad_implementation(
+    hass: HomeAssistant,
+    bad_config_entry: MockConfigEntry,
+) -> None:
+    """Test handling of a bad authentication implementation."""
+
+    await setup_platform(hass, bad_config_entry)
+    assert bad_config_entry.state is ConfigEntryState.SETUP_ERROR
+
+    # Ensure reauth flow starts
+    assert any(bad_config_entry.async_get_active_flows(hass, {"reauth"}))
+    result = await bad_config_entry.start_reauth_flow(hass)
+    assert result["type"] is FlowResultType.FORM
+    assert result["step_id"] == "reauth_confirm"
+    assert not result["errors"]