diff --git a/homeassistant/components/home_connect/diagnostics.py b/homeassistant/components/home_connect/diagnostics.py
index d2505853d23..e095bc503ab 100644
--- a/homeassistant/components/home_connect/diagnostics.py
+++ b/homeassistant/components/home_connect/diagnostics.py
@@ -4,7 +4,7 @@ from __future__ import annotations
 
 from typing import Any
 
-from homeconnect.api import HomeConnectAppliance
+from homeconnect.api import HomeConnectAppliance, HomeConnectError
 
 from homeassistant.core import HomeAssistant
 from homeassistant.helpers.device_registry import DeviceEntry
@@ -14,9 +14,14 @@ from .api import HomeConnectDevice
 
 
 def _generate_appliance_diagnostics(appliance: HomeConnectAppliance) -> dict[str, Any]:
+    try:
+        programs = appliance.get_programs_available()
+    except HomeConnectError:
+        programs = None
     return {
+        "connected": appliance.connected,
         "status": appliance.status,
-        "programs": appliance.get_programs_available(),
+        "programs": programs,
     }
 
 
diff --git a/tests/components/home_connect/snapshots/test_diagnostics.ambr b/tests/components/home_connect/snapshots/test_diagnostics.ambr
index 99f10fe2847..f3131eac52f 100644
--- a/tests/components/home_connect/snapshots/test_diagnostics.ambr
+++ b/tests/components/home_connect/snapshots/test_diagnostics.ambr
@@ -2,6 +2,7 @@
 # name: test_async_get_config_entry_diagnostics
   dict({
     'BOSCH-000000000-000000000000': dict({
+      'connected': True,
       'programs': list([
       ]),
       'status': dict({
@@ -23,6 +24,7 @@
       }),
     }),
     'BOSCH-HCS000000-D00000000001': dict({
+      'connected': True,
       'programs': list([
         'LaundryCare.WasherDryer.Program.Mix',
         'LaundryCare.Washer.Option.Temperature',
@@ -46,6 +48,7 @@
       }),
     }),
     'BOSCH-HCS000000-D00000000002': dict({
+      'connected': True,
       'programs': list([
       ]),
       'status': dict({
@@ -67,6 +70,7 @@
       }),
     }),
     'BOSCH-HCS000000-D00000000003': dict({
+      'connected': True,
       'programs': list([
       ]),
       'status': dict({
@@ -88,6 +92,7 @@
       }),
     }),
     'BOSCH-HCS000000-D00000000004': dict({
+      'connected': True,
       'programs': list([
       ]),
       'status': dict({
@@ -144,6 +149,7 @@
       }),
     }),
     'BOSCH-HCS000000-D00000000005': dict({
+      'connected': True,
       'programs': list([
       ]),
       'status': dict({
@@ -165,6 +171,7 @@
       }),
     }),
     'BOSCH-HCS000000-D00000000006': dict({
+      'connected': True,
       'programs': list([
       ]),
       'status': dict({
@@ -186,6 +193,7 @@
       }),
     }),
     'BOSCH-HCS01OVN1-43E0065FE245': dict({
+      'connected': True,
       'programs': list([
         'Cooking.Oven.Program.HeatingMode.HotAir',
         'Cooking.Oven.Program.HeatingMode.TopBottomHeating',
@@ -217,6 +225,7 @@
       }),
     }),
     'BOSCH-HCS04DYR1-831694AE3C5A': dict({
+      'connected': True,
       'programs': list([
         'LaundryCare.Dryer.Program.Cotton',
         'LaundryCare.Dryer.Program.Synthetic',
@@ -241,6 +250,7 @@
       }),
     }),
     'BOSCH-HCS06COM1-D70390681C2C': dict({
+      'connected': True,
       'programs': list([
         'ConsumerProducts.CoffeeMaker.Program.Beverage.Espresso',
         'ConsumerProducts.CoffeeMaker.Program.Beverage.EspressoMacchiato',
@@ -268,6 +278,7 @@
       }),
     }),
     'SIEMENS-HCS02DWH1-6BE58C26DCC1': dict({
+      'connected': True,
       'programs': list([
         'Dishcare.Dishwasher.Program.Auto1',
         'Dishcare.Dishwasher.Program.Auto2',
@@ -319,6 +330,7 @@
       }),
     }),
     'SIEMENS-HCS03WCH1-7BC6383CF794': dict({
+      'connected': True,
       'programs': list([
         'LaundryCare.Washer.Program.Cotton',
         'LaundryCare.Washer.Program.EasyCare',
@@ -356,6 +368,7 @@
       }),
     }),
     'SIEMENS-HCS05FRF1-304F4F9E541D': dict({
+      'connected': True,
       'programs': list([
       ]),
       'status': dict({
@@ -415,6 +428,7 @@
 # ---
 # name: test_async_get_device_diagnostics
   dict({
+    'connected': True,
     'programs': list([
       'Dishcare.Dishwasher.Program.Auto1',
       'Dishcare.Dishwasher.Program.Auto2',
diff --git a/tests/components/home_connect/test_diagnostics.py b/tests/components/home_connect/test_diagnostics.py
index d0bc5e77735..f2db6e2b67a 100644
--- a/tests/components/home_connect/test_diagnostics.py
+++ b/tests/components/home_connect/test_diagnostics.py
@@ -1,8 +1,9 @@
 """Test diagnostics for Home Connect."""
 
 from collections.abc import Awaitable, Callable
-from unittest.mock import MagicMock
+from unittest.mock import MagicMock, Mock
 
+from homeconnect.api import HomeConnectError
 import pytest
 from syrupy import SnapshotAssertion
 
@@ -63,14 +64,13 @@ async def test_async_get_device_diagnostics(
 
 
 @pytest.mark.usefixtures("bypass_throttle")
-async def test_async_device_diagnostics_exceptions(
+async def test_async_device_diagnostics_not_found(
     hass: HomeAssistant,
     config_entry: MockConfigEntry,
     integration_setup: Callable[[], Awaitable[bool]],
     setup_credentials: None,
     get_appliances: MagicMock,
     device_registry: dr.DeviceRegistry,
-    snapshot: SnapshotAssertion,
 ) -> None:
     """Test device config entry diagnostics."""
     get_appliances.side_effect = get_all_appliances
@@ -85,3 +85,45 @@ async def test_async_device_diagnostics_exceptions(
 
     with pytest.raises(ValueError):
         await async_get_device_diagnostics(hass, config_entry, device)
+
+
+@pytest.mark.parametrize(
+    ("api_error", "expected_connection_status"),
+    [
+        (HomeConnectError(), "unknown"),
+        (
+            HomeConnectError(
+                {
+                    "key": "SDK.Error.HomeAppliance.Connection.Initialization.Failed",
+                }
+            ),
+            "offline",
+        ),
+    ],
+)
+@pytest.mark.usefixtures("bypass_throttle")
+async def test_async_device_diagnostics_api_error(
+    api_error: HomeConnectError,
+    expected_connection_status: str,
+    hass: HomeAssistant,
+    config_entry: MockConfigEntry,
+    integration_setup: Callable[[], Awaitable[bool]],
+    setup_credentials: None,
+    get_appliances: MagicMock,
+    appliance: Mock,
+    device_registry: dr.DeviceRegistry,
+) -> None:
+    """Test device config entry diagnostics."""
+    appliance.get_programs_available.side_effect = api_error
+    get_appliances.return_value = [appliance]
+    assert config_entry.state == ConfigEntryState.NOT_LOADED
+    assert await integration_setup()
+    assert config_entry.state == ConfigEntryState.LOADED
+
+    device = device_registry.async_get_or_create(
+        config_entry_id=config_entry.entry_id,
+        identifiers={(DOMAIN, appliance.haId)},
+    )
+
+    diagnostics = await async_get_device_diagnostics(hass, config_entry, device)
+    assert diagnostics["programs"] is None