diff --git a/custom_components/goecharger_api2/service.py b/custom_components/goecharger_api2/service.py
index 765c550..04da436 100644
--- a/custom_components/goecharger_api2/service.py
+++ b/custom_components/goecharger_api2/service.py
@@ -73,8 +73,10 @@ async def set_pv_data(self, call: ServiceCall):
             }
             _LOGGER.debug(f"Service-set_pv_data(): set PV data: {payload}")
             try:
-                resp = await coordinator.async_write_key(Tag.IDS.key, payload)
+                resp = await coordinator.async_write_key(Tag.IDS.key, payload, require_ack=call.return_response)
                 if call.return_response:
+                    if not isinstance(resp, dict) or resp.get(Tag.IDS.key) != payload:
+                        return {"error": "The charger did not acknowledge PV data", "date": str(datetime.datetime.now().time())}
                     return {
                         "success": "true",
                         "date": str(datetime.datetime.now().time()),
diff --git a/tests/integration/test_service.py b/tests/integration/test_service.py
index 3dbd837..82fb164 100644
--- a/tests/integration/test_service.py
+++ b/tests/integration/test_service.py
@@ -15,7 +15,7 @@ def svc(hass):
     service_module._COORDINATOR_PER_CONFIG_ENTRY_ID_MAP.clear()
     coordinator = SimpleNamespace(
         intg_type="charger", mode="lan", name="test charger", _serial="123456", data={},
-        async_write_key=AsyncMock(return_value={Tag.IDS.key: True}))
+        async_write_key=AsyncMock(side_effect=lambda key, value, **kwargs: {key: value}))
     service = GoeChargerApiV2Service(hass, SimpleNamespace(entry_id="entry"), coordinator)
     yield service, coordinator
     service_module._COORDINATOR_PER_CONFIG_ENTRY_ID_MAP.clear()
@@ -30,7 +30,7 @@ async def test_valid_values_are_written(svc):
     result = await service.set_pv_data(_call(pgrid=-500, ppv=1500, pakku=200))
     assert result["success"] == "true"
     coordinator.async_write_key.assert_awaited_once_with(
-        Tag.IDS.key, {"pGrid": -500.0, "pPv": 1500.0, "pAkku": 200.0})
+        Tag.IDS.key, {"pGrid": -500.0, "pPv": 1500.0, "pAkku": 200.0}, require_ack=True)
 
 
 @pytest.mark.parametrize("bad", [math.nan, math.inf, -math.inf])
@@ -46,4 +46,13 @@ async def test_non_finite_pv_and_battery_value_become_zero(svc, bad):
     service, coordinator = svc
     await service.set_pv_data(_call(pgrid=100, ppv=bad, pakku=bad))
     coordinator.async_write_key.assert_awaited_once_with(
-        Tag.IDS.key, {"pGrid": 100.0, "pPv": 0.0, "pAkku": 0.0})
+        Tag.IDS.key, {"pGrid": 100.0, "pPv": 0.0, "pAkku": 0.0}, require_ack=True)
+
+
+@pytest.mark.parametrize("reply", [{}, None, {"err": "rejected"}, {"ids": True}, {"ids": {"pGrid": 1}}])
+async def test_pv_response_requires_matching_acknowledgement(svc, reply):
+    service, coordinator = svc
+    coordinator.async_write_key = AsyncMock(return_value=reply)
+    result = await service.set_pv_data(_call(pgrid=-500, ppv=1500, pakku=200))
+    assert "error" in result and "success" not in result
+    assert coordinator.async_write_key.call_args.kwargs == {"require_ack": True}
diff --git a/tests/integration/test_services_and_setup.py b/tests/integration/test_services_and_setup.py
index e5b3552..107062a 100644
--- a/tests/integration/test_services_and_setup.py
+++ b/tests/integration/test_services_and_setup.py
@@ -45,7 +45,7 @@ def _call(return_response=True, **data):
 
 def _service(hass, mode="lan", car=2, **kwargs):
     coordinator = make_coordinator(hass, data={Tag.CAR_CONNECTED.key: car}, mode=mode, **kwargs)
-    coordinator.async_write_key = AsyncMock(return_value={Tag.IDS.key: True})
+    coordinator.async_write_key = AsyncMock(return_value={Tag.IDS.key: {"pGrid": -500.0, "pPv": 0.0, "pAkku": 0.0}})
     return GoeChargerApiV2Service(hass, coordinator._config_entry, coordinator), coordinator
 
 
@@ -100,7 +100,7 @@ async def test_missing_grid_power_without_wanted_answer_returns_nothing(hass):
 async def test_successful_pv_data_returns_nothing_when_no_answer_is_wanted(hass):
     service, coordinator = _service(hass)
     assert await service.set_pv_data(_call(return_response=False, pgrid=-1, ppv=2, pakku=3)) is None
-    coordinator.async_write_key.assert_awaited_once_with(Tag.IDS.key, {"pGrid": -1.0, "pPv": 2.0, "pAkku": 3.0})
+    coordinator.async_write_key.assert_awaited_once_with(Tag.IDS.key, {"pGrid": -1.0, "pPv": 2.0, "pAkku": 3.0}, require_ack=False)
 
 
 @pytest.mark.parametrize("error", [ValueError("down"), TypeError("odd")])