diff --git a/core/loadpoint_api.go b/core/loadpoint_api.go
index 2d789d285..766992569 100644
--- a/core/loadpoint_api.go
+++ b/core/loadpoint_api.go
@@ -31,7 +31,7 @@ func (lp *LoadPoint) SetMode(mode api.ChargeMode) {
 	defer lp.Unlock()
 
 	if _, err := api.ChargeModeString(mode.String()); err != nil {
-		lp.log.WARN.Printf("invalid charge mode: %s", string(mode))
+		lp.log.ERROR.Printf("invalid charge mode: %s", string(mode))
 		return
 	}
 
diff --git a/server/mqtt.go b/server/mqtt.go
index 0f0870890..7319c4f9d 100644
--- a/server/mqtt.go
+++ b/server/mqtt.go
@@ -116,9 +116,12 @@ func (m *MQTT) listenSetters(topic string, site site.API, lp loadpoint.API) {
 	})
 	m.Handler.ListenSetter(topic+"/vehicle/set", func(payload string) {
 		if vehicle, err := strconv.Atoi(payload); err == nil {
-			vehicles := site.GetVehicles()
-			if vehicle < len(vehicles) {
-				lp.SetVehicle(vehicles[vehicle])
+			if vehicle >= 0 {
+				if vehicles := site.GetVehicles(); vehicle < len(vehicles) {
+					lp.SetVehicle(vehicles[vehicle])
+				}
+			} else {
+				lp.SetVehicle(nil)
 			}
 		}
 	})