diff --git a/assets/js/components/Sessions/SessionDetailsModal.vue b/assets/js/components/Sessions/SessionDetailsModal.vue
index 60d0e643d..343f424b9 100644
--- a/assets/js/components/Sessions/SessionDetailsModal.vue
+++ b/assets/js/components/Sessions/SessionDetailsModal.vue
@@ -229,7 +229,7 @@ export default defineComponent({
 			await this.updateSession({ vehicle: title });
 		},
 		async removeVehicle() {
-			await this.updateSession({ vehicle: null });
+			await this.updateSession({ vehicle: "" });
 		},
 		async changeLoadpoint(title: string) {
 			await this.updateSession({ loadpoint: title });
diff --git a/tests/sessions.spec.ts b/tests/sessions.spec.ts
index 7d8097b21..fd31f481c 100644
--- a/tests/sessions.spec.ts
+++ b/tests/sessions.spec.ts
@@ -352,6 +352,17 @@ test.describe("session details", async () => {
     const modal = page.getByTestId("session-details");
     await expectModalVisible(modal);
 
+    // select guest vehicle
+    await modal.getByLabel("Vehicle").selectOption("Guest vehicle");
+    await modal.getByRole("button", { name: "Close" }).click();
+    await expectModalHidden(modal);
+
+    page.reload();
+    await page.getByTestId("sessions-entry").nth(0).click();
+    await expectModalVisible(modal);
+    await expect(modal.getByLabel("Vehicle")).toHaveValue("");
+
+    // edit carport and select known vehicle
     await modal.getByLabel("Charging point").selectOption("Carport");
     await modal.getByLabel("Vehicle").selectOption("blauer e-Golf");
     await modal.getByRole("button", { name: "Close" }).click();