diff --git a/apps/web/process/leasing-object/validation.ts b/apps/web/process/leasing-object/validation.ts
index 60f3cf4..de74677 100644
--- a/apps/web/process/leasing-object/validation.ts
+++ b/apps/web/process/leasing-object/validation.ts
@@ -107,7 +107,7 @@ export function createValidationSchema({ apolloClient }: ValidationContext) {
           const isNotTrailer =
             evo_leasingobject_type?.evo_id !== null &&
             evo_leasingobject_type?.evo_id !== '8' &&
-            evo_model?.evo_trailer_sign === true;
+            evo_model?.evo_trailer_sign !== true;
 
           if (isNotTrailer && engineType !== 100_000_003 && engineVolume <= 0) {
             ctx.addIssue({