diff --git a/promotions/lib/controllers/backend/solidus_promotions/admin/promotions_controller.rb b/promotions/lib/controllers/backend/solidus_promotions/admin/promotions_controller.rb
index 6a1e9a9fb7e..f84386e21af 100644
--- a/promotions/lib/controllers/backend/solidus_promotions/admin/promotions_controller.rb
+++ b/promotions/lib/controllers/backend/solidus_promotions/admin/promotions_controller.rb
@@ -11,8 +11,7 @@ class PromotionsController < BaseController
 
       def create
         @promotion = model_class.new(permitted_resource_params)
-        @promotion.codes.new(value: params[:single_code]) if params[:single_code].present?
-
+        @promotion.codes.new(promotion: @promotion, value: params[:single_code]) if params[:single_code].present?
         if params[:code_batch]
           @code_batch = @promotion.code_batches.new(code_batch_params)
         end