diff --git a/src/layouts/vehicle-parts/vehicle-parts.vue b/src/layouts/vehicle-parts/vehicle-parts.vue
index 290910217..27a92ddf4 100644
--- a/src/layouts/vehicle-parts/vehicle-parts.vue
+++ b/src/layouts/vehicle-parts/vehicle-parts.vue
@@ -159,7 +159,7 @@ export default {
             Object.keys(store.getters.pageData(fmgPageValues.VEHICLE_PARTS)).length !== 0;
         },
         backButtonAction() {
-            const hasPartQuestions = this.hasPartQuestions(this.$store.getters.pageData(fmgPageValues.PART_QUESTIONS).partsOrQuestions);
+            const hasPartQuestions = this.hasPartQuestions(this.$store.getters.pageData(fmgPageValues.PART_QUESTIONS)?.partsOrQuestions);
             const backNavigationScenario = hasPartQuestions ? this.navigationScenarios.CLICKED_BACK_WITH_PART_QUESTION_ANSWERS : this.navigationScenarios.CLICKED_BACK_WITHOUT_PART_QUESTION_ANSWERS;
 
             this.$router.navigate(
diff --git a/src/mixins/vehicle-questions-mixin.js b/src/mixins/vehicle-questions-mixin.js
index 7a86066a8..4331529d4 100644
--- a/src/mixins/vehicle-questions-mixin.js
+++ b/src/mixins/vehicle-questions-mixin.js
@@ -2,10 +2,10 @@ export default {
 
     methods: {
         hasPartQuestions(partsOrQuestions) {
-            return partsOrQuestions.some(pq => pq.partQuestions?.length > 0);
+            return partsOrQuestions?.some(pq => pq.partQuestions?.length > 0);
         },
         hasGlassLocationWithMultipleParts(partsOrQuestions) {
-            return partsOrQuestions.some(pq => pq.parts?.length > 1);
+            return partsOrQuestions?.some(pq => pq.parts?.length > 1);
         },
         hasChildPartQuestions(partsOrQuestions) {
             return partsOrQuestions.some(pq => {