diff --git a/src/claim-request-management/claim-request-management.service.ts b/src/claim-request-management/claim-request-management.service.ts
index 2b9c16d..5ad5fba 100644
--- a/src/claim-request-management/claim-request-management.service.ts
+++ b/src/claim-request-management/claim-request-management.service.ts
@@ -207,6 +207,7 @@ import {
 import {
   asObjectRecord,
   collectPartyVinCandidates,
+  fanavaranIdOrConfigDefault,
   normalizeVin,
   parseFanavaranId,
   pickFanavaranPlaqueLookupFields,
@@ -4254,26 +4255,34 @@ export class ClaimRequestManagementService {
     const inquiryPlaque = pickFanavaranPlaqueLookupFields(
       asObjectRecord(inquiryMapped) ?? asObjectRecord(inquiryRaw),
     );
-    const plaqueKindId = this.firstPositiveFanavaranId(
+    const plaqueKindFromApi = this.firstPositiveFanavaranId(
       apiPlaque.kindId,
       inquiryPlaque.kindId,
       cachedDamage.plaqueKindId,
       lastDamagePayload?.PlaqueKindId,
     );
-    const plaqueSampleId = this.firstPositiveFanavaranId(
+    const plaqueSampleFromApi = this.firstPositiveFanavaranId(
       apiPlaque.sampleId,
       inquiryPlaque.sampleId,
       cachedDamage.plaqueSampleId,
       lastDamagePayload?.PlaqueSampleId,
     );
-    if (apiPlaque.kindId == null && plaqueKindId != null) {
+    const plaqueKindId = fanavaranIdOrConfigDefault(
+      plaqueKindFromApi,
+      input.defaults.PlaqueKindId,
+    );
+    const plaqueSampleId = fanavaranIdOrConfigDefault(
+      plaqueSampleFromApi,
+      input.defaults.PlaqueSampleId,
+    );
+    if (plaqueKindFromApi == null) {
       this.logger.log(
-        `[buildFanavaranDamageCasePayload] PlaqueKindId API miss; using DB value ${plaqueKindId}`,
+        `[buildFanavaranDamageCasePayload] PlaqueKindId API miss; using config default ${plaqueKindId}`,
       );
     }
-    if (apiPlaque.sampleId == null && plaqueSampleId != null) {
+    if (plaqueSampleFromApi == null) {
       this.logger.log(
-        `[buildFanavaranDamageCasePayload] PlaqueSampleId API miss; using DB value ${plaqueSampleId}`,
+        `[buildFanavaranDamageCasePayload] PlaqueSampleId API miss; using config default ${plaqueSampleId}`,
       );
     }
     const builtYear =
@@ -4385,6 +4394,12 @@ export class ClaimRequestManagementService {
         null,
       );
     }
+    if (accidentVehicleUsedId == null) {
+      accidentVehicleUsedId = input.defaults.AccidentVehicleUsedId;
+      this.logger.log(
+        `[buildFanavaranDamageCasePayload] AccidentVehicleUsedId API miss; using config default ${accidentVehicleUsedId}`,
+      );
+    }
 
     this.logger.log(
       `[buildFanavaranDamageCasePayload] Final DriverId=${driverFanavaranId ?? "NULL"} for nationalCode=${pickPersonNationalCode(person) ?? "MISSING"}, ` +
@@ -5187,7 +5202,8 @@ export class ClaimRequestManagementService {
       persistPayload?: boolean;
       /**
        * Re-run VIN inquiry / vehicle GET for AccidentVehicleUsedId.
-       * Submit always sets this so Mongo tenant default 1 cannot be reused.
+       * Submit always re-inquires. If the API still returns nothing, the
+       * tenant config default is used.
        */
       forceRefreshUsedId?: boolean;
     },
@@ -5402,6 +5418,14 @@ export class ClaimRequestManagementService {
         }
       }
 
+      if (parseFanavaranId(payload.AccidentVehicleUsedId) == null) {
+        payload.AccidentVehicleUsedId =
+          profile.defaults.AccidentVehicleUsedId;
+        this.logger.log(
+          `${logPrefix} AccidentVehicleUsedId API miss; using config default ${payload.AccidentVehicleUsedId}`,
+        );
+      }
+
       if (persistPayload) {
         await this.claimCaseDbService.findByIdAndUpdate(claimCaseId, {
           $set: {
diff --git a/src/lookups/fanavaran-last-car-policy.spec.ts b/src/lookups/fanavaran-last-car-policy.spec.ts
index 67d1239..d191623 100644
--- a/src/lookups/fanavaran-last-car-policy.spec.ts
+++ b/src/lookups/fanavaran-last-car-policy.spec.ts
@@ -1,5 +1,6 @@
 import {
   collectPartyVinCandidates,
+  fanavaranIdOrConfigDefault,
   filterPoliciesByLine,
   insuranceLineLabel,
   parseLastCarPolicyInput,
@@ -172,6 +173,12 @@ describe("fanavaran last car policy", () => {
     });
   });
 
+  it("uses tenant config default when the API id is missing", () => {
+    expect(fanavaranIdOrConfigDefault(15, 8)).toBe(15);
+    expect(fanavaranIdOrConfigDefault(null, 8)).toBe(8);
+    expect(fanavaranIdOrConfigDefault(0, 10)).toBe(10);
+  });
+
   it("matches VIN against ChassisNo when VIN is empty", () => {
     expect(
       vehicleMatchesCar(
diff --git a/src/lookups/fanavaran-last-car-policy.ts b/src/lookups/fanavaran-last-car-policy.ts
index c2ffe26..1459652 100644
--- a/src/lookups/fanavaran-last-car-policy.ts
+++ b/src/lookups/fanavaran-last-car-policy.ts
@@ -162,6 +162,14 @@ export function parseFanavaranId(value: unknown): number | null {
   return Number.isFinite(id) && id > 0 ? id : null;
 }
 
+/** Live Fanavaran / cache id wins; tenant `fanavaranClientConfigs.defaults` if the API returned nothing. */
+export function fanavaranIdOrConfigDefault(
+  resolved: unknown,
+  configDefault: number,
+): number {
+  return parseFanavaranId(resolved) ?? configDefault;
+}
+
 export function asObjectRecord(value: unknown): Record<string, unknown> | null {
   if (!value || typeof value !== "object") {
     return null;