diff --git a/src/main/java/com/ffii/fpsms/m18/service/M18BomForShopService.kt b/src/main/java/com/ffii/fpsms/m18/service/M18BomForShopService.kt
index 855e07b..6c09218 100644
--- a/src/main/java/com/ffii/fpsms/m18/service/M18BomForShopService.kt
+++ b/src/main/java/com/ffii/fpsms/m18/service/M18BomForShopService.kt
@@ -43,7 +43,7 @@ open class M18BomForShopService(
     private val purchaseOrderLineRepository: PurchaseOrderLineRepository,
     private val m18BomShopSyncLogRepository: M18BomShopSyncLogRepository,
     private val shopService: ShopService,
-    private val m18MasterDataService: M18MasterDataService,
+    private val m18VendorLookupService: M18VendorLookupService,
 ) {
     private val logger: Logger = LoggerFactory.getLogger(M18BomForShopService::class.java)
 
@@ -415,14 +415,14 @@ open class M18BomForShopService(
         cache[cacheKey]?.let { return it }
 
         val resolved = when (flowTypeId) {
-            2 -> m18MasterDataService.findVendorM18IdByCode(supplierCode, m18Config.BEID_PF)
+            2 -> m18VendorLookupService.findVendorM18IdByCode(supplierCode, m18Config.BEID_PF)
                 ?: directM18Id.also {
                     if (it == null) {
                         logger.warn("[M18 BOM] PF vendor M18 id not found for supplierCode=$supplierCode")
                     }
                 }
             3 -> shopService.findVendorByCode(supplierCode)?.m18Id?.takeIf { it > 0L }
-                ?: m18MasterDataService.findVendorM18IdByCode(supplierCode, m18Config.BEID_PP)
+                ?: m18VendorLookupService.findVendorM18IdByCode(supplierCode, m18Config.BEID_PP)
                 ?: directM18Id
             else -> shopService.findVendorByCode(supplierCode)?.m18Id?.takeIf { it > 0L }
                 ?: directM18Id
diff --git a/src/main/java/com/ffii/fpsms/m18/service/M18MasterDataService.kt b/src/main/java/com/ffii/fpsms/m18/service/M18MasterDataService.kt
index 9aeb8bb..3b01ec7 100644
--- a/src/main/java/com/ffii/fpsms/m18/service/M18MasterDataService.kt
+++ b/src/main/java/com/ffii/fpsms/m18/service/M18MasterDataService.kt
@@ -557,25 +557,6 @@ open class M18MasterDataService(
         )
     }
 
-    /** M18 vendor id for [code] scoped to [beId] (e.g. [M18Config.BEID_PF] vs [M18Config.BEID_PP]). */
-    open fun findVendorM18IdByCode(code: String, beId: String): Long? {
-        val trimmed = code.trim()
-        if (trimmed.isEmpty() || beId.isBlank()) return null
-        val conds = "(code=equal=$trimmed)=and=(beId=equal=$beId)"
-        val listResponse = try {
-            getList<M18VendorListResponse>(
-                stSearch = StSearchType.VENDOR.value,
-                params = null,
-                conds = conds,
-                request = M18CommonRequest(),
-            )
-        } catch (e: Exception) {
-            logger.warn("(findVendorM18IdByCode) M18 search failed code=$trimmed beId=$beId: ${e.message}")
-            null
-        }
-        return listResponse?.values?.firstOrNull()?.id?.takeIf { it > 0L }
-    }
-
     open fun saveVendors(request: M18CommonRequest) : SyncResult{
         logger.info("--------------------------------------------Start - Saving M18 Vendors--------------------------------------------")
         val vendors = getVendors(request)
diff --git a/src/main/java/com/ffii/fpsms/m18/service/M18VendorLookupService.kt b/src/main/java/com/ffii/fpsms/m18/service/M18VendorLookupService.kt
new file mode 100644
index 0000000..f41fbff
--- /dev/null
+++ b/src/main/java/com/ffii/fpsms/m18/service/M18VendorLookupService.kt
@@ -0,0 +1,43 @@
+package com.ffii.fpsms.m18.service
+
+import com.ffii.fpsms.api.service.ApiCallerService
+import com.ffii.fpsms.m18.model.M18CommonListRequest
+import com.ffii.fpsms.m18.model.M18VendorListResponse
+import com.ffii.fpsms.m18.model.StSearchType
+import org.slf4j.Logger
+import org.slf4j.LoggerFactory
+import org.springframework.stereotype.Service
+
+/**
+ * Lightweight M18 vendor search — kept separate from [M18MasterDataService] to avoid a Spring cycle
+ * ([M18BomForShopService] → [M18MasterDataService] → [com.ffii.fpsms.modules.master.service.BomService] → [M18BomForShopService]).
+ */
+@Service
+open class M18VendorLookupService(
+    private val apiCallerService: ApiCallerService,
+) {
+    private val logger: Logger = LoggerFactory.getLogger(M18VendorLookupService::class.java)
+
+    private val fetchListApi = "/search/search"
+
+    /** M18 vendor id for [code] scoped to [beId] (e.g. PF vs PP business entity). */
+    open fun findVendorM18IdByCode(code: String, beId: String): Long? {
+        val trimmed = code.trim()
+        if (trimmed.isEmpty() || beId.isBlank()) return null
+        val conds = "(code=equal=$trimmed)=and=(beId=equal=$beId)"
+        val listResponse = try {
+            apiCallerService.get<M18VendorListResponse, M18CommonListRequest>(
+                fetchListApi,
+                M18CommonListRequest(
+                    stSearch = StSearchType.VENDOR.value,
+                    params = null,
+                    conds = conds,
+                ),
+            ).block()
+        } catch (e: Exception) {
+            logger.warn("(findVendorM18IdByCode) M18 search failed code=$trimmed beId=$beId: ${e.message}")
+            null
+        }
+        return listResponse?.values?.firstOrNull()?.id?.takeIf { it > 0L }
+    }
+}