diff --git a/CanUds.c b/CanUds.c
index e7a23d4..6ca2357 100644
--- a/CanUds.c
+++ b/CanUds.c
@@ -557,18 +557,30 @@ static uint16_t SecurityAccess_27(tCanUds *env) {
         env->dataResponse[0] = UDS_SecurityAccess | 0b1000000;
         env->dataResponse[1] = env->data.data[1] & 0b01111111; // sub-function
 
-        env->dataResponse[2] = randomSecuritySeed >> 24;
-        env->dataResponse[3] = randomSecuritySeed >> 16;
-        env->dataResponse[4] = randomSecuritySeed >> 8;
-        env->dataResponse[5] = randomSecuritySeed;
+        // Доступ уже получен
+        if (env->SA.stateSecurityAccess) {
+            env->dataResponse[2] = 0;
+            env->dataResponse[3] = 0;
+            env->dataResponse[4] = 0;
+            env->dataResponse[5] = 0;
+        } else {
 
+            if (randomSecuritySeed == 0) {
+                randomSecuritySeed = 0x11223344;
+            }
+
+            env->dataResponse[2] = randomSecuritySeed >> 24;
+            env->dataResponse[3] = randomSecuritySeed >> 16;
+            env->dataResponse[4] = randomSecuritySeed >> 8;
+            env->dataResponse[5] = randomSecuritySeed;
+        }
         return 6;
     }
 
     if (com->sub_function == UDS_sub_sendKey) {
 
         if (env->data.len < 6) {
-            return setResponseError(env, UDS_SecurityAccess, UDS_error_incorrectMessageLengthOrInvalidFormat);
+            return setResponseError(env, UDS_SecurityAccess, UDS_error_requestOutOfRange);
         }
 
         // Ранее не получен запрос UDS_sub_requestSeed
@@ -605,6 +617,8 @@ static uint16_t SecurityAccess_27(tCanUds *env) {
 
         return 2;
     }
+
+    return setResponseError(env, UDS_SecurityAccess, UDS_error_invalidKey);
 }
 // конец --------------------------- Security Access -------------------------------------------------------------
 // конец --------------------------- Security Access -------------------------------------------------------------