diff --git a/src/lhisp-oauth-client.ts b/src/lhisp-oauth-client.ts
index 2205c71..cd546d8 100644
--- a/src/lhisp-oauth-client.ts
+++ b/src/lhisp-oauth-client.ts
@@ -4,9 +4,10 @@ import axios, { AxiosRequestConfig } from 'axios';
 import { 
     AccessToken, ContentType, defaultAuthContentType, 
     defaultAuthHeaderName, 
+    defaultGrantType, 
     defaultTokenHeaderName,
     ExecutarRequestParams, 
-    GrantType, LhispOauthClientConstructorParams,
+    LhispOauthClientConstructorParams,
 } from "./lhisp-oauth-client.t";
 
 export default class LhispOauthClient {
@@ -21,7 +22,7 @@ export default class LhispOauthClient {
     protected senhaCertificado?: string;
     protected authScope?: string;
     protected headers?: Headers;
-    protected grantType?: GrantType;
+    protected grantType?: string;
     protected agent: https.Agent;
     protected accessToken?: AccessToken;
     protected refreshToken?: AccessToken;
@@ -46,7 +47,7 @@ export default class LhispOauthClient {
         this.apiUrl = params.apiUrl;
         this.authUrl = params.authUrl;
         this.authScope = params.authScope;
-        this.grantType = params.grantType;
+        this.grantType = params.grantType || defaultGrantType;
         this.authContentType = params.authContentType || defaultAuthContentType;
         this.clientId = params.clientId;
         this.clientSecret = params.clientSecret;
@@ -60,6 +61,8 @@ export default class LhispOauthClient {
     }
 
     parseData({ data, contentType = ContentType.APPLICATION_JSON }: { data: any, contentType: string }) {
+        if(!data || Object.keys(data).length===0) return undefined;
+
         switch (contentType) {
             case ContentType.APPLICATION_JSON: return JSON.stringify(data);
             case ContentType.APPLICATION_X_WWW_FORM_URLENCODED: return qs.stringify(data);
@@ -90,18 +93,18 @@ export default class LhispOauthClient {
                 [this.authHeaderName]: this.getAuthHeaderValue(),
                 'Content-Type': this.authContentType,
             },
+            data: {},
         }
 
+        if(this.grantType) authRequestOpt.data.grant_type = this.grantType;
+        if(this.authScope) authRequestOpt.data.scope = this.authScope;
+
         if(this.sendAuthCredentialsOnRequestBody) {
-            let data: any = {};
-            if(this.grantType) data.grant_type = this.grantType;
-            if(this.authScope) data.scope = this.authScope;
-            if(this.clientId) data.client_id = this.clientId;
-            if(this.clientSecret) data.client_secret = this.clientSecret;
-
-            authRequestOpt.data = this.parseData({ data, contentType: this.authContentType });
+            if(this.clientId) authRequestOpt.data.client_id = this.clientId;
+            if(this.clientSecret) authRequestOpt.data.client_secret = this.clientSecret;
         }
 
+        authRequestOpt.data = this.parseData({ data: authRequestOpt.data, contentType: this.authContentType });
         const response = await axios.request(authRequestOpt);
         return this.buildAccessToken(response.data);
     }