diff --git a/cmd/api-errors.go b/cmd/api-errors.go
index 0632682a5..192500ae8 100644
--- a/cmd/api-errors.go
+++ b/cmd/api-errors.go
@@ -48,7 +48,6 @@ const (
 	ErrNone APIErrorCode = iota
 	ErrAccessDenied
 	ErrBadDigest
-	ErrBucketAlreadyExists
 	ErrEntityTooSmall
 	ErrEntityTooLarge
 	ErrIncompleteBody
@@ -193,11 +192,6 @@ var errorCodeResponse = map[APIErrorCode]APIError{
 		Description:    "The Content-Md5 you specified did not match what we received.",
 		HTTPStatusCode: http.StatusBadRequest,
 	},
-	ErrBucketAlreadyExists: {
-		Code:           "BucketAlreadyExists",
-		Description:    "The requested bucket name is not available.",
-		HTTPStatusCode: http.StatusConflict,
-	},
 	ErrEntityTooSmall: {
 		Code:           "EntityTooSmall",
 		Description:    "Your proposed upload is smaller than the minimum allowed object size.",
@@ -613,6 +607,14 @@ func toAPIErrorCode(err error) (apiErr APIErrorCode) {
 		apiErr = ErrWriteQuorum
 	case InsufficientReadQuorum:
 		apiErr = ErrReadQuorum
+	case UnsupportedDelimiter:
+		apiErr = ErrNotImplemented
+	case InvalidMarkerPrefixCombination:
+		apiErr = ErrNotImplemented
+	case InvalidUploadIDKeyCombination:
+		apiErr = ErrNotImplemented
+	case MalformedUploadID:
+		apiErr = ErrNoSuchUpload
 	case PartTooSmall:
 		apiErr = ErrEntityTooSmall
 	default:
diff --git a/cmd/api-errors_test.go b/cmd/api-errors_test.go
new file mode 100644
index 000000000..ca5f653ec
--- /dev/null
+++ b/cmd/api-errors_test.go
@@ -0,0 +1,135 @@
+/*
+ * Minio Cloud Storage, (C) 2016 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package cmd
+
+import (
+	"errors"
+	"testing"
+)
+
+func TestAPIErrCode(t *testing.T) {
+	testCases := []struct {
+		err     error
+		errCode APIErrorCode
+	}{
+		// Valid cases.
+		{
+			BadDigest{},
+			ErrBadDigest,
+		},
+		{
+			IncompleteBody{},
+			ErrIncompleteBody,
+		},
+		{
+			ObjectExistsAsDirectory{},
+			ErrObjectExistsAsDirectory,
+		},
+		{
+			BucketNameInvalid{},
+			ErrInvalidBucketName,
+		},
+		{
+			BucketExists{},
+			ErrBucketAlreadyOwnedByYou,
+		},
+		{
+			ObjectNotFound{},
+			ErrNoSuchKey,
+		},
+		{
+			ObjectNameInvalid{},
+			ErrInvalidObjectName,
+		},
+		{
+			InvalidUploadID{},
+			ErrNoSuchUpload,
+		},
+		{
+			InvalidPart{},
+			ErrInvalidPart,
+		},
+		{
+			InsufficientReadQuorum{},
+			ErrReadQuorum,
+		},
+		{
+			InsufficientWriteQuorum{},
+			ErrWriteQuorum,
+		},
+		{
+			UnsupportedDelimiter{},
+			ErrNotImplemented,
+		},
+		{
+			InvalidMarkerPrefixCombination{},
+			ErrNotImplemented,
+		},
+		{
+			InvalidUploadIDKeyCombination{},
+			ErrNotImplemented,
+		},
+		{
+			MalformedUploadID{},
+			ErrNoSuchUpload,
+		},
+		{
+			PartTooSmall{},
+			ErrEntityTooSmall,
+		},
+		{
+			BucketNotEmpty{},
+			ErrBucketNotEmpty,
+		},
+		{
+			BucketNotFound{},
+			ErrNoSuchBucket,
+		},
+		{
+			StorageFull{},
+			ErrStorageFull,
+		},
+		{
+			errSignatureMismatch,
+			ErrSignatureDoesNotMatch,
+		},
+		{
+			errContentSHA256Mismatch,
+			ErrContentSHA256Mismatch,
+		}, // End of all valid cases.
+
+		// Case where err is nil.
+		{
+			nil,
+			ErrNone,
+		},
+
+		// Case where err type is unknown.
+		{
+			errors.New("Custom error"),
+			ErrInternalError,
+		},
+	}
+
+	// Validate all the errors with their API error codes.
+	for i, testCase := range testCases {
+		errCode := toAPIErrorCode(testCase.err)
+		if errCode != testCase.errCode {
+			t.Errorf("Test %d: Expected error code %d, got %d", i+1, testCase.errCode, errCode)
+		}
+	}
+}
diff --git a/cmd/bucket-handlers_test.go b/cmd/bucket-handlers_test.go
index aa89287a8..60b693ac8 100644
--- a/cmd/bucket-handlers_test.go
+++ b/cmd/bucket-handlers_test.go
@@ -202,7 +202,7 @@ func testHeadBucketHandler(obj ObjectLayer, instanceType string, t TestErrHandle
 
 // Wrapper for calling TestListMultipartUploadsHandler tests for both XL multiple disks and single node setup.
 func TestListMultipartUploadsHandler(t *testing.T) {
-	ExecObjectLayerTest(t, testListMultipartUploads)
+	ExecObjectLayerTest(t, testListMultipartUploadsHandler)
 }
 
 // testListMultipartUploadsHandler - Tests validate listing of multipart uploads.
@@ -253,12 +253,12 @@ func testListMultipartUploadsHandler(obj ObjectLayer, instanceType string, t Tes
 		// 2 - bucket not found.
 		{"volatile-bucket-1", "", "", "", "", "0", http.StatusNotFound, false},
 		// 3 - invalid delimiter.
-		{bucketName, "", "", "", "-", "0", http.StatusBadRequest, false},
+		{bucketName, "", "", "", "-", "0", http.StatusNotImplemented, false},
 		// 4 - invalid prefix and marker combination.
 		{bucketName, "asia", "europe-object", "", "", "0", http.StatusNotImplemented, false},
 		// 5 - invalid upload id and marker combination.
-		{bucketName, "asia", "asia/europe/", "abc", "", "0", http.StatusBadRequest, false},
-		// 6 - invalid max upload id.
+		{bucketName, "asia", "asia/europe/", "abc", "", "0", http.StatusNotImplemented, false},
+		// 6 - invalid max uploads.
 		{bucketName, "", "", "", "", "-1", http.StatusBadRequest, false},
 		// 7 - good case delimiter.
 		{bucketName, "", "", "", "/", "100", http.StatusOK, true},