diff --git a/optimum/exporters/onnx/model_configs.py b/optimum/exporters/onnx/model_configs.py
index 8ffd5243507..bca7cf24acf 100644
--- a/optimum/exporters/onnx/model_configs.py
+++ b/optimum/exporters/onnx/model_configs.py
@@ -266,27 +266,25 @@ class ImageGPTOnnxConfig(GPT2OnnxConfig):
 
 class DecisionTransformerOnnxConfig(OnnxConfig):
     DUMMY_INPUT_GENERATOR_CLASSES = (DummyDecisionTransformerInputGenerator,)
-    NORMALIZED_CONFIG_CLASS = NormalizedConfig.with_args(
-        act_dim="act_dim", state_dim="state_dim", max_ep_len="max_ep_len", hidden_size="hidden_size", allow_new=True
-    )
+    NORMALIZED_CONFIG_CLASS = NormalizedConfig
 
     @property
     def inputs(self) -> Dict[str, Dict[int, str]]:
         return {
+            "states": {0: "batch_size", 1: "sequence_length"},
+            "actions": {0: "batch_size", 1: "sequence_length"},
             "timesteps": {0: "batch_size", 1: "sequence_length"},
             "returns_to_go": {0: "batch_size", 1: "sequence_length"},
             "attention_mask": {0: "batch_size", 1: "sequence_length"},
-            "actions": {0: "batch_size", 1: "sequence_length", 2: "act_dim"},
-            "states": {0: "batch_size", 1: "sequence_length", 2: "state_dim"},
         }
 
     @property
     def outputs(self) -> Dict[str, Dict[int, str]]:
         return {
-            "state_preds": {0: "batch_size", 1: "sequence_length", 2: "state_dim"},
-            "action_preds": {0: "batch_size", 1: "sequence_length", 2: "act_dim"},
+            "state_preds": {0: "batch_size", 1: "sequence_length"},
+            "action_preds": {0: "batch_size", 1: "sequence_length"},
             "return_preds": {0: "batch_size", 1: "sequence_length"},
-            "last_hidden_state": {0: "batch_size", 1: "sequence_length", 2: "last_hidden_state"},
+            "last_hidden_state": {0: "batch_size", 1: "sequence_length"},
         }
 
 
diff --git a/optimum/utils/input_generators.py b/optimum/utils/input_generators.py
index a6ce07bab32..0ac1805f97d 100644
--- a/optimum/utils/input_generators.py
+++ b/optimum/utils/input_generators.py
@@ -513,11 +513,11 @@ class DummyDecisionTransformerInputGenerator(DummyTextInputGenerator):
     """
 
     SUPPORTED_INPUT_NAMES = (
+        "states",
         "actions",
         "timesteps",
-        "attention_mask",
         "returns_to_go",
-        "states",
+        "attention_mask",
     )
 
     def __init__(self, *args, **kwargs):
@@ -531,6 +531,8 @@ def generate(self, input_name: str, framework: str = "pt", int_dtype: str = "int
             shape = [self.batch_size, self.sequence_length, self.state_dim]
         elif input_name == "actions":
             shape = [self.batch_size, self.sequence_length, self.act_dim]
+        elif input_name == "rewards":
+            shape = [self.batch_size, self.sequence_length, 1]
         elif input_name == "returns_to_go":
             shape = [self.batch_size, self.sequence_length, 1]
         elif input_name == "attention_mask":