diff --git a/src/diffusers/pipelines/pipeline_utils.py b/src/diffusers/pipelines/pipeline_utils.py
index 148e2a341c..687931498d 100644
--- a/src/diffusers/pipelines/pipeline_utils.py
+++ b/src/diffusers/pipelines/pipeline_utils.py
@@ -1829,18 +1829,34 @@ class DiffusionPipeline(ConfigMixin, PushToHubMixin):
                 if v.annotation != inspect.Parameter.empty:
                     type_hints[k] = v.annotation
 
-        for k, annotation in type_hints.items():
-            if inspect.isclass(annotation):
-                signature_types[k] = (annotation,)
-            elif get_origin(annotation) == Union:
-                signature_types[k] = get_args(annotation)
-            elif isinstance(annotation, types.UnionType):
-                # Handle PEP 604 union syntax (X | Y) introduced in Python 3.10+
-                signature_types[k] = get_args(annotation)
-            elif get_origin(annotation) in [List, Dict, list, dict]:
-                signature_types[k] = (annotation,)
+        # Get all parameters from the signature to ensure we don't miss any
+        all_params = inspect.signature(cls.__init__).parameters
+
+        for param_name, param in all_params.items():
+            # Skip 'self' parameter
+            if param_name == "self":
+                continue
+
+            # If we have type hints, use them
+            if param_name in type_hints:
+                annotation = type_hints[param_name]
+                if inspect.isclass(annotation):
+                    signature_types[param_name] = (annotation,)
+                elif get_origin(annotation) == Union:
+                    signature_types[param_name] = get_args(annotation)
+                elif isinstance(annotation, types.UnionType):
+                    # Handle PEP 604 union syntax (X | Y) introduced in Python 3.10+
+                    signature_types[param_name] = get_args(annotation)
+                elif get_origin(annotation) in [List, Dict, list, dict]:
+                    signature_types[param_name] = (annotation,)
+                else:
+                    logger.warning(f"cannot get type annotation for Parameter {param_name} of {cls}.")
+                    # Still add it with empty signature so it's in expected_types
+                    signature_types[param_name] = (inspect.Signature.empty,)
             else:
-                logger.warning(f"cannot get type annotation for Parameter {k} of {cls}.")
+                # No type annotation found - add with empty signature
+                signature_types[param_name] = (inspect.Signature.empty,)
+
         return signature_types
 
     @property