diff --git a/aiohomekit/controller/coap/connection.py b/aiohomekit/controller/coap/connection.py
index 786c3dc7..9654ddee 100644
--- a/aiohomekit/controller/coap/connection.py
+++ b/aiohomekit/controller/coap/connection.py
@@ -170,7 +170,7 @@ async def post_bytes(self, payload: bytes, timeout: int = 16.0):
 
     async def post(
         self, opcode: OpCode, iid: int, data: bytes
-    ) -> tuple[int, bytes | PDUStatus | ValueError]:
+    ) -> tuple[int, bytes | PDUStatus]:
         tid = random.randint(1, 254)
         req_pdu = encode_pdu(opcode, tid, iid, data)
         res_pdu = await self.post_bytes(req_pdu)
@@ -178,7 +178,7 @@ async def post(
 
     async def post_all(
         self, opcode: OpCode, iids: list[int], data: list[bytes]
-    ) -> list[bytes | PDUStatus | ValueError]:
+    ) -> list[bytes | PDUStatus]:
         req_pdu = encode_all_pdus(opcode, iids, data)
         res_pdu = await self.post_bytes(req_pdu)
 
@@ -478,8 +478,16 @@ async def read_characteristics(self, ids: list[tuple[int, int]]):
 
         results = dict()
         for (idx, result) in enumerate(pdu_results):
-            if isinstance(result, bytes):
-                aid_iid = ids[idx]
+            aid_iid = ids[idx]
+            if isinstance(result, PDUStatus):
+                logger.warning(
+                    "Failed to read aid %d iid %d" % (int(aid_iid[0]), int(aid_iid[1]))
+                )
+                results[aid_iid] = {
+                    "description": result.description,
+                    "status": -result.value,  # XXX
+                }
+            else:
                 # decode TLV to get byte value
                 value = decode_pdu_03(result) if len(result) > 0 else b""
                 # find characteristic so we can get the data type
@@ -502,20 +510,6 @@ async def read_characteristics(self, ids: list[tuple[int, int]]):
                         value,
                     )
                 )
-            else:
-                logger.warning(
-                    "Failed to read aid %d iid %d" % (int(aid_iid[0]), int(aid_iid[1]))
-                )
-                if isinstance(result, PDUStatus):
-                    results[aid_iid] = {
-                        "description": result.description,
-                        "status": -result.value,  # XXX
-                    }
-                else:
-                    results[aid_iid] = {
-                        "description": str(result),
-                        "status": -777,  # XXX something went badly wrong
-                    }
 
         logger.debug(f"Read characteristics: {results!r}")
         return results
@@ -555,11 +549,6 @@ async def write_characteristics(self, ids_values: list[tuple[int, int, Any]]):
                     "descripton": result.description,
                     "status": -result.value,  # XXX
                 }
-            elif isinstance(result, ValueError):
-                results[key] = {
-                    "desciption": str(result),
-                    "status": -777,  # XXX something went badly wrong
-                }
             else:
                 logger.debug(
                     "Wrote value for aid %d iid %d"
@@ -585,11 +574,6 @@ async def subscribe_to(self, ids: list[tuple[int, int]]):
                     "descripton": result.description,
                     "status": -result.value,  # XXX
                 }
-            elif isinstance(result, ValueError):
-                results[key] = {
-                    "desciption": str(result),
-                    "status": -777,  # XXX something went badly wrong
-                }
             else:
                 logger.debug(
                     "Subscribed to aid %d iid %d"
@@ -615,11 +599,6 @@ async def unsubscribe_from(self, ids: list[tuple[int, int]]):
                     "descripton": result.description,
                     "status": -result.value,  # XXX
                 }
-            elif isinstance(result, ValueError):
-                results[key] = {
-                    "desciption": str(result),
-                    "status": -777,  # XXX something went badly wrong
-                }
             else:
                 logger.debug(
                     "Unsubscribed from aid %d iid %d"
@@ -719,7 +698,5 @@ async def remove_pairing(self, pairing_id):
                 raise AuthenticationError("Remove pairing failed")
             else:
                 raise UnknownError("Remove pairing failed")
-        elif isinstance(result, ValueError):
-            raise UnknownError("Remove pairing failed") from result
 
         return True
diff --git a/aiohomekit/controller/coap/pdu.py b/aiohomekit/controller/coap/pdu.py
index de682538..377394f8 100644
--- a/aiohomekit/controller/coap/pdu.py
+++ b/aiohomekit/controller/coap/pdu.py
@@ -47,6 +47,9 @@ class PDUStatus(EnumWithDescription):
     INVALID_INSTANCE_ID = 4, "Invalid instance ID"
     INSUFFICIENT_AUTHENTICATION = 5, "Insufficient authentication"
     INVALID_REQUEST = 6, "Invalid request"
+    # custom error states
+    TID_MISMATCH = 256, "Transaction ID mismatch"
+    BAD_CONTROL = 257, "Control field doesn't have expected bits set"
 
 
 def encode_pdu(opcode: OpCode, tid: int, iid: int, data: bytes) -> bytes:
@@ -70,9 +73,7 @@ def encode_all_pdus(opcode: OpCode, iids: list[int], data: list[bytes]) -> bytes
     return req_pdu
 
 
-def decode_pdu(
-    expected_tid: int, data: bytes
-) -> tuple[int, bytes | PDUStatus | ValueError]:
+def decode_pdu(expected_tid: int, data: bytes) -> tuple[int, bytes | PDUStatus]:
     control, tid, status, body_len = struct.unpack("<BBBH", data[0:5])
     status = PDUStatus(status)
 
@@ -87,17 +88,15 @@ def decode_pdu(
     )
 
     if tid != expected_tid:
-        msg = f"Expected transaction {expected_tid} but got transaction {tid}"
-        logger.warning(msg)
-        return (body_len, ValueError(msg))
+        logger.warning(f"Expected transaction {expected_tid} but got transaction {tid}")
+        return (body_len, PDUStatus.TID_MISMATCH)
 
     if status != PDUStatus.SUCCESS:
         logger.warning(f"Transaction {tid} failed with error {status}")
         return (body_len, status)
 
     if control & 0b0000_1110 != 0b0000_0010:
-        msg = f"Transaction {tid} control doesn't have response bit set"
-        logger.warning(msg)
-        return (body_len, ValueError(msg))
+        logger.warning(f"Transaction {tid} control doesn't have response bit set")
+        return (body_len, PDUStatus.BAD_CONTROL)
 
     return body_len, data[5 : 5 + body_len]
diff --git a/tests/test_controller_coap_pdu.py b/tests/test_controller_coap_pdu.py
index 8506723f..63b5c3c3 100644
--- a/tests/test_controller_coap_pdu.py
+++ b/tests/test_controller_coap_pdu.py
@@ -65,7 +65,7 @@ def test_decode_with_bad_tid():
     res_len, res_val = decode_pdu(0x60, res_pdu)
 
     assert res_len == 0
-    assert isinstance(res_val, ValueError)
+    assert res_val == PDUStatus.TID_MISMATCH
 
 
 def test_decode_with_status_error():
@@ -84,4 +84,4 @@ def test_decode_with_bad_control():
     res_len, res_val = decode_pdu(0x99, res_pdu)
 
     assert res_len == 0
-    assert isinstance(res_val, ValueError)
+    assert res_val == PDUStatus.BAD_CONTROL