diff --git a/src/main/java/de/etecture/ga/exception/ResponseExceptionHandler.java b/src/main/java/de/etecture/ga/exception/ResponseExceptionHandler.java
new file mode 100644
index 0000000..6f38011
--- /dev/null
+++ b/src/main/java/de/etecture/ga/exception/ResponseExceptionHandler.java
@@ -0,0 +1,19 @@
+package de.etecture.ga.exception;
+
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.ControllerAdvice;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.context.request.WebRequest;
+import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler;
+
+@ControllerAdvice
+public class ResponseExceptionHandler extends ResponseEntityExceptionHandler {
+
+	@ExceptionHandler(value = { IllegalArgumentException.class })
+	protected ResponseEntity<Object> handleConflict(RuntimeException ex, WebRequest request) {
+		String bodyOfResponse = ex.getMessage();
+		return handleExceptionInternal(ex, bodyOfResponse, new HttpHeaders(), HttpStatus.NOT_ACCEPTABLE, request);
+	}
+}
\ No newline at end of file
diff --git a/src/test/java/de/etecture/ga/api/GarageApiControllerTest.java b/src/test/java/de/etecture/ga/api/GarageApiControllerTest.java
index 4b4a5a9..4c751ea 100644
--- a/src/test/java/de/etecture/ga/api/GarageApiControllerTest.java
+++ b/src/test/java/de/etecture/ga/api/GarageApiControllerTest.java
@@ -68,8 +68,8 @@ class GarageApiControllerTest {
 
 		this.mockMvc
 				.perform(
-						MockMvcRequestBuilders.get("/werkstatt/{werkstattId}/termin/{terminId}", testGarage.id(), "-5"))
-				.andDo(MockMvcResultHandlers.print()).andExpect(MockMvcResultMatchers.status().isNotFound());
+						MockMvcRequestBuilders.get("/werkstatt/{werkstattId}/termin/{terminId}", testGarage.id(), "9999a"))
+				.andDo(MockMvcResultHandlers.print()).andExpect(MockMvcResultMatchers.status().isNotAcceptable());
 
 		this.mockMvc
 				.perform(MockMvcRequestBuilders.get("/werkstatt/{werkstattId}/termin/{terminId}", 2,