diff --git a/inc/Services/ParameterService.hpp b/inc/Services/ParameterService.hpp
index db4ed28d0f9e32e68cd7c8f25a3c843222e79bfe..0338d76d0a45a51467f18c1457f52276476a9658 100644
--- a/inc/Services/ParameterService.hpp
+++ b/inc/Services/ParameterService.hpp
@@ -9,7 +9,6 @@
 
 // Number of stored parameters. MAX_PARAMS is just a dummy number for now.
 #define MAX_PARAMS 5
-// TODO: 1) Rework the parameter setting and report functions
 // TODO: 2) Implement flags and use them above
 // TODO: 3) Write more and better tests
 // TODO: 4) Make sure that docs are up to date
@@ -28,7 +27,7 @@
  * for parameter reporting and modification.
  *
  * The parameter list is stored in a map with the parameter IDs as keys and values
- * corresponding Parameter structs containing the PTC, PFC and the parameter's value.
+ * corresponding Parameter classes containing the PTC, PFC and the parameter's value.
  */
 
 
@@ -38,16 +37,18 @@ private:
 
 public:
 	/**
-	 * Initializes the parameter list.
+	 * @brief Initializes the parameter list.
 	 */
 	ParameterService();
 
 	/**
-	 * Adds a new parameter. If the parameter has not been added (either because the map is full or because it already
-	 * exists in it) then returns false.
-	 * The parameter IDs are given sequentially, starting from 0.
+	 * @brief Adds a new parameter. Returns false if the parameter has not been added
+	 * (either because the map is full or because it already exists in it).
+	 * @param id: the desired ID for this parameter
+	 * @param param: the parameter field to be included
+	 * @param flags: the flags to be set for this field (see Parameter.hpp)
 	 */
-	bool addNewParameter(uint8_t id, Parameter param, const char* flags = "110");
+	bool addNewParameter(uint16_t id, Parameter param, const char* flags = "110");
 
 	/**
 	 * This function receives a TC[20, 1] packet and returns a TM[20, 2] packet
@@ -70,7 +71,8 @@ public:
 	/**
 	 * This function receives a TC[20, 3] message and after checking whether its type is correct,
 	 * iterates over all contained parameter IDs and replaces the settings for each valid parameter,
-	 * while ignoring all invalid IDs.
+	 * while ignoring all invalid IDs. If the manual update flag is not set, the parameter's value should
+	 * not change.
 	 *
 	 * @param newParamValues: a valid TC[20, 3] message carrying parameter ID and replacement value
 	 * @return None
diff --git a/src/Services/ParameterService.cpp b/src/Services/ParameterService.cpp
index f79d99b3757096068e595ba4f79e1a8d4c6bbeff..ff178411a0dd266ad49755ff5e9441c3d9324e7a 100644
--- a/src/Services/ParameterService.cpp
+++ b/src/Services/ParameterService.cpp
@@ -7,21 +7,29 @@ ParameterService::ParameterService() {
 //	addNewParameter(3, 14);
 }
 
-bool ParameterService::addNewParameter(uint8_t id, Parameter param, const char* flags) {
+bool ParameterService::addNewParameter(uint16_t id, Parameter param, const char* flags) {
 	try {
-		// second element of the returned std::pair is whether the given item was inserted or not
-		param.setFlag(flags);
-		paramsList.insert(std::make_pair(id, param));
-		return true;
+		try {
+			paramsList.at(id);
+			return false;
+			// if it exists, an iterator will be returned with no exception thrown,
+			// so the function should return false
+			// todo: is it a better idea to use find() and if instead of an exception here?
+		}
+		catch (etl::map_out_of_bounds& mapOutOfBounds) {
+			param.setFlag(flags);
+			paramsList.insert(std::make_pair(id, param));
+			return true;
+		}
 	}
 	catch (etl::map_full &mapFull) {
 		return false;
+		// if the map is full, return false
 	}
 }
 
 void ParameterService::reportParameterIds(Message& paramIds) {
 	etl::vector<std::pair<uint16_t, ValueType>, MAX_PARAMS> validParams;
-//	paramIds.assertTC(20, 1);
 	Message reqParam(20, 2, Message::TM, 1);
 	// empty TM[20, 2] parameter report message
 
@@ -66,8 +74,6 @@ void ParameterService::reportParameterIds(Message& paramIds) {
 }
 
 void ParameterService::setParameterIds(Message& newParamValues) {
-	//newParamValues.assertTC(20, 3);
-
 	// assertion: correct message, packet and service type (at failure throws an
 	// InternalError::UnacceptablePacket which gets logged)
 
diff --git a/test/Services/ParameterService.cpp b/test/Services/ParameterService.cpp
index 57e5a1c228e3348a438c3d2c4a11bd7b08cd4adf..65bb50b322b0b44b9bebfb44cb6581730e26732b 100644
--- a/test/Services/ParameterService.cpp
+++ b/test/Services/ParameterService.cpp
@@ -36,9 +36,13 @@ TEST_CASE("Parameter Service - General") {
 		Services.reset();  // reset all services
 	}
 
-//	SECTION("Addition of already existing parameter") {
-//
-//	}
+	SECTION("Addition of already existing parameter") {
+		Parameter param0 = Parameter(1, 3);
+		pserv.addNewParameter(0, param0);
+
+		CHECK_FALSE(pserv.addNewParameter(0, param0));
+		Services.reset();
+	}
 
 	//SECTION("Passing of null-pointer as update function on construction")