diff --git a/CHANGELOG.md b/CHANGELOG.md
index c714ba6ae..c05007a28 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 - Fixed SonarQube junit path issue in GitHub Actions [#1284](https://github.com/ie3-institute/PowerSystemDataModel/issues/1284)
+- Fixed no errors thrown in `getMapping()` in `TimeSeriesMappingSource` [#1287](https://github.com/ie3-institute/PowerSystemDataModel/issues/1287)
+
 ### Changed
 - Replaced `return this` with `return thisInstance` in CopyBuilders [#1250](https://github.com/ie3-institute/PowerSystemDataModel/issues/1250)
 
diff --git a/src/main/java/edu/ie3/datamodel/io/source/TimeSeriesMappingSource.java b/src/main/java/edu/ie3/datamodel/io/source/TimeSeriesMappingSource.java
index 0c0a1d192..15e5b63e4 100644
--- a/src/main/java/edu/ie3/datamodel/io/source/TimeSeriesMappingSource.java
+++ b/src/main/java/edu/ie3/datamodel/io/source/TimeSeriesMappingSource.java
@@ -5,15 +5,12 @@
 */
 package edu.ie3.datamodel.io.source;
 
-import edu.ie3.datamodel.exceptions.FactoryException;
-import edu.ie3.datamodel.exceptions.SourceException;
-import edu.ie3.datamodel.exceptions.ValidationException;
+import edu.ie3.datamodel.exceptions.*;
 import edu.ie3.datamodel.io.factory.EntityData;
 import edu.ie3.datamodel.io.factory.timeseries.TimeSeriesMappingFactory;
 import edu.ie3.datamodel.models.input.InputEntity;
 import edu.ie3.datamodel.models.timeseries.TimeSeries;
 import edu.ie3.datamodel.utils.Try;
-import edu.ie3.datamodel.utils.Try.*;
 import java.util.*;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
@@ -41,12 +38,11 @@ public void validate() throws ValidationException {
    * @return That mapping
    */
   public Map<UUID, UUID> getMapping() throws SourceException {
-    return getMappingSourceData()
-        .map(this::createMappingEntry)
-        .filter(Try::isSuccess)
-        .map(t -> (Success<MappingEntry, FactoryException>) t)
-        .map(Success::get)
-        .collect(Collectors.toMap(MappingEntry::getAsset, MappingEntry::getTimeSeries));
+    return Try.scanStream(getMappingSourceData().map(this::createMappingEntry), "MappingEntry")
+        .transform(
+            s -> s.collect(Collectors.toMap(MappingEntry::getAsset, MappingEntry::getTimeSeries)),
+            SourceException::new)
+        .getOrThrow();
   }
 
   /**
diff --git a/src/test/groovy/edu/ie3/datamodel/io/source/TimeSeriesMappingSourceTest.groovy b/src/test/groovy/edu/ie3/datamodel/io/source/TimeSeriesMappingSourceTest.groovy
new file mode 100644
index 000000000..9b5da47e2
--- /dev/null
+++ b/src/test/groovy/edu/ie3/datamodel/io/source/TimeSeriesMappingSourceTest.groovy
@@ -0,0 +1,128 @@
+/*
+ * © 2025. TU Dortmund University,
+ * Institute of Energy Systems, Energy Efficiency and Energy Economics,
+ * Research group Distribution grid planning and operation
+ */
+package edu.ie3.datamodel.io.source
+
+import edu.ie3.datamodel.exceptions.FactoryException
+import edu.ie3.datamodel.exceptions.FailureException
+import edu.ie3.datamodel.exceptions.SourceException
+import spock.lang.Shared
+import spock.lang.Specification
+
+import java.util.stream.Stream
+import javax.xml.transform.Source
+
+class TimeSeriesMappingSourceTest extends Specification {
+
+  @Shared
+  MixedMappingSource validSource
+
+  def setupSpec() {
+    validSource = new MixedMappingSource(true, true)
+  }
+
+  class MixedMappingSource extends TimeSeriesMappingSource {
+
+    private boolean validAsset
+    private boolean validTimeSeries
+
+    MixedMappingSource(boolean validAsset, boolean validTimeSeries) {
+      this.validAsset = validAsset
+      this.validTimeSeries = validTimeSeries
+    }
+
+    @Override
+    Stream<Map<String, String>> getMappingSourceData() throws SourceException {
+      switch (getCase()){
+        case "VALID":
+          return Stream.of(
+          Map.of("asset", "b86e95b0-e579-4a80-a534-37c7a470a409", "timeSeries", "9185b8c1-86ba-4a16-8dea-5ac898e8caa5")
+          )
+        case "INVALID_ASSET":
+          return Stream.of(
+          Map.of("asset", "invalidAsset", "timeSeries", "3fbfaa97-cff4-46d4-95ba-a95665e87c26"),
+          Map.of("asset", "c7ebcc6c-55fc-479b-aa6b-6fa82ccac6b8", "timeSeries", "3fbfaa97-cff4-46d4-95ba-a95665e87c26")
+          )
+        case "INVALID_TIMESERIES":
+          return Stream.of(
+          Map.of("asset", "90a96daa-012b-4fea-82dc-24ba7a7ab81c", "timeSeries", "invalidTimeSeries"),
+          Map.of("asset","90a96daa-012b-4fea-82dc-24ba7a7ab81c","timeSeries","3fbfaa97-cff4-46d4-95ba-a95665e87c26")
+          )
+        case "INVALID_ALL":
+          return Stream.of(
+          Map.of("asset", "invalidAsset", "timeSeries", "invalidTimeSeries"),
+          Map.of("asset", "invalidAsset2", "timeSeries", "invalidTimeSeries2")
+          )
+      }
+    }
+
+    private String getCase() {
+      if (validAsset && validTimeSeries) {
+        return "VALID"
+      } else if (!validAsset && validTimeSeries) {
+        return "INVALID_ASSET"
+      } else if (validAsset && !validTimeSeries) {
+        return "INVALID_TIMESERIES"
+      } else if (!validAsset && !validTimeSeries) {
+        return "INVALID_ALL"
+      }
+    }
+
+    @Override
+    Optional<Set<String>> getSourceFields() throws SourceException {
+      return Optional.of(Set.of("asset", "timeSeries"))
+    }
+  }
+
+
+
+  def "valid mapping entries should correctly be processed"(){
+    given: "dummy mapping source with valid data"
+
+    when:
+    def actualMapping = validSource.getMapping()
+
+    then:
+    actualMapping.size() == 1
+    actualMapping.containsKey(UUID.fromString("b86e95b0-e579-4a80-a534-37c7a470a409"))
+    actualMapping.get(UUID.fromString("b86e95b0-e579-4a80-a534-37c7a470a409")) == UUID.fromString("9185b8c1-86ba-4a16-8dea-5ac898e8caa5")
+  }
+
+  def "should throw SourceException for invalid asset"(){
+    given: "DummyMappingSource"
+    validSource = new MixedMappingSource(false, true)
+    when:
+    validSource.getMapping()
+
+    then:
+    def ex = thrown(SourceException)
+    ex.cause.class == FailureException
+    ex.cause.message.startsWith("1 exception(s) occurred within \"MappingEntry\" data")
+  }
+
+  def "should throw SourceException for invalid timeSeries"(){
+    given: "DummyMappingSource"
+    validSource = new MixedMappingSource(true, false)
+    when:
+    validSource.getMapping()
+
+    then:
+    def ex = thrown(SourceException)
+    ex.cause.class == FailureException
+    ex.cause.message.startsWith("1 exception(s) occurred within \"MappingEntry\" data")
+  }
+
+  def "should throw SourceException for invalid timeSeries and asset"(){
+    given: "DummyMappingSource"
+    validSource = new MixedMappingSource(false, false)
+    when:
+    validSource.getMapping()
+
+    then:
+    def ex = thrown(SourceException)
+    ex.cause.class == FailureException
+    ex.cause.message.startsWith("2 exception(s) occurred within \"MappingEntry\" data")
+  }
+}