diff --git a/include/engine/Module.hpp b/include/engine/Module.hpp
index 966e3f13..9e950fc9 100644
--- a/include/engine/Module.hpp
+++ b/include/engine/Module.hpp
@@ -469,6 +469,8 @@ struct Module {
 	PRIVATE int meterIndex();
 	PRIVATE void doProcess(const ProcessArgs& args);
 	PRIVATE static void jsonStripIds(json_t* rootJ);
+	/** Sets module of expander and dispatches ExpanderChangeEvent if changed. */
+	PRIVATE void setExpanderModule(Module* module, uint8_t side);
 };
 
 
diff --git a/src/engine/Engine.cpp b/src/engine/Engine.cpp
index 876b581c..68b1c09c 100644
--- a/src/engine/Engine.cpp
+++ b/src/engine/Engine.cpp
@@ -235,26 +235,21 @@ struct Engine::Internal {
 
 
 static void Engine_updateExpander_NoLock(Engine* that, Module* module, uint8_t side) {
-	Module::Expander& expander = side ? module->rightExpander : module->leftExpander;
-	Module* oldExpanderModule = expander.module;
+	Module::Expander& expander = module->getExpander(side);
 
 	if (expander.moduleId >= 0) {
+		// Check if moduleId has changed from current module
 		if (!expander.module || expander.module->id != expander.moduleId) {
-			expander.module = that->getModule_NoLock(expander.moduleId);
+			Module* expanderModule = that->getModule_NoLock(expander.moduleId);
+			module->setExpanderModule(expanderModule, side);
 		}
 	}
 	else {
+		// Check if moduleId has unset module
 		if (expander.module) {
-			expander.module = NULL;
+			module->setExpanderModule(NULL, side);
 		}
 	}
-
-	if (expander.module != oldExpanderModule) {
-		// Dispatch ExpanderChangeEvent
-		Module::ExpanderChangeEvent e;
-		e.side = side;
-		module->onExpanderChange(e);
-	}
 }
 
 
@@ -502,8 +497,8 @@ void Engine::stepBlock(int frames) {
 
 	// Update expander pointers
 	for (Module* module : internal->modules) {
-		Engine_updateExpander_NoLock(this, module, false);
-		Engine_updateExpander_NoLock(this, module, true);
+		Engine_updateExpander_NoLock(this, module, 0);
+		Engine_updateExpander_NoLock(this, module, 1);
 	}
 
 	// Launch workers
@@ -760,23 +755,25 @@ void Engine::removeModule_NoLock(Module* module) {
 	}
 	// Update expanders of other modules
 	for (Module* m : internal->modules) {
-		if (m->leftExpander.module == module) {
-			m->leftExpander.moduleId = -1;
-			m->leftExpander.module = NULL;
-		}
-		if (m->rightExpander.module == module) {
-			m->rightExpander.moduleId = -1;
-			m->rightExpander.module = NULL;
+		for (uint8_t side = 0; side < 2; side++) {
+			Module::Expander& expander = m->getExpander(!side);
+			if (expander.moduleId == module->id) {
+				expander.moduleId = -1;
+			}
+			if (expander.module == module) {
+				m->setExpanderModule(NULL, !side);
+			}
 		}
 	}
+	// Update expanders of this module
+	for (uint8_t side = 0; side < 2; side++) {
+		Module::Expander& expander = module->getExpander(side);
+		expander.moduleId = -1;
+		module->setExpanderModule(NULL, side);
+	}
 	// Remove module
 	internal->modulesCache.erase(module->id);
 	internal->modules.erase(it);
-	// Reset expanders
-	module->leftExpander.moduleId = -1;
-	module->leftExpander.module = NULL;
-	module->rightExpander.moduleId = -1;
-	module->rightExpander.module = NULL;
 }
 
 
@@ -795,6 +792,8 @@ Module* Engine::getModule(int64_t moduleId) {
 
 
 Module* Engine::getModule_NoLock(int64_t moduleId) {
+	if (moduleId < 0)
+		return NULL;
 	auto it = internal->modulesCache.find(moduleId);
 	if (it == internal->modulesCache.end())
 		return NULL;
@@ -1046,6 +1045,8 @@ bool Engine::hasCable(Cable* cable) {
 
 
 Cable* Engine::getCable(int64_t cableId) {
+	if (cableId < 0)
+		return NULL;
 	SharedLock<SharedMutex> lock(internal->mutex);
 	auto it = internal->cablesCache.find(cableId);
 	if (it == internal->cablesCache.end())
diff --git a/src/engine/Module.cpp b/src/engine/Module.cpp
index 083b4c39..54080713 100644
--- a/src/engine/Module.cpp
+++ b/src/engine/Module.cpp
@@ -392,6 +392,18 @@ void Module::jsonStripIds(json_t* rootJ) {
 }
 
 
+void Module::setExpanderModule(Module* module, uint8_t side) {
+	Expander& expander = getExpander(side);
+
+	if (expander.module != module) {
+		expander.module = module;
+		// Dispatch ExpanderChangeEvent
+		Module::ExpanderChangeEvent e;
+		e.side = side;
+		onExpanderChange(e);
+	}
+}
+
 
 } // namespace engine
 } // namespace rack