diff --git a/res/controllers/Traktor-Kontrol-S2-MK3-hid-scripts.js b/res/controllers/Traktor-Kontrol-S2-MK3-hid-scripts.js
index 704cabf2a71..7b3a552b95b 100644
--- a/res/controllers/Traktor-Kontrol-S2-MK3-hid-scripts.js
+++ b/res/controllers/Traktor-Kontrol-S2-MK3-hid-scripts.js
@@ -670,19 +670,92 @@ TraktorS2MK3.wheelDeltas = function(deckNumber, value) {
 };
 
 TraktorS2MK3.fxHandler = function(field) {
+    /* We support 8 effects in total by having 2 effects per fx button. *
+     * First press of the button will load the preset at the index of the quick effect preset list *
+     * Second press will load the preset index + 4 *
+     * Arrange your quick effect preset list from 1 to 8 like this: 1/5, 2/6, 3/7, 4/8 */
     if (field.value === 0) {
         return;
     }
 
+    const availableGroups = ["[Channel1]", "[Channel2]"];
+    const fxButtonCount = 4;
+    let targetGroups = [];
     const fxNumber = parseInt(field.id[field.id.length - 1]);
-    const group = "[EffectRack1_EffectUnit" + fxNumber + "]";
+    let noShift = false;
 
-    // Toggle effect unit
-    TraktorS2MK3.fxButtonState[fxNumber] = !TraktorS2MK3.fxButtonState[fxNumber];
+    // Target decks whose shift button is pressed.
+    for (const group of availableGroups) {
+        if (TraktorS2MK3.shiftPressed[group]) { targetGroups.push(group); }
+    }
+
+    // If no shift button was pressed fall back to target all decks.
+    if (targetGroups.length === 0) {
+        targetGroups = availableGroups;
+        noShift = true;
+    }
+
+    const fxToApply = {};
+    const activeFx = {};
+    // Detect which fx should be enabled
+    for (const group of targetGroups) {
+        activeFx[group] = engine.getValue(`[QuickEffectRack1_${group}]`, "loaded_chain_preset") - 1;
+        if (activeFx[group] === fxNumber) {
+            // Pressing again the fx button
+            fxToApply[group] = fxNumber + fxButtonCount;
+        } else if (activeFx[group] === fxNumber + fxButtonCount) {
+            // Already on secondary fx so resetting back to fxNumber
+            fxToApply[group] = fxNumber;
+        } else {
+            // First press of a different fx button
+            fxToApply[group] = fxNumber;
+        }
+    }
+
+    /* When we target both decks - No shift pressed - we want *
+     * to reset fx to same value for both */
+    if (targetGroups.length === 2 && noShift) {
+        const [deck1, deck2] = targetGroups;
+        const activeFxDeck1 = activeFx[deck1];
+        const activeFxDeck2 = activeFx[deck2];
+        const fxToApplyDeck1 = fxToApply[deck1];
+        const fxToApplyDeck2 = fxToApply[deck2];
+
+        // If any of deck has already fx enabled but different value to apply
+        if ((activeFxDeck1 === fxNumber || activeFxDeck2 === fxNumber) && fxToApplyDeck1 !== fxToApplyDeck2) {
+        // find lower value to reset both to the same one
+            const fxToApplyAll = Math.min(fxToApplyDeck1, fxToApplyDeck2);
+            fxToApply[deck1] = fxToApplyAll;
+            fxToApply[deck2] = fxToApplyAll;
+        }
+    }
 
-    engine.setValue(group, "group_[Channel1]_enable", TraktorS2MK3.fxButtonState[fxNumber]);
-    engine.setValue(group, "group_[Channel2]_enable", TraktorS2MK3.fxButtonState[fxNumber]);
-    TraktorS2MK3.outputHandler(TraktorS2MK3.fxButtonState[fxNumber], field.group, "fxButton" + fxNumber);
+    // Now apply the new fx value
+    for (const group of targetGroups) {
+        engine.setValue(`[QuickEffectRack1_${group}]`, "loaded_chain_preset", fxToApply[group] + 1);
+    }
+};
+
+TraktorS2MK3.fxOutputHandler = function() {
+    const fxButtonCount = 4;
+    const availableGroups = ["[Channel1]", "[Channel2]"];
+
+    const activeFx = {};
+    for (const group of availableGroups) {
+        activeFx[group] = engine.getValue(`[QuickEffectRack1_${group}]`, "loaded_chain_preset") - 1;
+        // We want to lit the proper fx button even when we have applied a higher fxNumber
+        if (activeFx[group] > fxButtonCount) { activeFx[group] = activeFx[group] - fxButtonCount; }
+    }
+
+    /* There is no way on the controller to indicate which deck the effect applies *
+     * to, but keeping both lit indicates that different effects are in use.       */
+    for (let fxButton = 1; fxButton <= fxButtonCount; ++fxButton) {
+        let active = false;
+        for (const group of availableGroups) {
+            active = active || activeFx[group] === fxButton;
+        }
+        TraktorS2MK3.outputHandler(active, "[ChannelX]", "fxButton" + fxButton);
+    }
 };
 
 TraktorS2MK3.reverseHandler = function(field) {
@@ -836,6 +909,11 @@ TraktorS2MK3.registerOutputPackets = function() {
         this.samplerCallbacks.push(engine.makeConnection("[Sampler" + i + "]", "play", this.samplesOutputHandler));
     }
 
+    this.fxCallbacks = [];
+    for (const group of ["[Channel1]", "[Channel2]"]) {
+        this.fxCallbacks.push(engine.makeConnection(`[QuickEffectRack1_${group}]`, "loaded_chain_preset", this.fxOutputHandler));
+    }
+
     TraktorS2MK3.lightDeck(false);
 };
 
@@ -1015,6 +1093,8 @@ TraktorS2MK3.lightDeck = function(switchOff) {
     TraktorS2MK3.controller.setOutput("[ChannelX]", "fxButton2", softLight, false);
     TraktorS2MK3.controller.setOutput("[ChannelX]", "fxButton3", softLight, false);
     TraktorS2MK3.controller.setOutput("[ChannelX]", "fxButton4", softLight, false);
+    // Set FX button LED state according to active quick effects on start-up
+    if (!switchOff) { TraktorS2MK3.fxOutputHandler(); }
 
     TraktorS2MK3.controller.setOutput("[Channel1]", "reverse", softLight, false);
     TraktorS2MK3.controller.setOutput("[Channel2]", "reverse", softLight, false);