diff --git a/package.json b/package.json
index b454fef..74a3afd 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "cros-dpsl-js",
-  "version": "1.3.7",
+  "version": "1.3.8",
   "description": "Diagnostics processor support library for Chrome OS",
   "main": "./src/dpsl.js",
   "exports": "./src/dpsl.js",
diff --git a/src/README.md b/src/README.md
index 01c0912..e73187a 100644
--- a/src/README.md
+++ b/src/README.md
@@ -428,7 +428,7 @@ Source:
 | refreshRate | number | Refresh rate |
 | manufacturer | string | Three letter manufacturer ID |
 | modelId | number | Manufacturer product code |
-| serialNumber | number | 32 bits serial number |
+| serialNumber | number | 32 bits serial number. Starting from M120, this field is always empty due to privacy requirements. |
 | manufactureWeek | number | Week of manufacture |
 | manufactureYear | number | Year of manufacture |
 | edidVersion | string | EDID version |
@@ -445,7 +445,7 @@ Source:
 | refreshRate | number | Refresh rate |
 | manufacturer | string | Three letter manufacturer ID |
 | modelId | number | Manufacturer product code |
-| serialNumber | number | 32 bits serial number |
+| serialNumber | number | 32 bits serial number. Starting from M120, this field is always empty due to privacy requirements. |
 | manufactureWeek | number | Week of manufacture |
 | manufactureYear | number | Year of manufacture |
 | edidVersion | string | EDID version |
@@ -562,3 +562,8 @@ Source:
 | runBluetoothDiscoveryRoutine | () => Promise\<Routine\> | `os.diagnostics` | 1.3.7 |
 | runBluetoothScanningRoutine | (params: BluetoothScanningRoutineParams) => Promise\<Routine\> | `os.diagnostics`, `os.bluetooth_peripherals_info` | 1.3.7 |
 | runBluetoothPairingRoutine | (params: BluetoothPairingRoutineParams) => Promise\<Routine\> | `os.diagnostics`, `os.bluetooth_peripherals_info` | 1.3.7 |
+
+### dpsl.diagnostics.fan.*
+| Function Name | Definition | Permission needed to access | Released in `dpsl` version |
+------------ | ------------- | ------------- | ------------- |
+| runFanRoutine | () => Promise\<Routine\> | `os.diagnostics` | 1.3.8 |
diff --git a/src/__tests__/dpsl.test.js b/src/__tests__/dpsl.test.js
index 4951e35..725810e 100644
--- a/src/__tests__/dpsl.test.js
+++ b/src/__tests__/dpsl.test.js
@@ -683,6 +683,10 @@ describe('dpsl.diagnostics tests', () => {
           .runBluetoothPairingRoutine,
       'chromeOsRoutineFunction': 'runBluetoothPairingRoutine',
     },
+    {
+      'dpslRoutineFunction': dpsl.diagnostics.fan.runFanRoutine,
+      'chromeOsRoutineFunction': 'runFanRoutine',
+    },
   ];
 
   testCases.forEach((testCase) => {
diff --git a/src/diagnostics_manager.js b/src/diagnostics_manager.js
index 028ee77..301a94b 100644
--- a/src/diagnostics_manager.js
+++ b/src/diagnostics_manager.js
@@ -664,6 +664,27 @@ class BluetoothManager {
   }
 }
 
+/**
+ * Diagnostics fan Manager for dpsl.diagnostics.fan.* APIs.
+ */
+class FanManager {
+  /**
+   * Runs fan test. This routine checks whether the fan can be controlled.
+   * @return { !Promise<!Routine> }
+   * @public
+   */
+  async runFanRoutine() {
+    const functionName = 'runFanRoutine';
+    if (!isSupported(functionName)) {
+      throw new MethodNotFoundError(API_NAME, functionName,
+          /* chromeVersion */ 121);
+    }
+
+    return chrome.os.diagnostics.runFanRoutine().then(
+        (response) => new Routine(response.id));
+  }
+}
+
 /**
  * DPSL Diagnostics Manager for dpsl.diagnostics.* APIs.
  */
@@ -749,6 +770,12 @@ class DPSLDiagnosticsManager {
      * @public
      */
     this.bluetooth = new BluetoothManager();
+
+    /**
+     * @type {!FanManager}
+     * @public
+     */
+    this.fan = new FanManager();
   }
 
   /**