diff --git a/automotive/vehicle/aidl/impl/vhal/test/DefaultVehicleHalTest.cpp b/automotive/vehicle/aidl/impl/vhal/test/DefaultVehicleHalTest.cpp
index 36fa5e6..05e569a 100644
--- a/automotive/vehicle/aidl/impl/vhal/test/DefaultVehicleHalTest.cpp
+++ b/automotive/vehicle/aidl/impl/vhal/test/DefaultVehicleHalTest.cpp
@@ -671,8 +671,8 @@
 }
 
 TEST_F(DefaultVehicleHalTest, testGetValuesFinishBeforeTimeout) {
-    // timeout: 0.1s
-    int64_t timeout = 100000000;
+    // timeout: 1s
+    int64_t timeout = 1000000000;
     setTimeout(timeout);
 
     GetValueRequests requests;
@@ -681,17 +681,15 @@
 
     ASSERT_TRUE(getValuesTestCases(10, requests, expectedResults, expectedHardwareRequests).ok());
 
-    // The response would be returned after 0.05s.
-    getHardware()->setSleepTime(timeout / 2);
+    // The response would be returned after 0.01s.
+    getHardware()->setSleepTime(timeout / 100);
     getHardware()->addGetValueResponses(expectedResults);
 
     auto status = getClient()->getValues(getCallbackClient(), requests);
 
     ASSERT_TRUE(status.isOk()) << "getValues failed: " << status.getMessage();
 
-    // Wait for the response.
-    std::this_thread::sleep_for(std::chrono::nanoseconds(timeout));
-
+    ASSERT_TRUE(getCallback()->waitForGetValueResults(1, timeout)) << "no results in callback";
     auto maybeGetValueResults = getCallback()->nextGetValueResults();
     ASSERT_TRUE(maybeGetValueResults.has_value()) << "no results in callback";
     EXPECT_EQ(maybeGetValueResults.value().payloads, expectedResults) << "results mismatch";
@@ -699,8 +697,8 @@
 }
 
 TEST_F(DefaultVehicleHalTest, testGetValuesFinishAfterTimeout) {
-    // timeout: 0.1s
-    int64_t timeout = 100000000;
+    // timeout: 0.01s
+    int64_t timeout = 10000000;
     setTimeout(timeout);
 
     GetValueRequests requests;
@@ -709,17 +707,14 @@
 
     ASSERT_TRUE(getValuesTestCases(10, requests, expectedResults, expectedHardwareRequests).ok());
 
-    // The response would be returned after 0.2s.
-    getHardware()->setSleepTime(timeout * 2);
+    // The response would be returned after 0.1s.
+    getHardware()->setSleepTime(timeout * 10);
     getHardware()->addGetValueResponses(expectedResults);
 
     auto status = getClient()->getValues(getCallbackClient(), requests);
 
     ASSERT_TRUE(status.isOk()) << "getValues failed: " << status.getMessage();
 
-    // Wait for the response.
-    std::this_thread::sleep_for(std::chrono::nanoseconds(timeout * 5));
-
     for (size_t i = 0; i < expectedResults.size(); i++) {
         expectedResults[i] = {
                 .requestId = expectedResults[i].requestId,
@@ -728,6 +723,8 @@
         };
     }
 
+    ASSERT_TRUE(getCallback()->waitForGetValueResults(1, timeout * 100))
+            << "no results in callback";
     auto maybeGetValueResults = getCallback()->nextGetValueResults();
     ASSERT_TRUE(maybeGetValueResults.has_value()) << "no results in callback";
     ASSERT_THAT(maybeGetValueResults.value().payloads, UnorderedElementsAreArray(expectedResults))
@@ -960,8 +957,8 @@
 }
 
 TEST_F(DefaultVehicleHalTest, testSetValuesFinishBeforeTimeout) {
-    // timeout: 0.1s
-    int64_t timeout = 100000000;
+    // timeout: 1s
+    int64_t timeout = 1000000000;
     setTimeout(timeout);
 
     SetValueRequests requests;
@@ -970,17 +967,15 @@
 
     ASSERT_TRUE(setValuesTestCases(10, requests, expectedResults, expectedHardwareRequests).ok());
 
-    // The response would be returned after 0.05s.
-    getHardware()->setSleepTime(timeout / 2);
+    // The response would be returned after 0.01s.
+    getHardware()->setSleepTime(timeout / 100);
     getHardware()->addSetValueResponses(expectedResults);
 
     auto status = getClient()->setValues(getCallbackClient(), requests);
 
     ASSERT_TRUE(status.isOk()) << "setValues failed: " << status.getMessage();
 
-    // Wait for the response.
-    std::this_thread::sleep_for(std::chrono::nanoseconds(timeout));
-
+    ASSERT_TRUE(getCallback()->waitForSetValueResults(1, timeout)) << "no set value results";
     auto maybeSetValueResults = getCallback()->nextSetValueResults();
     ASSERT_TRUE(maybeSetValueResults.has_value()) << "no results in callback";
     EXPECT_EQ(maybeSetValueResults.value().payloads, expectedResults) << "results mismatch";
@@ -988,8 +983,8 @@
 }
 
 TEST_F(DefaultVehicleHalTest, testSetValuesFinishAfterTimeout) {
-    // timeout: 0.1s
-    int64_t timeout = 100000000;
+    // timeout: 0.01s
+    int64_t timeout = 10000000;
     setTimeout(timeout);
 
     SetValueRequests requests;
@@ -998,17 +993,14 @@
 
     ASSERT_TRUE(setValuesTestCases(10, requests, expectedResults, expectedHardwareRequests).ok());
 
-    // The response would be returned after 0.2s.
-    getHardware()->setSleepTime(timeout * 2);
+    // The response would be returned after 0.1s.
+    getHardware()->setSleepTime(timeout * 10);
     getHardware()->addSetValueResponses(expectedResults);
 
     auto status = getClient()->setValues(getCallbackClient(), requests);
 
     ASSERT_TRUE(status.isOk()) << "setValues failed: " << status.getMessage();
 
-    // Wait for the response.
-    std::this_thread::sleep_for(std::chrono::nanoseconds(timeout * 5));
-
     for (size_t i = 0; i < expectedResults.size(); i++) {
         expectedResults[i] = {
                 .requestId = expectedResults[i].requestId,
@@ -1016,6 +1008,7 @@
         };
     }
 
+    ASSERT_TRUE(getCallback()->waitForSetValueResults(1, timeout * 100)) << "no set value results";
     auto maybeSetValueResults = getCallback()->nextSetValueResults();
     ASSERT_TRUE(maybeSetValueResults.has_value()) << "no results in callback";
     ASSERT_THAT(maybeSetValueResults.value().payloads, UnorderedElementsAreArray(expectedResults))
@@ -1456,7 +1449,7 @@
     std::vector<SubscribeOptions> options = {
             {
                     .propId = GLOBAL_CONTINUOUS_PROP,
-                    .sampleRate = 20.0,
+                    .sampleRate = 100.0,
             },
     };
 
@@ -1469,16 +1462,20 @@
 
     ASSERT_TRUE(status.isOk()) << "unsubscribe failed: " << status.getMessage();
 
+    // Wait for the last events to come.
+    std::this_thread::sleep_for(std::chrono::milliseconds(100));
+
     // Clear existing events.
     while (getCallback()->nextOnPropertyEventResults().has_value()) {
         // Do nothing.
     }
 
-    // Wait for a while, make sure no new events are generated.
+    // Wait for a while, make sure no new events are generated. If still subscribed, this should
+    // generate around 10 events.
     std::this_thread::sleep_for(std::chrono::milliseconds(100));
 
-    ASSERT_FALSE(getCallback()->nextOnPropertyEventResults().has_value())
-            << "No property event should be generated after unsubscription";
+    ASSERT_EQ(getCallback()->countOnPropertyEventResults(), 0u)
+            << "Property event generation must stop after unsubscription";
 }
 
 class SubscribeInvalidOptionsTest
diff --git a/automotive/vehicle/aidl/impl/vhal/test/MockVehicleCallback.cpp b/automotive/vehicle/aidl/impl/vhal/test/MockVehicleCallback.cpp
index 0e46357..f51ce5c 100644
--- a/automotive/vehicle/aidl/impl/vhal/test/MockVehicleCallback.cpp
+++ b/automotive/vehicle/aidl/impl/vhal/test/MockVehicleCallback.cpp
@@ -16,6 +16,9 @@
 
 #include "MockVehicleCallback.h"
 
+#include <android-base/thread_annotations.h>
+#include <chrono>
+
 namespace android {
 namespace hardware {
 namespace automotive {
@@ -27,6 +30,7 @@
 using ::aidl::android::hardware::automotive::vehicle::SetValueResults;
 using ::aidl::android::hardware::automotive::vehicle::VehiclePropErrors;
 using ::aidl::android::hardware::automotive::vehicle::VehiclePropValues;
+using ::android::base::ScopedLockAssertion;
 using ::ndk::ScopedAStatus;
 using ::ndk::ScopedFileDescriptor;
 
@@ -46,21 +50,35 @@
 }  // namespace
 
 ScopedAStatus MockVehicleCallback::onGetValues(const GetValueResults& results) {
-    std::scoped_lock<std::mutex> lockGuard(mLock);
-    return storeResults(results, &mGetValueResults);
+    ScopedAStatus result;
+    {
+        std::scoped_lock<std::mutex> lockGuard(mLock);
+        result = storeResults(results, &mGetValueResults);
+    }
+    mCond.notify_all();
+    return result;
 }
 
 ScopedAStatus MockVehicleCallback::onSetValues(const SetValueResults& results) {
-    std::scoped_lock<std::mutex> lockGuard(mLock);
-    return storeResults(results, &mSetValueResults);
+    ScopedAStatus result;
+    {
+        std::scoped_lock<std::mutex> lockGuard(mLock);
+        result = storeResults(results, &mSetValueResults);
+    }
+    mCond.notify_all();
+    return result;
 }
 
 ScopedAStatus MockVehicleCallback::onPropertyEvent(const VehiclePropValues& results,
                                                    int32_t sharedMemoryFileCount) {
-    std::scoped_lock<std::mutex> lockGuard(mLock);
-
-    mSharedMemoryFileCount = sharedMemoryFileCount;
-    return storeResults(results, &mOnPropertyEventResults);
+    ScopedAStatus result;
+    {
+        std::scoped_lock<std::mutex> lockGuard(mLock);
+        mSharedMemoryFileCount = sharedMemoryFileCount;
+        result = storeResults(results, &mOnPropertyEventResults);
+    }
+    mCond.notify_all();
+    return result;
 }
 
 ScopedAStatus MockVehicleCallback::onPropertySetError(const VehiclePropErrors&) {
@@ -87,6 +105,22 @@
     return mOnPropertyEventResults.size();
 }
 
+bool MockVehicleCallback::waitForSetValueResults(size_t size, size_t timeoutInNano) {
+    std::unique_lock lk(mLock);
+    return mCond.wait_for(lk, std::chrono::nanoseconds(timeoutInNano), [this, size] {
+        ScopedLockAssertion lockAssertion(mLock);
+        return mSetValueResults.size() >= size;
+    });
+}
+
+bool MockVehicleCallback::waitForGetValueResults(size_t size, size_t timeoutInNano) {
+    std::unique_lock lk(mLock);
+    return mCond.wait_for(lk, std::chrono::nanoseconds(timeoutInNano), [this, size] {
+        ScopedLockAssertion lockAssertion(mLock);
+        return mGetValueResults.size() >= size;
+    });
+}
+
 }  // namespace vehicle
 }  // namespace automotive
 }  // namespace hardware
diff --git a/automotive/vehicle/aidl/impl/vhal/test/MockVehicleCallback.h b/automotive/vehicle/aidl/impl/vhal/test/MockVehicleCallback.h
index 0faaa1f..f17b273 100644
--- a/automotive/vehicle/aidl/impl/vhal/test/MockVehicleCallback.h
+++ b/automotive/vehicle/aidl/impl/vhal/test/MockVehicleCallback.h
@@ -22,6 +22,7 @@
 #include <aidl/android/hardware/automotive/vehicle/BnVehicleCallback.h>
 #include <android-base/thread_annotations.h>
 
+#include <condition_variable>
 #include <list>
 #include <mutex>
 #include <optional>
@@ -63,9 +64,12 @@
     std::optional<aidl::android::hardware::automotive::vehicle::VehiclePropValues>
     nextOnPropertyEventResults();
     size_t countOnPropertyEventResults();
+    bool waitForSetValueResults(size_t size, size_t timeoutInNano);
+    bool waitForGetValueResults(size_t size, size_t timeoutInNano);
 
   private:
     std::mutex mLock;
+    std::condition_variable mCond;
     std::list<aidl::android::hardware::automotive::vehicle::GetValueResults> mGetValueResults
             GUARDED_BY(mLock);
     std::list<aidl::android::hardware::automotive::vehicle::SetValueResults> mSetValueResults
diff --git a/automotive/vehicle/aidl/impl/vhal/test/SubscriptionManagerTest.cpp b/automotive/vehicle/aidl/impl/vhal/test/SubscriptionManagerTest.cpp
index eb3c663..cb8c8d1 100644
--- a/automotive/vehicle/aidl/impl/vhal/test/SubscriptionManagerTest.cpp
+++ b/automotive/vehicle/aidl/impl/vhal/test/SubscriptionManagerTest.cpp
@@ -231,7 +231,7 @@
     std::vector<SubscribeOptions> options = {{
             .propId = 0,
             .areaIds = {0},
-            .sampleRate = 10.0,
+            .sampleRate = 100.0,
     }};
 
     auto result = getManager()->subscribe(getCallbackClient(), options, true);
@@ -240,11 +240,13 @@
     result = getManager()->unsubscribe(getCallbackClient()->asBinder().get());
     ASSERT_TRUE(result.ok()) << "failed to unsubscribe: " << result.error().message();
 
+    // Wait for the last events to come.
+    std::this_thread::sleep_for(std::chrono::milliseconds(100));
+
     clearEvents();
 
-    std::this_thread::sleep_for(std::chrono::milliseconds(200));
+    std::this_thread::sleep_for(std::chrono::milliseconds(100));
 
-    // Theoretically trigger 10 times, but check for at least 9 times to be stable.
     ASSERT_TRUE(getEvents().empty());
 }
 
@@ -269,6 +271,9 @@
                                        std::vector<int32_t>({0}));
     ASSERT_TRUE(result.ok()) << "failed to unsubscribe: " << result.error().message();
 
+    // Wait for the last events to come.
+    std::this_thread::sleep_for(std::chrono::milliseconds(100));
+
     clearEvents();
 
     std::this_thread::sleep_for(std::chrono::seconds(1));
@@ -301,6 +306,9 @@
     result = getManager()->unsubscribe(getCallbackClient()->asBinder().get());
     ASSERT_TRUE(result.ok()) << "failed to unsubscribe: " << result.error().message();
 
+    // Wait for the last events to come.
+    std::this_thread::sleep_for(std::chrono::milliseconds(100));
+
     clearEvents();
 
     std::this_thread::sleep_for(std::chrono::seconds(1));