diff --git a/automotive/vehicle/2.0/default/impl/vhal_v2_0/tests/DefaultVhalImpl_test.cpp b/automotive/vehicle/2.0/default/impl/vhal_v2_0/tests/DefaultVhalImpl_test.cpp
index df5ada6..b5026a6 100644
--- a/automotive/vehicle/2.0/default/impl/vhal_v2_0/tests/DefaultVhalImpl_test.cpp
+++ b/automotive/vehicle/2.0/default/impl/vhal_v2_0/tests/DefaultVhalImpl_test.cpp
@@ -124,6 +124,17 @@
     android::ConcurrentQueue<VehiclePropValuePtr> mEventQueue;
     android::ConcurrentQueue<VehiclePropValuePtr> mHeartBeatQueue;
 
+    // Wait until receive enough events in receivedEvents.
+    void waitForEvents(std::vector<VehiclePropValuePtr>* receivedEvents, size_t count) {
+        while (receivedEvents->size() < count) {
+            mEventQueue.waitForItems();
+            auto newEvents = mEventQueue.flush();
+            for (size_t i = 0; i < newEvents.size(); i++) {
+                receivedEvents->push_back(std::move(newEvents[i]));
+            }
+        }
+    }
+
   private:
     void onHalEvent(VehiclePropValuePtr v) {
         if (v->prop != toInt(VehicleProperty::VHAL_HEARTBEAT)) {
@@ -314,26 +325,25 @@
 
     ASSERT_EQ(StatusCode::OK, status);
 
-    std::this_thread::sleep_for(std::chrono::milliseconds(500));
+    std::vector<VehiclePropValuePtr> receivedEvents;
+    waitForEvents(&receivedEvents, 5);
 
-    // Modify the speed after 0.5 seconds.
+    // Modify the speed after 5 events arrive.
     VehiclePropValue value;
     value.prop = toInt(VehicleProperty::PERF_VEHICLE_SPEED);
     value.value.floatValues.resize(1);
     value.value.floatValues[0] = 1.0f;
     ASSERT_EQ(StatusCode::OK, mHal->set(value));
 
-    std::this_thread::sleep_for(std::chrono::milliseconds(500));
-
-    auto events = mEventQueue.flush();
-    ASSERT_LE((size_t)10, events.size());
+    waitForEvents(&receivedEvents, 10);
 
     // The first event should be the default value.
-    ASSERT_EQ((size_t)1, events[0]->value.floatValues.size());
-    EXPECT_EQ(0.0f, events[0]->value.floatValues[0]);
+    ASSERT_EQ((size_t)1, receivedEvents[0]->value.floatValues.size());
+    EXPECT_EQ(0.0f, receivedEvents[0]->value.floatValues[0]);
     // The last event should be the value after update.
-    ASSERT_EQ((size_t)1, events[events.size() - 1]->value.floatValues.size());
-    EXPECT_EQ(1.0f, events[events.size() - 1]->value.floatValues[0]);
+    const auto& lastEvent = receivedEvents[receivedEvents.size() - 1];
+    ASSERT_EQ((size_t)1, lastEvent->value.floatValues.size());
+    EXPECT_EQ(1.0f, lastEvent->value.floatValues[0]);
 }
 
 TEST_F(DefaultVhalImplTest, testSubscribeInvalidProp) {
diff --git a/automotive/vehicle/2.0/default/tests/RecurrentTimer_test.cpp b/automotive/vehicle/2.0/default/tests/RecurrentTimer_test.cpp
index d7547f6..2e59dbf 100644
--- a/automotive/vehicle/2.0/default/tests/RecurrentTimer_test.cpp
+++ b/automotive/vehicle/2.0/default/tests/RecurrentTimer_test.cpp
@@ -69,7 +69,7 @@
     std::this_thread::sleep_for(milliseconds(100));
     // This test is unstable, so set the tolerance to 50.
     ASSERT_EQ_WITH_TOLERANCE(100, counter1ms.load(), 50);
-    ASSERT_EQ_WITH_TOLERANCE(20, counter5ms.load(), 5);
+    ASSERT_EQ_WITH_TOLERANCE(20, counter5ms.load(), 10);
 }
 
 }  // anonymous namespace