diff --git a/power/stats/aidl/android/hardware/power/stats/IPowerStats.aidl b/power/stats/aidl/android/hardware/power/stats/IPowerStats.aidl
index 7a95f74..edc43ea 100644
--- a/power/stats/aidl/android/hardware/power/stats/IPowerStats.aidl
+++ b/power/stats/aidl/android/hardware/power/stats/IPowerStats.aidl
@@ -32,7 +32,7 @@
      * A PowerEntity is defined as a platform subsystem, peripheral, or power domain that impacts
      * the total device power consumption.
      *
-     * @return List of information on each PowerEntity
+     * @return List of information on each PowerEntity for which state residency can be requested.
      */
     PowerEntity[] getPowerEntityInfo();
 
@@ -52,11 +52,12 @@
      *     Passing an empty list will return state residency for all available PowerEntitys.
      *     ID of each PowerEntity is contained in PowerEntityInfo.
      *
-     * @return StateResidency since boot for each requested PowerEntity
+     * @return StateResidencyResults since boot for each requested and available PowerEntity. Note
+     * that StateResidencyResult for a given PowerEntity may not always be available. Clients shall
+     * not rely on StateResidencyResult always being returned for every request.
      *
-     * Returns the following service-specific exceptions in order of highest priority:
-     *  - STATUS_BAD_VALUE if an invalid powerEntityId is provided
-     *  - STATUS_FAILED_TRANSACTION if any StateResidencyResult fails to be returned
+     * Returns the following exception codes:
+     *  - EX_ILLEGAL_ARGUMENT if an invalid powerEntityId is provided
      */
     StateResidencyResult[] getStateResidency(in int[] powerEntityIds);
 
@@ -66,7 +67,7 @@
      * An EnergyConsumer is a device subsystem or peripheral that consumes energy. Energy
      * consumption data may be used by framework for the purpose of power attribution.
      *
-     * @return List of EnergyConsumers that are available.
+     * @return List of EnergyConsumers for which energy consumption can be requested.
      */
     EnergyConsumer[] getEnergyConsumerInfo();
 
@@ -74,38 +75,40 @@
      * Reports the energy consumed since boot by each requested EnergyConsumer.
      *
      * @param energyConsumerIds List of IDs of EnergyConsumers for which data is requested.
-     *     Passing an empty list will return state residency for all available EnergyConsumers.
+     *     Passing an empty list will return results for all available EnergyConsumers.
      *
-     * @return Energy consumed since boot for each requested EnergyConsumer
+     * @return Energy consumed since boot for each requested and available EnergyConsumer. Note
+     * that EnergyConsumerResult for a given EnergyConsumer may not always be available. Clients
+     * shall not rely on EnergyConsumerResult always being returned for every request.
      *
-     * Returns the following service-specific exceptions in order of highest priority:
-     *  - STATUS_BAD_VALUE if an invalid energyConsumerId is provided
-     *  - STATUS_FAILED_TRANSACTION if any EnergyConsumerResult fails to be returned
+     * Returns the following exception codes:
+     *  - EX_ILLEGAL_ARGUMENT if an invalid energyConsumerId is provided
      */
     EnergyConsumerResult[] getEnergyConsumed(in int[] energyConsumerIds);
 
     /**
-     * Return information related to all channels monitored by Energy Meters.
+     * Return information related to all Channels monitored by Energy Meters.
      *
      * An Energy Meter is a device that monitors energy and may support monitoring multiple
      * channels simultaneously. A channel may correspond a bus, sense resistor, or power rail.
      *
-     * @return Channels monitored by Energy Meters.
+     * @return All Channels for which energy measurements can be requested.
      */
     Channel[] getEnergyMeterInfo();
 
     /**
-     * Reports accumulated energy for each specified channel.
+     * Reports accumulated energy for each specified Channel.
      *
      * @param channelIds IDs of channels for which data is requested.
      *     Passing an empty list will return energy measurements for all available channels.
      *     ID of each channel is contained in ChannelInfo.
      *
-     * @return Energy measured since boot for each requested channel
+     * @return Energy measured since boot for each requested and available Channel. Note
+     * that EnergyMeasurement for a given Channel may not always be available. Clients
+     * shall not rely on EnergyMeasurement always being returned for every request.
      *
-     * Returns the following service-specific exceptions in order of highest priority:
-     *  - STATUS_BAD_VALUE if an invalid channelId is provided
-     *  - STATUS_FAILED_TRANSACTION if any EnergyMeasurement fails to be returned
+     * Returns the following exception codes:
+     *  - EX_ILLEGAL_ARGUMENT if an invalid channelId is provided
      */
     EnergyMeasurement[] readEnergyMeter(in int[] channelIds);
 }
diff --git a/power/stats/aidl/default/FakeEnergyMeter.h b/power/stats/aidl/default/FakeEnergyMeter.h
index f0d4ee7..56dcdcc 100644
--- a/power/stats/aidl/default/FakeEnergyMeter.h
+++ b/power/stats/aidl/default/FakeEnergyMeter.h
@@ -60,9 +60,12 @@
             *_aidl_return = mEnergyMeasurements;
         } else {
             for (int32_t id : in_channelIds) {
-                if (id >= 0 && id < mEnergyMeasurements.size()) {
-                    _aidl_return->push_back(mEnergyMeasurements[id]);
+                // check for invalid ids
+                if (id < 0 || id >= mEnergyMeasurements.size()) {
+                    return ndk::ScopedAStatus(AStatus_fromExceptionCode(EX_ILLEGAL_ARGUMENT));
                 }
+
+                _aidl_return->push_back(mEnergyMeasurements[id]);
             }
         }
 
diff --git a/power/stats/aidl/default/PowerStats.cpp b/power/stats/aidl/default/PowerStats.cpp
index 1373502..7cf591e 100644
--- a/power/stats/aidl/default/PowerStats.cpp
+++ b/power/stats/aidl/default/PowerStats.cpp
@@ -81,14 +81,12 @@
         return getStateResidency(v, _aidl_return);
     }
 
-    binder_status_t err = STATUS_OK;
-
     std::unordered_map<std::string, std::vector<StateResidency>> stateResidencies;
 
     for (const int32_t id : in_powerEntityIds) {
-        // skip any invalid ids
+        // check for invalid ids
         if (id < 0 || id >= mPowerEntityInfos.size()) {
-            continue;
+            return ndk::ScopedAStatus(AStatus_fromExceptionCode(EX_ILLEGAL_ARGUMENT));
         }
 
         // Check to see if we already have data for the given id
@@ -106,12 +104,12 @@
             };
             _aidl_return->emplace_back(res);
         } else {
-            // Failed to retrieve results for the given id.
-            err = STATUS_FAILED_TRANSACTION;
+            // Failed to get results for the given id.
+            LOG(ERROR) << "Failed to get results for " << powerEntityName;
         }
     }
 
-    return ndk::ScopedAStatus::fromStatus(err);
+    return ndk::ScopedAStatus::ok();
 }
 
 ndk::ScopedAStatus PowerStats::getEnergyConsumerInfo(std::vector<EnergyConsumer>* _aidl_return) {
@@ -132,12 +130,10 @@
         return getEnergyConsumed(v, _aidl_return);
     }
 
-    binder_status_t err = STATUS_OK;
-
     for (const auto id : in_energyConsumerIds) {
-        // skip any invalid ids
+        // check for invalid ids
         if (id < 0 || id >= mEnergyConsumers.size()) {
-            continue;
+            return ndk::ScopedAStatus(AStatus_fromExceptionCode(EX_ILLEGAL_ARGUMENT));
         }
 
         auto optionalResult = mEnergyConsumers[id]->getEnergyConsumed();
@@ -146,12 +142,12 @@
             result.id = id;
             _aidl_return->emplace_back(result);
         } else {
-            // Failed to retrieve results for the given id.
-            err = STATUS_FAILED_TRANSACTION;
+            // Failed to get results for the given id.
+            LOG(ERROR) << "Failed to get results for " << mEnergyConsumerInfos[id].name;
         }
     }
 
-    return ndk::ScopedAStatus::fromStatus(err);
+    return ndk::ScopedAStatus::ok();
 }
 
 ndk::ScopedAStatus PowerStats::getEnergyMeterInfo(std::vector<Channel>* _aidl_return) {