diff --git a/phosphor-power-supply/power_supply.cpp b/phosphor-power-supply/power_supply.cpp
index 6908260..c68e9be 100644
--- a/phosphor-power-supply/power_supply.cpp
+++ b/phosphor-power-supply/power_supply.cpp
@@ -506,6 +506,8 @@
             }
             vinUVFault++;
         }
+        // Remember that this PSU has seen an AC fault
+        acFault = AC_FAULT_LIMIT;
     }
 
     if (vinUVFault &&
@@ -518,6 +520,11 @@
                         shortName, statusWord, statusMFR, statusInput)
                 .c_str());
         vinUVFault = 0;
+        // No AC fail, decrement counter
+        if (acFault)
+        {
+            --acFault;
+        }
     }
 }
 
@@ -607,6 +614,11 @@
                 }
 
                 clearFaultFlags();
+                // No AC fail, decrement counter
+                if (acFault)
+                {
+                    --acFault;
+                }
             }
 
             // Save off old inputVoltage value.
@@ -635,8 +647,8 @@
                         shortName, vinUVFault, actualInputVoltage)
                         .c_str());
                 // Do we have a VIN_UV fault latched that can now be cleared
-                // due to voltage back in range? Attempt to clear the fault(s),
-                // re-check faults on next call.
+                // due to voltage back in range? Attempt to clear the
+                // fault(s), re-check faults on next call.
                 clearVinUVFault();
             }
             else if (std::abs(actualInputVoltageOld - actualInputVoltage) >
diff --git a/phosphor-power-supply/power_supply.hpp b/phosphor-power-supply/power_supply.hpp
index ec58bf3..2c61f13 100644
--- a/phosphor-power-supply/power_supply.hpp
+++ b/phosphor-power-supply/power_supply.hpp
@@ -45,6 +45,9 @@
 constexpr auto LOG_LIMIT = 3;
 constexpr auto DEGLITCH_LIMIT = 3;
 constexpr auto PGOOD_DEGLITCH_LIMIT = 5;
+// Number of polls to remember that an AC fault occured. Should remain greater
+// than PGOOD_DEGLITCH_LIMIT.
+constexpr auto AC_FAULT_LIMIT = 6;
 
 /**
  * @class PowerSupply
@@ -380,6 +383,15 @@
     }
 
     /**
+     * @brief Returns true if an AC fault has occurred in the window of
+     * interest.
+     */
+    bool hasACFault() const
+    {
+        return acFault != 0;
+    }
+
+    /**
      * @brief Returns the device path
      *
      * This can be used for error call outs.
@@ -685,6 +697,13 @@
     size_t psCS12VFault = 0;
 
     /**
+     * @brief Set to AC_FAULT_LIMIT when AC fault is detected, decremented when
+     * AC fault has cleared. Effectively forms a timer since last AC failure.
+     * Zero indicates being outside the window of concern.
+     */
+    size_t acFault = 0;
+
+    /**
      * @brief Count of the number of read failures.
      */
     size_t readFail = 0;
diff --git a/phosphor-power-supply/psu_manager.cpp b/phosphor-power-supply/psu_manager.cpp
index 47f4372..242632b 100644
--- a/phosphor-power-supply/psu_manager.cpp
+++ b/phosphor-power-supply/psu_manager.cpp
@@ -558,6 +558,49 @@
     log<level::INFO>("Synchronize INPUT_HISTORY completed");
 }
 
+bool PSUManager::isBrownout(std::map<std::string, std::string>& additionalData)
+{
+    size_t presentCount = 0;
+    size_t notPresentCount = 0;
+    size_t acFailedCount = 0;
+    size_t pgoodFailedCount = 0;
+    for (const auto& psu : psus)
+    {
+        if (psu->isPresent())
+        {
+            ++presentCount;
+            if (psu->hasACFault())
+            {
+                ++acFailedCount;
+            }
+            else if (psu->hasPgoodFault())
+            {
+                ++pgoodFailedCount;
+            }
+        }
+        else
+        {
+            ++notPresentCount;
+        }
+    }
+
+    // In brownout if at least one PS has seen an AC fail and all present PSUs
+    // have an AC or pgood failure. Note an AC fail is only set if at least one
+    // PSU is present.
+    bool isBrownout =
+        acFailedCount && (presentCount == (acFailedCount + pgoodFailedCount));
+    if (isBrownout)
+    {
+        additionalData.emplace("NOT_PRESENT_COUNT",
+                               std::to_string(notPresentCount));
+        additionalData.emplace("VIN_FAULT_COUNT",
+                               std::to_string(acFailedCount));
+        additionalData.emplace("PGOOD_FAULT_COUNT",
+                               std::to_string(pgoodFailedCount));
+    }
+    return isBrownout;
+}
+
 void PSUManager::analyze()
 {
     auto syncHistoryRequired =
@@ -576,25 +619,10 @@
 
     std::map<std::string, std::string> additionalData;
 
-    auto notPresentCount = decltype(psus.size())(
-        std::count_if(psus.begin(), psus.end(),
-                      [](const auto& psu) { return !psu->isPresent(); }));
-
-    auto hasVINUVFaultCount = decltype(psus.size())(
-        std::count_if(psus.begin(), psus.end(), [](const auto& psu) {
-            return (psu->isPresent() && psu->hasVINUVFault());
-        }));
-
-    // The PSU D-Bus objects may not be available yet, so ignore if all
-    // PSUs are not present or the number of PSUs is still 0.
-    if ((psus.size() == (notPresentCount + hasVINUVFaultCount)) &&
-        (psus.size() != notPresentCount) && (psus.size() != 0))
+    // Only issue brownout failure if chassis pgood has failed and PSUs indicate
+    // AC failure
+    if (powerFaultOccurring && isBrownout(additionalData))
     {
-        // Brownout: All PSUs report an AC failure: At least one PSU reports
-        // AC loss VIN fault and the rest either report AC loss VIN fault as
-        // well or are not present.
-        additionalData["NOT_PRESENT_COUNT"] = std::to_string(notPresentCount);
-        additionalData["VIN_FAULT_COUNT"] = std::to_string(hasVINUVFaultCount);
         setBrownout(additionalData);
     }
     else
diff --git a/phosphor-power-supply/psu_manager.hpp b/phosphor-power-supply/psu_manager.hpp
index 4b4171a..5d2dce3 100644
--- a/phosphor-power-supply/psu_manager.hpp
+++ b/phosphor-power-supply/psu_manager.hpp
@@ -317,6 +317,13 @@
     void setPowerConfigGPIO();
 
     /**
+     * @brief Determine if system is in brownout failure
+     * @param additionalData AdditionalData property of the error log entry
+     * @return true if system is in brownout failure, false otherwise.
+     */
+    bool isBrownout(std::map<std::string, std::string>& additionalData);
+
+    /**
      * @brief Indicate that the system is in a brownout condition by creating an
      * error log and setting the PowerSystemInputs status property to Fault.
      *