diff --git a/src/import/chips/p9/procedures/hwp/memory/lib/power_thermal/throttle.C b/src/import/chips/p9/procedures/hwp/memory/lib/power_thermal/throttle.C
index 606c55624e6..a5b54489fb6 100644
--- a/src/import/chips/p9/procedures/hwp/memory/lib/power_thermal/throttle.C
+++ b/src/import/chips/p9/procedures/hwp/memory/lib/power_thermal/throttle.C
@@ -742,6 +742,16 @@ fapi2::ReturnCode set_runtime_m_and_watt_limit( const std::vector< fapi2::Target
     //Calculate max power available / number of dimms configured on the VDDR rail
     l_watt_target = (l_vmem_power_limit_dimm * l_max_dimms) / l_count_dimms_vec;
 
+    // If we have too many dimms, deconfigure the first MCS
+    // We know there are MCSs on the vector due to the check above
+    FAPI_ASSERT( (l_count_dimms_vec <= l_max_dimms),
+                 fapi2::MSS_DIMM_COUNT_EXCEEDS_VMEM_REGULATOR_LIMIT()
+                 .set_MAX_DIMM_AMOUNT(l_max_dimms)
+                 .set_DIMMS_SEEN(l_count_dimms_vec),
+                 "The number of dimms counted (%d) on the vector of MCS surpasses the limit (%d)",
+                 l_count_dimms_vec,
+                 l_max_dimms);
+
     FAPI_INF("Calculated ATTR_MSS_MEM_WATT_TARGET is %d, power_limit dimm is %d, max_dimms is %d, count dimms on vector is %d",
              l_watt_target,
              l_vmem_power_limit_dimm,
diff --git a/src/import/chips/p9/procedures/xml/error_info/p9_memory_mss_eff_config_thermal.xml b/src/import/chips/p9/procedures/xml/error_info/p9_memory_mss_eff_config_thermal.xml
index e10f8532f52..fdf43f9f158 100644
--- a/src/import/chips/p9/procedures/xml/error_info/p9_memory_mss_eff_config_thermal.xml
+++ b/src/import/chips/p9/procedures/xml/error_info/p9_memory_mss_eff_config_thermal.xml
@@ -217,5 +217,17 @@
     </callout>
  </hwpError>
 
-
+ <hwpError>
+    <rc>RC_MSS_DIMM_COUNT_EXCEEDS_VMEM_REGULATOR_LIMIT</rc>
+    <description>
+        The number of dimms counted on the vector of MCS passed into p9_mss_eff_config_thermal
+        exceeds the limit defined in ATTR_MSS_MRW_MAX_NUMBER_DIMMS_POSSIBLE_PER_VMEM_REGULATOR
+    </description>
+    <ffdc>MAX_DIMM_AMOUNT</ffdc>
+    <ffdc>DIMMS_SEEN</ffdc>
+    <callout>
+      <procedure>CODE</procedure>
+      <priority>HIGH</priority>
+    </callout>
+  </hwpError>
 </hwpErrors>