diff --git a/phosphor-power-sequencer/src/ucd90x_monitor.cpp b/phosphor-power-sequencer/src/ucd90x_monitor.cpp
new file mode 100644
index 0000000..2dc4675
--- /dev/null
+++ b/phosphor-power-sequencer/src/ucd90x_monitor.cpp
@@ -0,0 +1,564 @@
+/**
+ * Copyright © 2022 IBM Corporation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "ucd90x_monitor.hpp"
+
+#include "types.hpp"
+#include "utility.hpp"
+
+#include <fmt/format.h>
+#include <fmt/ranges.h>
+
+#include <gpiod.hpp>
+#include <nlohmann/json.hpp>
+#include <phosphor-logging/log.hpp>
+
+#include <algorithm>
+#include <chrono>
+#include <exception>
+#include <fstream>
+
+namespace phosphor::power::sequencer
+{
+
+using json = nlohmann::json;
+using namespace pmbus;
+using namespace phosphor::logging;
+
+const std::string compatibleInterface =
+    "xyz.openbmc_project.Configuration.IBMCompatibleSystem";
+const std::string compatibleNamesProperty = "Names";
+
+UCD90xMonitor::UCD90xMonitor(sdbusplus::bus_t& bus, std::uint8_t i2cBus,
+                             std::uint16_t i2cAddress,
+                             const std::string& deviceName,
+                             size_t numberPages) :
+    PowerSequencerMonitor(bus),
+    deviceName{deviceName},
+    match{bus,
+          sdbusplus::bus::match::rules::interfacesAdded() +
+              sdbusplus::bus::match::rules::sender(
+                  "xyz.openbmc_project.EntityManager"),
+          std::bind(&UCD90xMonitor::interfacesAddedHandler, this,
+                    std::placeholders::_1)},
+    numberPages{numberPages},
+    pmbusInterface{
+        fmt::format("/sys/bus/i2c/devices/{}-{:04x}", i2cBus, i2cAddress)
+            .c_str(),
+        "ucd9000", 0}
+{
+    log<level::DEBUG>(
+        fmt::format("Device path: {}", pmbusInterface.path().string()).c_str());
+    log<level::DEBUG>(fmt::format("Hwmon path: {}",
+                                  pmbusInterface.getPath(Type::Hwmon).string())
+                          .c_str());
+    log<level::DEBUG>(fmt::format("Debug path: {}",
+                                  pmbusInterface.getPath(Type::Debug).string())
+                          .c_str());
+    log<level::DEBUG>(
+        fmt::format("Device debug path: {}",
+                    pmbusInterface.getPath(Type::DeviceDebug).string())
+            .c_str());
+    log<level::DEBUG>(
+        fmt::format("Hwmon device debug path: {}",
+                    pmbusInterface.getPath(Type::HwmonDeviceDebug).string())
+            .c_str());
+
+    // Use the compatible system types information, if already available, to
+    // load the configuration file
+    findCompatibleSystemTypes();
+}
+
+void UCD90xMonitor::findCompatibleSystemTypes()
+{
+    try
+    {
+        auto subTree = util::getSubTree(bus, "/xyz/openbmc_project/inventory",
+                                        compatibleInterface, 0);
+
+        auto objectIt = subTree.cbegin();
+        if (objectIt != subTree.cend())
+        {
+            const auto& objPath = objectIt->first;
+
+            // Get the first service name
+            auto serviceIt = objectIt->second.cbegin();
+            if (serviceIt != objectIt->second.cend())
+            {
+                std::string service = serviceIt->first;
+                if (!service.empty())
+                {
+                    std::vector<std::string> compatibleSystemTypes;
+
+                    // Get compatible system types property value
+                    util::getProperty(compatibleInterface,
+                                      compatibleNamesProperty, objPath, service,
+                                      bus, compatibleSystemTypes);
+
+                    log<level::DEBUG>(
+                        fmt::format("Found compatible systems: {}",
+                                    compatibleSystemTypes)
+                            .c_str());
+                    // Use compatible systems information to find config file
+                    findConfigFile(compatibleSystemTypes);
+                }
+            }
+        }
+    }
+    catch (const std::exception&)
+    {
+        // Compatible system types information is not available.
+    }
+}
+
+void UCD90xMonitor::findConfigFile(
+    const std::vector<std::string>& compatibleSystemTypes)
+{
+    // Expected config file path name:
+    // /usr/share/phosphor-power-sequencer/<deviceName>Monitor_<systemType>.json
+
+    // Add possible file names based on compatible system types (if any)
+    for (const std::string& systemType : compatibleSystemTypes)
+    {
+        // Check if file exists
+        std::filesystem::path pathName{"/usr/share/phosphor-power-sequencer/" +
+                                       deviceName + "Monitor_" + systemType +
+                                       ".json"};
+        log<level::DEBUG>(
+            fmt::format("Attempting config file path: {}", pathName.string())
+                .c_str());
+        if (std::filesystem::exists(pathName))
+        {
+            log<level::INFO>(
+                fmt::format("Config file path: {}", pathName.string()).c_str());
+            parseConfigFile(pathName);
+            break;
+        }
+    }
+}
+
+void UCD90xMonitor::interfacesAddedHandler(sdbusplus::message_t& msg)
+{
+    // Only continue if message is valid and rails / pins have not already been
+    // found
+    if (!msg || !rails.empty())
+    {
+        return;
+    }
+
+    try
+    {
+        // Read the dbus message
+        sdbusplus::message::object_path objPath;
+        std::map<std::string,
+                 std::map<std::string, std::variant<std::vector<std::string>>>>
+            interfaces;
+        msg.read(objPath, interfaces);
+
+        // Find the compatible interface, if present
+        auto itIntf = interfaces.find(compatibleInterface);
+        if (itIntf != interfaces.cend())
+        {
+            // Find the Names property of the compatible interface, if present
+            auto itProp = itIntf->second.find(compatibleNamesProperty);
+            if (itProp != itIntf->second.cend())
+            {
+                // Get value of Names property
+                const auto& propValue = std::get<0>(itProp->second);
+                if (!propValue.empty())
+                {
+                    log<level::INFO>(
+                        fmt::format(
+                            "InterfacesAdded for compatible systems: {}",
+                            propValue)
+                            .c_str());
+
+                    // Use compatible systems information to find config file
+                    findConfigFile(propValue);
+                }
+            }
+        }
+    }
+    catch (const std::exception&)
+    {
+        // Error trying to read interfacesAdded message.
+    }
+}
+
+bool UCD90xMonitor::isPresent(const std::string& inventoryPath)
+{
+    // Empty path indicates no presence check is needed
+    if (inventoryPath.empty())
+    {
+        return true;
+    }
+
+    // Get presence from D-Bus interface/property
+    try
+    {
+        bool present{true};
+        util::getProperty(INVENTORY_IFACE, PRESENT_PROP, inventoryPath,
+                          INVENTORY_MGR_IFACE, bus, present);
+        log<level::INFO>(
+            fmt::format("Presence, path: {}, value: {}", inventoryPath, present)
+                .c_str());
+        return present;
+    }
+    catch (const std::exception& e)
+    {
+        log<level::INFO>(
+            fmt::format("Error getting presence property, path: {}, error: {}",
+                        inventoryPath, e.what())
+                .c_str());
+        return false;
+    }
+}
+
+void UCD90xMonitor::formatGpioValues(
+    const std::vector<int>& values, unsigned int /*numberLines*/,
+    std::map<std::string, std::string>& additionalData) const
+{
+    log<level::INFO>(fmt::format("GPIO values: {}", values).c_str());
+    additionalData.emplace("GPIO_VALUES", fmt::format("{}", values));
+}
+
+void UCD90xMonitor::onFailure(bool timeout, const std::string& powerSupplyError)
+{
+    std::string message;
+    std::map<std::string, std::string> additionalData{};
+
+    try
+    {
+        onFailureCheckRails(message, additionalData, powerSupplyError);
+        log<level::DEBUG>(
+            fmt::format("After onFailureCheckRails, message: {}", message)
+                .c_str());
+        onFailureCheckPins(message, additionalData);
+        log<level::DEBUG>(
+            fmt::format("After onFailureCheckPins, message: {}", message)
+                .c_str());
+    }
+    catch (const std::exception& e)
+    {
+        log<level::ERR>(
+            fmt::format("Error when collecting metadata, error: {}", e.what())
+                .c_str());
+        additionalData.emplace("ERROR", e.what());
+    }
+
+    if (message.empty())
+    {
+        // Could not isolate, but we know something failed, so issue a timeout
+        // or generic power good error
+        message = timeout ? powerOnTimeoutError : shutdownError;
+    }
+    logError(message, additionalData);
+    if (!timeout)
+    {
+        createBmcDump();
+    }
+}
+
+void UCD90xMonitor::onFailureCheckPins(
+    std::string& message, std::map<std::string, std::string>& additionalData)
+{
+    // Create a lower case version of device name to use as label in libgpiod
+    std::string label{deviceName};
+    std::transform(label.begin(), label.end(), label.begin(), ::tolower);
+
+    // Setup a list of all the GPIOs on the chip
+    gpiod::chip chip{label, gpiod::chip::OPEN_BY_LABEL};
+    log<level::INFO>(fmt::format("GPIO chip name: {}", chip.name()).c_str());
+    log<level::INFO>(fmt::format("GPIO chip label: {}", chip.label()).c_str());
+    unsigned int numberLines = chip.num_lines();
+    log<level::INFO>(
+        fmt::format("GPIO chip number of lines: {}", numberLines).c_str());
+
+    // Workaround libgpiod bulk line maximum by getting values from individual
+    // lines
+    std::vector<int> values;
+    try
+    {
+        for (unsigned int offset = 0; offset < numberLines; ++offset)
+        {
+            gpiod::line line = chip.get_line(offset);
+            line.request({"phosphor-power-control",
+                          gpiod::line_request::DIRECTION_INPUT, 0});
+            values.push_back(line.get_value());
+            line.release();
+        }
+    }
+    catch (const std::exception& e)
+    {
+        log<level::ERR>(
+            fmt::format("Error reading device GPIOs, error: {}", e.what())
+                .c_str());
+        additionalData.emplace("GPIO_ERROR", e.what());
+    }
+
+    formatGpioValues(values, numberLines, additionalData);
+
+    // Only check GPIOs if no rail fail was found
+    if (message.empty())
+    {
+        for (size_t pin = 0; pin < pins.size(); ++pin)
+        {
+            unsigned int line = pins[pin].line;
+            if (line < values.size())
+            {
+                int value = values[line];
+
+                if ((value == 0) && isPresent(pins[pin].presence))
+                {
+                    additionalData.emplace("INPUT_NUM",
+                                           fmt::format("{}", line));
+                    additionalData.emplace("INPUT_NAME", pins[pin].name);
+                    message =
+                        "xyz.openbmc_project.Power.Error.PowerSequencerPGOODFault";
+                    return;
+                }
+            }
+        }
+    }
+}
+
+void UCD90xMonitor::onFailureCheckRails(
+    std::string& message, std::map<std::string, std::string>& additionalData,
+    const std::string& powerSupplyError)
+{
+    auto statusWord = readStatusWord();
+    additionalData.emplace("STATUS_WORD", fmt::format("{:#06x}", statusWord));
+    try
+    {
+        additionalData.emplace("MFR_STATUS",
+                               fmt::format("{:#014x}", readMFRStatus()));
+    }
+    catch (const std::exception& e)
+    {
+        log<level::ERR>(
+            fmt::format("Error when collecting MFR_STATUS, error: {}", e.what())
+                .c_str());
+        additionalData.emplace("ERROR", e.what());
+    }
+
+    // The status_word register has a summary bit to tell us if each page even
+    // needs to be checked
+    if (statusWord & status_word::VOUT_FAULT)
+    {
+        for (size_t page = 0; page < numberPages; page++)
+        {
+            auto statusVout = pmbusInterface.insertPageNum(STATUS_VOUT, page);
+            if (pmbusInterface.exists(statusVout, Type::Debug))
+            {
+                uint8_t vout = pmbusInterface.read(statusVout, Type::Debug);
+
+                if (vout)
+                {
+                    // If any bits are on log them, though some are just
+                    // warnings so they won't cause errors
+                    log<level::INFO>(
+                        fmt::format("{}, value: {:#04x}", statusVout, vout)
+                            .c_str());
+
+                    // Log errors if any non-warning bits on
+                    if (vout & ~status_vout::WARNING_MASK)
+                    {
+                        additionalData.emplace(
+                            fmt::format("STATUS{}_VOUT", page),
+                            fmt::format("{:#04x}", vout));
+
+                        // Base the callouts on the first present vout failure
+                        // found
+                        if (message.empty() && (page < rails.size()) &&
+                            isPresent(rails[page].presence))
+                        {
+                            additionalData.emplace("RAIL_NAME",
+                                                   rails[page].name);
+
+                            // Use power supply error if set and 12v rail has
+                            // failed, else use voltage error
+                            message =
+                                ((page == 0) && !powerSupplyError.empty())
+                                    ? powerSupplyError
+                                    : "xyz.openbmc_project.Power.Error.PowerSequencerVoltageFault";
+                        }
+                    }
+                }
+            }
+        }
+    }
+    // If no vout failure found, but power supply error is set, use power supply
+    // error
+    if (message.empty())
+    {
+        message = powerSupplyError;
+    }
+}
+
+void UCD90xMonitor::parseConfigFile(const std::filesystem::path& pathName)
+{
+    try
+    {
+        log<level::DEBUG>(
+            std::string("Loading configuration file " + pathName.string())
+                .c_str());
+
+        std::ifstream file{pathName};
+        json rootElement = json::parse(file);
+        log<level::DEBUG>(fmt::format("Parsed, root element is_object: {}",
+                                      rootElement.is_object())
+                              .c_str());
+
+        // Parse rail information from config file
+        auto railsIterator = rootElement.find("rails");
+        if (railsIterator != rootElement.end())
+        {
+            for (const auto& railElement : *railsIterator)
+            {
+                log<level::DEBUG>(fmt::format("Rail element is_object: {}",
+                                              railElement.is_object())
+                                      .c_str());
+
+                auto nameIterator = railElement.find("name");
+                if (nameIterator != railElement.end())
+                {
+                    log<level::DEBUG>(fmt::format("Name element is_string: {}",
+                                                  (*nameIterator).is_string())
+                                          .c_str());
+                    Rail rail;
+                    rail.name = (*nameIterator).get<std::string>();
+
+                    // Presence element is optional
+                    auto presenceIterator = railElement.find("presence");
+                    if (presenceIterator != railElement.end())
+                    {
+                        log<level::DEBUG>(
+                            fmt::format("Presence element is_string: {}",
+                                        (*presenceIterator).is_string())
+                                .c_str());
+
+                        rail.presence = (*presenceIterator).get<std::string>();
+                    }
+
+                    log<level::DEBUG>(
+                        fmt::format("Adding rail, name: {}, presence: {}",
+                                    rail.name, rail.presence)
+                            .c_str());
+                    rails.emplace_back(std::move(rail));
+                }
+                else
+                {
+                    log<level::ERR>(
+                        fmt::format(
+                            "No name found within rail in configuration file: {}",
+                            pathName.string())
+                            .c_str());
+                }
+            }
+        }
+        else
+        {
+            log<level::ERR>(
+                fmt::format("No rails found in configuration file: {}",
+                            pathName.string())
+                    .c_str());
+        }
+        log<level::DEBUG>(
+            fmt::format("Found number of rails: {}", rails.size()).c_str());
+
+        // Parse pin information from config file
+        auto pinsIterator = rootElement.find("pins");
+        if (pinsIterator != rootElement.end())
+        {
+            for (const auto& pinElement : *pinsIterator)
+            {
+                log<level::DEBUG>(fmt::format("Pin element is_object: {}",
+                                              pinElement.is_object())
+                                      .c_str());
+                auto nameIterator = pinElement.find("name");
+                auto lineIterator = pinElement.find("line");
+                if (nameIterator != pinElement.end() &&
+                    lineIterator != pinElement.end())
+                {
+                    log<level::DEBUG>(fmt::format("Name element is_string: {}",
+                                                  (*nameIterator).is_string())
+                                          .c_str());
+                    log<level::DEBUG>(
+                        fmt::format("Line element is_number_integer: {}",
+                                    (*lineIterator).is_number_integer())
+                            .c_str());
+                    Pin pin;
+                    pin.name = (*nameIterator).get<std::string>();
+                    pin.line = (*lineIterator).get<unsigned int>();
+
+                    // Presence element is optional
+                    auto presenceIterator = pinElement.find("presence");
+                    if (presenceIterator != pinElement.end())
+                    {
+                        log<level::DEBUG>(
+                            fmt::format("Presence element is_string: {}",
+                                        (*presenceIterator).is_string())
+                                .c_str());
+                        pin.presence = (*presenceIterator).get<std::string>();
+                    }
+
+                    log<level::DEBUG>(
+                        fmt::format(
+                            "Adding pin, name: {}, line: {}, presence: {}",
+                            pin.name, pin.line, pin.presence)
+                            .c_str());
+                    pins.emplace_back(std::move(pin));
+                }
+                else
+                {
+                    log<level::ERR>(
+                        fmt::format(
+                            "No name or line found within pin in configuration file: {}",
+                            pathName.string())
+                            .c_str());
+                }
+            }
+        }
+        else
+        {
+            log<level::ERR>(
+                fmt::format("No pins found in configuration file: {}",
+                            pathName.string())
+                    .c_str());
+        }
+        log<level::DEBUG>(
+            fmt::format("Found number of pins: {}", pins.size()).c_str());
+    }
+    catch (const std::exception& e)
+    {
+        log<level::ERR>(
+            fmt::format("Error parsing configuration file, error: {}", e.what())
+                .c_str());
+    }
+}
+
+uint16_t UCD90xMonitor::readStatusWord()
+{
+    return pmbusInterface.read(STATUS_WORD, Type::Debug);
+}
+
+uint64_t UCD90xMonitor::readMFRStatus()
+{
+    const std::string mfrStatus = "mfr_status";
+    return pmbusInterface.read(mfrStatus, Type::HwmonDeviceDebug);
+}
+
+} // namespace phosphor::power::sequencer