Brand: HP
Category: Computer
Document Type: Manual
Language: EN
Available Languages: EN , ES
Manual for HP ProOne 400 G2 20 inch All-in-One
Uploaded: Nov. 21, 2025, 6:44 p.m.
Manual Publish Date: 2015-11-01
Warranty Information
This manual does not contain specific warranty period information.
This manual provides comprehensive information on the HP ProOne 400 G2 20 inch All-in-One computer. It covers product features, illustrated parts catalog, routine care, SATA drive guidelines, disassembly preparation, removal and replacement procedures, computer setup utilities, troubleshooting, system backup and recovery, POST error messages, password security, and BIOS resetting. It also includes appendices on power cord set requirements, statement of volatility, and specifications.
Key sections detail component identification (front, side, rear, internal), parts catalog for system and miscellaneous parts, mass storage devices, processors, memory modules, and cables. It guides users through routine care, safety precautions, and cleaning procedures for the computer case, keyboard, monitor, and mouse.
Troubleshooting and error codes
| Control panel message | Description | Recommended action |
|---|---|---|
| 419-Out of Memory Space for Option ROMs | Recently added PCI expansion card contains an option ROM too large to download during POST. | 3. Reconfigure card resources and/or run Computer Setup or Windows utilities. If a PCI expansion card was recently added, remove it to see if the problem remains. |
| 41A-Front USB1/USB2 Not Connected | Front USB cable has been detached or unseated from system board. | Reconnect or replace front USB cable. |
| 41B-Device in PCI Express Slot Failed To Initialize | There is an incompatibility or problem with a PCle device and the system or PCIe link could not be configured to a valid bus width or speed. | Try rebooting the system. If the error reoccurs, the device may not work with this system. |
| 43A-USB Type-C I2C Not Connected | Cable is required between I2C on card and USB-C on the system board. | Install cable between I2C on card and USB-C on the system board. |
| 43B-More Than One USB type-C Cards Are Installed | More than one USB type-C card is installed. | Remove USB type-C card so only one is installed. |
| 500-BIOS Recovery | A system BIOS recovery has occurred. | Not applicable. |
| 70x-Wireless Mode Not Supported | The system has detected a wireless module installed in the system that is not supported and has been disabled. | Replace with a supported module. |
| 800-Keyboard Error | Keyboard failure. | 1. Reconnect keyboard with computer turned off. 2. Check connector for bent or missing pins. 3. Ensure that none of the keys are depressed. 4. Replace keyboard. |
| 801-Keyboard or System Unit Error | Keyboard failure. | 1. Reconnect the keyboard with computer turned off. 2. Ensure that none of the keys are depressed. 3. Replace the keyboard. 4. Replace the system board. |
| 900-CPU Fan Not Detected | CPU fan is not connected or may have malfunctioned. | 1. Reseat CPU fan. 2. Reseat fan cable. 3. Replace CPU fan. |
| 901-Chassis, Rear Chassis, or Front Chassis Fan not Detected | Chassis, rear chassis, or front chassis fan is not connected or may have malfunctioned. | 1. Reseat chassis, rear chassis, or front chassis fan. 2. Reseat fan cable. 3. Replace chassis, rear chassis, or front chassis fan. |
| 903-Computer Cover Has Been Removed Since Last System Startup | N/A | N/A |
| 904-SATA Cabling Error | One or more SATA devices are improperly attached. For optimal performance, the SATA 0 and SATA 1 ports should be used for hard drives before other ports. | Ensure SATA connectors are used in ascending order. For one device, use SATA 0. For two devices, use SATA 0 and SATA 1. For three devices, use SATA 0, SATA 1, and SATA 2. |
| 90B-Fan Failure | The system has detected that a cooling fan is not operating correctly. | 1. Reseat fan. 2. Reseat fan cable. 3. Replace fan. |
| 90D-System Temperature | Thermal shutdown occurred. The system BIOS has detected your machine was previously shut down to avoid overheating. Overheating may occur if the cooling vents are blocked or the operating temperature exceeds the system specifications. The machine should return to normal operation once the situation is resolved. | Make sure system has proper airflow. |
| 90E-Power Supply Fan Not detected | Power supply fan is not connected or may have malfunctioned. | 1. Reseat power supply fan. 2. Reseat fan cable. 3. Replace power supply fan. |
| 910-Filter Warning | Airflow filter is dirty. | Replace the airflow filter. |