Lenovo ThinkPad T400 and R400 Service Manual

About this manual

This manual provides service and reference information for the ThinkPad T400 and R400 laptops. It includes safety information, handling instructions for electro‑static discharge, and detailed guidelines for servicing the hardware.

The document covers FRU (Field Replaceable Unit) identification and replacement, diagnostic tools such as PC‑Doctor, power‑management features, password recovery, and a comprehensive parts list with part numbers. It is intended for trained service technicians.

What's inside

• Safety information
• Important service information
• FRU replacement procedures
• Diagnostics using PC‑Doctor
• Power management
• Password recovery
• Specifications
• Parts list

Frequently asked questions

How do I remove the power‑on password on a ThinkPad T400 or R400?

The procedure is described in the section titled “How to remove the power‑on password”.

What is the part number for this hardware maintenance manual?

The manual’s part number is 43Y6629_03.