JinJin48

SAP Consultant | BTP · S/4HANA · US Global Rollout

June 26, 2026 · 12 min read

SAP PM Maintenance BOM

The Maintenance BOM is the master data object that defines the component and spare parts structure of an equipment or functional location in SAP Plant Maintenance. It stores which materials are installed in or belong to a technical object, enabling automatic parts reservation and goods issue when a Work Order is created. Unlike the Production BOM (PP, CS01) or the Material BOM (MM), the Maintenance BOM uses BOM Usage 4 and is created via transaction IB01, making it a PM-owned master record tightly coupled to the equipment hierarchy.

Part 1: Maintenance BOM — Core Concepts (All Modules)#

1.1 What Is the Maintenance BOM?#

A Bill of Materials (BOM) in the maintenance context is a structured list of the components — spare parts, sub-assemblies, and consumables — that make up a piece of equipment or a functional location. In SAP PM, the Maintenance BOM serves as the authoritative parts reference used when planning and executing Work Orders: the system can explode the BOM to propose the materials needed for a specific maintenance task.

1.2 BOM Types and Usages#

The BOM Usage code is the most critical classification in BOM design. It determines which transactions create the BOM, which explosion functions use it, and how the system selects the correct BOM at Work Order creation. Using the wrong usage code causes BOMs to be invisible to PM processes.

Design principle: Always assign BOM Usage 4 to all PM BOMs. A BOM with Usage 1 (PP) is not visible to IB01/IB02 and will not explode in PM Work Orders — a common source of “no components found” issues during go-live.

1.3 Organizational Levels and Data Hierarchy#

Data hierarchy with a concrete example

Client
   │
   └── Plant 1000
          │
          └── Equipment 10001234
                 Centrifugal Pump #3, Cooling Water Circuit
                 │
                 └── BOM Header
                        Alternative 1, BOM Usage 4 (PM)
                        │
                        ├── BOM Item 0010
                        │      Impeller Seal Kit, Qty 1
                        │
                        └── BOM Item 0020
                               Lubricant Grease NLGI2, Qty 2

1.4 Integration with Other Master Data Objects#

The Maintenance BOM sits at the intersection of the equipment hierarchy and the materials management world. It does not function in isolation — its value is only realized when equipment, material masters, and Work Orders are all properly aligned.

Part 2: PM-Specific Field Details#

2.0 Scope of PM Ownership#

Legend: ◎ = Owner / Critical, ○ = Direct involvement

2.1 BOM Header (STKO)#

The BOM header identifies the technical object that the BOM belongs to, its plant scope, and its administrative validity. Getting the header configuration right is the prerequisite for all downstream BOM explosion and Work Order integration.

2.2 BOM Items — Component Assignment (STPO)#

The BOM item level is where spare parts are specified in detail. Each item row represents one component. The item category and spare parts indicator drive how the component behaves in a Work Order — whether it generates a reservation, triggers procurement, or serves as reference information only.

2.3 BOM Items — Storage Location#

The default storage location on a BOM item tells the Work Order where to pick the component from. Setting this correctly at the BOM level reduces data-entry effort for PM planners and eliminates mis-picks in the PM spare parts store.

2.4 BOM Items — Procurement Type#

Non-stock BOM items (item category N) trigger a procurement path rather than a warehouse reservation when included in a Work Order. Understanding the distinction between stock and non-stock items in a PM BOM is essential for designing the integration between PM Work Orders and MM purchasing.

Prerequisite: For non-stock items to generate purchase requisitions automatically, the Work Order type must be configured with the “Create PR” indicator in Customizing (transaction OIOY or order type parameters). Confirm this setting with the PM Customizing team at project start.

What to Read Next#

L1) Big Picture

L2-A) Master Data

L2-B) Transaction