Scenario 25 — MM ↔ PM Integration (Spare Parts for Maintenance Orders)
📊 Business Case
This scenario is where MM hands off to Plant Maintenance (PM). When equipment breaks down, the maintenance team raises a maintenance order that needs a spare part. The order generates a purchase requisition with account assignment F (Internal/PM order) — so the cost of the spare flows to the maintenance work order, not directly to a cost center or into inventory. After the repair, the order's accumulated cost is settled to the cost center of the affected line. It shows MM's role as a central enabler feeding other SAP modules.
🕐 When to use it
Whenever a maintenance/repair job needs a part bought specifically for that job — the spare is consumed against the maintenance order rather than stocked.
❓ Why it matters
It teaches account assignment F and how a PR is triggered from PM (not manually). Cost accumulates on the maintenance order so the true cost of each repair is visible before settlement.
👤 Who triggers it
The maintenance planner creates the order (IW31); the MM buyer converts the PR to a PO and handles GR/IV; PM/CO settles the order at month-end (KO88).
🔁 The key distinction
Cost goes to the order, not inventory. With account assignment F there is no stock posting — the spare is expensed straight to the maintenance order and shows in the order cost report.
💰 Financial Impact — The Easy-Money Example
A CNC machine needs a new bearing (SP-BEARING-01, PKR 5,000). Because the PO carries account assignment F against maintenance order 8000001234, the money never touches inventory — it lands on the order and later settles to the production cost center:
The big idea: account assignment F means the spare is never an inventory asset — it is expensed directly to the maintenance order at GR. The order is a temporary cost collector; KO88 settlement then pushes the accumulated cost onto the responsible cost center, so management sees the full cost of the repair.
🇵🇰 The Business Story
🎯 What you'll learn
- Account assignment
F(Internal Order / PM Order) on the PO line - PR triggered FROM the PM module (not manually) — MRP-like external integration
- Cost accumulation on the maintenance order, then settled at month-end
- Material Master ERSA type for spare parts
- How the MM consultant supports the PM consultant in real projects
⚙️ Prerequisite Setup
- Skip this scenario (PM is typically PM consultant work, not MM)
- OR work with a PM consultant to enable basic PM (work order types, notification types)
- OR substitute with cost center accounting (Scenario 5 — Consumable Direct) — same MM mechanics, simpler account assignment
SP-BEARING-01 (ERSA, spare part) — create steps. First time? the why behind every field.
🔧 Step-by-Step — Transaction Flow
25.1 — PM Maintenance Order · IW31
PM consultant / maintenance planner creates a maintenance order:
- IW31 · Order Type: PM01 · Technical Object: CNC-PK01-MIL01 · Plant: PK01
- Operations tab: Repair sequence
- Components tab: Required spare part SP-BEARING-01, Qty 1 EA
- Save → Maintenance Order # (e.g., 8000001234)
- This auto-creates PR if component not in stock + Procurement Type external
MM consultant's role: Ensure spare part material master is created (MM01 ERSA) with Purchasing view + valuation class.
25.2 — Convert PR to PO · ME21N with account assignment F
- ME21N · pull in auto-created PR
- Verify Account Assignment:
F(Internal Order) - Order field shows the PM order # (8000001234)
- G/L auto-determined (e.g., 410100 Maintenance Material Expense)
- Save
Posting at GR: Material Cost Dr / GR-IR Cr — cost tagged to PM order, not cost center directly.
25.3 — Goods Receipt · MIGO mvt 101
Standard GR. Cost flows to PM order via account assignment F.
| Maintenance Expense (410100) | Dr 5,000 | PM Order: 8000001234 |
| GR/IR (191100) | Cr 5,000 | — |
25.4 — Settle PM Order to Cost Center · KO88 (end of month)
PM/CO consultant runs KO88 to settle the maintenance order's accumulated cost to the receiver (cost center PKKHI-PROD).
- KO88 · Order: 8000001234 · Settlement period
- Settlement rule: 100% to cost center PKKHI-PROD
- Execute → cost moves from order to cost center
- Create spare part material masters (ERSA type, ITAS prevention via Source List, alternative vendors)
- Maintain reorder points and safety stocks for critical spares
- Set up procurement type "F" (external) on spare materials
- Handle GR/IV for spare parts purchased via PM orders
- Coordinate with the PM team on consignment/safety stock arrangements
✅ Verification
| # | T-code | Check |
|---|---|---|
| 1 | IW33 | Maintenance order 8000001234 shows the spare component and the linked PR/PO |
| 2 | ME23N | PO line has Account Assignment Category F with order 8000001234 and G/L 410100 |
| 3 | MB03 / FB03 | GR document: Maintenance Expense 410100 Dr / GR-IR Cr — no inventory (300xxx) line |
| 4 | S_ALR_87013611 | After KO88, cost center PKKHI-PROD shows the settled 5,000 (order balance returns to zero) |
🎓 Interview-Ready Answers
Q: What does account assignment category F mean, and why use it for a spare part?
F = order (internal/PM/maintenance order). It tells SAP the procured item is consumed against that order rather than received into stock. At GR there is no inventory posting — the cost is expensed (e.g. to 410100 Maintenance Material Expense) and tagged to the order. Use it when a part is bought for a specific repair job so the order carries its true cost.
Q: How does a purchase requisition get created from Plant Maintenance?
When the maintenance order (IW31) has a non-stock component (or a stock item that's unavailable) with external procurement, releasing/saving the order auto-generates a PR carrying account assignment F and the order number. MM doesn't type it manually — it flows in like an MRP-driven requisition, and the buyer converts it to a PO.
Q: If the cost hits the order at GR, how does it reach the cost center?
The maintenance order is a temporary cost collector. At month-end, KO88 settles it according to its settlement rule — typically 100% to the responsible cost center (e.g. PKKHI-PROD). The cost moves from the order to the cost center and the order balance returns to zero.
Q: What is the MM consultant actually responsible for in this PM scenario?
Not PM config. MM owns the spare-part material masters (ERSA type with purchasing view and valuation class), source lists / alternative vendors, reorder points and safety stock for critical spares, the external procurement setting, and the GR/invoice verification for parts bought via PM orders. MM enables the buy; PM and CO own the maintenance cost.