Part-03 - Every SAP Module Explained: FI, CO, MM, SD, PP, HCM – How They Connect & Who Uses Them | FreeLearning365

 

PART 03 · PHASE 0 · FOUNDATION SERIES

Every SAP Module Explained — What They Do, Who Uses Them, How They Connect

“Most people learn SAP modules in isolation and wonder why nothing works. The secret is that SAP modules are not separate products — they are organs of the same body. Remove one and the others start failing.”

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🧠 The Module Architecture – One Company, One System, Many Lenses

SAP S/4HANA is not a collection of separate software products stitched together.
It is one integrated system that you can think of as having different “lenses” or “departments.”
Each module handles one domain – but they share data, trigger each other’s processes, and are deeply interconnected.

The Complete Module Landscape

Module	What it does	Who uses it
FI – Finance	Legal financial record (external)	CFO, accountants, auditors
CO – Controlling	Internal management reporting	Management, cost analysts
MM – Materials Mgmt	Procurement & inventory	Buyers, warehouse staff
SD – Sales & Distrib	Sales, shipping, billing	Sales reps, logistics
PP – Production Planning	Factory planning & execution	Production planners, shop floor
HCM – Human Capital	HR, payroll, time	HR team, payroll
PM – Plant Maintenance	Equipment maintenance	Maintenance technicians
WM/EWM – Warehouse	Warehouse operations	Warehouse managers
QM – Quality Mgmt	Inspections, quality control	Quality engineers
PS – Project Systems	Project management	Project managers

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📒 FI – Financial Accounting: The Legal Backbone

FI is non‑negotiable. Every company that runs SAP must run FI.
It is the financial record of every business transaction – the one that external auditors, tax authorities, and shareholders see.

FI Sub‑Modules and What They Do

Sub‑module	Purpose	Key T‑codes
GL (General Ledger)	Master financial journal – every sale, purchase, salary ends here	FB50 (entry), S_ALR_87012284 (balance sheet)
AP (Accounts Payable)	Everything you owe to vendors	FK03 (vendor), F110 (payment run)
AR (Accounts Receivable)	Everything customers owe you	FD03 (customer), F-28 (incoming payment)
AA (Asset Accounting)	Fixed assets – buildings, machinery	AS01 (create), AFAB (depreciation)

🔗 Real Scenario – How FI connects to MM automatically

Vertex Manufacturing receives 5,000 steel rods via MIGO (Goods Receipt).
SAP automatically creates this FI posting:

• Debit: Raw Material Stock account $85,000

• Credit: GR/IR Clearing account $85,000

✅ No manual journal entry. No accounting staff involvement.
This is the power of integration – a warehouse transaction creates a financial entry in real time.

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📊 CO – Controlling: The Internal Management Layer

While FI answers “What happened legally and financially?”
CO answers “Why did it happen and where did the money go internally?”
CO is for management decisions, not statutory reporting.

CO Element	Purpose	T‑code
Cost Centers	Departments that incur costs (Marketing, IT, Factory)	KS01 (create), KSB1 (line items)
Profit Centers	Business segments with mini P&L	KE51 (create)
Internal Orders	Temporary cost collectors for events/campaigns	KO01 (create), KO88 (settle)
CO‑PA	Profitability analysis by customer, product, region	KEB0 (planning)

💡 FI vs CO – The Key Difference
FI is external‑facing (auditors, tax, banks).
CO is internal‑facing (management, operations).
In S/4HANA’s Universal Journal (ACDOCA) , FI and CO postings are now in the same table – one source of truth for both. This is one of the biggest simplifications in S/4HANA vs ECC.

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🛒 MM – Materials Management: Procurement & Inventory

MM covers everything related to buying things and managing physical inventory.
If your company buys raw materials, components, or services – MM is in play.

Process	What it does	T‑codes
Purchasing	PR, RFQ, PO, contracts	ME21N (PO), ME2M (PO by material)
Inventory Management	Goods receipts, issues, transfers, physical inventory	MIGO (movements), MMBE (stock overview)
Invoice Verification	Match vendor invoice to PO + GR	MIRO (entry), MIR7 (parking)
Vendor Evaluation	Score vendors on delivery, quality, price	ME6H

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💰 SD – Sales and Distribution: Revenue Generation

SD manages the complete customer‑facing process – from inquiry to invoice to payment.

Process	What it does	T‑codes
Sales	Inquiries, quotations, sales orders, contracts	VA01 (sales order), VA05 (list)
Shipping	Outbound deliveries, picking, packing, goods issue	VL01N (delivery), VL06O (monitor)
Billing	Invoice creation, credit/debit memos	VF01 (billing), VF04 (due list)
Pricing	Automatic price lists, discounts, surcharges, taxes	VK11 (condition record)

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🏭 PP – Production Planning: The Factory Engine

PP runs the factory. It takes sales demand, determines raw materials, schedules production, and ensures finished goods are ready on time.

Component	What it is	T‑code
BOM (Bill of Materials)	Recipe: Product X = A (2) + B (1) + C (500g)	CS01 (create)
Routing	Process: Which machines, sequence?	CA01 (create)
MRP (Material Requirements Planning)	Brain: Given demand + stock, what to buy/produce?	MD01N (run)
Production Orders	Work order for the factory floor	CO01 (create), CO11N (confirm)

🔁 Real Scenario – PP to MM to FI integration (The Data Flow)

Step	Module	Action	Result
1	PP	MRP run determines we need 2,000 steel brackets → creates planned order	Requirement identified
2	PP→MM	Planned order → Production Order. PP generates Purchase Requisition for missing raw materials. MM converts PR→PO to vendor.	PO created
3	MM→FI	Vendor delivers. Goods receipt (MIGO).	FI entry: Debit Raw Stock, Credit GR/IR
4	PP→CO	Factory consumes materials. Goods issue from PP. Cost collected on Production Order in CO. Order settles to CO cost center.	Actual cost recorded

🧠 Four modules. One seamless data flow. Zero manual handoffs.
This is the magic of an integrated ERP.

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👥 HCM – Human Capital Management

HCM manages everything related to employees – from hiring to payroll to retirement.
(Modern landscapes often supplement/ replace HCM on‑prem with SAP SuccessFactors cloud.)

Sub‑module	Purpose	T‑code
OM (Org Management)	Company hierarchy – org units, positions, reporting lines	PPOME
PA (Personnel Admin)	Employee master data – personal info, bank, contract	PA30 (infotypes), PA40 (hiring)
TM (Time Management)	Work schedules, time recording, overtime, absences	PT60 (time eval)
PY (Payroll)	Wage calculation, taxes, statutory compliance, bank file	PC00_M99_CALC (payroll run)

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🗺️ The Module Dependency Map – What Triggers What

text

SD Sales Order (VA01)
       │
       ▼
MM Availability Check (MMBE)
       │
       ▼ (if stock insufficient)
PP MRP Requirement (MD01N)
       │
       ▼
PP Production Order (CO01)
       │
       ▼ (goods issue)
MM Goods Issue (MIGO)
       │
       ▼
SD Delivery (VL01N)
       │
       ▼
SD Billing (VF01)
       │
       ▼
FI Accounting Document (automatic)
       │
       ▼
FI Accounts Receivable → FI Incoming Payment (F-28)
       │
       ▼
CO‑PA Profitability (KEB0)

No email. No phone call. No manual entry.
Every step triggers the next automatically.

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🔧 PM, QM, WM/EWM, PS – The Supporting Cast

Module	What it does	Key T‑codes
PM – Plant Maintenance	Preventive maintenance, breakdown repairs, spare parts	IW31 (maintenance order)
QM – Quality Management	Inspection plans, quality notifications, usage decisions	QE01 (results recording)
WM – Warehouse Management	Bin management, transfer orders (basic)	LT0A (transfer order)
EWM – Extended WM	Labor management, yard mgmt, slotting (advanced)	/SCWM/...
PS – Project Systems	WBS elements, project planning, billing	CJ20N (project builder)

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📌 Mini Assignment

Draw a simple diagram of your own company (or one you know).

1. In each box, write which SAP module would handle that department’s processes.

2. Then draw arrows showing which departments exchange data.

🎯 You have just created your first‑ever SAP system landscape sketch – the same thing consultants do in week 1 of a real project.

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🔜 What’s Next in This Series

Part 04 – Top 25 SAP T‑codes You Must Know (as a Beginner)
The only transaction codes that actually matter in your first 90 days.

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