MM / P2Padvanced

MM MRP Part 5: Troubleshooting MRP — Exception Messages, Dates, Sources and Missing Proposals

Key takeaway

Diagnose MRP problems: no proposal created, wrong quantity or dates, proposals from the wrong source, excessive proposals, and how to read exception messages (reschedule in/out, cancel, start date in past) — with a master data first analysis path.

Explanation

📌 KEY POINTS
✅ No proposal: MRP type ND, no planning file entry, material blocked, requirements not MRP-relevant, stock or receipts already cover it.
✅ Wrong dates: planned delivery time, GR processing time, purchasing processing time, factory calendar.
✅ Wrong quantity: lot size, rounding, safety stock, scrap.
✅ Wrong source: quota arrangement, source list MRP relevance, special procurement key.
⚠️ Exception messages exist so planners act — unprocessed messages mean stale plans.

━━━━━━━━━━━━━━━━━━━━
▶ WHERE WE ARE
Part 4 covered firming. Now troubleshooting.

━━━━━━━━━━━━━━━━━━━━
▶ 1. NO PROPOSAL

MRP type/status, planning file, requirement relevance, coverage by receipts.

━━━━━━━━━━━━━━━━━━━━
▶ 2. DATES

Lead times, processing times, calendars, scheduling margin key.

━━━━━━━━━━━━━━━━━━━━
▶ 3. QUANTITIES

Lot size, rounding, safety stock, minimum/maximum.

━━━━━━━━━━━━━━━━━━━━
▶ 4. SOURCES

Quotas, source lists, special procurement keys.

━━━━━━━━━━━━━━━━━━━━
▶ 5. EXCEPTION MESSAGES

Reschedule in/out, cancel, start date in past; prioritize and act.

━━━━━━━━━━━━━━━━━━━━
▶ STEP BY STEP

Pick a problem material; open MD04.
Check MRP views and planning file.
Rerun MD02 after fixes.

✅ CHECKPOINT: every material issue maps to a master data or configuration cause.

Code example

ABAP Code

===== STEP 1: path =====MD04 (elements, exceptions) → MM03 MRP views (type, lot size, times, safety stock, procurement type) → planning file / MD01N log → rerun MD02 ===== STEP 2: exception messages (typical) =====Reschedule in | reschedule out | cancel process | start date in the past | finish date in the past ===== STEP 3: common fixes =====MRP type ND → PD | lead time corrected | lot size/rounding | source list MRP relevance | remove obsolete firmed proposals

Real project scenario

MRP created requisitions two weeks earlier than buyers expected. The material's planned delivery time was 21 days while the supplier delivered in 7, and a GR processing time of 5 days had been copied from a QM-inspected material. Correcting both aligned dates with reality.

Common mistakes

Blaming MRP logic.
Ignoring exception messages.
Not checking planning file.
Copying master data blindly.
Manual workarounds.

Best practices

Start with MD04 and MRP views.
Process exceptions daily.
Validate lead times.
Fix master data at source.
Document common causes.

Interview angle

Questions: "Why is no proposal created?", "Why are MRP dates wrong?", "What are exception messages?"
Strong answer: causes for missing proposals, dates, quantities, sources; exception messages and actions; master data first analysis.

Practice this lesson

Quick check

1. MRP creates requisitions two weeks earlier than needed. Which fields should be checked first?

2. A material gets no MRP proposals at all. Which is a likely cause?

3. A component is procured externally for one plant but produced in-house for another plant, and both plants use the same material master with plant-specific MRP data. Which field controls how the system determines the procurement type for a specific plant during MRP?

Interview questions

1. Planners report missing proposals, wrong dates and wrong suppliers from MRP. How do you troubleshoot systematically?

Answer it in your own words first, then compare.

2. During hypercare after go-live, production planners report that a custom extension field added to the purchase requisition (used to trigger a PP-MRP relevant flag) is not being picked up in MRP runs, though it displays correctly on the PR screen. How do you troubleshoot this integration issue involving extensibility and PP?