8d-problem-solving

8D Problem Solving

Goal

Produce a validated, audit-ready 8D report with proven root causes and effective corrective actions that prevent recurrence — accepted by the customer and filed in the quality system.

Required Execution Checklist

Quick-reference for agents and practitioners. All items must be complete before D8 closure.

• [ ] D0: Safety and regulatory risk assessed and documented
• [ ] D0: Suspect material identified and physically segregated
• [ ] D1: Cross-functional team assembled with champion identified
• [ ] D2: Problem described with measured values, part number, quantity, and Is/Is-Not
• [ ] D3: Containment implemented (past tense) with date and effectiveness evidence
• [ ] D4: Root cause of occurrence identified and validated with data or experiment
• [ ] D4: Root cause of escape identified and validated with data or experiment
• [ ] D5: One PCA per root cause selected, with verification plan
• [ ] D6: PCA implemented; verification data confirms zero recurrence; ICA formally removed
• [ ] D7: PFMEA, Control Plan, and Work Instructions updated (revision numbers documented)
• [ ] D7: Horizontal deployment assessed and actioned
• [ ] D8: Champion sign-off obtained; customer notified of closure

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When to use

Use 8D for customer-reported defects, internal escapes reaching downstream processes, field failures, or any non-conformance requiring documented root cause analysis. Mandatory for most automotive OEM customer complaints (Ford 8D, BMW G8D, VW QMSS, Stellantis).

Prerequisites

• Defect or failure clearly identified and quantified
• Access to affected parts, process records, and measurement data
• Cross-functional team availability (quality, production, engineering minimum)

Workflow

D0 — Emergency Response (before the team is assembled)

Ask these questions first:

1. Is this a safety or regulatory issue? If yes → escalate immediately, notify customer
2. Is there any potential for a product recall or regulatory event (safety, emissions, homologation compliance)?

• If yes → STOP the standard 8D timeline. Escalate immediately to management and regulatory owner. Do not proceed without documented management awareness. The 8D continues only with their authorisation.

1. Are suspect parts already at the customer or in the field? If yes → launch containment now (D3) before completing D1-D2
2. Capture initial evidence: photos, batch numbers, lot traceability, measurement data

D0 is complete when: safety is assessed, regulatory escalation decision documented, suspect material is identified and flagged.

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D1 — Team Formation

Build a cross-functional team. Required functions:

• Champion (sponsor, authority to release resources)
• Team leader (owns the 8D, drives completion)
• Quality engineer (methodology, documentation)
• Production / process owner (process knowledge)
• Engineering (design or process engineering)

Optional: supplier quality, logistics, customer representative.

Document: names, functions, team leader, start date, target closure date.

Validation: Is every affected process step represented? Does someone have authority to change the process?

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D2 — Problem Description

Define the problem precisely using Is/Is-Not and 5W2H. A weak D2 produces a weak D4.

Is/Is-Not scoping (see [is-is-not-scoping](../is-is-not-scoping/) skill):

| Question | IS | IS NOT |

|----------|----|--------|

| What is the problem? | e.g., dimensional out-of-spec | cosmetic scratch |

| What object/part? | Part number X, revision B | Part number Y |

| Where is it found? | Station 3, incoming inspection | Final test |

| When did it start? | Batch from 2026-05-12 | Earlier batches |

| How many? | 47 of 200 inspected (23.5%) | — |

| Trend? | Consistent since batch date | No spike |

5W2H:

• Who detected it? When? Where?
• What is the exact non-conformance (measured value vs. specification)?
• Why is it a problem (customer impact)?
• How was it detected? How many are affected?

D2 is complete when: a stranger could read it and know exactly what is wrong, on what, when, how many, and where in the supply chain.

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D3 — Interim Containment Actions (ICA)

ICA must stop the non-conforming product from reaching the customer while D4-D5 are in progress.

Typical ICAs:

• Sort / 100% inspection of suspect stock (in-process + field + customer)
• Ship-hold on all batches in the date range
• Add a specific inspection step at outgoing QC
• Customer notification and stock recovery (if product escaped)

ICA validation — ask:

• Does this ICA physically prevent the defect from escaping? (Yes/No — not "we will try")
• What is the evidence it is working? (inspection records, zero escapes since ICA date)
• Is it documented with an implementation date and responsible person?
• Is it temporary? (an ICA is not a permanent fix)

D3 is complete when: suspect product is contained with objective evidence, customer notified if applicable.

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D4 — Root Cause Analysis

Find TWO root causes:

1. Root cause of occurrence — why did the defect happen?
2. Root cause of escape (detection failure) — why was it not detected before reaching the customer/next process?

Use these tools (see referenced skills):

• [5-Why](../5why-root-cause/) for each root cause
• [Fishbone / Ishikawa](../fishbone-analysis/) for brainstorming categories
• [Is/Is-Not](../is-is-not-scoping/) to scope the problem boundaries

Root cause validation:

• Can you reproduce the defect by deliberately creating the root cause?
• Does removing the root cause prevent the defect in a trial run?
• Is it backed by data, not opinion?

Reject these as final root causes:

• "Human error" (not systemic — ask WHY the error was possible)
• "Operator didn't follow instructions" (ask WHY they didn't, or couldn't)
• "Supplier delivered bad parts" (ask WHY your incoming inspection did not catch it)

Evidence rule: A root cause must be proven by data or physical experiment — not by logical reasoning alone. If you can only argue it is plausible, it is a hypothesis. Reproduce the defect by triggering the root cause; eliminate the defect by removing it. Both tests required.

D4 is complete when: both root causes are validated with objective evidence, not opinion.

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D5 — Choose Permanent Corrective Actions (PCA)

For each root cause from D4, select a permanent corrective action that:

• Directly addresses that specific root cause (not a symptom)
• Can be verified as effective
• Is feasible within the available time and resources

Evaluation matrix (for each candidate PCA):

• Does it address the root cause? (Yes/No)
• Can effectiveness be measured? (metric + target)
• Is it risk-free to implement? (FMEA check)
• Timeline: realistic?

Document: PCA description, responsible owner, target implementation date, verification method.

D5 is complete when: one PCA per root cause is selected and documented with verification plan.

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D6 — Implement and Verify Effectiveness

Implement the PCAs. After implementation:

Verification requirements:

• Run sufficient production volume to achieve statistical confidence — define sample size based on the observed defect rate and risk level (higher defect rate or safety-related defect → larger sample required). Do not use fixed generic numbers; align the sample with the detection probability needed.
• Guidance: if pre-PCA defect rate was p, the verification sample should be large enough that the probability of observing zero defects if p is still present is below 5%. Formula: n ≥ log(0.05) / log(1 − p).
• Measure the original defect metric before and after
• Confirm zero recurrence of the exact defect mode

Verification evidence to capture:

• Process control charts or inspection data after PCA
• Before/after comparison (defect rate or measurement data)
• Signed-off by quality and production

ICA (D3) can only be removed after D6 verification is complete with objective evidence.

D6 is complete when: data confirms the defect is eliminated, ICA formally removed.

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D7 — Prevent Recurrence (Systemisation)

The most valuable — and most skipped — discipline. Prevents the same root cause from appearing elsewhere.

Required updates:

• [ ] PFMEA updated: add/revise failure mode, update occurrence and detection ratings
• [ ] Control Plan updated: add control for root cause and escape
• [ ] Work Instructions / SOPs updated and re-issued
• [ ] Incoming inspection updated (if supplier or material related)
• [ ] Lessons learned documented and shared with similar product lines
• [ ] Training conducted for affected operators / inspectors

Horizontal deployment:

• Are there similar part numbers, processes, or product families that could have the same root cause?
• If yes → extend PCAs to those areas and document

D7 is complete when: all process documents are updated and changes are live in production.

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D8 — Team Recognition

Formally close the 8D:

• Team leader presents the completed 8D to the champion
• Champion validates all disciplines are complete with evidence
• Team is formally recognised (acknowledgement — not necessarily financial)
• 8D report is filed in the quality records system
• Closure communicated to the customer (if customer-initiated complaint)

D8 is complete when: champion signs off, customer notified of closure.

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Validation — is the 8D complete?

Before closing, verify:

• [ ] D2 problem description is objective and quantified
• [ ] D3 ICA has implementation date and verification evidence
• [ ] D4 has two root causes (occurrence + escape), both validated with evidence
• [ ] D5 PCAs directly address D4 root causes
• [ ] D6 verification data shows zero recurrence after PCA
• [ ] D7: FMEA, control plan, and work instructions are all updated
• [ ] D8: champion sign-off and customer notification (if applicable)

Common mistakes

• Skipping D0: jumping to D2 before confirming the customer has no more suspect stock
• Weak D2: vague problem description leads to wrong root cause
• D3 as D6: treating containment as the permanent fix ("we added 100% inspection" is not a PCA)
• Symptom as root cause: "machine was miscalibrated" — why? "supplier sent wrong material" — why wasn't it caught?
• Not updating D7 documents: the most common audit finding

Output Format

At the start of each use, ask the user:

> "How would you like to receive the output?

> A — Structured Markdown (formatted tables and sections, ready to copy)

> B — Plain tables (simplified structure for Excel or Word)

> C — Narrative report (flowing text for a formal document or email)

>

> Default: A."

Adapt all output sections to the chosen format. If the platform or session context already defines a format preference, skip this question.

Reference files

• [D0–D8 detailed guide](references/d0-d8-guide.md)
• [8D report template](assets/8d-template.md)

Changelog

| Version | Date | Author | Change |

|---------|------|--------|--------|

| 1.0 | 2026-06-01 | @RBraga01 | Initial release |

| 1.1 | 2026-06-03 | @RBraga01 | Added Required Execution Checklist, D-level validation criteria, OEM gate rules |