D8 is where many 8Ds close too early. The report says “closed”, the team moves on, and the same defect comes back months later. Before you close, the 8D should show that the fix worked over time, that similar products and processes were checked, that the documents were updated, and that the customer was told what you are closing and why. Formats differ by customer, so check their 8D template and supplier manual for who decides closure.
D8 closure checklist: what must be true
- D6 data covers enough time: results from the period, lots or volumes you set in advance, after the change, with no repeat of the defect. See D6 verification of effectiveness.
- Containment is ended on purpose: extra sorting or inspection stopped against an exit criterion, not quietly dropped.
- D7 read-across is done: similar parts, lines, tools and plants were checked, with the result recorded for each. See D7: prevent recurrence.
- Documents are updated and released: PFMEA, control plan, work instructions, inspection plans and training records, each with a revision and date.
- Actions are closed with evidence: every D3, D5 and D7 action has an owner, a completion date and a record, not just “done”.
- The customer is informed: you sent the final 8D and evidence, and any closure the customer requires is recorded on their side or in their portal.
- Lessons learned are captured: written where the next team will find them.
- The team is recognised: a short acknowledgement of who did the work.
Customer agreement: what it means and what it doesn’t
Many customers close the complaint in their own system once they review the final 8D. That is their decision, made in their process. Your D8 should record what you sent, when, and any reply. If the customer has not responded, say the 8D is submitted and awaiting their review rather than calling it closed. A pre-send readiness check can point out gaps before you send, but it is advisory only and is not a customer decision.
Check the whole 8D before you mark it closed. Get a free Accept / Conditional / Reject advisory with missing evidence and questions.
8D Gate is a free pre-send readiness advisory. It doesn't replace the customer's decision. We don't store your 8D body in our database; you can delete anytime. Anthropic processes the text for the review.
Lessons learned that someone will actually use
- One or two sentences on what went wrong in the system, not who made a mistake.
- Where it was stored: PFMEA library, design guidelines, a lessons-learned register or the next APQP checklist.
- Which future projects or parts it applies to.
- Who owns keeping it up to date.
A lesson that lives only in the 8D file is rarely read again. Linking it to a standard or a checklist is what makes it count in D7 and D8.
Team recognition
The original 8D method ends with recognising the team. It does not need to be formal: a thank-you from the champion at a shift meeting, a note in the plant newsletter or a mention in the management review. Name the people, including operators and technicians who supplied the key facts. Reviewers rarely check this, but teams that are recognised tend to engage again on the next 8D.
Illustrative D8 closure notes from different sectors
These examples are fictional and only show the structure.
- Automotive: “No repeat in 12 production lots after the die change. Sorting ended at lot 2410-03 per exit criterion. Read-across to two sister dies completed. Control plan rev F released. Final 8D sent to the customer on 4 Nov; awaiting their portal closure.”
- Electronics: “AOI program updated on both SMT lines; no repeat on 9 weeks of production. Stencil guideline added to the design checklist. Team thanked at the monthly quality meeting.”
- Medical device: “Bond process change validated and released through change control. Effectiveness review completed per our CAPA procedure. Lesson added to the PFMEA library.”
- Food packaging: “Seal jaw temperature alarm active on lines 1–3. No seal-width failures in 6 weeks of sampling. Customer informed with final records.”
Common weak D8s
- Closing on the day the fix is installed, with no D6 data over time.
- “Read-across: not applicable” with no reason given.
- Documents listed as “to be updated”.
- Calling the 8D closed when the customer has not yet reviewed it.
- Lessons learned that just repeat the root cause.
- Containment still running with no plan to end it.
If your 8D has been sent back before, see what to do when an 8D is rejected. The free printable 8D / D4 checklist (PDF) covers D1–D8.
FAQ
- How long should D6 data run before D8?
- Long enough to cover the conditions that caused the defect, such as several lots, shifts or a tool cycle. Agree the period with the customer where their manual sets one.
- Who decides that the 8D is closed?
- Usually the customer, in their own process, for a customer complaint. Internally, the champion confirms that every action is complete. Record both in D8.
- What does 8D Gate check?
- It gives a pre-send readiness check on the 8D text: an Accept / Conditional / Reject advisory with missing evidence and questions. It isn’t a customer decision. The review tool is v0.1: it reviews English 8D reports, and the interface and report are in English. Templates are also available in German, Czech and Polish.
Free pre-send readiness check
Before the 8D goes out, run the text through the free supplier 8D readiness check.
Paste text or upload PDF, DOCX, or Excel. You get an Accept / Conditional / Reject advisory, a score, section ratings, missing evidence, and questions to close gaps, with a PDF download. It is a pre-send readiness check for your team, not a customer decision.
8D Gate is a free pre-send readiness advisory. It doesn't replace the customer's decision. We don't store your 8D body in our database; you can delete anytime. Anthropic processes the text for the review.
Get the free 8D / D4 checklist
Keep the one-page version ready for the next complaint. It covers D1–D8 and goes deeper on containment, D4 root cause, and verification.
Get the free 8D / D4 checklist