Complaint management process: steps, ISO 9001 duties and KPIs

A complaint management process runs in nine steps, from intake and acknowledgement through initial assessment, evidence gathering, investigation and decision to response, remedy and closure. The sequence follows the complaints-handling process set out in the ISO 10002 guideline, with remedy in the ERP and analysis added at the end.

Delays build up at the hand-offs between systems and people. The batch sits in the ERP, the photos in a field engineer's inbox, the inspection record in the quality system and the contract terms in document management. Every question to the customer or a colleague starts another wait, and meanwhile nobody sees the customer's deadline approaching. In automotive supply chains the investigation in step 5 runs as an 8D report, whose gathering work an AI agent can prepare as well, while root cause and corrective action stay with the quality team.

ISO 9001 has no single clause on complaints; the duties are spread across customer communication, customer satisfaction, management review and corrective action. That is how the ISO 9001 Auditing Practices Group sets it out in its guidance on customer complaints; the group brings together experts from ISO/TC 176 and the International Accreditation Forum to write guidance for auditors.

ISO 10002:2018 adds guidance on complaints handling in organisations and is aligned with ISO 9001:2015. It contains recommendations rather than requirements, so an auditor cannot raise a nonconformity against it, only against ISO 9001 itself. Interpretation in a specific case belongs to your quality function and your certification body.

The clause numbers below are the same in ISO 9001:2015 and in ISO 9001:2026, published on 16 September 2026. Certified organisations have until 30 September 2029 to transition, and from 31 March 2028 initial accredited certifications are issued only against the new edition.

A customer complaint is raised against your company; a supplier complaint is one you raise against a supplier. The principles mirror each other, and a customer complaint often triggers a supplier complaint, or at least a check for one, as Germany's quality association DGQ notes in its article on process, law and goodwill.

On the supplier side the clock starts at goods receipt. Under German commercial law, section 377 of the Commercial Code (HGB) requires the buyer in a purchase that is a commercial transaction for both parties to inspect the goods promptly after delivery, insofar as this is practicable in the ordinary course of business, and to notify the seller without undue delay if a defect becomes apparent; otherwise the goods are considered approved, unless the defect was not apparent on inspection. For cross-border sales governed by the UN Convention on Contracts for the International Sale of Goods (CISG), Articles 38 and 39 set comparable duties, with an outer limit of two years from handover unless a contractual guarantee period says otherwise. How these rules apply to your contracts, your incoming inspection and individual cases is for your legal department or counsel to assess.

In the automotive industry the VDA, Germany's automotive industry association, describes a common complaint process for carmakers and suppliers in its volume on the standardised complaint process, second edition 2020, and its QDX format carries complaint notices, acknowledgements and 8D reports between systems. Carmakers rate suppliers, among other things, by rejected parts per million; Ford requires suppliers to share the ppm measured at Ford plants with everyone in the supplying plant. In the workflow the supplier complaint therefore stays linked to the customer complaint that triggered it, so that cost recovery is not lost.

Six KPIs are enough to run a complaint process: two for speed, one for cost, two for the quality of decisions and one for the supply chain. Each needs a fixed definition, otherwise every site measures something different. In a published 8D case study at an automotive supplier, customer assistants interpreted the same response time rules differently, so the existing measurement could not be relied on.

A Workflow Assessment measures exactly these values as a baseline from twelve months of system data and a sample of real cases, before an agent changes anything. With case volume and handling time, the AI ROI calculator estimates how many hours an agent frees up and when a build pays for itself.

An AI agent changes the steps that consist of searching, matching and writing: gathering evidence, preparing the decision and requesting what is missing. The complaint stays a single record in the system of record, the ERP or the quality system, instead of being spread across emails and spreadsheets.

The agent follows the same five steps as every workflow, namely intake, context, proposal, release and write-back. It reads the notification, pulls context from the ERP, the quality system and document management, files its proposal with sources in the record and writes back status and response only after release. Five tasks move to the agent as preparation work.

A person always decides refusals, a complaints or quality specialist decides goodwill above the threshold, and the agent never triggers payments such as credit notes or refunds. All three have legal and financial consequences and shape the customer relationship. In the complaint handling workflow, proposals below the threshold are released with one click, and every refusal goes to a person.

The DGQ points out that offering goodwill needs careful wording so that it does not create an unintended legal effect, such as an acknowledgement of the claim or a longer limitation period. Agree the templates for such letters with your legal department; the agent uses only approved templates and flags any deviation.

Finance sets the thresholds for one-click release and reviews them monthly. Every decision records the evidence considered, the rule applied and the person who decided, in line with ISO 9001 clause 8.7, which asks for the authority that decided on a nonconformity. The ISO 9001 Auditing Practices Group's guidance of May 2026 also asks auditors to check whether complaints involving AI outputs are recorded, analysed and addressed, and whether decisions influenced by AI outputs can be traced.

Before the agent prepares one-click proposals, it runs in shadow mode on live cases. The comparison with the handlers' decisions per category is the evidence for widening release rights.