What product and process audits are
Product and process audits are the two audits that happen on the shop floor rather than in a meeting room, and together they check that a plant is actually making conforming product by a capable method. A product audit takes a sample of parts and measures them against the drawing and control plan — dimensions, parameters, function, packaging, labelling — to confirm the product conforms. A process audit examines the process that made those parts — the control plan, work instructions, parameters, setup and error-proofing — to confirm the method is capable and followed. One asks is the part right?; the other asks is the way we make it right?
These sit below the more familiar system audit, which checks the management system against the clauses of ISO 9001 or IATF 16949. All three are internal audits and all three run on the same lifecycle — template, plan, conduct, findings, closure — set out in the audit management pillar. What makes product and process audits distinctive is their content: parameter-level measurements, sample sizes and defect grades, rather than clause-by-clause conformity statements. For Indian automotive component suppliers especially, this floor-level layer is where IATF 16949 expects real depth.
Product audit versus process audit
The two are easy to confuse because they happen in the same place, but they answer different questions and produce different records:
| Aspect | Product audit | Process audit |
|---|---|---|
| Object | A sample of finished or in-process parts | The manufacturing process and its controls |
| Question | Does the product conform to specification? | Is the process capable and being followed? |
| Reference | Drawing, control plan, specification and tolerances | Control plan, work instructions, process parameters |
| What is recorded | Parameter measurements, samples, defects, compliance | Parameter settings, control presence, practice conformity |
| Typical standard | IATF 16949 product audit requirement | VDA 6.3; AIAG CQI for special processes |
In practice the two are complementary and often scheduled together: a product audit that finds a dimension drifting toward its tolerance limit points straight at a process audit of the operation that controls it. Capturing both on one system means a product-audit defect and the process-audit finding behind it live in the same non-conformance register, rather than two disconnected reports. See product and process audit software for the product view.
The three audit layers
Mature manufacturing quality runs three complementary layers of audit, each at its own depth and cadence:
System audit
The management system against the clauses of ISO 9001 or IATF 16949 — the broadest, least frequent layer, usually annual per process.
Clause-mappedProcess audit
A manufacturing process against its control plan and parameters — more frequent, focused on capability and adherence, often to VDA 6.3.
Parameter-levelProduct audit
A sample of parts against specification — the most focused layer, verifying the output itself conforms, with measurements and defects.
Sample-basedSitting alongside these, many automotive plants add layered process audits — short, frequent checks of a handful of critical controls, conducted daily by operators and supervisors and periodically by managers and senior leaders using the same small checklist. LPAs are not a fourth kind of audit so much as a cadence: they keep critical controls verified between the deeper process and product audits, and they put leadership on the floor regularly. All of them are just audit types plus checklists on one engine, so a plant can run the whole stack without stitching tools together.
Anatomy of a product audit
A product audit is built around the control plan. For each characteristic it lists, the audit records a defined set of fields, and it is the structure of those fields that makes a product audit different from a clause-based one:
Tying the audit to the control plan number and part in the header is what keeps it honest — the audit is judged against the exact characteristics the product was designed and quoted against, including the special characteristics that carry the most risk. Measuring several samples per parameter, rather than one, is what lets a product audit catch a process drifting within tolerance before it produces a reject.
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Anatomy of a process audit
A process audit is checklist-based like a system audit, but its questions are about the manufacturing process rather than the management system. Run to a method such as VDA 6.3, it walks the process element by element and asks whether each is under control:
- Parameters within limits — are the machine and process settings within the control-plan window, and recorded?
- Controls in place — are the specified inspections, gauges and error-proofing present and working?
- Standard work followed — is the operator working to the current work instruction, with the right setup and changeover?
- Reaction plan known — does the line know what to do when a parameter goes out of limit or a defect is found?
Special processes — heat treatment, plating, welding, coating — are audited to the relevant AIAG CQI assessment on top of the general process audit, because their quality cannot be fully verified in the finished part. A process audit finding is graded and closed exactly like any other non-conformance, so a drifting parameter drives the same CAPA discipline as a clause breach.
Sample checks and defect grading
What gives product audits their bite is sampling and defect grading. Rather than a single yes/no, the auditor measures several sample pieces per characteristic and grades what is found. A common scheme classifies defects by severity — a critical or safety defect, a major functional defect, and a minor cosmetic one — so the audit result reflects not just whether a defect exists but how much it matters. Recording multiple samples also exposes variation: five parts all near the top of tolerance is a different, more worrying signal than five parts scattered comfortably in the middle, even though both technically pass. A system that stores each sample value and each defect grade, rather than a single verdict, is what lets the audit see that pattern and feed it back into the process audit and, ultimately, into corrective action.
How Fast Audit runs product and process audits
Fast Audit Software ships a dedicated product-audit type built for exactly this floor-level content, on the shared Fast Suite platform:
Because it runs on the shared platform, product and process audits share their planning, competency, findings and closure machinery with system and supplier audits — one calendar, one auditor pool, one register across all layers. For automotive suppliers that is the whole IATF audit stack on one system. See product and process audit software and ISO 9001 & IATF 16949 audit software; confirm sampling and defect-grading expectations with your customer and certification body.
Frequently asked questions
What is a product audit?
A product audit is an evaluation of a finished or in-process product against its specification — checking dimensions, parameters, function, packaging and labelling against the drawing and control plan to confirm the product actually conforms to requirements. It usually takes a sample of parts from what has been produced and measures defined characteristics, recording each measurement, whether it meets specification, and any defects found. Where a process audit asks whether the process is right, a product audit asks whether the thing the process made is right.
What is a process audit?
A process audit is an evaluation of a manufacturing process against its defined requirements — the control plan, work instructions, process parameters, setup, error-proofing and operator practice — to confirm the process is capable and being followed as documented. It checks the conditions under which product is made rather than the product itself: are the parameters within limits, are the controls in place, is the standard work followed. In automotive, process audits are often run to VDA 6.3, and special processes to the AIAG CQI standards.
What is the difference between a product audit and a process audit?
A product audit examines the output — a sample of parts measured against specification to confirm conformity. A process audit examines the method — the parameters, controls and practices that produce the parts, to confirm the process is capable and followed. A system audit sits above both, checking the management system against the standard's clauses. The three are complementary layers: a product can pass while the process that made it is drifting, and a process can look compliant while producing defects, so a mature programme runs all three.
What is a layered process audit (LPA)?
A layered process audit is a system of frequent, short audits of the same high-risk process controls, conducted by multiple layers of the organisation — operators and supervisors daily, managers weekly, senior leaders monthly. The same small checklist is used at every layer, so critical controls are verified far more often than an annual system audit would allow, and leadership sees the shop floor regularly. LPAs are widely used in automotive manufacturing to sustain process discipline between the deeper process and product audits.
What does a product audit check against?
A product audit checks against the product's control plan and drawing — the defined characteristics, their specifications and tolerances, and the special characteristics that matter most for safety or function. For each characteristic the auditor records the parameter checked, the specification, the measured values across a sample of parts, any defects graded by category, and whether the result complies. Referencing the control plan number and the part or component keeps the audit tied to the exact requirements the product was designed and quoted against.
How does Fast Audit run product and process audits?
Fast Audit has a dedicated product-audit type whose checklist captures parameter checks, the specification, several sample observations per characteristic, defect categories and a compliance verdict, with header details for the department, part, cavity or mould numbers, sample reference and control plan number. The audit is planned, assigned to a competent auditor and conducted like any other, and it produces a formatted product and process audit report per audit. Non-conforming results become graded findings that flow into the same CAPA closure loop as every other audit.