Second Party Audit and Supplier System Audit — From "Scoring to Pass" to "Coaching for Improvement"
Abstract: The second party audit (customer audit of suppliers) is an important means of quality management extension for original equipment manufacturers (OEMs). However, many companies treat second party audits as an "annual check-in" — passing the score but leaving problems unresolved. This article discusses the planning of second party audits, the scoring system, the closure of findings, and coaching-style audits, as well as their integration with the 9.1 supplier management series.
1. Positioning of Second Party Audits
Second party audits (customer audits of suppliers) differ from:
- First party audits: Internal audits within the company
- Third party audits: Audits conducted by certification bodies
The purpose is not to "nitpick" but to verify whether suppliers have the capability to consistently meet requirements and to promote the improvement of their quality management system and processes.
Together with 9.1.1 Admission, 9.1.2 Audit and Coaching, and 9.1.3 Performance Exit, second party audits form a chain — they are the core scenario for in-depth verification + coaching.
2. Audit Planning
1. Selection of Audit Targets
| Priority | Conditions |
|---|---|
| High | Class A materials, new suppliers, performance yellow card, after major changes |
| Medium | Class B, regular re-audits |
| Low | Class C, historically stable performance, extended audit cycle |
2. Audit Scope
- System compliance (ISO 9001 / IATF 16949 clauses)
- Process audit (VDA 6.3 approach): key processes, CP, FMEA, MSA, SPC
- Product audit (if applicable)
- CSR implementation (10.1.1)
3. Audit Schedule
- Agenda, interview personnel, on-site route, sampling batches
- Send the checklist in advance (based on VDA 6.3 or industry templates)
3. Scoring and Grading
It is recommended to use modular scoring + critical nonconformity veto:
| Module | Weight Example |
|---|---|
| System and documentation | 20% |
| Process control and FMEA/CP | 35% |
| Measurement and laboratory | 15% |
| Change and traceability | 15% |
| Improvement and CAR closure | 15% |
Result Grading:
- A: Priority cooperation, simplified inspection
- B: Qualified, review as scheduled
- C: Conditionally qualified, limited-time improvement
- D: Fail, reduce volume/exit (linked to 9.1.3)
Critical nonconformities (safety, regulations, characteristic loss of control) can directly result in a D grade, regardless of the total score.
4. Findings and CAR
- Severe: Impact on safety/regulations/line stoppage → Immediate CAR, short-term verification
- General: System/record deficiencies → CAR + follow-up
- Observation items: Trend risks → Supplier self-inspection
CAR Requirements: Root cause, corrective action, preventive action to prevent recurrence, evidence — consistent with the 8D approach.
5. Coaching-style Audits
Excellent second party auditors do more than just "find problems"; they also share best practices:
- End-of-audit meeting: Start by acknowledging strengths, then discuss gaps
- For C-grade suppliers: Consider joint improvement projects (quality engineer on-site)
- Extend common issues to other suppliers (using anonymous cases)
Avoid: Auditors who do not understand processes and only focus on documentation; audits and procurement having "two sets of standards."
6. Relationship with IATF 16949
The standard emphasizes embedded management (embedded software, etc.) and CSR. Second party audits should verify:
- Consistency between PPAP and mass production
- Timeliness of change notifications (2.5.1)
- Management of sub-suppliers
7. Summary
The value of second party audits = verification + risk identification + coaching + data input for performance evaluation.
Upgrading audits from "scoring to pass" to supply chain quality investment will enable OEMs and suppliers to move from a zero-sum game to a win-win situation.
Knowledge code: 2.4.2
Version: v20260524
Author: Quality Think Tank