For years, FMEA risk evaluation was based on the Risk Priority Number (RPN = Severity × Occurrence × Detection). However, RPN often gave misleading results, as different risks could have the same RPN value but very different customer impacts.
👉 To solve this, the AIAG-VDA FMEA Handbook (2019) introduced Action Priority (AP).
Action Priority (AP) is now the official standard for prioritizing actions in FMEA. It ensures safety-critical and high-severity risks are never ignored, even if their occurrence is low or detection is strong.
What is Action Priority (AP) in FMEA? #
- Definition: Action Priority is a decision method that uses Severity (S), Occurrence (O), and Detection (D) ratings to assign risk levels as High (H), Medium (M), or Low (L).
- Purpose: To guide teams on which failure modes require action first.
- Focus: Severity is always given the highest importance.
📌 Key Point: AP is not a numeric multiplication (like RPN) but a priority-based decision table.
Why Action Priority Replaced RPN #
- Severity-driven approach: In RPN, a high-severity safety risk could get a low RPN if occurrence and detection were good → risk overlooked.
- Consistency: RPN thresholds (e.g., RPN > 100 = action needed) were arbitrary and varied by company.
- Clarity: AP gives clear categories (H, M, L) instead of ambiguous numbers.
- Customer Focus: AP ensures risks with safety, regulatory, or compliance impact are always addressed.
AIAG-VDA Action Priority Categories #
| AP Level | Meaning | Action Required |
|---|---|---|
| High (H) | Risk must be reduced | Immediate action required |
| Medium (M) | Risk reduction recommended | Team to decide based on feasibility |
| Low (L) | Risk may not need action | Justification must be documented |
📌 High (H) = mandatory action.
📌 Medium (M) = evaluate action, document decision.
📌 Low (L) = acceptable risk, but justification must be noted.
How Action Priority Works #
- Based on combinations of S, O, D ratings.
- AIAG-VDA provides a decision table where severity is the dominant factor.
- Examples:
- Severity 10 (safety risk) → AP = High, even if Occurrence = 2 and Detection = 2.
- Severity 5 (comfort issue), Occurrence 6, Detection 6 → AP = Medium.
- Severity 2 (minor effect), Occurrence 2, Detection 3 → AP = Low.
Example – RPN vs AP #
| Failure Mode | Severity | Occurrence | Detection | RPN | Old RPN Decision | AP Result |
|---|---|---|---|---|---|---|
| Airbag fails to deploy | 10 | 2 | 3 | 60 | “Low risk” | High (H) |
| Scratch on trim | 3 | 6 | 5 | 90 | “Medium risk” | Low (L) |
👉 RPN misleads by suggesting the scratch is riskier than the airbag failure.
👉 AP correctly prioritizes the safety-critical failure as High priority.
Case Study – PFMEA for Bolting Process #
- Function: Secure suspension bolt at 100 ± 5 Nm.
- Failure Mode: Under-torque.
- Effect: Suspension loosens during driving → Severity = 9.
- Cause: Torque wrench calibration drift → Occurrence = 4.
- Control: Manual torque check → Detection = 7.
👉 RPN = 9 × 4 × 7 = 252 (high, but not urgent by some thresholds).
👉 AP = High (H) → mandatory corrective action.
Action taken: Introduced automatic torque monitoring system → Detection improved to 3 → AP reduced to Medium (M).
Best Practices for Using Action Priority #
- Rate Severity first → safety and compliance always drive urgency.
- Use AP instead of RPN for all new FMEAs (DFMEA, PFMEA, FMEA-MSR).
- Document justification for Medium (M) or Low (L) ratings.
- Review AP decisions with the cross-functional team regularly.
- Update AP after corrective actions (e.g., new detection system).
- Communicate clearly with customers when High AP risks are identified and addressed.
Common Mistakes to Avoid #
- Still using RPN as the main priority driver.
- Ignoring Severity because Occurrence is low.
- Overestimating detection effectiveness (e.g., manual checks considered “strong”).
- Not documenting why risks rated Medium or Low were accepted.
Why Action Priority Improves FMEA #
- Eliminates the false security of low RPN numbers.
- Ensures safety-critical risks always get immediate action.
- Aligns suppliers and OEMs with a globally consistent method.
- Strengthens audit readiness since AP decisions are transparent and traceable.
Key Takeaways #
- Action Priority (AP) = High (H), Medium (M), Low (L).
- AP replaced RPN in AIAG-VDA FMEA (2019).
- Severity is always the dominant factor in AP decisions.
- AP ensures safety, compliance, and customer-critical risks are never ignored.
- Teams must document and justify every AP decision.
Next Resource #
👉 Learn more about FMEA Optimization – Step 6 of the AIAG-VDA Approach
