What is FMEA Severity rating?

FMEA Severity (S) is a numerical rating from 1 to 10 that evaluates the seriousness of a potential failure mode's effect. A rating of 1 indicates no discernible effect, while 10 indicates a hazardous effect affecting safety. Ratings of 9 or 10 require immediate priority attention regardless of other factors, per AIAG VDA Handbook standards.

How is RPN calculated in FMEA?

Risk Priority Number (RPN) is calculated by multiplying Severity (S) x Occurrence (O) x Detection (D), yielding a value from 1 to 1,000. The AIAG VDA 4th Edition (2019) recommends using Action Priority (AP) instead of RPN, because AP better prioritizes risk by weighting Severity and Occurrence over Detection.

What is the difference between AIAG and VDA FMEA ratings?

The AIAG VDA FMEA Handbook (4th Edition, 2019) is a harmonized standard replacing the separate AIAG FMEA 4th Edition and VDA Volume 4. Key changes include: Action Priority (AP) tables replacing traditional RPN thresholds, updated harmonized SOD criteria, and a new 7-step FMEA methodology. All tables on fmearatings.com reflect the current AIAG VDA standard.

What are the standard FMEA Severity, Occurrence, and Detection (SOD) ratings?

FMEA ratings use a scale from 1 to 10. Severity measures failure impact (1 = no effect, 10 = safety risk), Occurrence ranks failure probability, and Detection assesses how likely controls will find the failure before reaching the customer.

How do I use the FMEA Severity Table 1-10 according to AIAG & VDA standards?

The AIAG VDA FMEA Handbook provides updated criteria for the 1-10 scale. A rating of 9 or 10 always indicates a potential safety or regulatory non-compliance issue. The focus has shifted from calculating RPN to understanding the functional impact of each failure mode.

What is the difference between RPN and Action Priority (AP) in FMEA?

RPN is calculated by multiplying Severity x Occurrence x Detection. The new Action Priority (AP) system uses a logic-based table to categorize risk as High, Medium, or Low. AP is preferred over RPN because it prioritizes the combined impact of severity and occurrence rather than just the product of three numbers.

Where can I find a PFMEA and DFMEA Occurrence Table?

Comprehensive PFMEA and DFMEA occurrence tables are available on fmearatings.com. These tables help assign a ranking from 1 (nearly impossible) to 10 (persistent failure) based on historical data, preventive controls, and predicted failure rates.

Why is a Detection ranking of 10 critical in a risk assessment?

A Detection ranking of 10 means there is no control in place to detect the failure mode. Even if occurrence is low, a detection ranking of 10 often triggers an immediate need for improved inspection methods or automated sensors to protect the end-user.

VDA 2: Production Process and Product Approval (PPA)

The German Automotive Standard for Quality Qualification and Supplier Part Approval

What is VDA Volume 2?

VDA Volume 2 (often referred to simply as VDA 2) is a quality standard established by the German Association of the Automotive Industry (Verband der Automobilindustrie). It defines requirements for the Production Process and Product Approval (PPA) process—known in German as Produktionsprozess- und Produktfreigabe.

The primary purpose of VDA 2 is to prove that supplier-manufactured parts meet customer expectations, regulatory specifications, and quality targets under actual serial production conditions.

VDA 2 (PPA) vs. AIAG (PPAP): Key Differences

While both standards aim to qualify parts before serial production, German OEMs (like Volkswagen Group, BMW, Mercedes-Benz) historically follow VDA 2, while North American OEMs (Ford, GM, Stellantis) follow the AIAG PPAP manual.

Feature	VDA Volume 2 (PPA)	AIAG PPAP Manual
Terminology	PPA Process (Produktionsprozess- und Produktfreigabe)	PPAP (Production Part Approval Process)
Submission Levels	Levels 0 to 3 (Level 2 & 3 are most common)	Levels 1 to 5 (Level 3 is the default)
Focus Area	Strong emphasis on process capability, logistics, and embedded software	Emphasis on static documentation compliance and dimensional results
Trigger for Submission	Defined triggers such as change of supplier, tool relocation, design alterations	Strictly defined PPAP triggers in section 3 of the AIAG manual

VDA 2 Submission Levels (Vorlagestufen)

Depending on the risk level of the component and supplier history, the customer will assign one of the following submission levels:

Level 0: Retention at Supplier

The supplier performs the full PPA study and documents all findings. No documents or samples are submitted to the customer unless specifically requested.

Level 1: Minimal Submission

Only the cover page (PPA Release Form) and selected basic documents are submitted to the customer.

Level 2: Standard Submission

Submission of the cover page, material testing data, dimensional reports, and sample parts. FMEA verification is typically reviewed at this level.

Level 3: Full Submission (Dossier)

Submission of the complete PPA dossier, including design approvals, process flows, FMEA, Control Plan, capacity verification, and sample parts.

The Role of FMEA in VDA 2

FMEA (Failure Mode and Effects Analysis) is a crucial prerequisite for achieving PPA approval. A VDA 2 submittal requires the supplier to prove they have identified all design risks (DFMEA) and manufacturing risks (PFMEA).

During a VDA 2 review or a customer audit (such as VDA 6.3), auditors will scrutinize the FMEA to ensure:

All critical, regulatory, and safety-related characteristics (Special Characteristics) are correctly addressed and traced back to the FMEA.
Occurrence rates (O) are backed by historical process capability study data (e.g., Cpk values).
High-risk items are resolved using Action Priority (AP) rules.

The harmonization of the AIAG and VDA standards in the 2019 handbook directly benefits suppliers by establishing a unified 7-step FMEA format that is accepted by both VDA 2 and AIAG PPAP processes.