Complete Learning Module

Safety Mechanisms & Diagnostics

Master the full spectrum of hardware and software safety mechanisms, diagnostic coverage calculation, and PMHF methodology per ISO 26262 Part 5 and Annex D.

14
Chapters
6
Interactive Tools
1
Case Study
1
Video

What You'll Learn

Build complete competency in safety mechanisms & diagnostics through structured, progressive learning.

Select Mechanisms from Annex D

Navigate ISO 26262 Part 5 Annex D to select appropriate safety mechanisms with correct conditions of use for your hardware.

Calculate Diagnostic Coverage

Apply the ISO 26262 DC calculation methodology to determine combined coverage from multiple safety mechanisms.

Define FDTI and Fault Reactions

Specify Fault Detection Time Intervals, Fault Reaction Time Intervals, and safe state transitions for each mechanism.

Verify PMHF Compliance

Calculate PMHF from SPF and latent fault contributions and demonstrate compliance with ASIL B, C, and D targets.

Integrate Mechanisms in AUTOSAR

Configure AUTOSAR WdgM, DEM, FiM, and E2E modules to implement ISO 26262-compliant safety mechanisms in production code.

Verify Mechanisms with Fault Injection

Design fault injection test campaigns to verify safety mechanism activation, timing, and diagnostic coverage claims.

14 Comprehensive Chapters

Each chapter builds your safety mechanisms & diagnostics expertise systematically from foundations to advanced application.

1

Overview

Understand what safety mechanisms are, how they relate to diagnostic coverage, and their role in ISO 26262 Part 5.

Mechanism definitionDC conceptPart 5 context
2

ISO 26262 Part 5 Requirements

Navigate the normative requirements of ISO 26262 Part 5 for hardware safety mechanisms and diagnostic coverage.

Clause-by-clauseNormative vs informativeWork products
3

Mechanism Categories

Classify safety mechanisms by detection type, reaction type, and applicable hardware element categories.

Detection categoriesReaction categoriesElement applicability
4

ISO 26262 Annex D Catalog

Survey every mechanism in ISO 26262 Part 5 Annex D with conditions of use, coverage values, and dependencies.

Full Annex D walkthroughCoverage valuesConditions of use
5

Diagnostic Coverage Calculation

Calculate diagnostic coverage percentages using the ISO 26262 formula with failure rate contributions per mechanism.

DC formulaFailure rate inputsCombined mechanisms
6

FDTI & Timing Requirements

Define Fault Detection Time Intervals and Fault Reaction Time Intervals for each safety mechanism.

FDTI definitionFRTI constraintsTiming budget
7

Fault Reaction & Safe States

Design fault reaction functions and safe state transitions triggered by detected faults for different severity levels.

Reaction typesSafe state definitionTransition timing
8

Hardware Safety Mechanisms

Deep-dive into hardware-implemented mechanisms: ECC, CRC, redundancy, comparison, watchdog, and clock monitors.

ECC & CRCHW redundancyClock monitoring
9

Sensor Safety Mechanisms

Apply sensor-specific safety mechanisms: plausibility, range checks, gradient monitoring, and redundant sensing.

Range & gradientCross-sensor plausibilityRedundant sensors
10

E-Gas 3-Level Monitoring

Analyze the E-Gas monitoring concept as the production reference for layered safety mechanisms in powertrain.

3 monitoring levelsMechanism layeringDC contribution per level
11

Fault Injection Testing

Design and execute fault injection tests to verify safety mechanism activation, coverage, and timing compliance.

HW fault injectionSW fault injectionCoverage verification
12

AUTOSAR Integration

Map safety mechanisms to AUTOSAR BSW modules: WdgM, DEM, FiM, E2E, and diagnostic communication.

WdgM patternsDEM configurationFiM dependency
13

PMHF Methodology

Apply the complete PMHF methodology: failure rate data sources, calculation steps, ASIL verification, and documentation.

FIT data sourcesPMHF calculationASIL verification
14

ASIL Requirements by Level

Map SPFM, LFM, and PMHF targets to ASIL A through D with mechanism selection implications at each level.

SPFM & LFM targetsASIL A-D comparisonDesign implications
Interactive Learning

6 Interactive Tools

Experiment with visual tools that bring safety mechanisms & diagnostics concepts to life.

Annex D Mechanism Browser

Browse all ISO 26262 Part 5 Annex D safety mechanisms with filtering by element type, coverage level, and ASIL.

Diagnostic Coverage Calculator

Calculate combined diagnostic coverage from multiple mechanisms using the ISO 26262 formula with failure rate inputs.

PMHF Compliance Calculator

Compute PMHF from SPF and LF contributions and verify against ASIL B, C, and D targets.

Fault Reaction State Machine

Design fault detection to safe state transition sequences with timing verification and trigger conditions.

FDTI Budget Planner

Allocate Fault Detection Time Interval budgets across detection, reaction, and safe state activation timing.

AUTOSAR Safety Module Mapper

Map your safety mechanism requirements to the correct AUTOSAR BSW modules and configuration parameters.

Real-World Application

Safety Mechanisms & PMHF Analysis for an ASIL-D Power Steering Torque Sensor

Design the complete safety mechanism set for an ASIL-D EPS torque sensor channel, calculate diagnostic coverage, verify PMHF compliance, and map to AUTOSAR BSW.

  • Annex D selection: 6 mechanisms applied - ECC, CRC, dual-channel comparison, range check, gradient check, timeout monitoring
  • Diagnostic coverage calculation: 97.3% DC achieved for ASIL-D SPFM requirement of ≥ 99%
  • FDTI budget: sensor fault detection within 5 ms, safe state (zero torque assist) within 30 ms
  • PMHF result: 4.1 × 10⁻⁹ h⁻¹ versus ASIL-D target of < 10⁻⁸ h⁻¹ - compliant with 60% margin
  • Fault injection: 240 test cases executed covering all 6 mechanisms, 100% activation rate confirmed

Diagnostic Coverage Summary

Mechanism: Dual-channel comparison - DC: 99% (high), FIT contribution: 12.4 FIT, ASIL-D: compliant
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Ready to Master Safety Mechanisms & Diagnostics?

Deep-dive through 14 comprehensive chapters with interactive Annex D tools and a complete ASIL-D EPS case study.

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14 Chapters6 ToolsCase StudyVideo