OBD Systems Technician Course

Lesson 1 • OBD-II Standard Protocol Basics

Introduces the standardized communication protocols and service modes defined by OBD-II. Prepares students to interpret scan tool data in later chapters.

Lesson 2 • Emissions Monitoring Fundamentals

Covers the primary pollutants OBD monitors and the thresholds that trigger fault detection. Links emissions chemistry to diagnostic system design.

Lesson 3 • OBD System Architecture Overview

Explains the structural layout of an OBD system including sensors, ECU, and communication links. Connects hardware roles to diagnostic data generation.

Lesson 1 • Live Data Stream Interpretation

Develops skill in reading real-time sensor data streams to identify out-of-range values. Connects live data analysis to root-cause hypothesis formation.

Lesson 2 • Types of OBD Diagnostic Tools

Differentiates code readers, professional scan tools, and PC-based interfaces by capability. Guides appropriate tool selection for specific diagnostic tasks.

Lesson 3 • Retrieving and Clearing Fault Codes

Teaches systematic retrieval of diagnostic trouble codes (DTCs) and proper clearing procedures. Emphasizes when clearing codes is appropriate versus premature.

Lesson 4 • Connecting to the Vehicle DLC

Covers safe physical connection procedures and protocol handshake verification. Ensures students avoid communication errors before data retrieval begins.

Lesson 1 • Body, Chassis, and Network Codes

Covers B, C, and U code categories for body, chassis, and communication network faults. Expands diagnostic scope beyond powertrain systems.

Lesson 2 • Manufacturer-Specific Code Interpretation

Addresses enhanced codes beyond the generic OBD-II set that require OEM resources. Teaches students to access and apply manufacturer service information.

Lesson 3 • DTC Structure and Classification

Decodes the five-character DTC format including system, type, and fault identifiers. Establishes a consistent framework for all subsequent code analysis.

Lesson 4 • Pending, Stored, and Permanent DTCs

Distinguishes code status types and their implications for repair verification. Students apply correct test drive cycles to confirm repairs.

Lesson 1 • Oxygen Sensor Diagnostics

Evaluates upstream and downstream oxygen sensor performance using waveform analysis. Connects sensor behavior to fuel trim corrections and catalyst monitoring.

Lesson 2 • Exhaust Gas Recirculation Diagnosis

Tests EGR valve operation and flow using OBD monitor data and bidirectional controls. Links EGR faults to NOx emissions and engine performance symptoms.

Lesson 3 • Air Intake and MAF Sensor Diagnosis

Evaluates mass airflow sensor accuracy and intake system integrity using OBD data. Identifies vacuum leaks and sensor contamination as common fault sources.

Lesson 4 • Fuel System Monitoring and Diagnosis

Analyzes fuel trim data and injector performance parameters from OBD live data. Students distinguish lean and rich conditions and identify their root causes.

Lesson 1 • Emissions Inspection Failure Analysis

Diagnoses vehicles that fail emissions inspections due to MIL status or incomplete monitors. Students develop repair strategies that restore inspection readiness.

Lesson 2 • Readiness Monitor Status and Drive Cycles

Explains how readiness monitors are set and why incomplete monitors cause inspection failures. Students execute proper drive cycles to complete all required monitors.

Lesson 3 • Evaporative Emission System Testing

Diagnoses EVAP system leaks and purge valve faults using OBD monitor results and smoke testing. Covers both large and small leak detection methodologies.

Lesson 4 • Secondary Air Injection Diagnosis

Tests air pump, switching valves, and check valves using OBD monitor data and component testing. Links secondary air faults to cold-start emissions failures.

Lesson 1 • Shift Solenoid and Pressure Diagnosis

Diagnoses shift solenoid electrical faults and hydraulic pressure issues using OBD codes and live data. Connects solenoid faults to specific gear engagement failures.

Lesson 2 • Speed Sensor and ABS Integration

Diagnoses wheel speed sensor faults that affect both ABS and transmission shift logic. Students trace speed sensor signals through shared vehicle networks.

Lesson 3 • Transmission Control Module Overview

Explains TCM inputs, outputs, and communication with the ECU in modern vehicles. Establishes the data framework needed for transmission fault diagnosis.

Lesson 1 • CAN Bus Signal Testing

Measures CAN bus voltage levels and waveforms using a multimeter and oscilloscope. Students identify bus shorts, opens, and termination resistor faults.

Lesson 2 • Vehicle Network Architecture

Explains CAN, LIN, and other network topologies used in modern vehicles. Provides the structural foundation for diagnosing communication faults.

Lesson 3 • Module Programming and Relearning

Covers module replacement procedures including programming, coding, and relearn routines. Ensures students restore full system function after module replacement.

Lesson 4 • U-Code Network Fault Diagnosis

Systematically diagnoses U-code communication faults by isolating the offending module or wire. Connects network fault patterns to specific bus topology failures.

Lesson 1 • Intermittent Fault Diagnosis

Develops strategies for capturing and diagnosing faults that do not occur consistently. Students use data logging and trigger conditions to isolate elusive faults.

Lesson 2 • Root Cause vs. Symptom Distinction

Trains students to distinguish between the root cause of a fault and its downstream symptoms. Prevents misdiagnosis caused by treating secondary effects as primary faults.

Lesson 3 • Diagnostic Time Management

Applies efficiency principles to diagnostic workflows in a professional shop environment. Students balance thoroughness with time constraints to maximize productivity.

Lesson 4 • Post-Repair Verification Procedures

Confirms repairs are complete and no new faults were introduced during the repair process. Students perform final scans, drive cycles, and functional tests before vehicle return.