Study guide
ASE L1 study guide
Read a lesson, then practice the ideas you want to remember.
Lessons
- Fuel Trim and Oxygen Sensors — Free Study Guide 2026
- Input Sensors — Free Study Guide 2026
- Network Communication and U-Codes — Free Study Guide 2026
- OBD-II Standards and Communication — Free Study Guide 2026
- Output Actuators and ECM Control — Free Study Guide 2026
- Scan Tool Diagnostics — Free Study Guide 2026
- Air Injection and Secondary Air — Free Study Guide 2026
- Catalytic Converter Operation and Diagnosis
- EGR System Diagnosis — Free Study Guide 2026
- Emission Standards and Pollutants — Free Study Guide 2026
- EVAP and PCV Systems — Free Study Guide 2026
- Air Induction System Diagnosis — Free Study Guide 2026
- Gasoline Direct Injection — Free Study Guide 2026
- Port Fuel Injection — Free Study Guide 2026
- Turbocharger and Supercharger Diagnosis
- Variable Valve Timing and Intake Tuning
- Charging and Starting System Diagnosis — Free Study Guide 2026
- Diagnostic Strategy and Logical Sequencing
- Drivetrain Issues Affecting Engine Performan
- Engine Mechanical Diagnosis — Free Study Guide 2026
- Fuel System Pressure and Flow — Free Study Guide 2026
- Ignition System Types and Coil Operation
- Primary Ignition Diagnosis — Free Study Guide 2026
- Secondary Ignition Diagnosis — Free Study Guide 2026
- Spark Plugs and Diagnostic Reading — Free Study Guide 2026
- Ignition Timing and Knock Sensor — Free Study Guide 2026
- Drive Cycle for Readiness Monitors — Free Study Guide 2026
- Diagnosing Fuel Trim and Lean/Rich Codes
- Inspection and Maintenance Programs — Free Study Guide 2026
- Diagnosing Misfire and Multiple-Cylinder Mis
- Diagnosing P0420/P0430 Catalyst Codes — Free Study Guide 2026
- Current Exam Facts — Free Study Guide 2026
- How to Use This Guide — Free Study Guide 2026