Diesel Diagnostics and Aftertreatment Systems

01 DD01 - Diesel Diagnostic Mindset and Safety Workflow

• DD01-L01 – Diesel System Overview, Complaint Sorting, and First Scan
• DD01-L02 – Diesel Safety: High Pressure Fuel, Hot Exhaust, Rotating Components, and PPE
• DD01-L03 – Diagnostic Intake: Smoke, Power Loss, No-Start, Warning Lamps, and Customer Interview

02 DD02 - Diesel Engine Fundamentals and Combustion Strategy

• DD02-L01 – Compression Ignition, Air Charge, Fuel Delivery, and Torque Production
• DD02-L02 – Common Rail, Unit Injector, Mechanical Diesel, and Modern ECU Control Differences
• DD02-L03 – Diesel Sensor Inputs: MAF, MAP, ECT, IAT, Rail Pressure, Boost, and NOx Context

03 DD03 - Diesel Scan Tool Workflow, DTCs, Freeze Frame, and Live Data

• DD03-L01 – Generic vs Enhanced Diesel Data and Manufacturer-Specific Codes
• DD03-L02 – Freeze Frame, Pending Codes, Permanent Codes, and Service Information Priority
• DD03-L03 – Live Data Baseline: Rail Pressure, Boost, MAF, EGR Command, DPF Load, and DEF Data

04 DD04 - Fuel Supply, Low-Pressure Side, and Filter Diagnostics

• DD04-L01 – Tank, Lift Pump, Filter, Water Separator, and Low-Pressure Supply Logic
• DD04-L02 – Air Intrusion, Filter Restriction, Water Contamination, and Priming Errors
• DD04-L03 – Low-Pressure Testing, Volume Checks, and No-Parts-Cannon Fuel Diagnosis

05 DD05 - High-Pressure Common Rail and Injector Diagnostics

• DD05-L01 – High-Pressure Pump, Rail Pressure Control, IMV/SCV, and Pressure Sensor Logic
• DD05-L02 – Injector Return Flow, Balance Rates, Correction Values, and Leak-Off Testing
• DD05-L03 – Hard Start, No-Start, Rail Pressure Drop, and Injector Fault Case Workflow

06 DD06 - Air Management, Turbocharging, Boost Control, and Charge Leaks

• DD06-L01 – Turbocharger Basics, VGT/VNT Control, Wastegate Strategy, and Boost Targets
• DD06-L02 – Charge-Air Leaks, Intercooler Restrictions, MAP/MAF Plausibility, and Smoke Clues
• DD06-L03 – Underboost, Overboost, Limp Mode, Actuator, Vacuum, and Solenoid Testing

07 DD07 - EGR Systems, Intake Carbon, Swirl Flaps, and NOx Reduction

• DD07-L01 – Diesel EGR Purpose, Cooler, Valve, Bypass, and Flow Monitoring
• DD07-L02 – Intake Carbon, Swirl Flaps, Throttle Plate, and Airflow Restriction Diagnosis
• DD07-L03 – EGR Codes, NOx Effects, Smoke, Rough Running, and Legal Repair Boundaries

08 DD08 - DPF Fundamentals, Soot Load, Ash Load, and Differential Pressure

• DD08-L01 – DPF Purpose, Passive Regeneration, Active Regeneration, Soot vs Ash
• DD08-L02 – Differential Pressure Sensor, Temperature Sensors, Hoses, and Plausibility Checks
• DD08-L03 – Soot Load, Ash Load, Restriction, Backpressure, and Replacement Decision Logic

09 DD09 - Regeneration Strategy, Failed Regens, and Forced Regeneration Boundaries

• DD09-L01 – Regeneration Preconditions: Temperature, Fuel Level, Speed, Load, and Fault Status
• DD09-L02 – Failed Regeneration Diagnosis: Thermostat, Sensors, Driving Pattern, EGR, Injectors, and Oil Dilution
• DD09-L03 – Forced Regeneration: Tool Requirements, Fire Risk, Stop Conditions, and Documentation

10 DD10 - SCR, DEF/AdBlue, NOx Sensors, and Emissions Compliance

• DD10-L01 – SCR System Logic: DEF Tank, Pump, Injector, Mixer, Catalyst, and NOx Sensors
• DD10-L02 – DEF Quality, Crystallization, Heater Faults, Dosing Tests, and Pressure Checks
• DD10-L03 – NOx Conversion, Countdown Warnings, Derate Strategy, and Legal Boundaries

11 DD11 - Glow Plug, Intake Heater, Cold Start, and Compression Clues

• DD11-L01 – Glow Plug System Logic, Control Modules, Relays, and Cylinder-Specific Faults
• DD11-L02 – Cold Start Smoke, Compression Clues, Cranking Speed, Battery Support, and Fuel Timing
• DD11-L03 – Testing Glow Plugs, Intake Heaters, Current Draw, and Safe Electrical Procedure

12 DD12 - Diesel No-Start, Hard Start, Stall, and Limp Mode Case Workflow

• DD12-L01 – Crank-No-Start Diesel Flow: Air, Fuel, Compression, Timing, Authorization, and Codes
• DD12-L02 – Hard Start Hot vs Cold, Rail Pressure Build, Injector Leakage, and Sensor Dropout
• DD12-L03 – Stall and Limp Mode: Boost, Fuel Pressure, EGR, DPF, SCR, and Network Clues

13 DD13 - Smoke Diagnostics: Black, White, Blue, and Grey Smoke

• DD13-L01 – Black Smoke: Overfueling, Air Restriction, Boost Loss, EGR, and Injector Patterns
• DD13-L02 – White Smoke: Cold Combustion, Coolant, Injector Dribble, Timing, and Compression
• DD13-L03 – Blue/Grey Smoke: Oil Consumption, Turbo Seals, Crankcase Ventilation, and Engine Wear

14 DD14 - Sensor, Wiring, Power, Ground, and Communication Faults

• DD14-L01 – 5V Reference, Sensor Ground, Signal Plausibility, and Multiple-Code Patterns
• DD14-L02 – Harness Rub, Heat Damage, Water Intrusion, Connector Pin Fit, and Intermittent Faults
• DD14-L03 – CAN Communication, Module Codes, Low Voltage, and When Diesel Faults Are Network Faults

15 DD15 - Cooling, Oil, Crankcase Ventilation, and Mechanical Health

• DD15-L01 – Diesel Cooling System, Thermostat, Fan Strategy, ECT Plausibility, and Overheat Codes
• DD15-L02 – Oil Quality, Dilution, Pressure, Turbo Lubrication, and DPF Regeneration Side Effects
• DD15-L03 – Crankcase Ventilation, Blow-By, Compression Testing, Leak-Down, and Mechanical Escalation

16 DD16 - Heavy-Duty, Light-Duty, Euro, and Pickup Diesel Differences

• DD16-L01 – Light-Duty Diesel vs Heavy-Duty Diesel Diagnostic Scope and Tool Access
• DD16-L02 – Euro Diesel, Pickup Diesel, Commercial Vehicle, and OBD/HD-OBD Differences
• DD16-L03 – Fleet Service, Duty Cycle, Maintenance History, Fuel Quality, and Repeat-Fault Prevention

17 DD17 - Aftertreatment Case Studies: DPF, SCR, EGR, Boost, and NOx

• DD17-L01 – DPF Case Study: High Soot Load, Bad Differential Pressure Data, or Real Restriction?
• DD17-L02 – SCR Case Study: AdBlue Warning, NOx Sensor Fault, Dosing Issue, or Catalyst Failure?
• DD17-L03 – Boost and EGR Case Study: Underboost, Smoke, Limp Mode, and False DPF Blame

18 DD18 - Repair Decisions, Verification, Documentation, and Customer Communication

• DD18-L01 – Clean, Test, Repair, Replace, Regenerate, Program, or Escalate Decision Logic
• DD18-L02 – Post-Repair Verification: Final Scan, Live Data, Road Test, Monitor Status, and Emissions Readiness
• DD18-L03 – Customer Report: Legal Disclosure, Maintenance Advice, Risk Language, and Warranty Protection

19 DD19 - Capstone Diesel Diagnostic Workflow and Professional Release

• DD19-L01 – Build the Complete Diesel Diagnostic Decision Tree
• DD19-L02 – Timed Workshop Simulation: First 30 Minutes of a Diesel Fault Vehicle
• DD19-L03 – Final Capstone Case: Scan, Interpret, Test, Repair, Verify, and Release

20 CAPSTONE - Integrated Diesel Diagnostic and Aftertreatment Cases and Professional Release

• Capstone Final Assessment and Professional Release Logic