Engine Course Curriculum - D201

D201

DEF and Aftertreatment Diagnostics

This course teaches a structured approach to DEF supply, dosing, DPF and SCR faults. Students use codes, live data, electrical testing and OEM procedures to diagnose faults and verify repairs without unnecessary parts replacement.

What Students Will Be Able to Do
  • Review the entire system before diagnosing an individual code.
  • Interpret soot load, ash load, pressure, temperature and NOx data.
  • Evaluate DEF quality, pressure, purge, heater and dosing concerns.
  • Test common aftertreatment power, ground, signal and heater circuits.
  • Identify regeneration prerequisites and safety requirements.
  • Choose appropriate cleaning, repair or replacement recommendations.
  • Complete resets, relearns and post repair verification where applicable.
Level Intermediate
Duration 3 days / 18 instructional hours
Tuition $1,495 CAD
Delivery Theory demonstrations and hands on shop training
Prerequisite D101 or equivalent aftertreatment service experience.
Completion Certificate of Completion
Day 1 - System scan and DEF supply diagnosis
Topics and Knowledge Practical Learning Activities
  • Complaint verification and full system code review
  • Inducement and derate conditions
  • DEF quality, contamination and freeze concerns
  • Pump, line, purge, heater and pressure operation
  • Test DEF quality
  • Review scan data and complete a DEF supply diagnostic exercise
Day 2 - DPF and SCR diagnosis
Topics and Knowledge Practical Learning Activities
  • Differential pressure, soot load and ash load interpretation
  • Temperature sensor and regeneration data
  • NOx sensors and SCR conversion efficiency
  • Doser function, crystallization, restriction and leakage
  • Analyze a regeneration data set
  • Inspect or test a dosing system
  • Compare upstream and downstream NOx information
Day 3 - Electrical testing and repair verification
Topics and Knowledge Practical Learning Activities
  • Wiring diagrams, connectors, power, ground and signal tests
  • Stationary regeneration prerequisites and safety
  • Cleaning versus replacement factors
  • Reset, relearn, monitored road test and documentation
  • Diagnose an introduced circuit fault
  • Prepare a repair and verification plan
  • Complete a final monitored test or case study

Student Evaluation

  • Safety and professional shop practices
  • Participation in demonstrations and practical activities
  • Short knowledge checks or review questions
  • Completion of assigned inspection, diagnostic or measurement worksheets
  • Final practical task, case study or instructor evaluation

Course Completion

Students who meet the attendance requirements and successfully participate in the required learning and evaluation activities will receive a Certificate of Completion for this course.

Build practical heavy-duty repair skills with training designed around real shop work.

Contact us to discuss the right starting level, upcoming class dates, group training or a customized program for your fleet or repair shop.

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