This course reviews the diagnostic procedure, theory, and operation of the General Motors 6.6
Liter Duramax Engine. Common rail diagnosis will be emphasized in this course such as fuel
pressure testing both on the high and low pressure side plus injector testing and fuel injector
control module (FICM) operation. Duramax engine LLY-LBZ and LMM will be discussed. Service
information will be used to aid the technician in vehicle diagnosis. This will be supplemented
with the use of the scan tool in interpreting data and using bidirectional controls that are available.

Duramax Systems Overview Injector Operation Fuel system Operation, hi/low pressure systems Fuel Injector Control Module (FICM) Turbocharging operation, including variable geometry turbos After-treatment systems (DPF, NOx/EGR) Biodiesel issues, Biodiesel blends Electronic Engine Controls Operation Diagnostic Strategies Fault Code determination and diagnosis PCM input and output Starting systems Hard Start, No Start & Performance Diagnostics Electronic Engine Control Testing Fuel Charging & Controls Crankcase Pressure Testing High Pressure Oil System Technician Tips: Repair Procedure Pattern Failures Pinpoint Test shortcuts


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