ASE H2 Diesel Engines (Transit Bus) study plan

ASE H2 Diesel Engines (Transit Bus) · Give each week a clear focus.

8 weeks · About 7 hours per week

Week 1

Fuel System and Engine Controls

Map each major fuel system subsystem (low-pressure supply, high-pressure pump, injectors, ECM inputs/outputs) onto a hand-drawn diagram from memory
Explain the difference between pilot, main, and post injection events and why each exists
Trace a no-start complaint through fuel supply, rail pressure, and injector command in a written diagnostic sequence
Define key sensor relationships (rail pressure, cam/crank, MAP, MAF, IAT) and how each affects fueling

A one-page diagnostic flowchart for a crank-no-start condition with at least 8 decision points and expected values noted

Week 2

Interpret scan-tool data parameters for fuel pressure, injection timing, and balance rates and state pass/fail logic for each
Describe how to test for injector return-flow faults and what results indicate
Explain ECM limp-home and derate strategies and the conditions that trigger them
List the steps to verify a fuel quality or contamination complaint before condemning components

Completed 25-question self-quiz on fuel and engine controls with written explanations for every missed item

Week 3

Describe turbocharger operation from exhaust energy input to boost output, including wastegate and VGT control
Diagnose boost leaks, low boost, and overboost using pressure and airflow data
Explain the function and failure modes of the charge-air cooler and intake/exhaust restrictions
Identify aftertreatment hardware (DOC, DPF, SCR) and how each interacts with exhaust flow

A labeled turbo system diagram plus a written low-power diagnostic tree covering at least 6 possible causes

Week 4

Explain DPF regeneration types (passive, active, parked) and the conditions required for each
Diagnose excessive soot loading and frequent regen complaints by listing contributing causes
Describe engine brake operation and how to test its function
Explain SCR/urea dosing basics and common fault symptoms

A comparison table of regen types with triggers, conditions, and failure symptoms, plus a 10-item practice test scored at 80% or better

Week 5

Describe cylinder head inspection steps including flatness, valve recession, and injector cup sealing
Explain valve train components and how to identify a worn or misadjusted valve train by symptom
List engine block inspection checks (liner protrusion, deck flatness, main bore) and their acceptance logic
Connect compression and cylinder leakage test results to specific head or block faults

A written case study interpreting a set of compression and leakage readings and naming the most likely fault with justification

Week 6

Trace the full lubrication circuit and identify pressure and flow failure points
Diagnose low oil pressure complaints by separating gauge/sensor error from mechanical causes
Explain cooling system operation including thermostat, bypass, and deaeration
Diagnose overheating and coolant loss by distinguishing internal from external leaks

Two completed diagnostic worksheets: one low-oil-pressure scenario and one overheating scenario, each with a ranked cause list

Week 7

Build a general diagnostic routine for performance complaints using intake, fuel, compression, and exhaust checkpoints
Explain starting system circuit testing from battery to starter control
Explain charging system testing including alternator output and voltage-drop checks
Interpret battery state-of-charge and load test results and state pass/fail criteria

A written no-crank and no-charge diagnostic procedure each with voltage-drop test points and expected readings

Week 8

Apply lockout/tagout, high-pressure fuel, and high-voltage safety practices to listed job scenarios
Identify personal protective equipment and shop hazards for each major system covered
Complete a full-length timed practice exam and categorize every miss by domain
Review the two weakest domains using the categorized miss list

A scored full-length practice exam with a written remediation list naming each weak objective and the action to fix it

Week 2: Score 80% or better on the fuel and engine controls self-quiz and explain every missed item in writing

Week 4: Correctly describe all three regeneration types and score 80% or better on the air/exhaust/emissions practice test

Week 6: Complete both lubrication and cooling diagnostic worksheets with a defensible ranked cause list

Week 8: Score 80% or better on a full-length timed practice exam with every miss categorized by domain