ASE T2 Diesel Engines (Medium/Heavy Truck) study guide
ASE T2 Diesel Engines (Medium/Heavy Truck) · Work through your exam, one topic at a time.
ASE T2, Diesel Engines, is one of the eight Medium-Heavy Truck certification tests in the ASE T Series (T1–T8). ASE describes the T Series as identifying and recognizing Medium and Heavy Truck Technicians who can demonstrate the knowledge and skills necessary to diagnose, service, and repair different systems of Class 4 through Class 8 trucks and tractors. The ASE T2 Diesel Engines (Medium/Heavy Truck) study guide has 8 sections and about 2,246 words.
01Cylinder Head and Valve Train Diagnosis and Repair
A diesel head diagnosis starts with sealing and geometry. Know the difference between a compression leak (past rings, valves, or injector sleeve) and a coolant or oil leak (past the head gasket, liner seals, or a cracked casting).
311 words, about 2 min02Engine Block Diagnosis and Repair
Block work centers on the rotating and reciprocating assembly and the cylinder bores. Know how to evaluate cylinder taper, out-of-round, and ridge wear with a bore gauge, and when honing or boring/over-sizing is required.
290 words, about 1 min03Lubrication and Cooling Systems Diagnosis and Repair
Lubrication: know the oil pump types, relief valve function, oil cooler, filters (full-flow and bypass), and the difference between pressure and flow problems. Understand oil pressure specs at idle and rated speed, and causes of low pressure (dilution, worn pump, bearing clearance, relief stuck open, restricted pickup).
298 words, about 1 min04Air Induction and Exhaust Systems Diagnosis and Repair
Induction: know the air filter and restriction indicator, intake piping and clamps, turbocharger operation (compressor, turbine, wastegate or VGT), charge-air cooler, and boost pressure testing. Understand turbo failure modes: oil starvation, foreign object damage, overspeed, and seal leakage (oil in intake or exhaust).
267 words, about 1 min05Fuel System Diagnosis and Repair
Know the diesel fuel path: tank, lift pump, filters/water separator, high-pressure pump, rail or unit injectors, and return. Understand common-rail pressure control, injector operation, and the difference between low-pressure (suction/transfer) and high-pressure faults.
278 words, about 1 min06Starting and Charging Systems Diagnosis and Repair
Starting: know battery construction, state of charge, cold cranking amps, and how to test with a conductance or load tester. Understand series/parallel battery connections on heavy trucks (often 12V batteries in series-parallel for 12V or 24V systems), cable sizing, and voltage drop testing.
251 words, about 1 min07Engine Electrical/Electronic Systems Diagnosis and Repair
Know the ECM, sensors, and actuators that manage a diesel: crankshaft and camshaft position, coolant and intake air temperature, oil and rail pressure, mass airflow, and throttle/pedal position. Understand the difference between a hard fault (open/short) and a performance fault (out-of-range signal), and how to use scan-tool data, freeze frames, and fault codes.
267 words, about 1 min08Engine Brakes and Retarders Diagnosis and Repair
Know the types of engine retarders: compression-release (Jake) brakes, exhaust brakes, and hydraulic retarders. Understand compression-release operation: the master piston and slave piston, the oil circuit, and the solenoid that controls it.
284 words, about 1 min