ASE T2 Diesel Engines practice test
The T2 test is the heart of the truck series — 55 scored questions on diesel diagnosis, fuel systems, turbocharging, and the aftertreatment stack (DPF, EGR, SCR/DEF) that dominates modern diesel work. Required for Master Truck status.
A tractor shows gradual power loss, higher exhaust temperatures, and black smoke under load. A pressure test of the charge air cooler shows it will not hold the specified pressure. Technician A says the leaking cooler explains all three symptoms. Technician B says the engine should also be checked for a soot-plugged air filter before condemning the cooler. Who is correct?
How the T2 test works
55 scored questions
+ ~10 unscored research questions
90 minutes
computer-based, at a test center
$62 per test
plus one $34 registration fee per order
Valid 5 years
then a shorter recertification test
ASE does not publish one universal passing percentage; the passing standard is set by test. TorquePrep uses 80% as a conservative practice target, not as an official ASE cut score. The certificate is issued once ASE verifies your required work experience.
What the T2 test covers
The official task list for T2 Diesel Engines (Medium-Heavy Truck) breaks down into these content areas — the practice bank above draws from all of them:
- General diesel diagnosis — hard start, low power, smoke color, noise, crankcase pressure
- Cylinder head and valve train — including overhead adjustment
- Engine block, lubrication, and cooling systems
- Air induction and exhaust — turbochargers, charge air coolers, restrictions
- Fuel systems — supply, filtration, water separation, and high-pressure injection
- Emissions and aftertreatment — EGR, DPF regeneration, SCR/DEF, sensors
Frequently asked
- How many questions are on the ASE T2 test?
- The T2 test has 55 scored questions plus about 10 unscored research questions, with a 90-minute time limit — the largest T-series test.
- Is T2 required for Master Truck status?
- Yes. Master Medium-Heavy Truck Technician status requires passing T2 through T8.
- What should I focus on for T2?
- Aftertreatment logic (DPF regen strategies, SCR/DEF faults) and air-side diagnosis (turbo, charge air cooler, restrictions) — modern trucks generate most diesel work in exactly those systems.
Exam length, timing, fees, and content areas checked September 11, 2026 against the official ASE test table and ASE study guides.
Other ASE practice tests
Driving trucks, not just wrenching on them?
HaulSchool has free CDL practice tests — general knowledge, air brakes, and every endorsement — plus plain-English DOT physical guides.
Free CDL practice tests at HaulSchool →