ASE T2 Diesel Engines Exam Prep
Built by tradespeople. Aligned to the ASE T2 task list. Ready for heavy-duty technicians writing the Medium/Heavy Truck Diesel Engines certification.
520 practice questions across 8 full-length tests
Aligned to the current ASE T2 task list
Detailed answer explanations — not just an answer key
U.S. units and SAE references throughout
The ASE T2 Diesel Engines exam has approximately 60 scored multiple-choice questions (plus up to 10 unscored pre-test questions). The questions are split across the content areas below from the ASE T2 task list. Our book follows the same structure so your study time matches the exam.
| Knowledge Domain / Major Work Activity | Number of Questions |
|---|---|
| A — General engine diagnosis B — Cylinder head and valve train diagnosis and repair C — Engine block diagnosis and repair D — Lubrication and cooling systems diagnosis and repair E — Air induction and exhaust systems diagnosis and repair F — Fuel supply and injection systems diagnosis and repair G — Engine brakes Total | 13 8 6 8 8 12 5 60 |
Source: ASE T2 Medium/Heavy Truck Diesel Engines task list (ase.com). Task counts reflect the approximate exam weighting. This is a study aid. Red Seal Training Academy is not affiliated with ASE.
Which Path Are You On?
Technician writing T2 for the first time
You are working toward your ASE Master Medium/Heavy Truck certification and need to pass T2 Diesel Engines. Use our 8 full-length tests to pace yourself and find weak areas.
Recertification every 5 years
ASE certifications expire every 5 years and require recertification to stay current. Our full bank covers the updated task list so you can refresh quickly and confidently.
Re-testing after a previous attempt
If your last attempt did not go the way you wanted, use our detailed answer explanations to fix the knowledge gaps, not just memorize answers. Every question in the book has a written explanation.
Try 3 Free Sample Questions
One question of each type you will see on the real exam. Scroll to see the answer and explanation.
What is the main purpose of a turbocharger wastegate?
A. To increase maximum boost pressure at full load
B. To limit maximum boost pressure and protect the engine
C. To recirculate exhaust gas back into the intake
D. To cool the compressed intake air
Answer: B
Explanation:
The wastegate is a bypass valve that opens when boost pressure reaches a set limit, diverting exhaust around the turbine and preventing overspeed of the turbo and overboost of the engine. Without a wastegate, boost would climb uncontrolled at high RPM and destroy the engine. Intercoolers cool the air; EGR valves recirculate exhaust.
A medium-duty diesel engine is being tested for blow-by. What is the correct procedure?
A. Measure crankcase pressure at idle with a manometer
B. Measure crankcase pressure or blow-by flow at rated RPM and full load
C. Disconnect the PCV valve and observe the crankcase
D. Pressurize the crankcase with shop air and check for leaks
Answer: B
Explanation:
Blow-by is measured at rated RPM and full load with a blow-by meter or a slack-tube manometer. Idle readings are misleading because blow-by increases with cylinder pressure, which peaks at full load. Excessive blow-by indicates worn rings, scored cylinders, or a cracked piston. Each engine manufacturer publishes a max allowable blow-by figure.
A diesel engine starts hard when cold, produces white smoke during cranking, and runs rough for the first minute before smoothing out. Glow plugs and grid heaters test good. What is the most likely cause?
A. Low battery voltage
B. Low compression on one or more cylinders
C. Worn fuel injectors
D. Faulty intake air heater relay
Answer: B
Explanation:
White smoke on cold start combined with hard starting and rough running until the engine warms up is a classic low-compression symptom. Cold cylinders can’t compress the air enough to ignite the fuel reliably; once the cylinders warm, expansion of the rings and components improves compression and combustion. Glow plugs and grid heaters are confirmed good. A compression test on each cylinder is the next diagnostic step.
Our book has 520 questions like these, with an explanation for every one.
ASE T2 Diesel Engines ASE Exam — Frequently Asked Questions
What is the ASE T2 certification?
ASE T2 Diesel Engines is one of eight Medium/Heavy Truck certifications offered by the National Institute for Automotive Service Excellence (ASE). It certifies that a technician is qualified to diagnose and repair medium and heavy truck diesel engines. Passing T2 contributes toward ASE Master Medium/Heavy Truck Technician status.
How many questions are on the T2 exam?
The T2 exam has approximately 60 scored multiple-choice questions, plus up to 10 unscored pre-test questions that ASE uses to validate future items. You will see around 70 questions total, but only 60 count toward your score.
What is the pass mark?
ASE does not publish a fixed pass mark. Exams are scaled, and the effective passing score is typically around 70% of the scored questions.
How long do I get to write the exam?
You are given 75 minutes for the T2 exam. Exams are delivered by computer at Prometric test centers across the U.S.
Do I need work experience to sit the exam?
Yes. ASE requires two years of relevant hands-on work experience before certification is issued. You can take the exam with less experience, but certification is not awarded until the experience requirement is met. Relevant formal training can substitute for up to one year.
How often do I need to recertify?
ASE certifications are valid for five years. You can recertify by writing a shorter recertification exam, or by passing the full exam again. Recertification is required to maintain ASE status.