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100+ Free ASE T2 Diesel Engines (Medium/Heavy Truck) Practice Questions

Pass your ASE T2 — Diesel Engines (Medium/Heavy Truck) Certification exam on the first try — instant access, no signup required.

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On a variable-geometry turbocharger (VGT), sticking vanes due to soot/carbon will MOST likely cause:

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B
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Key Facts: ASE T2 Diesel Engines (Medium/Heavy Truck) Exam

55

Scored Multiple-Choice Questions

ASE Medium/Heavy Truck test series

65

Total Questions Incl. Unscored

ASE test structure

90 min

Testing Time

ASE T2 test information

~$59

ASE Registration Fee

ASE registration information

2 years

Work Experience Required

ASE certification requirements

5 years

Certification Validity

ASE recertification information

ASE lists Diesel Engines (T2) as a 90-minute Medium/Heavy Truck test with 55 scored multiple-choice questions plus unscored items (65 total). Scoring is criterion-referenced and set by ASE rather than a fixed published percentage, and certification requires two years of relevant work experience (training can substitute for up to one year). Fuel System is the largest content area, followed by General Engine Diagnosis; this free practice bank provides 100 selected-response items aligned to all eight official content areas.

Sample ASE T2 Diesel Engines (Medium/Heavy Truck) Practice Questions

Try these sample questions to test your ASE T2 Diesel Engines (Medium/Heavy Truck) exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1A medium-duty diesel engine has low power but no diagnostic trouble codes. Which check should the technician perform FIRST?
A.Verify a restricted air filter or exhaust by reading intake restriction and exhaust backpressure
B.Replace all fuel injectors as a set
C.Rebuild the turbocharger
D.Replace the ECM
Explanation: Low-power complaints with no codes are most often caused by air or exhaust restriction. Measuring intake restriction and exhaust backpressure against spec is a fast, non-intrusive first step that confirms or rules out airflow as the cause before invasive work.
2Technician A says blue exhaust smoke usually indicates oil consumption. Technician B says black exhaust smoke usually indicates incomplete combustion or excess fuel. Who is correct?
A.Technician A only
B.Both A and B
C.Technician B only
D.Neither A nor B
Explanation: Blue smoke comes from oil being burned (worn rings, valve guides, turbo seals). Black smoke indicates excess fuel or insufficient air for complete combustion. Both technicians describe these classic smoke colors correctly.
3White smoke from a diesel exhaust during a cold start that clears as the engine warms is MOST likely caused by:
A.Worn piston rings
B.A plugged diesel particulate filter
C.Unburned fuel due to low combustion temperature
D.An overcharged battery
Explanation: White smoke on a cold start is typically atomized, unburned fuel because cylinder temperatures are too low for complete combustion. As the engine warms and combustion temperatures rise, the white smoke normally clears.
4During a cylinder cutout (kill) test on an electronically controlled diesel, the engine RPM does NOT drop when one cylinder is disabled. This indicates that cylinder is:
A.Producing normal power
B.The strongest cylinder
C.Over-fueled
D.Contributing little or no power
Explanation: In a cylinder cutout test, disabling a healthy cylinder causes a noticeable RPM/load drop. If RPM does not change when a cylinder is killed, that cylinder was already contributing little or no power, pointing to a weak injector, low compression, or a mechanical fault in that cylinder.
5A diesel engine is hard to start when cold but starts normally when warm. Glow systems are not used on this engine. Which is the MOST likely cause?
A.Air in the fuel system or low cranking compression
B.A faulty alternator
C.An overfilled crankcase
D.A clogged cabin air filter
Explanation: Cold hard-start with normal warm starting commonly points to air in the fuel system or marginal cranking compression, since heat helps overcome these deficiencies when warm. These should be verified before condemning electronic components.
6When performing a cylinder compression test on a medium/heavy diesel, the engine should be:
A.At idle with fuel on
B.Cranked at specified speed with fuel shut off and all injectors removed or one cylinder isolated per manufacturer procedure
C.Running at governed RPM
D.Cold with the air intake blocked
Explanation: A diesel compression test is performed by cranking the engine at the manufacturer-specified speed with fuel disabled and the proper adapter installed per procedure so combustion does not interfere with the reading. Following the OEM method ensures accurate, comparable cylinder values.
7An engine has excessive crankcase blowby. This condition is MOST directly an indicator of:
A.A weak battery
B.A restricted fuel return line
C.Worn piston rings, cylinder walls, or valve guides
D.A faulty coolant thermostat
Explanation: Excessive blowby is combustion gas leaking past worn rings, scored cylinder walls, or damaged valve guides into the crankcase. Measuring blowby helps quantify internal engine wear and the need for an overhaul.
8A diesel engine surges at idle. Technician A says air in the fuel system can cause idle surge. Technician B says a sticking fuel control actuator or faulty rail pressure control can cause idle surge. Who is correct?
A.Technician A only
B.Technician B only
C.Neither A nor B
D.Both A and B
Explanation: Idle surge can result from air entering the fuel system, which intermittently leans the mixture, or from a sticking fuel control/rail pressure regulator that cannot hold a stable pressure. Both causes are valid and should be investigated.
9The BEST tool for locating an internal coolant-to-oil leak before disassembly is:
A.A cooling system pressure test combined with checking oil for coolant contamination
B.A timing light
C.A fuel pressure gauge only
D.A tire tread depth gauge
Explanation: Pressurizing the cooling system while monitoring for coolant loss into the oil (milky oil, rising level) helps localize internal leaks such as a cracked head, failed liner seal, or bad head gasket before teardown. Combining this with oil inspection confirms cross-contamination.
10An engine knocks under load. Which is the LEAST likely mechanical cause and should be verified electronically first?
A.Worn connecting rod bearings
B.A loose alternator belt
C.Incorrect injection timing
D.Excessive piston-to-wall clearance
Explanation: Rod bearing wear, piston slap, and incorrect injection timing all produce load-related knock. A loose alternator belt causes a squeal or charging issue, not a combustion/mechanical knock, so it is the least likely cause of a load knock.

About the ASE T2 Diesel Engines (Medium/Heavy Truck) Exam

ASE T2 — Diesel Engines is the diesel-engine certification test in the ASE Medium/Heavy Truck (T) series for professional truck technicians. The official test contains 55 scored multiple-choice questions (65 total including unscored items) delivered in 90 minutes at Prometric test centers, covering general engine diagnosis, cylinder head and block repair, lubrication and cooling, air induction and exhaust/aftertreatment, fuel systems, starting and charging, and engine brakes.

Assessment

55 scored multiple-choice (65 total incl. 10 unscored) (official ASE); this practice bank is 100 selected-response items

Time Limit

90 minutes

Passing Score

Criterion-referenced (set by ASE)

Exam Fee

~$59 (ASE registration) (ASE (National Institute for Automotive Service Excellence))

ASE T2 Diesel Engines (Medium/Heavy Truck) Exam Content Outline

20 questions

General Engine Diagnosis

Low-power, hard-start, no-start, excessive-smoke, knock, and oil/coolant contamination diagnosis using compression tests, cylinder-cutout, blowby measurement, and used-oil analysis.

7 questions

Cylinder Head & Valve Train Diagnosis & Repair

Cylinder head warpage and crack detection, valve guides and seats, valve lash adjustment, rocker arms, and head resurfacing with correct gasket selection.

9 questions

Engine Block Diagnosis & Repair

Block deck flatness, cylinder bore and liner wear, wet-liner protrusion, crankshaft end play, bearing clearance measurement, and reciprocating-assembly inspection.

11 questions

Lubrication & Cooling Systems Diagnosis & Repair

Oil pressure diagnosis, oil cooler, oil analysis, thermostats, water pump, fan clutch, coolant chemistry/SCA, and wet-liner cavitation prevention.

11 questions

Air Induction & Exhaust Systems Diagnosis & Repair

Intake restriction, turbocharger and VGT, charge air cooler, EGR valve/cooler, and aftertreatment including DOC, DPF regeneration, and SCR/DEF diagnosis.

29 questions

Fuel System Diagnosis & Repair

Common-rail, HEUI, and unit-injector systems, transfer and high-pressure pumps, rail pressure control, injector return and contribution testing, calibration codes, and fuel contamination.

7 questions

Starting & Charging System Diagnosis & Repair

Battery testing, starter and cranking circuit, voltage-drop testing of cables and grounds, alternator output, and AC ripple/diode diagnosis.

5 questions

Engine Brakes

Compression-release and exhaust engine brake operation, ECM enable conditions, hydraulic actuation through the oil system, and slave-piston lash adjustment.

How to Pass the ASE T2 Diesel Engines (Medium/Heavy Truck) Exam

What You Need to Know

  • Passing score: Criterion-referenced (set by ASE)
  • Assessment: 55 scored multiple-choice (65 total incl. 10 unscored) (official ASE); this practice bank is 100 selected-response items
  • Time limit: 90 minutes
  • Exam fee: ~$59 (ASE registration)

Keys to Passing

  • Complete 500+ practice questions
  • Score 80%+ consistently before scheduling
  • Focus on highest-weighted sections
  • Use our AI tutor for tough concepts

ASE T2 Diesel Engines (Medium/Heavy Truck) Study Tips from Top Performers

1Weight your study time by the content areas: Fuel System and General Engine Diagnosis together make up about half the test.
2Practice Technician A/Technician B items by evaluating each statement independently before choosing, since many answers are 'both' or 'neither'.
3Drill diagnostic logic: confirm air, fuel, and compression with measurements before condemning parts, and use voltage-drop testing for electrical faults.
4Learn the modern fuel systems cold: common-rail, HEUI, and unit injectors differ in actuation, and injector calibration codes matter on common-rail.
5Review aftertreatment flow (DOC, DPF regeneration, SCR/DEF) and engine brake enable conditions, which are common knowledge gaps.

Frequently Asked Questions

How many questions are on the ASE T2 Diesel Engines test?

The official ASE T2 test has 55 scored multiple-choice questions, with about 10 additional unscored research questions for a total near 65. This free practice bank provides 100 selected-response questions aligned to the same eight ASE T2 content areas so you can practice well beyond the official length.

How much time do I get on ASE T2?

ASE allots 90 minutes for the T2 Diesel Engines test. Because the scored portion is 55 questions, pacing is manageable, but the diagnostic and Technician A/Technician B items reward careful reading rather than rushing.

What passing score do I need on ASE T2?

ASE uses a criterion-referenced passing standard set by ASE rather than a single fixed published percentage. The cut score is determined through ASE's standard-setting process, so focus on mastering each content area instead of targeting a specific number.

What are the eligibility requirements for ASE T2 certification?

ASE certification requires two years of relevant hands-on work experience. Relevant formal training can substitute for up to one year of that requirement. You can take the test before completing the experience, but the certification is awarded once work experience is verified.

Which content area is most heavily weighted on ASE T2?

Fuel System Diagnosis and Repair is the largest area at 29 of the modeled questions, followed by General Engine Diagnosis at 20. Air Induction and Exhaust and Lubrication and Cooling are next at 11 each, so prioritize fuel systems and diagnosis while still covering all eight areas.

Where is the ASE T2 test administered?

ASE T2 is delivered by appointment at Prometric test centers. You register through ASE, schedule a Prometric appointment, and take the computer-based test at the center; ASE certifications are valid for five years before recertification is required.