100+ Free ASE T1 Gasoline Engines (Medium/Heavy Truck) Practice Questions
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A gasoline truck engine sets a P0420 (catalyst efficiency below threshold). Before replacing the converter, the technician should FIRST:
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Key Facts: ASE T1 Gasoline Engines (Medium/Heavy Truck) Exam
60
Total Questions (50 scored)
ASE Medium/Heavy Truck T1 test page
75 min
Time Limit
ASE T1 test information
~$59
ASE Registration Fee
ASE test registration
Criterion-referenced
Scoring Method
ASE scoring policy
2 years
Required Work Experience
ASE certification requirements
Prometric
Test Provider
ASE testing logistics
ASE lists the Medium/Heavy Truck Gasoline Engines (T1) test as a 60-question test (50 scored plus 10 unscored research questions) with a 75-minute time limit, delivered by Prometric. Scoring is criterion-referenced, meaning a passing score is set by ASE against a defined competency standard rather than a fixed percentage. Certification requires two years of relevant work experience (training can substitute for up to one year), each T-series test is taken individually, and T1 is not required for the Master Medium/Heavy Truck credential. This free practice bank provides 100 selected-response items across all eight official content areas.
Sample ASE T1 Gasoline Engines (Medium/Heavy Truck) Practice Questions
Try these sample questions to test your ASE T1 Gasoline 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 truck with a large-displacement gasoline engine has a rough idle and low power. A cylinder compression test shows one cylinder reading 90 psi while the others read about 155 psi. Which of the following is the MOST likely cause of the low reading?
2Technician A says a cylinder leakage (leak-down) test pinpoints where compression is escaping. Technician B says air heard at the throttle body or air intake during a leak-down test indicates a leaking intake valve. Who is correct?
3During a running compression test on a gasoline truck engine, the snap-throttle reading is much lower than the cranking compression reading on the same cylinder. This MOST likely indicates:
4A gasoline-powered medium truck has white smoke from the exhaust, coolant loss with no external leaks, and a sweet smell. The MOST likely cause is:
5A truck gasoline engine has a steady knocking noise that increases with load and is loudest at idle when warm. Disabling the suspected cylinder's ignition reduces the noise. This MOST likely indicates:
6Which condition would MOST likely cause low oil pressure at idle but acceptable pressure at higher RPM on a gasoline truck engine?
7A gasoline truck engine consumes oil but shows no external leaks and produces blue smoke mainly on deceleration after a sustained pull. The MOST likely cause is:
8A no-start gasoline truck engine cranks normally. Which step should be performed FIRST to logically narrow the cause?
9Technician A says a vacuum gauge reading that is low and steady can indicate late ignition/valve timing or an intake manifold leak. Technician B says a needle that drops regularly indicates a burned or leaking valve. Who is correct?
10A gasoline truck engine has an exhaust restriction (suspected plugged catalytic converter). Which symptom set is MOST consistent with this condition?
About the ASE T1 Gasoline Engines (Medium/Heavy Truck) Exam
ASE T1 — Gasoline Engines (Medium/Heavy Truck) certifies technicians who diagnose and repair large-displacement gasoline and propane (LPG) engines in medium- and heavy-duty trucks. The test covers general engine diagnosis, cylinder head and valvetrain, engine block, lubrication and cooling, ignition, fuel/air/exhaust, emissions controls, and computerized engine controls.
Assessment
50 scored multiple-choice (60 total incl. 10 unscored) (official ASE); this practice bank is 100 selected-response items
Time Limit
75 minutes
Passing Score
Criterion-referenced (set by ASE)
Exam Fee
~$59 (ASE registration) (ASE (National Institute for Automotive Service Excellence))
ASE T1 Gasoline Engines (Medium/Heavy Truck) Exam Content Outline
General Engine Diagnosis
Verifying the customer concern and using compression, cylinder leakage, running compression, vacuum, exhaust smoke and noise, oil consumption, no-start, and exhaust-restriction diagnosis on gasoline and LPG truck engines.
Cylinder Head & Valve Train Diagnosis & Repair
Burned/leaking valves, valve guide and seal wear, head warpage measurement, hydraulic lifters, rocker arms, valve springs, camshaft lobe wear, and post-valve-job sealing.
Engine Block Diagnosis & Repair
Cylinder bore measurement and honing, bearing wear and clearance with Plastigauge, crankshaft endplay, bearing failure analysis, piston ring end gap, and blow-by diagnosis.
Lubrication & Cooling Systems Diagnosis & Repair
Head gasket and combustion-leak testing, thermostat operation, cooling-system pressure testing, oil pressure verification, fan clutch operation, and oil cooler internal leaks.
Ignition System Diagnosis & Repair
Coil swap testing, spark plug reading and wear, secondary ignition scope analysis, misfire codes, no-spark and waste-spark systems, spark knock, and ignition timing.
Fuel, Air Induction & Exhaust Systems Diagnosis & Repair
Fuel pressure and delivery, vacuum leaks, air filter effects, exhaust backpressure, lean codes, injector balance, LPG fuel systems, throttle-body service, and acceleration stumble.
Emissions Control Systems Diagnosis & Repair
EGR, catalyst efficiency, EVAP small/large leaks and purge, PCV, exhaust gas analysis, secondary air injection, and catalyst failure analysis.
Computerized Engine Controls Diagnosis & Repair
ECT, MAF, MAP, TPS, and oxygen sensor diagnosis, fuel-trim analysis, crank sensor and communication faults, DTC strategy, knock sensor, idle control, PCM grounds, and failsafe strategy.
How to Pass the ASE T1 Gasoline Engines (Medium/Heavy Truck) Exam
What You Need to Know
- Passing score: Criterion-referenced (set by ASE)
- Assessment: 50 scored multiple-choice (60 total incl. 10 unscored) (official ASE); this practice bank is 100 selected-response items
- Time limit: 75 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 T1 Gasoline Engines (Medium/Heavy Truck) Study Tips from Top Performers
Frequently Asked Questions
How many questions are on the ASE T1 Gasoline Engines test?
ASE lists the Medium/Heavy Truck Gasoline Engines (T1) test with 60 total questions, of which 50 are scored and 10 are unscored research questions that do not count toward your result. This free practice bank provides 100 selected-response items so you can drill every content area more deeply than the live test length.
How much time do I get and how is ASE T1 scored?
ASE allots 75 minutes for the T1 test, delivered through Prometric. ASE scoring is criterion-referenced, which means a passing result is determined against a defined competency standard set by ASE rather than a fixed percentage or a curve against other test-takers.
What does ASE T1 cost and what are the eligibility requirements?
ASE registration for a single specialty test such as T1 is approximately $59; confirm the current amount when you register. To become certified you also need two years of relevant hands-on work experience, although an approved training program can substitute for up to one of those two years.
Is ASE T1 required for the Master Medium/Heavy Truck Technician certification?
No. T1 is taken individually and is not one of the tests required to earn the Master Medium/Heavy Truck Technician credential, which is built from other T-series tests. Many gasoline-fleet technicians still pursue T1 because medium-duty trucks frequently use large gasoline or propane engines.
What content area should I study most for ASE T1?
General Engine Diagnosis is by far the largest area, followed by Computerized Engine Controls, then Ignition and Fuel/Air/Exhaust. Weight your preparation toward systematic diagnostic strategy (compression, leak-down, scan-tool data, and fuel trims) because most T1 questions test how you isolate a fault, not just part identification.
Are there any 2026 changes to the ASE T1 test?
As of 2026 ASE continues to list the Medium/Heavy Truck T1 test under the standard T-series structure with a 75-minute limit and criterion-referenced scoring. Always verify the live test page and your myASE account for the current registration fee, scheduling, and any content-area updates before you test.