All 45 exams / S-series / ASE S2 Diesel Engines
S2
ASE S2 Diesel Engines
School buses
What's on the S2 exam?
1
General Engine Diagnosis
2
In-Chassis Engine Inspection and Repair
3
Lubrication and Cooling Systems Diagnosis and Repair
4
Air Induction and Exhaust Systems Diagnosis and Repair
5
Fuel System Diagnosis and Repair
6
Starting System Diagnosis and Repair
Content-area outline only, authored from ASE's public task-list structure. No test question, answer, or diagnostic scenario is reproduced from ASE or any prep publisher.
S2 quick reference S-series
Categoryrepair technician
Work experience2
Question count65
Time allowed90 minutes
Fee$62
Recert cycle5 years
Recert pathRetest (28-question, 45-minute recert version) every 5 years, or the ASE Renewal App.
Source: https://ase.com/wp-content/uploads/ASE_SchoolBus_Study_Guide.pdf.
Checked 2026-07-30.
Track this one
Already hold S2? Add it to your recert tracker.
Enter the date you earned S2 and the tracker flags exactly when it's due, and whether you're still inside the Renewal App credit window instead of a full retest.
Open the recert trackerCompare this test against the rest of the family in the full certification matrix, or use the which-test wizard to see if it fits your role.