ASE A9 Cheat Sheet.
The night-before summary, built like the exam.

The numbers to remember

• 75 minutes total time limit for the standard A9 test — pace yourself at roughly a minute and a quarter per question.
• 60 total questions, but only 50 are scored — 10 are unscored research questions used to gather statistics for future forms, and you can't tell them apart from the ones that count, so answer every question as if it does.
• Test fee: $62 per test, plus a separate $34 registration fee charged per order (not per individual test).
• 90-day window from the date of purchase to schedule and actually sit for the test — don't let a registration lapse unused.
• Certification, once earned, is valid for 5 years before recertification is required.
• Recertification version is shorter: 25 questions in just 30 minutes.

Blueprint areas and weights

• Fuel System Diagnosis and Repair — 13 questions / 26% of the scored test, the single largest named content area.
• Air Induction and Exhaust Systems Diagnosis and Repair — 12 questions / 24%, covering turbochargers, intake, and exhaust-side diagnosis.
• General Diagnosis — 9 questions / 18%, spanning overall diesel-engine diagnostic reasoning rather than one single system.
• These three areas alone add up to roughly two-thirds of the scored test — weight your last-night review toward them rather than spreading attention evenly across the full outline.

Diagnostic quick rules

• Verify before diagnosing. Don't jump to a probable cause until the reported complaint is confirmed to actually reproduce.
• Isolate before replacing. The test consistently favors narrowing a fault to a specific circuit or component over recommending a part swap as a first move.
• Match the tool to the symptom. Scan-tool data, pressure/flow testing, and visual or mechanical inspection each answer different diagnostic questions — picking the right one is often the actual test point.
• Confirm the repair. A fix isn't finished until the original symptom is verified resolved with no new codes or symptoms appearing.

Top traps

• Assuming a Technician A/B question must have exactly one correct technician — on plenty of questions both are right, and on others both are wrong.
• Treating a passing score as full certification on its own — ASE also requires full-time, hands-on work experience, or an approved combination of formal training and experience, before the credential is actually issued.
• Ignoring pacing — 75 minutes for 60 questions leaves little room to stall on any single item, so flag a tough one and keep moving rather than getting stuck.
• Forgetting the registration fee is separate from the test fee and applies per order rather than per individual test taken.