If you work on cars and light trucks, the ASE Automobile and Light Truck (A Series) certification tests are the most widely recognized way to prove your skills. Awarded by the National Institute for Automotive Service Excellence (ASE), these certifications tell employers and customers that you can diagnose and repair real vehicles, not just follow a flat-rate menu.

Nine separate tests can feel like a big mountain to climb. The good news is that ASE spells out exactly what each test covers, down to the number of questions from every content area.

In this guide, we’ll walk you through the format, all nine tests and their content areas, what changed for 2026, the official resources worth downloading, and the questions technicians ask most often.

What Is the ASE A Series?

The A Series is not one exam. It includes nine individual certification tests, A1 through A9, each covering one major automotive system. You can take them one at a time, in any order, and passing each test (plus documented work experience) earns its own ASE certification.

Technicians certified in A1 through A8 are recognized as ASE-Certified Master Automobile Technicians. A9 (Light Vehicle Diesel Engines) is a separate certification and is not required for Master status.

ASE questions are built around shop situations. Instead of asking for a definition, a typical item describes a customer concern or a test result and asks for the most likely cause, the next diagnostic step, or the correct repair.

What Is the ASE A Series Exam Format?

Here are the key facts, based on the ASE A1-A9 test page and the ASE Automobile and Light Truck Study Guide (2026):

  • Tests: Nine separate tests (A1-A9), purchased and scheduled individually.
  • Length: 40 to 50 scored questions per test, with 60 to 90 minutes of testing time depending on the test.
  • Unscored questions: Every certification test includes 10 questions that don’t count toward your score. You can’t tell which ones they are, so answer every question.
  • Total size: 415 scored questions across all nine tests (505 including unscored items). The eight Master tests, A1-A8, add up to 365 scored questions.
  • Question types: Four-option multiple choice, including one-answer items, “Technician A says / Technician B says” items, EXCEPT items, and questions based on a schematic, chart, or illustration.
  • Delivery: Initial certification tests are taken in person at a Prometric test center. Remote online testing is available for recertification tests.
  • Language: A1-A9 are offered with a Spanish-English split-screen option.
  • Results: A score report is emailed right after your appointment, and results can usually be viewed in your myASE account within 24 hours.
  • Passing score: ASE doesn’t publish a fixed passing percentage for the A Series.
  • Fees: $34 registration fee per order plus $62 per certification test, per the ASE registration and fees page.

What Content Outline Does the ASE A Series Use?

The current tests follow the ASE Automobile and Light Truck Study Guide, effective 2026. For each test, the guide lists lettered content areas, the number of scored questions from each, and a detailed task list. Here is how all nine tests break down.

A1: Engine Repair (45 scored questions, 75 minutes)

A1 is about mechanical engine diagnosis and repair. Diagnosis carries the most weight, at 40% of the test.

  • A. General Engine Diagnosis (18)
  • B. Cylinder Head and Valve Train Diagnosis and Repair (6)
  • C. Engine Block Diagnosis and Repair (4)
  • D. Lubrication and Cooling Systems Diagnosis and Repair (8)
  • E. Fuel, Electrical, Ignition, Air Induction and Exhaust Systems Diagnosis and Service (9)

Study tip: Know how to interpret compression, cylinder leakage, vacuum, and oil pressure tests. Many questions start with a noise, a leak, or a test reading.

A2: Automatic Transmission/Transaxle (45 scored questions, 75 minutes)

  • A. Transmission/Transaxle Diagnosis (26), covering general, mechanical/hydraulic, and electronic diagnosis
  • B. In-Vehicle Transmission/Transaxle Maintenance and Repair (12)
  • C. Transmission/Transaxle Unit Removal, Inspection, and Installation (7)

What questions look like: Expect a shift complaint paired with line pressure readings, scan tool data, or a clutch application chart, and decide which component is at fault.

A3: Manual Drive Train and Axles (40 scored questions, 60 minutes)

  • A. Clutch (6); B. Transmission (7); C. Transaxle (7)
  • D. Drive Shaft/Half-Shaft and Universal Joint/Constant Velocity (CV) Joint (5)
  • E. Drive Axle (7)
  • F. Four-Wheel Drive/All-Wheel Drive (8)

A4: Suspension and Steering (40 scored questions, 60 minutes)

  • A. Steering Systems (12)
  • B. Suspension Systems (12)
  • C. Wheel Alignment (11)
  • D. Wheel and Tire (5)

Study tip: Connect each alignment angle (camber, caster, toe, steering axis inclination, and thrust angle) to the pull or tire wear pattern it causes.

A5: Brakes (45 scored questions, 75 minutes)

  • A. Hydraulic, Power Assist, and Parking Brake Systems (19)
  • B. Drum Brake (5)
  • C. Disc Brake (11)
  • D. Electronic Brake Control Systems: Antilock Brake System (ABS), Traction Control System (TCS), and Electronic Stability Control (ESC) (10)

A6: Electrical/Electronic Systems (50 scored questions, 90 minutes)

A6 has the longest time limit in the series, reflecting the reading and schematic work its questions require.

  • A. General Electrical/Electronic System Diagnosis (13): voltage drop, shorts, opens, parasitic draw, schematics, and network communication
  • B. Battery and Starting System (9); C. Charging System (5)
  • D. Lighting Systems (6)
  • E. Body Electrical Systems (17): instrument cluster and infotainment, comfort and convenience accessories, security and anti-theft, and safety systems such as supplemental restraints

A7: Heating and Air Conditioning (50 scored questions, 75 minutes)

  • A. Heating, Ventilation, A/C (HVAC), and Engine Cooling System Service, Diagnosis, and Repair (21)
  • B. Refrigeration System Component Diagnosis and Repair (10)
  • C. Operating Systems and Related Controls Diagnosis and Repair (19)

What questions look like: You’ll read high- and low-side pressures and decide whether they point to an overcharge, a restriction, or a weak compressor. Know how to identify R-134a and R-1234yf systems and handle recovery and recycling.

A8: Engine Performance (50 scored questions, 75 minutes)

  • A. General Diagnosis (12), including power balance and compression testing
  • B. Ignition System Diagnosis and Repair (8)
  • C. Fuel, Air Induction, and Exhaust Systems Diagnosis and Repair (9), including fuel trim analysis
  • D. Emissions Control Systems Diagnosis and Repair (8)
  • E. Computerized Engine Controls Diagnosis and Repair (13): DTCs, freeze frame data, OBD II monitors, and DMM testing

A9: Light Vehicle Diesel Engines (50 scored questions, 75 minutes)

  • A. General Diagnosis (9)
  • B. Cylinder Head and Valve Train (5); C. Engine Block (5)
  • D. Lubrication and Cooling Systems (6)
  • E. Air Induction and Exhaust Systems (12), including turbochargers and aftertreatment
  • F. Fuel System (13)

What Changed in the 2026 Study Guide?

The biggest changes are in A1 and A2. Both tests dropped from 50 to 45 scored questions (55 total with unscored items), and their content areas were reorganized. A1 now includes 18 questions on General Engine Diagnosis, and A2 combines its diagnosis topics into a single 26-question area. The other seven tests kept the same number of questions. If you studied from an older guide or prep book, check the 2026 task lists for A1 and A2 before test day.

How Should You Use the ASE A Series Blueprint to Build a Study Plan?

Because each test is scheduled separately, the blueprint helps you decide both what to study and which test to take first.

  1. Pick your order. Start with the system you work on every day. A brake and front-end tech might start with A5 and A4, while a drivability tech might start with A8.
  2. Weight your time. Within each test, study in proportion to question counts. A6 Body Electrical (17 questions) and A2 diagnosis (26) deserve far more hours than a 4- or 5-question area.
  3. Take a baseline. Answer a mixed set of practice questions before you review so you know where you actually stand.
  4. Map every miss to a task. Tie each missed question to a task statement in the study guide, then review that task in a textbook or service information.
  5. Group related tests. A6 electrical skills feed directly into A8, A7 controls, and A5 electronic brake control, so taking them close together saves review time.

What Official Resources Should You Use?

Commonly used ASE A Series study textbooks:

  • ASE Certification Test Prep – Car/Light Truck Study Guide Package A1-A9 (ISBN 978-1934855607)
  • Automotive Technology: Principles, Diagnosis, and Service, 6th Edition (ISBN 978-0135257272)

Frequently Asked Questions About the ASE A Series

What is the passing score for the ASE A Series tests?
ASE doesn’t publish a fixed passing percentage. Your score report shows whether you passed and how you performed in each content area, which is useful if you need to retest.

How soon will I get my ASE A Series test results?
Your score report is emailed right after your appointment. In most cases, you can view and print results in myASE within 24 hours.

Do I need all nine tests?
No. Each test is its own certification. Master Automobile Technician status requires A1 through A8. A9 is optional.

Can I take the tests before I have work experience?
Yes. You’ll get a score report, but ASE holds your certificate until it reviews and approves your work experience. The A Series requires two years of hands-on experience, and relevant training can count for up to half.

If I fail an A Series test, how soon can I retake a test?
You must wait 30 full days before you can purchase and schedule the same test again.

How long does ASE certification last?
Five years. You can renew by passing a recertification test, which is about half the length of the original, or by using the ASE Renewal App, which is available for A1-A9.

Can I take an A Series test any time of year?
Testing is offered year-round, with short breaks between ASE’s quarterly registration windows. Once you buy a test, you have 90 days to schedule and take it.

Start Preparing for the ASE A Series With Pocket Prep

Whichever test you take first, Pocket Prep’s ASE A Series practice questions help you study in short sessions between jobs. You’ll get 800 practice questions across all nine A Series subjects, each with a detailed explanation, plus 9 mock exams to rehearse test day. Use Build Your Own Quiz to focus on the test you’ve scheduled and Missed Questions to close gaps. You’ve got this, one test at a time!