- Overview: What the G1 Blueprint Actually Tests
- Domain 1: Engine Systems (16%)
- Domain 2: Automatic Transmission/Transaxle (7%)
- Domain 3: Manual Drive Train and Axles (11%)
- Domain 4: Suspension and Steering (24%)
- Domain 5: Brakes (20%)
- Domain 6: Electrical (15%)
- Domain 7: Heating, Ventilation, and Air Conditioning (7%)
- Turning Domain Weights Into a Study Plan
- Question Format and Test-Day Mechanics
- FAQ
- Suspension and Steering carries 24% of the G1 exam - the single largest domain.
- Brakes is second at 20%, meaning these two domains cover nearly half the test.
- The exam has 55 scored questions plus 10 unscored research items, 65 total, in 90 minutes.
- Automatic Transmission/Transaxle and HVAC are each only 7%, so don't overweight your prep there.
Overview: What the G1 Blueprint Actually Tests
The ASE G1 Auto Maintenance and Light Repair test is built from seven content areas, and NIASE (the National Institute for Automotive Service Excellence) weights each one differently. That weighting isn't cosmetic - it tells you exactly where to spend your study hours. Two domains, Suspension and Steering and Brakes, together make up 44% of the exam. The remaining five domains split the rest, ranging from 7% up to 16%.
If you're just getting oriented with the credential itself, start with What Is ASE G1? or the broader ASE G1 Certification overview before diving into domain-level prep. This guide assumes you already know the basics and want a working map of the content you'll actually be tested on.
Domain 1: Engine Systems (16%)
Engine Systems is the third-largest domain and covers general engine diagnosis, maintenance, and light repair tasks that a service technician performs before a job gets escalated to a specialist. Expect questions on cooling system checks, oil and filter service, belt and hose inspection, basic fuel and ignition system maintenance, and interpreting warning lights tied to engine performance.
Engine Systems
Candidates must understand routine maintenance intervals, fluid checks, and the early diagnostic steps a G1-level technician takes before referring a vehicle for advanced engine work.
- Cooling system inspection and coolant service procedures
- Oil, filter, and lubrication maintenance intervals
- Belt, hose, and drive component visual inspection
- Recognizing engine-related warning lamps and basic sensor symptoms
Domain 2: Automatic Transmission/Transaxle (7%)
This is one of two domains tied at the lowest weight on the exam. Questions here focus on fluid level and condition checks, basic shift-quality symptoms, and general maintenance rather than internal transmission rebuilds - that level of depth belongs to a more advanced ASE test, not G1.
Automatic Transmission/Transaxle
Focus on maintenance-level knowledge: what a light-repair technician checks and services, not internal component diagnosis.
- Fluid level, color, and condition inspection
- Basic linkage, cooler line, and leak checks
- Recognizing symptoms that require referral to a specialist
Key Takeaway
Because Automatic Transmission/Transaxle and HVAC are each only 7% of the exam, spend proportionally less review time here than on Suspension and Steering or Brakes - but don't skip them entirely, since a handful of missed questions in a low-weight domain still counts against your score.
Domain 3: Manual Drive Train and Axles (11%)
Manual Drive Train and Axles covers clutches, manual transmissions, driveshafts, differentials, and four-wheel/all-wheel-drive components at a maintenance and light-repair level. Expect scenario questions about noise diagnosis, fluid checks, and basic inspection procedures for U-joints, CV joints, and differential housings.
Manual Drive Train and Axles
Understand the maintenance touchpoints of manual drivetrains - the parts a G1 technician inspects and services regularly.
- Clutch inspection and basic adjustment concepts
- Driveshaft, U-joint, and CV joint condition checks
- Differential and transaxle fluid service
- Common noise and vibration symptom recognition
Domain 4: Suspension and Steering (24%)
This is the domain that decides most outcomes. At 24% of the test, Suspension and Steering is worth studying first and reviewing last. Content spans steering linkage inspection, power steering fluid and belt checks, suspension component wear (ball joints, control arms, bushings, struts and shocks), wheel bearing service, and basic alignment and tire wear pattern interpretation.
Suspension and Steering
The single largest content area on the G1 exam - treat it as your primary study priority.
- Steering linkage, rack-and-pinion, and power steering system checks
- Suspension component wear inspection: ball joints, control arms, bushings
- Strut and shock absorber condition assessment
- Wheel bearing inspection and basic alignment/tire wear diagnosis
Domain 5: Brakes (20%)
Brakes is the second-largest domain, and combined with Suspension and Steering, these two areas make up 44% of the exam - nearly half your score. Expect coverage of hydraulic brake systems, disc and drum brake inspection, parking brake mechanisms, brake fluid service, and basic ABS/electronic brake system awareness at a maintenance level.
Brakes
Master hydraulic principles and component wear inspection - this domain rewards candidates who understand both the "why" and the "what to check."
- Hydraulic system operation, bleeding, and fluid service
- Disc brake pad, rotor, and caliper inspection
- Drum brake shoe, wheel cylinder, and hardware inspection
- Parking brake adjustment and basic ABS/electronic brake awareness
Domain 6: Electrical (15%)
Electrical is the fourth-largest domain, covering battery service, starting and charging system checks, basic wiring and circuit diagnosis, and lighting system maintenance. Questions typically present a symptom (a slow crank, a dim headlight, a warning lamp) and ask you to identify the most likely cause or correct diagnostic sequence.
Electrical
Focus on foundational circuit logic and component-level maintenance rather than advanced electronic diagnostics.
- Battery testing, charging, and terminal maintenance
- Starting system inspection and basic diagnosis
- Charging system checks (alternator output, belt condition)
- Lighting circuits and basic wiring/fuse troubleshooting
Domain 7: Heating, Ventilation, and Air Conditioning (7%)
HVAC ties Automatic Transmission/Transaxle as the smallest domain on the exam. Expect general questions about refrigerant handling awareness, basic system component identification, heater core and blower operation, and routine maintenance checks rather than deep refrigerant-cycle diagnostics.
Heating, Ventilation, and Air Conditioning
Cover the fundamentals of climate control systems at a light-repair level.
- Basic A/C component identification and function
- Heater core, blower motor, and airflow control checks
- General refrigerant system safety awareness
Turning Domain Weights Into a Study Plan
Once you understand the seven domains, the next step is sequencing your review so time-on-task matches point-value. A simple rule: spend roughly proportional effort to each domain's percentage weight, front-loading Suspension and Steering and Brakes since together they represent nearly half the scored questions.
Suspension and Steering + Brakes
- Drill steering, suspension wear points, and hydraulic brake fundamentals - your two highest-weight domains at 24% and 20%.
Engine Systems + Electrical
- Cover routine engine maintenance and basic electrical diagnosis, the two mid-weight domains at 16% and 15%.
Manual Drive Train, Transmission, and HVAC
- Finish the three lighter domains (11%, 7%, 7%), then mix in timed practice questions across all seven areas.
For a full walkthrough of pacing, resources, and review techniques built around this exact weighting, see the ASE G1 Study Guide 2026: How to Pass on Your First Attempt. If you want a condensed, printable version of the facts above for last-minute review, the ASE G1 Cheat Sheet 2026: One-Page Review of Must-Know Facts is built for that purpose.
Question Format and Test-Day Mechanics
Knowing the domains is only half the picture - you also need to understand how the test is delivered. The G1 exam consists of 55 scored multiple-choice questions plus 10 unscored research questions, for 65 total questions, with 90 minutes allowed. The research questions are indistinguishable from scored ones, so treat every question on screen as if it counts.
Registration runs through Prometric, with a fee of $62 plus a $34 registration fee per order, or $96 total when G1 is the only test purchased in that order. The exam is offered in English and Spanish at Prometric test centers. For the full cost breakdown, including how fees change when bundling multiple tests, read ASE G1 Certification Cost 2026: Complete Pricing Breakdown.
Once earned, the credential is valid for five years and renewed by passing the shorter G1R recertification test - 28 questions in 45 minutes, a fraction of the original exam's length.
| Domain | Weight | Approx. Scored Questions* |
|---|---|---|
| Suspension and Steering | 24% | ~13 |
| Brakes | 20% | ~11 |
| Engine Systems | 16% | ~9 |
| Electrical | 15% | ~8 |
| Manual Drive Train and Axles | 11% | ~6 |
| Automatic Transmission/Transaxle | 7% | ~4 |
| Heating, Ventilation, and Air Conditioning | 7% | ~4 |
*Approximate figures calculated from the 55 scored-question total and published domain percentages; exact question counts per attempt may vary slightly.
Understanding this distribution also helps you gauge realistic difficulty. If Suspension and Steering or Brakes feel shaky in practice, that's where a missed question costs the most - a dynamic explored further in How Hard Is the ASE G1 Exam? Complete Difficulty Guide 2026 and in the data-driven ASE G1 Pass Rate 2026: What the Data Shows. Once you're confident in the scoring threshold you're aiming for, check ASE G1 Passing Score 2026: Exactly What You Need to Pass to calibrate how many questions you can afford to miss per domain.
Employers hiring for entry-level and quick-service positions - oil change centers, tire and brake shops, general service departments - often look for the G1 credential specifically because it maps to maintenance and light repair work rather than deep diagnostics. If you're weighing whether the credential is worth pursuing relative to the effort, Is the ASE G1 Certification Worth It? Complete ROI Analysis 2026 and ASE G1 Salary Guide 2026: Complete Earnings Analysis cover that decision in depth, while ASE G1 Jobs looks at where the credential shows up in hiring postings.
Whatever domain you tackle first, pairing content review with realistic timed questions is the fastest way to convert domain knowledge into exam performance. You can run full-length simulated sessions on the main practice test platform, then return to weak domains using the breakdowns above. Repeating that cycle - practice on the practice site, review the domain box, retest - is more efficient than passive reading alone.
Frequently Asked Questions
Start with Suspension and Steering (24%) and Brakes (20%) since together they account for 44% of the scored questions - the highest return on study time.
Exact per-attempt counts can vary, but based on the 55 scored questions and published weights, Suspension and Steering yields roughly 13 questions and Brakes roughly 11, while Automatic Transmission/Transaxle and HVAC each yield roughly 4.
They aren't scored, but since they're mixed in with the 55 scored questions and not identified, you should answer every question on the 65-question, 90-minute exam as if it counts.
Yes, but proportionally less than higher-weight domains. A light review of fluid checks and basic symptom recognition is enough given its small share of the exam.
No. Certification also requires one year of full-time relevant hands-on experience or an approved training/experience combination; you can test early, but certification is withheld until that requirement is met.