ASE Mechanic Prep Exam: A1-A8
Gear Ratio & OBD-II Tools
Only for iPhone
Free · In‑App Purchases · Designed for iPhone. Not verified for macOS.
iPhone
Pass all 8 ASE tests. Gear ratio calculator for drivetrain work. Compression calculator for engine builds. 500+ OBD-II codes at your fingertips. 445+ practice questions.
ASE MECHANIC PREP: YOUR COMPLETE A1-A8 CERTIFICATION TOOLKIT
The tools you use in the shop. The questions you see on the test. One app.
GEAR RATIO CALCULATOR
Figure out final drive ratios, speedometer correction, and RPM at any speed.
Enter your ring and pinion teeth. Select your transmission gear. Input your tire size.
The app calculates:
- Final drive ratio
- Effective gear ratio in any gear
- RPM at any speed
- Speed at any RPM
- Speedometer correction for tire changes
Save multiple vehicle setups. Compare stock versus modified. Know exactly what happens before you swap gears.
COMPRESSION RATIO CALCULATOR
Building an engine? Need to verify specs? Calculate compression ratio from:
- Bore and stroke
- Combustion chamber volume
- Head gasket thickness
- Piston dome or dish volume
- Deck clearance
Get accurate compression ratio and fuel octane recommendations. No more guessing if you need premium.
OBD-II CODE REFERENCE
Over 500 diagnostic trouble codes with:
- Plain English descriptions
- Common causes
- Diagnostic steps
- Related codes
Search by code or description. Works offline. The code database every mechanic needs.
TIRE SIZE CALCULATOR
Compare tire sizes instantly:
- Diameter difference
- Speedometer error
- Revolutions per mile
- Width and sidewall changes
Know if that tire upgrade will fit before you buy.
1000+ PRACTICE QUESTIONS
All eight ASE A-series tests:
A1 - Engine Repair
- Compression and leak-down testing
- Valve train service
- Timing belt and chain
- Cooling and lubrication systems
A2 - Automatic Transmission
- Fluid diagnosis
- Pressure testing
- Torque converter operation
- Electronic controls
A3 - Manual Drivetrain
- Clutch service
- Synchronizer operation
- Differential setup
- CV and U-joint service
A4 - Suspension and Steering
- Alignment angles
- Power steering diagnosis
- Ball joint and bushing inspection
- Electronic steering systems
A5 - Brakes
- Hydraulic system diagnosis
- ABS operation
- Rotor measurement
- Pad and shoe service
A6 - Electrical Systems
- Voltage drop testing
- Parasitic draw diagnosis
- Wiring diagram reading
- CAN bus communication
A7 - Heating and Air Conditioning
- Refrigerant handling
- System diagnosis
- Component testing
- EPA regulations
A8 - Engine Performance
- Scan tool interpretation
- Fuel trim analysis
- Ignition diagnosis
- Emissions systems
BUILT FOR THE SHOP
Dark theme for working under vehicles.
High contrast for greasy screens.
Large buttons for dirty hands.
Works offline.
WHO NEEDS THIS APP
- Automotive technology students
- Working mechanics seeking certification
- Technicians recertifying (every 5 years)
- Service advisors
- Dealership employees
- DIY enthusiasts
FREE TO START
5 questions per day free. Calculators in limited mode. Upgrade for unlimited access.
PRO - LIFETIME ACCESS
- Unlimited practice questions (all 8 tests)
- Full gear ratio calculator
- Full compression ratio calculator
- Complete OBD-II code database
- Tire size calculator
- Reference library
PASS YOUR ASE. ADVANCE YOUR CAREER.
ASE certification is required at most dealerships and respected at every shop. With recertification every 5 years, this app pays for itself again and again.
This app is for educational purposes and reference only. Always follow manufacturer specifications and shop procedures for actual repair work.
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Information
- Seller
- Deeun Inc.
- Size
- 4.7 MB
- Category
- Education
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- ASE Mechanic Exam Prep Pro Monthly $6.99
- Pro - Lifetime Access $17.99
- Copyright
- © 2026 Deeun Inc.