Free Classroom & Shop Resources for Auto and Diesel Programs
Car Code Finder is a free, verified fault-code reference and ASE-style practice-test library used by DIYers, technicians, and students. Everything on this page is free for your program to use — no signup, no student accounts, no student data collected, nothing to procure or install. Put it on the shop laptops and your students' phones today.
- Cost to schools
- Free — no accounts, no license
- Student data collected
- None
- Content
- 13,600+ codes · 9 practice tests (257 questions)
Why Instructors Use It
Verified, with sources
Every answer is checked against manufacturer and government documentation, and pages cite their sources — unlike user-generated flashcard decks. The methodology is public at how we verify.
Works in the bay
Fast code lookup on any phone — gas OBD-II plus the diesel families your program teaches: Cummins, Duramax, Power Stroke, PACCAR, Detroit Diesel, and J1939 SPN/FMI.
Zero friction
No accounts means no procurement process, no IT review, and no student-privacy paperwork. Share a link and you're done.
ASE-Style Practice Tests
Self-graded in the browser, with a plain-English explanation for every answer. Several align to ASE A-series certification areas.
ASE A8: Engine Performance
59 questions
Brakes & ABS (ASE A5)
41 questions
Electrical & Charging (ASE A6)
40 questions
Automatic Transmission & Drivetrain (ASE A2)
39 questions
Diesel Aftertreatment: DPF, DEF & SCR (ASE A9)
30 questions
Cooling System
12 questions
EVAP & Emissions Codes
12 questions
OBD-II Diagnostics: The Basics
12 questions
Engine Sensors 101
12 questions
Also useful for SkillsUSA Automotive Service competition practice. Full hub at /learn/.
Classroom & Shop Tools
- Code lookup — 13,600+ gas, diesel, EV, and equipment fault codes with causes ranked by likelihood, step-by-step diagnostics, and honest severity ratings.
- Guided symptom flows — decision-tree diagnostics (no-crank, exhaust smoke) that work as lab exercises: students walk the tree, then defend the outcome.
- Printable diagnostic worksheet — a structured worksheet embedded in our P0087 deep-dive guide; print it for any diagnosis lab.
- Quick-reference tools — torque specs, OBD-II pinout, TPMS reset procedures, tire-size decoder, and more.
- My Garage — students can save codes for a project vehicle; stored only in their own browser, no account.
ASE A8 Task-Area Coverage
Our 59-question A8 Engine Performance practice test mapped against the official A8 content areas, so you can see exactly what it covers when documenting curriculum resources.
| Official A8 content area | Official test weight | Our questions | Related on-site material |
|---|---|---|---|
| A. General Diagnosis | 12 Q (24%) | 12 of 59 | Guided symptom flows P0300 misfire |
| B. Ignition System Diagnosis and Repair | 8 Q (16%) | 8 of 59 | Misfire codes explained P0301 cylinder 1 misfire |
| C. Fuel, Air Induction and Exhaust Systems Diagnosis and Repair | 9 Q (18%) | 12 of 59 | P0171 system too lean P0087 fuel rail pressure deep dive |
| D. Emissions Control Systems Diagnosis and Repair | 8 Q (16%) | 8 of 59 | EVAP & Emissions quiz P0420 catalyst efficiency |
| E. Computerized Engine Controls Diagnosis and Repair | 13 Q (26%) | 19 of 59 | How to read OBD-II codes OBD-II basics quiz |
Content-area names, question counts, and percentages are quoted from the official ASE Automobile Study Guide (2025 edition). The mapping of our questions to areas is our own, with each question assigned to its primary content area. Our bank meets or exceeds the official question count in every content area. Car Code Finder is not affiliated with or endorsed by ASE.
Shop-Wall QR Poster
Print the poster and put it on the shop wall — students scan it to look up any code from the bay. Open the printable poster →
Student Privacy, In Plain Language
The site has no accounts and no logins. We do not collect names, emails, or any personal information from students — there is simply nowhere on the site to enter them. Quiz results are computed in the browser and never transmitted. The optional Garage feature stores saved codes in the student's own browser only. We use privacy-respecting, aggregate analytics to understand overall traffic. Because no student personal data is collected, there is no FERPA or COPPA data-sharing conversation to have — a link is just a link. Details: privacy policy.
Founding Instructor Panel
We're inviting the first instructors who adopt the site to shape what gets built next: which practice-test areas to expand, what printable materials would actually get used, and which codes or systems your students struggle with. Suggest a topic and we'll verify it, publish it, and credit your program.
Email us your feedback →Frequently Asked Questions
Is Car Code Finder really free for schools?
Yes. The entire site — all practice tests, code lookups, guides, and tools — is free with no signup and no accounts. The site is supported by clearly-marked affiliate links on repair-parts recommendations; there is nothing to purchase, license, or install for classroom use.
Do students need to create accounts?
No. There are no accounts and no logins anywhere on the site. Practice tests are self-graded in the browser, and the optional "Garage" save feature stores data only in the student's own browser (localStorage) — nothing is transmitted or collected.
How is the content verified?
Every code page is built from documented references — manufacturer service information, owner-manual documentation, and government sources — and pages cite their sources. Content that can't be verified against documentation is either clearly hedged or not published. The full methodology is public at carcodefinder.com/verification/.
Can I print the practice tests and worksheets?
Yes — the practice tests and the diagnostic worksheet are printable from the browser, and the shop-wall QR poster is designed for printing. More printable classroom material is being added based on instructor feedback.