How to use every tool on Check Engine Help
Step-by-step guides for each feature so you can get the most out of your diagnosis.
Code Lookup
What it does: Look up any OBD‑II trouble code and get the plain‑English meaning, severity, driveability impact, likely causes, and owner steps.
How to use it
Navigate to Codes from the menu or type a code into the search bar on the home page.
Type any code like P0300, B1234, or U0100. You can also search by keyword (e.g. "misfire", "oxygen sensor").
Each code page shows the meaning, severity level, driveability rating, common causes, owner‑friendly steps, and what a shop would check.
AI-Powered Diagnosis
What it does: Submit your vehicle info and trouble codes to get a full AI‑generated diagnostic report. including root‑cause analysis, repair priorities, estimated costs, and a mechanic brief.
How to use it
Go to Start Diagnosis and enter your VIN or year/make/model. If you enter a VIN, the year, make, and model fill in automatically.
Type the codes from your scanner separated by commas (e.g. P0300, P0171, P0174). You can also paste a freeze-frame screenshot.
Describe any symptoms. rough idle, stalling, unusual noise, when the light came on. The more detail you give, the better the diagnosis.
The AI analyzes your codes together (not in isolation), weighs vehicle‑specific patterns, and returns a full report with causes ranked by likelihood, repair steps, estimated costs, and a DIY/shop recommendation.
Symptom-Only Mode
What it does: Don't have a code scanner? Describe what your car is doing and the AI will suggest likely causes, possible codes, and next steps.
How to use it
On the diagnosis page, click "Describe symptoms instead" to switch from code entry to symptom entry.
Click common symptom tags (Rough idle, Stalling, Loss of power, etc.) or type a freeform description of the problem.
The AI returns a list of likely trouble codes, probable causes, urgency level, and whether you should drive or tow.
Mechanic Brief
What it does: After a full diagnosis, you can download a one‑page PDF summary designed to hand to your mechanic or shop. so they know exactly what you've found before they start working.
What's in the brief
Year, make, model, VIN, mileage. everything the shop needs to look up parts and TSBs.
All trouble codes with their descriptions and severity levels, ranked by priority.
Root cause analysis, related code clusters, and recommended diagnostic steps. in mechanic‑friendly language.
Safety Recall Check
What it does: Search the NHTSA database for open recalls on your vehicle. Recall repairs are always free at any authorized dealer.
How to use it
Navigate to Safety & Recalls from the menu.
A VIN gives the most accurate results. Otherwise enter year, make, and model.
Each recall shows the affected component, risk summary, and what the dealer will fix. If there are open recalls, call your dealer to schedule the free repair.
Your Account
What it does: Track your diagnostic history, saved vehicles, and case results all in one place.
Getting started
Go to Login / Register and create a free account with your email. Accounts are required for full diagnostic cases.
After logging in, go to My Account to see your vehicles, open cases, and past diagnoses.
Add vehicles to your profile so you can quickly start new diagnoses without re‑entering your info each time.
Common Questions
Not for code lookup or symptom mode. For full diagnostic cases, you'll need your codes. Basic Bluetooth scanners work great and cost ~$20 on Amazon.
Yes. Unlimited code lookups, no account needed, no credit card. The free tier covers code meanings, severity, driveability, causes, and owner steps.
Our AI cross-references manufacturer data, TSBs, and common failure patterns for your specific vehicle. It's not a replacement for hands-on diagnosis, but it gives you a strong starting point and helps you avoid unnecessary repairs.
Yes. The entire site is mobile-friendly. You can run a diagnosis, look up codes, and download your mechanic brief right from your phone at the shop.
Email us at info@checkenginehelp.com. we're happy to help.