Know what’s likely wrong before you pay a mechanic.
AI-powered vehicle diagnosis, repair guidance, second opinions, and your complete vehicle history — all in one place.
Free to start · No account needed · Built for most 1996+ OBD-II cars and light trucks
Already have a repair quote? Check if it’s fair — or plug in a Bluetooth LE OBD adapter for live sensor data.
A straight answer, not just a chatbot.
Three things a generic chatbot can’t do: check a shop’s price against real labor rates for your state, read live sensor data straight from your car, and ground every answer in real NHTSA recall data with an honest confidence score — including “this one’s worth a shop’s time.”
AI Diagnosis
DESCRIBE · DIAGNOSEFree to tryLive OBD Reader
LIVE · PLUG INRecall Checker
NHTSA DATAPlus the rest of the toolkit
Fair-Quote Check
PASTE · VERDICTAlready have a quote? Paste it for a second opinion on the price and the repair.VIN Decoder
17-DIGIT VINDecode any VIN into year, make, engine and build details.Code Lookup
P / B / C / U CODESLook up any trouble code with severity and likely causes.Parts Finder
AMAZON LINKSJump straight to the exact part with a buy link.Digital Garage
YOUR VEHICLESKeep every vehicle, its history and maintenance in one place.Saved History
EVERY DIAGNOSISEvery past diagnosis saved and searchable.From symptom to fix in three steps.
Describe it or plug in
Tell RedlineAi what’s wrong in plain English — a sound, a light, a code, even a photo. Or plug in a Bluetooth LE OBD adapter for live data.
We cross-check real data
Your symptom is weighed against NHTSA recalls, owner complaints, and known failure patterns for your exact year, make and model.
Get a clear answer
The most likely cause, an honest confidence score, a repair-cost range, what to check next, and where to buy the part.
Know the price before you’re quoted one.
The same problem, two very different bills. A straight answer up front is what keeps you from paying for a repair you never needed.
a new catalytic converter for a flashing check-engine light — after an $80–$200 diagnostic fee just to be told.
the worn oxygen sensor behind the scary code. RedlineAi ranks the likely causes and tells you what to test before anyone orders parts — free to start.
A typical real-world pattern, not a promise — some cats really are dead. The point is knowing which one you have before you pay.
Built for DIYers and the shops that fix them.
For DIYers & owners
Get a straight answer before you turn a wrench — or before you hand over your keys.
- Plain-English diagnosis with a confidence score
- Repair-cost ranges
- Step-by-step checks and repair videos
- Direct Amazon links to the exact part
For shops & mechanics
A second opinion that speaks your language — and helps you justify the repair to the customer. One plan covers the whole crew.
- Unlimited diagnoses across your team
- Multiple seats — invite your techs by email
- Technician mode + live OBD sensor data in the diagnosis
- Repair-justification write-ups & customer-ready cost breakdowns
Know what’s fair before you pay.
Get a plain-English second opinion on likely causes, urgency, and typical repair costs before approving the work.
Understand the problem before making the decision
Common questions.
How does the diagnosis work?
Describe what the car is doing in plain English — a noise, a warning light, a smell, a trouble code — and tell us the year, make and model. RedlineAi weighs that against real NHTSA recall and owner-complaint data for your exact vehicle and comes back with the most likely cause, the tests that confirm it, a repair-cost range and an honest confidence score. It’s free to try and needs no account. Start a free diagnosis →
How does the quote check work?
Paste what the shop told you — the job, the price, your car. RedlineAi checks whether the recommended repair actually matches the symptoms and codes, then compares the price against typical parts costs and real shop labor rates for your state, so you see a fair range before you say yes. It’s a second opinion, not a hit piece: when a quote is fair, it says so.
Do I need an OBD scanner?
No. Just describe the symptom in plain English — a noise, a warning light, a trouble code, even a photo. If you do have a scanner, plug it into the Live OBD Reader (available on our paid plans) and RedlineAi folds live sensor data straight into the diagnosis. See what each plan includes →
Is this just a ChatGPT wrapper?
No. Every diagnosis is grounded in real NHTSA recall and owner-complaint data for your exact year, make and model, and comes back with an honest confidence score instead of a confident-sounding guess. Safety-critical issues — brakes, steering, fuel — are flagged in red before anything else.
Will it tell me when to just go to a shop?
Yes. RedlineAi is built to be honest, not to keep you DIY-ing past your comfort zone. When a problem is safety-critical or beyond a driveway fix, it says so plainly — and the shop & tech mode can even help justify the repair.
Does it work on my car?
If it’s a car or truck sold in the US since 1996 — the OBD-II era — then yes: every make, every model. The more detail you give about year, make, model and engine, the sharper the answer gets.
Can I cancel anytime?
Yes. Start free with no card. Paid plans are month-to-month — cancel or change plans anytime from your account. No contracts, no phone calls. See plans →
Find out what’s wrong before you pay to be told.
Describe the symptom and get the likely cause for your exact car — your first one is on the house. No credit card, no waiting room.
Free plan forever · No account needed to try it · Upgrade only if you need more