# Pistonly: AI Car Diagnostics — Scan codes, AI finds the fault > AI-powered car diagnostics and service history tracker for OBD2 users. (iPhone/iPad app by Aliaksei Yelin.) - Source: https://appshunter.io/ios/app/pistonly-ai-car-diagnostics/id6791636728 (this page in markdown: same URL + `.md`) - Developer: [Aliaksei Yelin](https://appshunter.io/developer/1502827500) - Category: Utilities - Price: Free with in-app purchases - Rating: 5.00/5 from 1 App Store ratings · 1 written reviews indexed - Age rating: 4+ - Requires: iOS 17.0 · 20 MB - Languages: American English, German (Germany), Russian - Released: 2026-07-21 - Data updated: 2026-08-20 - Monetization: freemium - User reviews in markdown: https://appshunter.io/ios/app/pistonly-ai-car-diagnostics/id6791636728/reviews.md ## What is Pistonly? Pistonly is an AI mechanic. Most OBD2 scanners show a code and leave you to Google it. Pistonly reads the code, checks it against your car's service history, names the likely cause, and tells you whether the car is safe to drive. THE AI DIAGNOSTICIAN • Add your car by VIN: make, model, generation and engine fill themselves in. • Keep a simple service book: what was done, when, which parts changed. • Add codes live from an adapter, or type in a dealer scan: PIWIS, ISTA, VCDS/ODIS, XENTRY, Techstream and more. • The AI works through your history, ranks the likely causes and gives you an ordered checklist. It also says which past repairs helped and which didn't. • No history yet? It asks a few questions and turns your answers into a checklist and a service record. • Then keep asking. The chat already knows this car's codes, its history and its last verdict, so you never explain anything twice. • Every explanation comes two ways: plain language, or full mechanic detail. CAN I DRIVE IT? Every fault code carries a plain answer: drive on, drivable but fix it, or better not to drive. Your garage turns all of it into a health score out of 100, so one glance tells you whether the car got better or worse. FREE REPAIRS YOU'RE OWED Pistonly checks the manufacturer's safety recalls for your model and year. A dealer does recall work free of charge, whoever owns the car now, and most owners never find out. Campaigns the regulator marks "do not drive" or "park outside" are flagged in red. BUYING A USED CAR The pre-purchase check looks for codes cleared right before the viewing, monitors that were reset, mileage that disagrees between modules and open recalls, then puts it all in a report you can show the seller. Pro. A FULL OBD2 TOOLBOX (with an ELM327 adapter) • Live sensors: every PID your ECU supports, in real time • Control units: browse ECUs and per-module codes. A scan saves every address as it answers, stops on demand and resumes where it left off. • Modules confirmed on cars of the same model show up before you scan anything • On-board monitors (Mode 06) and I/M readiness • Service functions: actuator tests and resets • Odometer cross-check across modules, to catch a rolled-back odometer • Enhanced manufacturer PIDs (UDS Mode 22) • Drive Mode: a full-screen dashboard for the phone mount, with lap timing • Acceleration test, trip computer and 1 Hz logging with CSV export • Miles or kilometres, switchable in Settings FREE • The AI diagnostician: 3 full analyses every month • Fault codes in plain English, with the can-I-drive verdict • Safety recalls, the health score, your garage, service book and interview • Control units, live sensors, Mode 06, readiness, acceleration test, trip computer PISTONLY PRO • Unlimited AI diagnoses, and follow-up questions in chat • Pre-purchase check and odometer rollback check • Drive Mode and lap timing • Service functions, enhanced PIDs and CSV data logging • More than one car in your garage, each with its own history • Or bring your own Claude (Anthropic) or Perplexity API key Monthly, annual, or a one-time lifetime unlock. Subscriptions cancel anytime. PRIVATE BY DESIGN No account, no sign-up. Your garage, history and VIN stay on your device, and your VIN is never sent to our servers. Signed in to iCloud? Everything backs up to your private iCloud and comes back on a new phone. Pistonly is advisory: strong hypotheses and a checklist, not a final verdict, and no replacement for a professional inspection. Works with any ELM327-compatible Bluetooth OBD2 adapter. No adapter? Try the built-in demo, or type codes in by hand. Marques and logos are trademarks of their owners; Pistonly is not affiliated with any manufacturer. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://held-jackrabbit-8cc.notion.site/Pistonly-Privacy-Policy-3a0893c247bf80e7b6d4d17f590bd631 ## Key features - AI fault code analysis - Car service history logging - Guided repair checklists - Live sensor data - Odometer cross-check - Plain language explanations ## Pricing and in-app purchases Base price: Free. **Subscriptions** | Subscription | Price | Period | | --- | --- | --- | | Pistonly Pro — Monthly | $4.99 | per month | | Pistonly Pro — Annual | $29.99 | per year | **One-time purchases** | Purchase | Price | Type | | --- | --- | --- | | Pistonly Pro Lifetime | $39.99 | one-time | ## Recent user reviews (1 of 1) All indexed reviews: https://appshunter.io/ios/app/pistonly-ai-car-diagnostics/id6791636728/reviews.md ### 5/5 — That’s what I looking for *2026-07-22* This app really helps me to understand what the problem with my engine. And also I can clear error codes, check engine is always annoying. Now I don’t have that problem anymore. ## Frequently asked questions about Pistonly ### What is Pistonly? Pistonly is an AI-powered car diagnostics app that reads OBD2 fault codes, analyzes your car's service history, and provides likely causes and repair checklists. It aims to simplify car maintenance for users. ### How does Pistonly's AI diagnostician work? You add your car by VIN, input fault codes, and the AI analyzes this data along with your service history to rank likely causes and generate a guided checklist. It learns from your input as you tick off fixes. ### Can Pistonly read codes from any OBD2 scanner? Yes, Pistonly can read fault codes from any OBD2 scanner or diagnostic report. You can also manually enter codes if you don't have an adapter. ### What features are included in the free version of Pistonly? The free version offers 3 AI analyses per month, fault-code reading with plain-English descriptions, a garage and service book, control unit browsing, live sensors, Mode 06, readiness checks, and an acceleration test. ### What are the benefits of Pistonly Pro? Pistonly Pro provides unlimited AI diagnoses, a drive log for AI sensor analysis, odometer rollback checks, service functions like actuator tests and resets, enhanced PIDs, and CSV data logging. It also supports multiple cars. ### Does Pistonly have ads? No, Pistonly does not have advertisements. The app offers a free tier with limitations and a premium subscription for full access. ### What devices does Pistonly support? Pistonly is available on iPhone and iPad devices, running on iOS. ### How often is Pistonly updated? Pistonly was last updated on July 31, 2026, with version 1.2. The release date was July 21, 2026. ## Version history (last 5 releases) ### 1.5 — 2026-08-18 ASK ABOUT YOUR CAR, NOT JUST READ CODES After the AI gives its verdict you can keep asking: what to check first, whether it's safe to drive, what the repair usually costs. The diagnostician already knows this car's codes, its history and what it told you last time, so you don't re-explain anything. Pro. FREE REPAIRS YOU DIDN'T KNOW ABOUT Pistonly now checks the manufacturer's safety recalls for your model and year. Recall work is done free of charge by a dealer, whoever owns the car now, and most owners never find out. Campaigns the regulator marks "do not drive" or "park outside" are flagged in red. DRIVE MODE Phone in the mount, speed in huge digits, revs as a bar you can read at a glance, best acceleration times and the distance of this drive. The screen stays awake while it's open. Pro. MODULE SCANS THAT SURVIVE A DROPPED CONNECTION The scan used to save nothing until it finished: lose the link at address sixty and the whole hour was gone. Now every address is saved the moment it answers, you can stop the scan on purpose, and the next run picks up exactly where it left off instead of starting over. MODULES OTHER OWNERS ALREADY FOUND Addresses confirmed on cars of the same model and generation now show up before you scan anything. You can read codes from them right away; clearing still waits until the address is confirmed on your own car, because clearing writes to the module. ALSO • Stop and resume applies to reading and clearing codes in bulk too. • The "can I drive" verdict is passed into the AI analysis, so the banner and the AI can't contradict each other. ### 1.4 — 2026-08-08 CAN I DRIVE IT? NOW YOU GET AN ANSWER Every fault code now comes with a straight verdict: better not to drive, drivable but fix it, or fine to drive. It works offline, the moment the code is read, with no waiting and no subscription. The code list itself is topped by the worst one it found, so you know where you stand before you read a single line. A HEALTH SCORE FOR YOUR CAR One number out of 100, in your garage, built from what Pistonly has actually seen: active faults weighted by how serious they are, servicing that is overdue, and what your last recorded drive showed. Tap it and every deduction is listed with its weight. If Pistonly has nothing to go on yet, it says so instead of inventing a score. PRE-PURCHASE CHECK (PRO) Looking at a used car? One pass collects what the seller would rather you missed: codes cleared just before the viewing (the monitors give it away), permanent codes, faults sitting in other control units, and mileage that disagrees between modules. You get a verdict and a report you can share on the spot. FIXED: MODULES YOUR CAR ACTUALLY HAS Addresses for VW/Audi/Seat/Škoda/Porsche control units were wrong, so scans came back empty and modules stayed locked. They are now the real ones. And the module scan lives on the Modules screen itself, right next to the rows it unlocks. FIXED: "LIGHT IS ON, NO CODES FOUND" When two control units answered at once, one of them could be ignored and its codes lost. Codes are now read per control unit and merged. ALSO • Readiness asks what is actually lit on your dashboard before saying anything about passing an inspection. • Past AI verdicts are reachable from Garage, from the activity feed and from the diagnostician itself. ### 1.3 — 2026-08-06 RECORD A DRIVE, LET THE AI READ IT Record a whole drive and Pistonly logs every sensor your ECU exposes. The AI then reads the entire drive at once — comparing idle, cruising and hard pulls separately, because a reading that's off at idle but normal under load means something very different from one that's off everywhere. It works even with no fault codes, for when the car just feels wrong and the light never comes on. Before you spend an AI call, the app already flags patterns on its own, offline and instantly: a lean mixture and where it's lean, a thermostat stuck open, charging trouble, an unstable idle, timing pulled under load. MAINTENANCE SCHEDULE Your garage now shows what's due. Pistonly reads your service book together with the drives it recorded and flags what's overdue — by distance or by time, whichever ran out first. A car that mostly sits still still ages its oil. WILL YOU PASS THE EMISSIONS TEST? The readiness screen now answers that question directly instead of showing raw monitor flags. A lit check engine light fails the test even when every monitor is complete, while a single incomplete monitor is normally allowed — the old screen got both wrong. It also spots the tell-tale pattern of recently cleared codes, which is worth knowing before you buy a used car. NOW IN GERMAN The whole app is available in German. ALSO • Clearing codes now shows exactly what will and won't be erased, and warns that it resets the readiness monitors — so you don't clear them right before an inspection. • Fixed buttons that only responded when you tapped the text itself. ### 1.2 — 2026-07-31 RECORD A DRIVE, LET THE AI READ IT Record a whole drive and Pistonly logs every sensor your ECU exposes. The AI then reads the entire drive at once comparing idle, cruising and hard pulls separately, because a reading that's off at idle but normal under load means something very different from one that's off everywhere. It works even with no fault codes, for when the car just feels wrong and the light never comes on. Before you spend an AI call, the app already flags patterns on its own, offline and instantly: a lean mixture and where it's lean, a thermostat stuck open, charging trouble, an unstable idle, timing pulled under load. MAINTENANCE SCHEDULE Your garage now shows what's due. Pistonly reads your service book together with the drives it recorded and flags what's overdue - by distance or by time, whichever ran out first. A car that mostly sits still still ages its oil. WILL YOU PASS THE EMISSIONS TEST? The readiness screen now answers that question directly instead of showing raw monitor flags. A lit check engine light fails the test even when every monitor is complete, while a single incomplete monitor is normally allowed - the old screen got both wrong. It also spots the tell-tale pattern of recently cleared codes, which is worth knowing before you buy a used car. NOW IN GERMAN The whole app is available in German. ALSO • Clearing codes now shows exactly what will and won't be erased, and warns that it resets the readiness monitors - so you don't clear them right before an inspection. • Fixed buttons that only responded when you tapped the text itself. ### 1.1 — 2026-07-30 - The AI diagnostician now asks for specific readings: oil pressure, coil resistance and more, and refines the diagnosis from your answers. - Share a verdict as a card. - Bigger car catalogue. - Improvements for restoring and redeeming purchases. ## More apps by Aliaksei Yelin - [DevPrep: Coding Interview](https://appshunter.io/ios/app/devprep-coding-interview/id1527624816) - [Carto: Журнал техобслуживания](https://appshunter.io/ios/app/carto/id6455785963) - [Prudo](https://appshunter.io/ios/app/prudo/id6790168265) All apps by Aliaksei Yelin: https://appshunter.io/developer/1502827500 --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-20.*