OBD2 Logger vs Diagnose AI
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
OBD2 Logger
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OBD2 Logger turns your iPhone into a precision data logger for any modern car. Plug a Bluetooth ELM327 adapter into your vehicle's OBD2 port, pair it once, and stream live engine, hybrid, battery, and emissions data straight into per-session CSV files on your phone. No accounts. No cloud. No analytics. Your driving data never leaves your device. LIVE READOUT • 40+ standard SAE J1979 PIDs, automatically discovered from your car: RPM, vehicle speed, coolant temp, throttle, MAF, intake MAP, fuel trims, catalyst temperatures, and more. • Manufacturer-specific Mode 21 PIDs on profiled vehicles — including HV pack voltage, MG1/MG2 motor torque, and battery cell-block temperatures on Toyota/Lexus hybrids. • Values grouped by category (Engine, Hybrid, Battery, Emissions, Diagnostics) and updated every second. • One CSV per logging session, written into the app's Files container — open it in Numbers, Excel, pandas, DuckDB, or any other tool with no preprocessing. • Wide-table format: ISO-8601 timestamps, one column per active PID, blank cells where the ECU returned no data (no spurious forward-fill). • Smart-stop after extended idle so you don't end up with a tail of empty rows when you forget to tap Stop. WORKS IN THE BACKGROUND • Keeps logging while you drive with Maps in the foreground or the screen off, using Apple's standard background location mode for trip-tracking apps. The system location indicator is shown the entire time. We don't store your location. VEHICLE PROFILES • Ships with three profiles: a generic Mode-01 fallback, a Toyota hybrid family profile, and a 2020 Lexus RX 450h/450hL profile validated against a real vehicle. • VIN auto-read on connect; year, make, model, and trim pre-filled from NHTSA's free public vPIC API. • Import any third-party profile JSON to add coverage for your car. The format is documented and human-readable. DON'T HAVE AN ADAPTER YET? • Tap "Try demo mode" on the second onboarding step to explore the app end-to-end with synthetic data — no hardware required. WHAT YOU NEED • Any Bluetooth Low Energy ELM327 adapter (Veepeak OBDCheck BLE+, vLinker MC+, OBDLink, etc. — most BLE clones work). USB-only and Wi-Fi-only adapters are NOT supported. • A car with an OBD2 port (1996+ in the US, 2001+ in the EU). PRIVACY • Nothing is collected, transmitted, or stored on our servers — we don't have servers. The only outbound call the app ever makes is one VIN decode per vehicle to NHTSA's vPIC API. • Your CSVs and vehicle records live in the app's Files container, accessible to you in the iOS Files app under On My iPhone → OBD2 Logger. • Open source: github.com/NathanNam/obd2-logger
Diagnose AI
This app transforms your phone into an automotive health assistant. It connects to your car's OBD-II system via Bluetooth to translate fault codes into plain English, offering AI-powered diagnostics and DIY action plans. Manage multiple vehicles and review scan history for informed repairs.
- AI-powered plain-English diagnostics
- One-tap Bluetooth OBD-II scanning
- DIY action plans and guidance
- Multi-vehicle garage management
- Full scan history
- Premium dark automotive interface
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Know what's your car is telling you Bruh.. and what to check before you buy one. Diagnose AI turns OBD-II fault codes, warning lights, recall information, and guided vehicle checks into clear findings you can act on. FOR YOUR CAR • Connect a compatible Bluetooth OBD-II adapter • Understand stored and pending trouble codes in plain English • See how urgent a problem may be and what to check next • Save your vehicles and scan history • Ask follow-up questions about a completed scan BEFORE YOU BUY • Enter a VIN to review available recall campaigns • Follow a guided visual inspection • Add supported OBD-II findings when available • See what needs attention, what needs review, and what was not checked • Export a Buyer Report to keep or share No adapter yet? No Worries Try the demo scan and explore the experience without connecting to a vehicle. Diagnose AI provides informational guidance and does not replace a qualified mechanic, professional pre-purchase inspection, official recall-repair confirmation, or vehicle history report. Vehicle and adapter support vary. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Screenshots
Verdict
The clearest difference is in-app purchases: OBD2 Logger at none against Diagnose AI's 2. OBD2 Logger also leads on update cadence (every 6 weeks vs every 4 months). Diagnose AI's advantage is device support (3 vs 1) and iOS requirement (15.0 vs 17.0). On price and ads there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Diagnose AI sells 2 in-app purchases, starting at $2.99 per month. OBD2 Logger asks for nothing beyond the download.
OBD2 Logger ships an update every 6 weeks, Diagnose AI every 4 months. The most recent releases landed on October 4, 2026 and October 23, 2026 respectively.
| Parameter | OBD2 Logger | Diagnose AI |
|---|---|---|
| Price | Free | Free |
| Rating | — | 5.0 (1 ratings) — better |
| Number of ratings | — | 1 — better |
| Update frequency | Every 6 weeks — better | Every 4 months |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | — | Freemium |
| Devices | iPhone | iPhone, iPad, iPod — better |
| Requires iOS | 17.0 | 15.0 — better |
| Further details — not scored | ||
| Size | 3 MB | 44 MB |
| Age rating | 4+ | 4+ |
| Developer | Daehyun Nam | Shivansh Chhhabra |
In-app purchases
OBD2 Logger
No in-app purchases
Diagnose AI
- Pro Monthly$2.991 Month
- Pro Yearly$19.991 Year
Questions
Is OBD2 Logger free?
Is Diagnose AI free?
Do OBD2 Logger or Diagnose AI have ads?
Which is updated more often, OBD2 Logger or Diagnose AI?
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