# OBD2 Logger

> OBD2 Logger (iPhone/iPad app by Daehyun Nam.)

- Source: https://appshunter.io/ios/app/obd2-logger/id6766004425 (this page in markdown: same URL + `.md`)
- Developer: [Daehyun Nam](https://appshunter.io/developer/919392206)
- Category: Utilities
- Price: Free
- Age rating: 4+
- Requires: iOS 17.0 · 3 MB
- Languages: English
- Released: 2026-05-06
- Data updated: 2026-06-25
- User reviews in markdown: https://appshunter.io/ios/app/obd2-logger/id6766004425/reviews.md

## What is OBD2 Logger?

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


## Version history (last 2 releases)

### 1.1.0 — 2026-06-15

Adds support for Kia Niro Hybrid (2023+) — first non-Toyota hybrid in the
  app. Decodes 60+ live signals including SOC, cell-block temperatures,
  max/min cell voltages, HV pack current (signed: positive = charging,
  negative = regen), inverter coolant temp, plus the full engine telemetry
  (RPM, speed, throttle, MAF, fuel rate, catalyst temps, odometer, and
  more).

  Under the hood: Mode 22 (UDS) protocol support with extended diagnostic
  session entry, multi-frame ISO-TP reassembly, and a more flexible
  formula evaluator. Lays the groundwork for modern Hyundai-Kia, VW/Audi,
  and other manufacturers that have moved most telemetry behind UDS.

  Bug fixes:
  • Prevents duplicate CSV columns when a profile redeclares a standard PID.
  • Live Readout now stays in sync with the active sampler instead of
    showing the "Start logging…" message during ongoing sessions.
  • Sensor-sentinel readings (e.g., inverter coolant temp at 0xFF) now
    produce blank cells instead of spurious 255°C values.

### 1.0.0 — 2026-05-06

No release notes.

## More apps by Daehyun Nam

- [Tic Tac Toe (3x3)](https://appshunter.io/ios/app/tic-tac-toe-3x3/id942660859)

All apps by Daehyun Nam: https://appshunter.io/developer/919392206

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*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 2026-06-25.*