# KM eFlash vs OBD2 Scanner + Engine Sound

The clearest difference is in-app purchases: KM eFlash at none against OBD2 Scanner + Engine Sound's 2. KM eFlash also leads on ads (none vs shown) and update cadence (every 3 days vs every 9 days). On price, device support and iOS requirement there is nothing between them.

Both are free to download. OBD2 Scanner + Engine Sound sells 2 one-off in-app purchases. KM eFlash asks for nothing beyond the download.

KM eFlash ships an update every 3 days, OBD2 Scanner + Engine Sound every 9 days. The most recent releases landed on October 17, 2026 and October 16, 2026 respectively.

## The numbers

| Metric | KM eFlash | OBD2 Scanner + Engine Sound |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.0 (1 ratings)](https://appshunter.io/ios/app/obd2-scanner-plus-engine-sound/id6789023964/reviews)** |
| Number of ratings | — | **1** |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | **Every 3 days** | Every 9 days |
| Monetization | — | Free with in-app purchases |
| Size | 52 MB | 6 MB |
| Requires iOS | **16.4** | 17.0 |
| Devices | iPhone | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [KM Engineers GmbH](https://appshunter.io/developer/1799146204) | [Sena Takasawa](https://appshunter.io/developer/1887478690) |

## What reviewers say

### KM eFlash

[App page](https://appshunter.io/ios/app/km-eflash/id6742645180)

**Features:** macOS Compatibility

**In-app purchases:** none


### OBD2 Scanner + Engine Sound

[App page](https://appshunter.io/ios/app/obd2-scanner-plus-engine-sound/id6789023964)

Monitor your car's engine performance and hear its sound in real-time. Customize your dashboard with various widgets and track your drives with detailed maps and trip data. Offers a demo mode and optional Pro features for an enhanced experience.

**Highlights:** Real-time OBD2 data display, Engine sound simulation based on RPM, Customizable dashboard with widgets, Trip computer and fuel economy tracking, Speed and RPM on map view, HUD mode for windshield projection

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Remove Ads | $1.99 | one-time |
| car_ui Pro (One-Time) | $4.99 | one-time |


## Frequently asked questions

### Is KM eFlash free?

KM eFlash is free to download, with no in-app purchases.

### Is OBD2 Scanner + Engine Sound free?

OBD2 Scanner + Engine Sound is free to download, with in-app purchases available.

### Do KM eFlash or OBD2 Scanner + Engine Sound have ads?

OBD2 Scanner + Engine Sound shows ads; KM eFlash does not.

### Which is updated more often, KM eFlash or OBD2 Scanner + Engine Sound?

KM eFlash ships an update every 3 days, and OBD2 Scanner + Engine Sound every 9 days. Most recently, KM eFlash was updated on October 17, 2026 and OBD2 Scanner + Engine Sound on October 16, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*