# simos.app — VAG ECU Diagnostics & Logging

> VAG Simos ECU diagnostics, logging, and flashing tool for petrol engines. (iPhone/iPad app by Tycho Sebastian Holzer.)

- Source: https://appshunter.io/ios/app/simosapp/id6760018423 (this page in markdown: same URL + `.md`)
- Developer: [Tycho Sebastian Holzer](https://appshunter.io/developer/1882338941)
- Category: Utilities, Developer Tools
- Price: Free
- Rating: 5.00/5 from 2 App Store ratings
- Age rating: 4+
- Requires: iOS 17.6 · 5 MB
- Languages: American English
- Released: 2026-03-12
- Data updated: 2026-08-31
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/simosapp/id6760018423/reviews.md

## What is simos.app?

simos.app is a diagnostic, data logging and flashing tool built specifically 
for VAG petrol engines running Simos 18.1, 18.2, 18.6, 18.10 and Simos 12.1 
ECUs. The platforms found in most modern TSI and TFSI engines across 
Audi, VW, Škoda, SEAT, Cupra and Porsche.

LIVE DATA LOGGING
Read ECU parameters directly in real time. Monitor boost pressure, 
injection timing, lambda, temperatures, torque and more at high 
sample rates over a Bluetooth LE connection.

ECU IDENTIFICATION
Read software versions, calibration IDs and hardware info straight 
from the control unit.

LOG ANALYSIS
Visualize recorded sessions with multi-channel graphs. Spot 
correlations between parameters without leaving the app.

FLASHING
Update your ECU and TCU to the latest version for your vehicle or flash a custom tune.
Full features available for Simos 18.1/18.10 and 18.6.
Flashing stock files or pre-unlocked ecus for Simos 18.2, 18.4, 18.41 and Simos 12.1.

––
Built for enthusiasts, tuners and workshops who need more than a 
generic scan tool. Basic knowledge of ECU diagnostics is recommended.

This app is for informational and diagnostic purposes only. Any 
modifications to vehicle systems are the sole responsibility of the 
user and must comply with local laws and regulations.
––

Bluetooth LE OBD adapter required.
Get yours here: https://simos.app/dongle
Other compatible adapters: Macchina A0, DIY A0 clone https://github.com/Switchleg1/AMAleg require custom firmware: https://simos.app/dongle/firmware

## Key features

- Real-time ECU parameter monitoring
- Live data logging via Bluetooth LE
- ECU identification (software/calibration IDs)
- Multi-channel graph analysis of logged sessions
- ECU and TCU flashing (stock and custom tunes)
- Support for Simos 18.x and 12.1 ECUs


## Frequently asked questions about simos.app

### What VAG ECUs does simos.app support?

simos.app is built for VAG petrol engines running Simos 18.1, 18.2, 18.4, 18.41, 18.6, 18.10, and Simos 12.1 ECUs. Full features are available for Simos 18.1/18.10 and 18.6, with flashing capabilities for Simos 18.2, 18.4, 18.41, and Simos 12.1.

### What kind of data can I log with simos.app?

You can monitor and log various ECU parameters in real time, including boost pressure, injection timing, lambda, temperatures, and torque. The app allows for high sample rates over a Bluetooth LE connection.

### Can simos.app be used to update my car's ECU?

Yes, simos.app allows you to update your ECU and TCU to the latest version for your vehicle or flash a custom tune. This feature is available for specific Simos ECU versions.

### What hardware is required to use simos.app?

A Bluetooth LE OBD adapter is required to use simos.app. Compatible adapters include the one sold on simos.app/dongle, or the Macchina A0 and DIY A0 clone with custom firmware.

### Is simos.app suitable for beginners?

The app is built for enthusiasts, tuners, and workshops. Basic knowledge of ECU diagnostics is recommended for optimal use of its advanced features.

### How often is simos.app updated?

The latest version, 1.9.3, was released on 2026-07-16. Updates are frequent, ensuring the tool remains compatible with the latest ECU software and features.

### What is the user sentiment for simos.app?

Based on the available data, simos.app has a high user rating of 5.0 stars from 2 ratings, indicating strong positive sentiment among its users.

### Does simos.app have ads?

No, simos.app does not contain advertisements. It is a free application focused on providing diagnostic and tuning tools without interruptions.

## Version history (last 5 releases)

### 1.9.7 — 2026-08-28

- HSL unit fixes & added SC8F90, SCGA10
- DQ250 HSL fixed
- ECU response timeout fixed

### 1.9.6 — 2026-08-24

- Added HSL for Simos 18.x and DQ250
- Added CarPlay min/max values
- Fixed writing long coding
- Fixed reset all ecu adaptions

### 1.9.5 — 2026-08-04

- Fixed logging in flash unlock
- Fixed ECU response timeout
- Allow ECU detection of Simos 19.x
- Added Simos 19.x logging

### 1.9.4 — 2026-07-24

- Apple in App Purchases
- Fixed compatability with simos tools dongle firmware (Use simos tools dongle with simos.app)
- Worked on ECU response timeout while flashing
- Preparation for HSL logging
- Sync vehicles to cloud
- Upload log with VIN, attached to synced vehicle

### 1.9.3 — 2026-07-16

fixes for flashing and in app purchases

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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 2026-08-31.*