# BK400 vs J1939FaultCode

The clearest difference is in-app purchases: BK400 at none against J1939FaultCode's 1. BK400 also leads on ads (none vs shown) and update cadence (weekly vs fortnightly). On price and iOS requirement there is nothing between them.

Both are free to download. J1939FaultCode sells 1 one-off in-app purchase. BK400 asks for nothing beyond the download.

BK400 ships an update weekly, J1939FaultCode fortnightly. The most recent releases landed on October 25, 2026 and October 28, 2026 respectively.

## The numbers

| Metric | BK400 | J1939FaultCode |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | **Weekly** | Fortnightly |
| Size | 21 MB | 14 MB |
| Requires iOS | **15.0** | 16.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [祖策 谢](https://appshunter.io/developer/983519195) | [洋 刘](https://appshunter.io/developer/6775317751) |

## What reviewers say

### BK400

[App page](https://appshunter.io/ios/app/bk400/id6760681499)

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

**In-app purchases:** none


### J1939FaultCode

[App page](https://appshunter.io/ios/app/j1939faultcode/id6778431735)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| J1939 Pro | $2.99 | one-time |


## Frequently asked questions

### Is BK400 free?

BK400 is free to download, with no in-app purchases.

### Is J1939FaultCode free?

J1939FaultCode is free to download, with in-app purchases available.

### Do BK400 or J1939FaultCode have ads?

J1939FaultCode shows ads; BK400 does not.

### Which is updated more often, BK400 or J1939FaultCode?

BK400 ships an update weekly, and J1939FaultCode fortnightly. Most recently, BK400 was updated on October 25, 2026 and J1939FaultCode on October 28, 2026.

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