# OTR Diagnostics vs TopGuru

The clearest difference is rating: OTR Diagnostics at 4.0 against TopGuru's 3.5. OTR Diagnostics also leads on in-app purchases (none vs 29) and review sentiment (55% vs 29%). TopGuru's advantage is chart position (#171 vs unranked) and ratings volume (404 vs 99). On price, update cadence, ads and monetization model there is nothing between them.

Both are free to download. TopGuru sells 20 in-app purchases, starting at $9.99 per month. OTR Diagnostics asks for nothing beyond the download.

OTR Diagnostics holds the better App Store score, 4.0 against 3.5. Both are backed by a comparable volume of ratings — 99 and 404 respectively. Written reviews point the same way: 55% of OTR Diagnostics's written reviews are positive against 29% of TopGuru's.

OTR Diagnostics ships an update fortnightly, TopGuru every 3 weeks. Both last shipped on September 23, 2026.

## The numbers

| Metric | OTR Diagnostics | TopGuru |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.0 (99 ratings)](https://appshunter.io/ios/app/otr-diagnostics/id1508165885/reviews)** | [3.5 (404 ratings)](https://appshunter.io/ios/app/topguru/id6451488210/reviews) |
| Number of ratings | 99 | **404** |
| Positive reviews | **55.2% of reviews** | 29.3% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Fortnightly** | Every 3 weeks |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Best chart rank | — | **#171** |
| Size | 266 MB | 2.2 GB |
| Requires iOS | 17.6 | **11.0** |
| Devices | iPhone, iPad | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [OTR Performance](https://appshunter.io/developer/1508165884) | [HK TOPDON TECHNOLOGY Co., LIMITED](https://appshunter.io/developer/1846276192) |

## What reviewers say

### OTR Diagnostics

[App page](https://appshunter.io/ios/app/otr-diagnostics/id1508165885)

This app helps heavy-duty truck owners diagnose and resolve common issues like fault codes, regen problems, and derates. It provides plain-language explanations of error codes, allows for bi-directional commands to fix issues, and monitors live truck data to prevent downtime.

**Highlights:** AI-powered fault code explanation, Bi-directional commands for repairs, Reset active/inactive fault codes, Run forced DPF/SCR regens, Live data monitoring, Fault code history tracking

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

**In-app purchases:** none

**What reviewers like**

- 💰 Saves money on repairs
- 🛠️ Clears fault codes
- 🔄 Performs forced regens
- ✅ Works with various engines
- 👍 Easy to use

**What reviewers complain about**

- 💸 Overpriced
- 🐛 Buggy and unstable app
- 🔌 Frequent Bluetooth disconnects
- 📉 Updates cause problems
- ❌ Some features disappeared after updates

**Reported bugs**

- App constantly disconnects from device
- Generic code option disappeared
- Forced regen is no longer consistent
- AI assistant not working
- App asks to do things not available in app

**Requested features**

- Remember email address for login
- Allow offline functionality without data connection
- Add option to change speed
- More detailed diagnostic information
- Allow basic subscription to work on multiple VINs


### TopGuru

[App page](https://appshunter.io/ios/app/topguru/id6451488210)

**Currently charting:** #171 Top Grossing · Utilities (US App Store)

Transform your phone or tablet into a powerful vehicle diagnostic tool via Bluetooth. Access full system diagnosis, OBDII functions, bi-directional controls, and essential maintenance services for a wide range of car brands. Generate detailed diagnostic reports for efficient troubleshooting.

**Highlights:** Full System Diagnosis, Full OBD2 Functions, Bi-directional Control, 8 Special Maintenance Functions, AutoVIN Vehicle Identification, Diagnostic Report Generation, Wireless Bluetooth 5.0 Connection

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

**In-app purchases (20)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly Auto-renewal | $9.99 | per month |
| Monthly Auto-renewal | $19.00 | per month |
| Quarterly Auto-renewal | $24.99 | per 3 months |
| Annual Auto-renewal | $49.99 | per year |
| Annual Auto-renewal | $99.00 | per year |
| Diag Bundle Renewal | $49.99 | one-time |
| TopGuru Diagnostic Bundle | $49.99 | one-time |
| TopGuru IMMO Bundle | $49.99 | one-time |
| Renewal Bundle | $99.00 | one-time |
| TopScan Pro Renewal Bundle | $99.00 | one-time |
| Harley Moto Software | $99.99 | one-time |
| Harley Moto Software Renewal | $99.99 | one-time |
| Moto Diag Bundle Renewal-Moto | $99.99 | one-time |
| Moto Diag Bundle | $99.99 | one-time |
| Moto Diag Bundle Renewal | $99.99 | one-time |
| 22 Special Functions Bundle | $129.99 | one-time |
| Renault Gateway 10 Tokens | $129.99 | one-time |
| Renault Gateway 5 Tokens | $147.99 | one-time |
| 17 Special Functions Bundle | $179.00 | one-time |
| FCA Gateway 1-year (EU only) | $229.99 | one-time |

**What reviewers like**

- 👍 Works well on most vehicles
- 🚀 Powerful features for the price
- 💡 Useful for DIY and professional mechanics

**What reviewers complain about**

- 🐛 Frequent app crashes and bugs
- ⏱️ Slow and cumbersome to use due to constant updates
- 🔒 Concerns about data privacy and security
- 💰 Subscription model after initial purchase

**Reported bugs**

- Incompatibility with certain vehicle models
- Login and account issues
- Unreliable Bluetooth connectivity

**Requested features**

- iPad optimization and full-screen support
- Expanded vehicle coverage, especially for motorcycles
- Ability to save and export diagnostic data


## Frequently asked questions

### Is OTR Diagnostics free?

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

### Is TopGuru free?

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

### Which has better reviews, OTR Diagnostics or TopGuru?

OTR Diagnostics is rated higher. OTR Diagnostics averages 4.0 out of 5 from 99 ratings, while TopGuru averages 3.5 from 404 ratings.

### Do OTR Diagnostics or TopGuru have ads?

Neither OTR Diagnostics nor TopGuru shows ads.

### Which is updated more often, OTR Diagnostics or TopGuru?

OTR Diagnostics ships an update fortnightly, and TopGuru every 3 weeks. Most recently, OTR Diagnostics was updated on September 23, 2026 and TopGuru on September 23, 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.*