# OTR Diagnostics vs SmarTemp 3.0

The clearest difference is rating: OTR Diagnostics at 4.0 against SmarTemp 3.0's 3.3. OTR Diagnostics also leads on review sentiment (55% vs 18%) and ratings volume (99 vs 6). SmarTemp 3.0's advantage is monetization model (free vs free with in-app purchases) and iOS requirement (9.0 vs 17.6). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

OTR Diagnostics holds the better App Store score, 4.0 against 3.3. That said, the two scores are not equally well evidenced: OTR Diagnostics has 99 ratings behind it against 6, so its average is the more settled of the two. Written reviews point the same way: 55% of OTR Diagnostics's written reviews are positive against 18% of SmarTemp 3.0's.

OTR Diagnostics ships an update fortnightly, SmarTemp 3.0 every 5 weeks. The most recent releases landed on October 15, 2026 and October 7, 2026 respectively.

## The numbers

| Metric | OTR Diagnostics | SmarTemp 3.0 |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.0 (99 ratings)](https://appshunter.io/ios/app/otr-diagnostics/id1508165885/reviews)** | [3.3 (6 ratings)](https://appshunter.io/ios/app/smartemp-30/id1546720847/reviews) |
| Number of ratings | **99** | 6 |
| Positive reviews | **55.2% of reviews** | 18.2% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Fortnightly** | Every 5 weeks |
| Monetization | Free with in-app purchases | **Free** |
| Size | 267 MB | 30 MB |
| Requires iOS | 17.6 | **9.0** |
| Devices | iPhone, iPad | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [OTR Performance](https://appshunter.io/developer/1508165884) | [Globus Sistemas Eletronicos Ltda](https://appshunter.io/developer/1211409010) |

## 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


### SmarTemp 3.0

[App page](https://appshunter.io/ios/app/smartemp-30/id1546720847)

Control your parking heater remotely. Schedule heating or ventilation, monitor interior temperature, and check battery charge. Access additional service information online.

**Highlights:** Remote heater operation, Time-based heating schedules, Individual heating programming, Heating and ventilation modes, Interior temperature display, Battery charge monitoring

**In-app purchases:** none


## Frequently asked questions

### Is OTR Diagnostics free?

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

### Is SmarTemp 3.0 free?

SmarTemp 3.0 is free to download, with no in-app purchases.

### Which has better reviews, OTR Diagnostics or SmarTemp 3.0?

OTR Diagnostics is rated higher. OTR Diagnostics averages 4.0 out of 5 from 99 ratings, while SmarTemp 3.0 averages 3.3 from 6 ratings.

### Do OTR Diagnostics or SmarTemp 3.0 have ads?

Neither OTR Diagnostics nor SmarTemp 3.0 shows ads.

### Which is updated more often, OTR Diagnostics or SmarTemp 3.0?

OTR Diagnostics ships an update fortnightly, and SmarTemp 3.0 every 5 weeks. Most recently, OTR Diagnostics was updated on October 15, 2026 and SmarTemp 3.0 on October 7, 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.*