First vs OTR Diagnostics
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
First
Connect your mobile device to a commercial vehicle's diagnostic port to monitor its health status. Understand fault codes, view vehicle specifications, and track trip data to improve uptime and aid in service and repair.
- Connect to vehicle diagnostic port
- Monitor vehicle health status
- View active and inactive fault codes
- Display vehicle specifications (VIN, ECU info)
- Track trip data (fuel, miles, speed, hours)
- Generate and share vehicle reports
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NEXIQ First-Link™ is an application that provides important features to the drivers and service technicians of commercial vehicles and equipment. These features help the driver connect the mobile device to the diagnostic port; they also monitor the vehicle's health status and increase the vehicle's uptime. If a Check Engine Light is illuminated, the application assists the driver to understand the cause so that he can seek assistance (i.e., service and repair), if needed. Service technicians can utilize the information gathered by the application to aid in vehicle service and repair. Features include: • Faults – Active and Inactive fault codes present at the time of connection are displayed. • Vehicle Specs – Vehicle information including VIN, ECU software and hardware information is displayed. • Life / Trip – Displays trip-specific information related to fuel usage, miles, maximum speed, cruise control speed, hours of operation, etc. • Parameters – Displays parameters specific to the modules on the vehicle (e.g., engine, transmission, etc.) • Report – Generates a session-specific report containing vehicle information (i.e., faults, vehicle specs, parameters, and life/trip information); can be uploaded to the cloud, emailed, etc. • Sharing - Enables the driver to share vehicle information gathered to dispatch, service providers, etc. • OnCommand® Support - Optional feature to allow users to upload health reports to the OnCommand® servers. • Blue-Link Mini firmware update to v1.09, if the adapter has older firmware.
OTR Diagnostics
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.
- 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
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OTR Diagnostics — Trusted by 10,000+ Truck Owners Dealing with regen problems, nonstop alerts, fault codes, and unexpected derates on your heavy duty truck? You are not alone. More than 10,000 truck owners and fleets trust OTR Diagnostics to take control, cut downtime, and avoid expensive dealer visits. Powered by OTR Assist + OTR LINK 2 This is more than a scan tool. OTR Assist is your AI partner, breaking down fault codes in plain language and helping you troubleshoot and decide if you can keep driving or need service now. Paired with OTR LINK 2, our proprietary Bluetooth adapter, you get faster connection speeds, more accurate fault code data, and more live data parameters than ever before. It is 5X better than previous hardware. Ask us how to get a FREE upgrade today. Commands That Keep You Moving With bi-directional commands built right into OTR Diagnostics, you are no longer stuck waiting on a shop to do what you can handle yourself. Reset active and inactive fault codes Reset the entire aftertreatment system Reset derates that slow you down Reset soot levels after a DPF service Run forced DPF or SCR regens right from the cab These commands put you back in control, saving you time, money, and downtime. Fault Code Insights Go beyond a flashing dash light. OTR Diagnostics helps you understand fault codes with the same level of detail as dealer software, but in plain language you can actually use. Decode your dash lights Uncover the root causes of issues Track how often a problem occurs Know which repairs or parts are needed Live Data Monitoring Want to know if your regen is working? Want to monitor exhaust temps, soot levels, or DEF? OTR Diagnostics lets you see your truck’s vitals in real time so you can spot issues before they stop you. Common live data parameters include: DPF fluid level DPF soot level EGR valve position Aftertreatment exhaust temps Boost pressure Accelerator pedal position Engine fuel delivery pressure Available live data may vary depending on the engine model your device is connected to. Explore Your History Recurring problems? OTR Diagnostics logs every fault code and command so you can see when issues happened, when they were cleared, and how long regens lasted. Proven. Tested. Backed by Support We run OTR Diagnostics, OTR Assist, and OTR LINK 2 on our own fleet of test trucks including late model Paccar MX engines to make sure everything works before it reaches you. That is why more than 10,000 drivers already trust OTR Diagnostics. Made in Michigan. Built for You We engineer, assemble, and ship right from our shop in Macomb, MI. If you are nearby, stop in and see us. Coverage We support a wide range of heavy duty engines: Cummins: CM871, CM2150, CM2250, CM2350 (2008–2024) Detroit Diesel: DD60, MBE, DD13, DD15, DD16 (2008–2024) Paccar: MX11, MX13 (2011–2024), PX7, PX9 (2008–2024) Volvo: D11, D13, D13TC, D16 (2014–2024) Mack: MP7, MP8, MP8HE, MP10 (2014–2024) For the full list of compatible models, call or text us at 586-799-4375. Need Help or Have Questions? Call or text us anytime at 586-799-4375 or email support@otrperformance.com.
Screenshots
Verdict
The clearest difference is rating: OTR Diagnostics at 4.0 against First's 2.3. OTR Diagnostics also leads on review sentiment (55% vs 17%) and update cadence (fortnightly vs every 5 months). First's advantage is monetization model (free vs free with in-app purchases) and iOS requirement (11.0 vs 17.6). On price, ads, in-app purchases and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
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 2.3. That said, the two scores are not equally well evidenced: OTR Diagnostics has 99 ratings behind it against 16, so its average is the more settled of the two. Written reviews point the same way: 17% of First's written reviews are positive against 55% of OTR Diagnostics's.
First ships an update every 5 months, OTR Diagnostics fortnightly. The most recent releases landed on October 5, 2026 and October 6, 2026 respectively.
| Parameter | First | OTR Diagnostics |
|---|---|---|
| Price | Free | Free |
| Rating | 2.3 (16 ratings) | 4.0 (99 ratings) — better |
| Positive reviews | 16.7% of reviews | 55.2% of reviews — better |
| Number of ratings | 16 | 99 — better |
| Update frequency | Every 5 months | Fortnightly — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free — better | Free with in-app purchases |
| Devices | iPhone, iPad, iPod — better | iPhone, iPad |
| Requires iOS | 11.0 — better | 17.6 |
| Further details — not scored | ||
| Size | 128 MB | 267 MB |
| Age rating | 4+ | 4+ |
| Developer | Snap-on Inc. | OTR Performance |
Customer experience
First
OTR Diagnostics
Bugs and requests
First
Not enough reviews yet to summarise bugs or requests.
OTR Diagnostics
Reported bugs
10 issues- 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
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- Bluetooth connection rejects
- App doesn't work without data connection
- Forced regen not activating after updates
- Login authentication errors
- Cannot start regen process on newer models
Requested features
5 requests- 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
In-app purchases
First
No in-app purchases
OTR Diagnostics
No in-app purchases







