Every iPhone needs a few good machine diagnostics apps. We benchmark 225+ of them on App Store rating, freshness, and pricing, then surface the standouts so you don't have to scroll the App Store yourself.
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.
This app provides advanced diagnostics for Jeep, Chrysler, and Dodge vehicles. It allows users to read and clear trouble codes, view live sensor data, and access settings across all vehicle modules, including ABS and transmission.
This app provides a centralized platform for managing heavy equipment. It offers tools for finding parts, accessing manuals, diagnosing issues, and tracking machine health. Users can also connect with dealers and access support resources.
What are the best machine diagnostics apps for iPhone?
OTR Diagnostics tops our machine diagnostics apps ranking as of June 2026, with a 4.0-star average from 96 App Store ratings, and it's free to download.
Are there free machine diagnostics apps for iPhone?
Yes — 20 of the top machine diagnostics apps we rank are free to download, including OTR Diagnostics and OBD JScan.
Does OTR Diagnostics have ads or in-app purchases?
OTR Diagnostics has no ads and has no in-app purchases, according to its App Store listing as of June 2026.
How many machine diagnostics apps are on the App Store?
We track 225+ machine diagnostics apps on the iOS App Store as of June 2026, ranked by rating, recency, and analysis of real user reviews.
What does OTR Diagnostics do?
OTR Diagnostics is a heavy-duty truck scan tool that helps owners and fleets diagnose and resolve issues like fault codes, regen problems, and unexpected derates. It provides plain-language explanations of fault codes, allows for bi-directional commands to fix common problems, and monitors live truck data in real-time.
What are the key features of OTR Diagnostics?
Key features include AI-powered fault code insights that break down complex codes into understandable terms, bi-directional commands to reset fault codes, aftertreatment systems, derates, and soot levels, and the ability to run forced DPF or SCR regens directly from the cab. It also offers live data monitoring for critical engine parameters.