HEM Data Products

Mini HD-OBD Inspector™ with TamperDetect™

Description & Purpose

The Mini HD-OBD Inspector™ is an inspection/maintenance (I/M) tool for heavy-duty and medium-duty vehicles developed by HEM Data. It acquires heavy-duty, on-board diagnostic (HD-OBD) data from the vehicle’s CAN bus using either J1939 or J1979. The Mini Inspector acquires all the available data to assess the vehicle’s overall duty cycle and condition including all transmitted parameters, and Diagnostic Messages (DMs), reporting Readiness and DTCs (active, pending, permanent, historical).

HD-OBD was phased in during the 2013-2015 model years for on-road trucks. Older models and off-road vehicles are supported if the data is available on the vehicle’s J1939 network.

Mini Inspector has been used to evaluate over 70,000 heavy and medium duty trucks. This inspection data is stored in HEM Data’s HD-OBD Inspection Dashboard™. The Inspection Dashboard has an advanced TamperDetect™ algorithm using the HD-OBD data to determine if the vehicle has been tampered to delete or override the emissions system.

Part of a report showing a tampered vehicle

Mini HD-OBD Inspector is a small, easily portable solution and quick to install. Just attach the hardware to the vehicle network connector, turn on the engine, and open the smart phone app. Complete the test and view the report all within 2 minutes!

The tool is designed for federal and state governments, service technicians, researchers, and companies who resell or buy used trucks and off-road vehicles. HD-OBD testing is important for environmental and human health to minimize diesel engine emissions and to have emission equipment operate efficiently. It is illegal to resell vehicles with tampered or deleted emissions.


Mini Inspector consists of three major components

  • Mini Streamer™ hardware (dongle)
  • iPad or iPhone
  • Mini HD-OBD Inspector™ software
  • HD-OBD Inspector Dashboard™ (vehicle database)


HEM Data’s Mini Streamer hardware sends data to a smart device wirelessly. The Mini Streamer acquires all the data available from the vehicle. The Mini Streamer hardware conveniently fits directly on the vehicle’s 9-pin J1939 connector. If the vehicle has the 16-pin J1962 connector (light-duty automobile style trapezoidal connector) or a non-standard connector, then an adapter is used. The Mini Streamer acquires both J1939 and J1979 data and is able to acquire data from three CAN networks simultaneously. Protocol speeds supported are CAN250, CAN500, and CAN1000.

J1939 Mini Streamer™

Mini HD-OBD Inspector Software™

Mini HD-OBD Inspector is supported on both an iPad and iPhone. The app receives the data from the Mini Streamer hardware using a direct WiFi connection. The app displays real-time information to the user as the test is progressing. The app sends the data to the Dashboard when the smart device has internet access. The analyzed results are conveniently displayed in the app for quick feedback.

Parameters table showing live data

The screenshot above shows the live values table. The screenshot below shows all active, previous, and pending trouble codes on the vehicle.

Active, previous, and pending trouble codes

HD-OBD Mini Inspector Dashboard

HEM Data’s HD-OBD Inspection Dashboard analyzes both J1939 and J1979 data. This is important since J1939 Diagnostic Message (DM) equivalents are reported differently in J1979. A sample screen is shown near the top.

Using TamperDetect™, the dashboard analyzes whether the vehicle’s OBD system and emission control equipment have been tampered or deleted. The vehicle report is available directly from the app so the user feedback is virtually instantaneous on the iPad or iPhone.

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