Selecting the right scan tool to diagnose electrical systems

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Updated May 31, 2018

Bosch has produced a technical bulletin for fleet terminals and service centers on the importance to scan tool selection to reducing downtime across a truck fleet.

The company writes the complex connections of systems in fleet vehicles can create a complicated diagnosis process, with electrical systems being especially time consuming. Equipping a shop with a professional scan tool will help identify electrical issues faster and get trucks back on the road.

To ensure you select the best scan tool for your shop, Bosch says to start by assessing the features you need for your fleet and what capabilities will best aid your technicians.


If your technicians are troubleshooting trucks and systems from different manufacturers, consider an aftermarket scan tool with all makes/models coverage. An all makes tool will allow your techs to move between more vehicles using a familiar tool, saving time. An aftermarket tool will also communicate with most modules on the truck, not just one manufacturers’ components like an OEM tool. Technicians can use the same scanner to read codes, control and diagnose engines, transmissions, trailers, brake systems and more, Bosch says.

Work at the Truck

On-tool repair assets can save time and keep technicians at the vehicle to diagnose, test and repair. Bosch says to look for a scan tool with information that can help your techs diagnose and repair issues faster. Interactive wiring diagrams, likely repairs, component location and tolerance specs on the tool can prevent a tech from searching for info on a laptop or manual and make them more efficient

When you demo a tool, check the functionality of the special tests. Bosch adds some tools include step-by-step instructions on how to perform the tests and what techs should observe. More information is better than less especially when diagnosing complex electrical systems.

Recording Capabilities

Bosch says diagnosing electrical faults goes beyond scanning a vehicle and testing a part. Your techs may need to complete several drive cycles to replicate an issue, closely watching how multiple vehicle systems perform. Long-term data recording will help techs track lingering issues. Saving and comparing the recordings can identify trends that can lead to a permanent repair, the company says.

In addition to recording data, Bosch says your technicians will need access to live data and data graphing during diagnostic testing. While conducting system checks and other troubleshooting efforts, the ability to simultaneously watch the live data stream allows the technician to better locate the source of the issue. Ask your techs what kind of graphing they prefer and how many PIDs they need to see at the same time. Before you invest in a new tool, Bosch says to make sure it shows data the way your techs expect and can understand.

Software Updates

Coverage updates are the most important part of a diagnostic tool. Any tool you purchase should have updates available at least twice a year to stay current and repair newer vehicles, Bosch says. Repair asset subscriptions are another way to give techs more information on vehicle issues to make diagnosing and repairing faster.

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