Scan tools are a must in your diagnostic arsenal

Technical Editor Dave Cappert answers your questions about scan tools.

What is Mode 6?

Mode 6 is a diagnostic mode built into OBDII that performs on-board monitoring of test results for non-continuously monitored systems. Mode 6 data is real time and unrecorded, so it can reveal a lot of information about system faults like ignition misfire, fuel control and other engine management details. This means that Mode 6 data may be able to reveal a problem before it trips the MIL or sets a DTC. Albeit helpful, Mode 6 data may not be available on all scan tools or vehicle systems. Ask your equipment rep whether the scan tool you’re considering can tap into Mode 6 data. Within the last several model years, the carmakers have boosted Mode 6 availability, functionality and the importance of its data.

A diagnostic procedure I came across involves an actuator test. Is this something a scan tool can do?

Yes, depending on the system a scan tool’s connected to, it can perform different actuator tests. The scan tool essentially sends a command to an actuator, like a relay or solenoid, to see whether that actuator can really do its job. This capability also depends on whether the vehicle manufacturer enables this function in its onboard electronics.
Are scan tools mainly intended for diagnosing issues with engine controls?

Not anymore. Today’s vehicles are more interconnected and networked than ever. Multiple computers share information in an onboard network that controls all phases of vehicle operation. Scan tools can now “converse” with this network through bidirectional communications. This enables you to both read and send values to various onboard systems. This includes the Controller Area Network, entertainment and information systems, anti-lock brakes and transmission control.

I’d like to be able to access service information through a scan tool. Is this possible?

Yes, in some cases different scan tool manufacturers provide onboard service information through their tools. This can be a real time-saver when getting to the heart of system problems. Compare how this feature stacks up against your existing service information subscription.

What’s the best way to comparison shop for my scan tool needs?

Start by defining your budget and the population of vehicles you plan to service. Be honest about your needs. It’s not practical to invest in equipment for cars you never service, so stay objective about needed applications. Build a scan tool spreadsheet and enter your criteria into it as your research unfolds.

Next, talk to some tool and equipment reps about their offerings and add those details to your spreadsheet. Include a category for future expandability so you don’t overlook what could be possible to increase your scan tool capabilities.

Now, check around with other techs and shop owners about their experience with the scan tools you’re considering. If you’re a member of the PTEN-sponsored International Automotive Technicians Network (iATN) at, you may want to check into the Tool & Equipment forum there. There’s a lot of collective expertise on tap that may help guide your scan tool quest.

Can scan tools perform J2534 reprogramming functions?

In some cases, yes. Check with your equipment rep on the specific scan tool you’re considering to see if this is an option.

What about updates and subscriptions?

Scan tools handle application updates a couple of different ways. Handheld scan tools often use plug-in cartridge updates for new or different applications. PC-based scan tools usually update through a software download. The key thing is to be clear on how this works and the costs involved going forward. When it comes to scan tools, it’s not just the original acquisition price; you also have to keep update costs in mind going forward.

So, which scan tool is best for the money?

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