A: Mode 6 can provide additional data for diagnostics. To use it, view the monitor status prior to repairs to see how the system failed. Then, investigate the component or data parameter related to the fault. This can help pinpoint the problem. Finally, review what it takes to enable the monitor, so you can see what it takes to pass or fail that monitor.
Q: One of our techs said we should make sure any scan tool we purchase has freeze-frame capabilities. Is this a hard feature to find?
A: Freeze-frame is a standard feature built into all OBDII systems that basically takes a snapshot of data when an emissions-related diagnostic trouble code (DTC) sets. By default, some scan tools may be able to retrieve only one frame of captured data on demand. Some manufacturers build in expanded freeze-frame data capture routines that reveal more than a standard frame. To pull this expanded data, it usually requires a scan tool with expanded freeze-frame retrieval capabilities or an original equipment scan tool. To be sure, talk to your equipment rep about the freeze-frame functionality for any scan tool you’re considering.
Q: Which is the better choice, a PC-based scan tool or a handheld scan tool?
A: Both platforms have their advantages. Let’s start with the PC-based scan tool. One advantage of the PC-based scan tool is the ability to look at data and waveforms on a relatively large screen. Since the overwhelming majority of laptops these days have displays in the 15" range, it provides great legibility for displayed information. With a PC-based scan tool, you can also get your software updates via the Internet. Handheld scan tools provide a lot of diagnostic power in a relatively small size and also include other test capabilities in one package. A handheld scan tool may also be easier to hold than a PC-based version, as a PC scan tool requires a flat spot to position the laptop. Of course, the arguments for either side go out the window if you decide to go with an OE scan tool. OE scan tools come in one platform or the other depending on the manufacturer, so you won’t have the luxury of choosing a platform in this case.
Q: What about Controller Area Networking (CAN) capabilities? How do I know if my scan tool can handle these systems?
A: CAN technology first appeared on cars starting in 2002 and had to be implemented on all cars by 2008. Since CAN-equipped vehicles use multiple computers that must talk to each other, it’s critical that your scan tool have that same communication capability. Most full-featured scan tools today have CAN abilities, but make sure to clarify applications with your equipment rep to ensure coverage. Software updates frequently expand coverage to vehicles not previously covered in an earlier release.
Q: We’re just getting into the diagnostics business and have learned that some states have replaced emissions testing with OBDII checks? What’s the thinking behind this?
A: Presently, there are thirty-three states with active emissions programs, otherwise known as I/M (inspection/maintenance) programs. Of these states, the majority of them require only OBDII checks as the main component of their programs. The remaining states use a combination of tailpipe emissions tests in conjunction with OBDII checks. Despite all the buzz surrounding I/M programs and loaded-mode dynamometer testing that took place in the mid-90s, the EPA eventually changed course and took a more practical route to emissions testing. Realizing that OBDII technology did a pretty good job of self-detection when it came to failures, the tide began to shift when states ran “advisory” programs proving the effectiveness of OBDII.
Not long ago, the scan tool was simply one of the tools you could use to help diagnose emissions problems. My, how times change.
Technical Editor Dave Cappert answers your questions about scan tools.