How To Effectively Use A Scan Tool

Owning a scan tool can really pay off for you in the short term and in the long run. And to make this pay off happen, you need to be aware of this: A scan tool is just a tool that needs to be used in conjunction with a few others (like a multimeter, fuel pressure gauge, etc.) and specific testing information. This ‘specific testing information’ may be a repair manual, or an internet site with automotive testing info (like this one).

Let me give you an example that might bring this home: a ratchet wrench is a must-have tool if you plan on replacing your front brake pads. But just the ratchet wrench is not gonna' get the whole job done. You'll need a jack, jack stands, the right sockets (to attach to the ratchet wrench) to remove the caliper bolts, etc.

Does this mean that you're gonna' spend a fortune on tools to do your own brakes? NO. Are you gonna' save money? YES, considering that most repair shops (at least at the ones where I have worked at) charge around $500 to $700 to replace front brake pads and rotors. And if you plan on driving your vehicle, you're gonna' eventually need new brake pads again.

For the scan tool to be an effective money saving tool, you're gonna' need more than a scan tool to effectively troubleshoot the problem lighting up the check engine light.

The Strategy That Will Get The Most Out Of Your Scan Tool

By now, you're probably starting to see that the most effective strategy (to save money and time) is to test the sensor or sensors that your scan tool is telling you are bad. Never take the scan tool at its word that the sensor is bad. Instead, test it to make sure.

You can easily accomplish this by researching the diagnostic trouble codes in a repair manual or on the Internet.

Of course, you're also gonna' need to invest in more tools. There's no way around this and I want to be very frank with you. Without the appropriate tools and the appropriate testing info (such as that found in repair manuals) to test the sensor your scan tool is accusing of being bad, you are always gonna' be groping in the dark. This always results in replacing good parts that don't need to be replaced.

As I mentioned before, you don't have to spend an arm and a leg on these tools. But spend you will have to.

So, if you have already invested in a scan tool, learn more about it either in books or on-line. Troubleshooting check engine light problems don't have to be a nightmare and an exercise in wasting time and money if you remember that reading the diagnostic trouble codes is only the first step of the journey.

What Is Live Data?

Scan tools can be divided into two main types. code readers and code readers with Live Data capability.

Live Data is the capability to display some of the input and output that the PCM in your car sees and sends out.

The benefit of being able to see Live Data are several, here's a basic list:

  • You're able to see the specific signals of the sensor you need or want to test (as long as the scan tool has a PID for the sensor).
  • Since most sensors can be independently tested with a multimeter, being able to compare the signal output (on your multimeter) to what the PCM is seeing will help you in troubleshooting an open-circuit problem or a bad PCM.
  • It'll speed up your diagnostic since you're able to get a quick view of what the sensor is doing or not doing.

Related Articles

The following two are scan tool reviews you might be interested in reading: