While most modes are simply used to extract information from a vehicle’s computer, Mode 8 is a little different. Mode 8 allows bi-directional communication between the scan tool itself and the vehicle, allowing the tool to give commands to the vehicle.
This mode is one of the most effective for technicians who want to change settings and parameters on a vehicle’s computer. It can be used for a wide range of functions, but should always be used with caution.
Mode 8: Bi-Directional Communication
Mode 8 is available primarily on full-feature scan tools. Basic code readers, which hold less functions and come at a fraction of the cost, won’t come with Mode 8. If you want to use bi-directional communication, you’ll need an advanced scan tool like the Autel AL519, which generally costs $80 to $120 online. A code reader like the MaxiScan MS310 runs for less than $50, but doesn’t come with Mode 8.
So what can you do with Mode 8? Depending on your skill level and free time, quite a lot. Mode 8 allows the scan tool to run multiple self-tests by sending commands to the powertrain control module, or PCM. The function also allows the scan tool to control on-board (aka in-car) system or components.
There are many uses for Mode 8, so we’ll give you one example of it’s capabilities. Say a vehicle comes in with an obvious fuel system issue. By using Mode 8, a technician can test multiple parts in an attempt to find the problem. The technician uses Mode 8 to tell the fuel pump to engage. If the fuel pump runs, the technician can move on to another component. If, however, the fuel pump doesn’t engage, voila!, the cause of the issue has been found.
Talk to Your Car with Mode 8
There is a nearly unlimited number of uses for Mode 8. You can tell the vehicle’s computer to disable components, and can even make adjustments to sensors.
Just be sure you know what you’re doing, because it’s possible to make a change that significantly changes your vehicle’s performance or efficiency. Like your home computer, you don’t want to make adjustments that could crash the whole system.
If you do use Mode 8 correctly, you’ll be able to make a wide variety of changes and adjustments, and could even have a little fun tinkering with your car or truck.