Upgrade Your Code Reading With an App-Based Scan Tool

More Car Repair Bang for the Buck!

smartphone car repair
Using a smartphone to diagnose engine problems is the way to go. Getty

In the old days, you could diagnose most car problems with a stethoscope and a trained ear. If a repair shop was equipped with an exhaust gas analyzer and a distributor machine with oscilloscope, it was considered high tech. Times change, and so does the equipment needed to troubleshoot engine problems. In fact, it can be almost impossible to figure out what’s wrong with a vehicle today without access to the diagnostic codes stored in your car’s on board computer.

There are ways to gain access to these stored messages free, but if you wanted to do it at home or on a regular basis you were stuck buying a pricey code reader that still didn’t give you as much information as the pros were getting with their machines. A scan tool was even more cost prohibitive! (Check out this great Car Tech article on the difference between a code reader and a scan tool for more info!) 
Sometimes, the changing tide of the times goes your way. Technology has finally caught up with automotive troubleshooting, and there are now a number of apps you can buy which use the computing power of your smart phone to drive a powerful application that connects to your car’s computer, reads the codes, and in many cases provides some insight as to what those codes are telling you. It’s a major breakthrough in DIY repair that has broken a barrier that many saw as insurmountable when it came to working on their own cars or trucks.

Early versions of smart phone driven code readers relied on a tether — the phone’s data cable — to transfer the car’s data to the phone. This is par for the course when it comes to affordable standalone code readers, but the idea of your phone relying on a data cable for transferring info is so 2005.

The new generation of apps use a Bluetooth connection to read your codes, reset things like the Check Engine Light, and follow automotive data streams in real time. 

How Does It Work?
Since 1996 all vehicles were equipped with on board computers that take constant readings on the status of your car's systems. This data didn't do much for vehicles early on, but the computer would make a note -- so to speak -- if anything wasn't within the acceptable data parameters of a good running engine. These notes were stored in the computer as DTCs, or Diagnostic Trouble Codes. A technician could download these codes (using all sorts of odd methods, including something resembling morse code) and get information about what your engine needed to run better, or run at all. As technology progressed, so did the computers and the way they used all of the data, morphing into new generations of codes called OBD (for On Board Diagnostics) and then OBD-II. A modern car has a sensor on just about everything, and the computer not only watches the data, it reacts to changes in things like exhaust gas, cylinder head temperature and fuel efficiency, often "fixing" issues as they arise. The amount of data that a technician can download is massive, so a real computer was needed.

The technician connects the computer to a port under the dash which allows him or her to download information, reset things like Check Engine Lights, and even change settings within the car. Techs still use laptops every day, but the smart phone has become so powerful you can do lots of automotive computer work right from your phone. The cable has been replaced with a Bluetooth transmitter so you are no longer connected via a wire. In fact, you can leave the Bluetooth transmitter connected to your dash and see data in real time while your phone is safely sitting in your cupholder. 
Unless you need a dedicated reader that you want to knock around the toolbox, I strongly suggest investing in an app-driven scan tool. You'll be amazed at what they can do! 

For more info on new school code readers and my experience with a specific app-based tool, check out my review of the BlueDriver bluetooth powered scan tool and app!