Troubleshooting Made Easy: A Guide to Using OBD2 Scanners for Car Diagnostics

If you’ve had more than your fair share of breakdowns, and are wondering why the ‘check engine’ light keeps coming up in the dash, then an easy way to find out is by using an OBD2 scan tool. This is the latest version of standard vehicle on-board diagnostics. It connects to your car’s DLC (direct link connector), or simply the OBD2 port, and scans vital engine and vehicle parameters. The tools can display faults as codes, or detailed readouts that pinpoint what the exact problem is. Some will also display recommended steps so that issues don’t happen again.

How Car Scanners Came About

OBD2 scanner

Diagnostics tools have been a thing since the 1960s, but were meant for different car makes and models until the late 1980s. This is when the tools were first used to measure fuel use and efficiency in fuel-injected cars. The data was scanned from preprogrammed software in the car’s ECU, that controlled (among other things) the fuelling and timing. Results deviating from defined ranges often meant engine issues that could hurt performance or lead to unwanted repairs. The diagnostic system was called OBD1 and read basic engine parameters.

Standardised connectors that could be used across all vehicle types were introduced in the late 1990s. leading to efficient OBD2 scanners. These connect directly to any car (regardless of make and model) and allow for more comprehensive diagnostic capabilities. Besides engine problems, the tools can detect faults in the transmission, the chassis and systems like the braking or steering. OBD2 ports became mandatory in all vehicles sold in Australia from 2007 onwards, so with rare exceptions, all cars are easy to hook up to an OBD2 scanner to display anything that’s gone wrong.

How They Work

Scanners are small enough to fit in the hand. They connect to the car’s OBD2 port (usually located under the steering wheel) via a cable or wirelessly with Bluetooth or Wi-Fi. They scan the software in the ECU, and present finds as a series of letters and numbers, or basically codes. More advanced units have comprehensive readouts that can find other potential issues that basic coder readers can’t.

Connecting the scanner is simple. The car ignition needs to be in the “on” position, but you don’t have to necessarily start the engine. On initial setup, most scanners require you to enter make, model and year. Basic units then allow you to do a diagnostic test. Any detected faults are either given as codes or a full readout.

Most scanners also have a clearing mode, meaning you can erase codes and faults in the ECU that light up the appropriate warning lights in the dash, Others can additionally show real-time performance parameters, such as current coolant temperature, engine speed, battery status, and more. Moreover, there’s also the possibility of accessing current and historical driving data, such as distance travelled or fuel consumption in a defined period, a feature fleet owners will find handy.

Code Readers, Scanners and More

OBD2 scanner

Not all diagnostics tools are equal though. And this depends on your needs and how much you’re willing to spend. Simple code readers are the cheapest choice, but you will need some type of reference for the displayed codes. Letters display issues with the Body (B), Chassis (C), Powertrain (P), or a communications fault (U), then followed by a series of numbers. The first number after the letter is either a 0, indicating a generic code, or 1 a manufacturer-specific code. The next number identifies the vehicle system in which the fault is located. 1 refers to the fuel and air metering, 2 to the fuel injector circuitry, 3 to the ignition, 4 to the exhaust and emissions, 5 to the idle or cruise control, 6 – the ECU and auxiliary outputs, and 7 and 8 to the transmission. The last two numbers define the exact code in question. For instance, a P0301 code denotes a generic powertrain issue, relating to the ignition in cylinder one.

Even basic readers supply most of the information car owners need. They also run emission tests to check for rich or lean mixtures, show your car’s VIN, and even display the current software version and whether it needs updating.

Full OBD2 scanners are often bigger, but still manageable with one hand, and offer more data. This relates to specific sensors, like the MAF or EVAP units on newer cars. They also do a self-diagnostics test to diagnose systems or parts that aren’t currently in operation, such as checking brake disc thickness. A related type of diagnostic tool, the four-mode scanner will additionally clear codes and lights that come up in general maintenance, such as the oil pressure light when changing the oil.

Finally, if you’re a mechanic or tuner, then bi-directional scanners make more sense. These have all the basic features but can also do active tests as well, such as assessing brake force without actually applying the brakes. Some can be embedded with updated or modified software to change basic parameters like fuelling and turbo boost pressure to change power curves. This is a boon for anyone adding performance parts and needs to balance out power delivery with any changes.

So, Why Have a Diagnostic Tool?

If you need precise and quick fault detection, then even basic code readers can save you thousands on repairs. The tools identify and pinpoint exactly what’s wrong with the car, even before lifting the hood or having the mechanic inspect it. This alone removes labour costs, and you won’t be paying extra for issues that simply aren’t there.

Scanners are also a mechanic’s best friend. They remove guesswork, give accurate results and save time with quicker repairs. And the devices can used across multiple vehicles, with the same precision. For car enthusiasts and tuners, they additionally offer a safe way of modifying any car for better performance. Lastly, the tools are a great way to keep your car in top condition, cut down on fuel costs, and diagnose potential problems that can soon become a safety and financial trap.