How to Use an OBD2 Scanner
An OBD2 scanner will save you hundreds on trips to the mechanic and they're pretty easy to use.
Aug 10, 2018
Have you ever been bothered by the check engine light but didn’t want to pay a mechanic to take a look at what’s causing it? Would you like to minimize emissions and increase the efficiency of the engine? Well, an OBD2 Scanner can assist you to achieve that and much more. This article will tell you the basics of using an On-Board Diagnostics (OBD) tool and how it can help you.
What is an OBD2 Scanner?
The OBD2 Scanner was developed when the need for a common standard for the computer interface of all vehicles was realized. This was to ensure that all cars met the same standards and that you would not need to buy different scan tools for each different model of car.
The On-Board Diagnostic, version II is used in the fuel injection ignition system and the automatic transmission. The scanner easily monitors sensors to collect data from all the systems of the car, including the engine. These computers then send commands to fire the cylinders and utilize this data to help make the combustion process much more efficient. The sensors measure values such as the engine rpm, engine temperatures, speed, camshaft, and crankshaft opening as well as the throttle opening.
They do so by calculating the correct amount of gasoline as well as the accurate time for ignition such that it would result in a clean, efficient, power source in terms of economy and pollution.
The computer looks at a number of metrics that can tell you a lot about how your car is operating. All in all, OBD2 Scanners are an important tool for any driver, even if they aren’t enthusiasts or mechanically inclined. It’s a great tool even if all you want is a second opinion on a mechanic’s recommendations.
The Check Engine Light
The OBD2 Scanner makes the lives of drivers better by saving them time and money. However, you can imagine the panic when it starts giving them an error. This error indicates a malfunction in the vehicle that should be checked out immediately.
The pesky “Check Engine Light” on the dashboard is also called the Malfunction Indicator Light or the MIL. This light, when turned on, means that the PCM (Powertrain Control Module) has received an error message from a sensor in the car.
The PCM uses and stores “Trouble Codes” that help identify which sensor sent out the message and where the problem underlies. An OBD scanner can help you find out what’s causing the check engine light to illuminate and can help you clear it.
The trouble codes are a series of letters and numbers that can help you identify and pinpoint the source of the error message.
Each code begins with a letter. These letters help you identify which system the error is coming from. The meanings of these letters are below:
P: The letter P stands for “Powertrain” and covers the fuel system, engine, transmission, ignition, etc. This contains the largest set of codes.
B: B stands for the “Body” which relates to the seatbelts, airbags, power seating
C: C means “Chassis” and covers everything related to the chassis including the brake fluid, axle, ABS etcetera.
U: U means undefined. These relate to the other aspects of the vehicle.
The letters are followed by a series of 4 numbers. The first number is either 1 or 0. The 0 codes refer to a generic code while the 1 code refers to manufacturer specific code.
The second number refers to the specific subsystem. For example, 7 might mean transmission. Here’s what the other ones mean:
0: Fuel and air metering and auxiliary emission controls
1: Fuel and air metering
2: Fuel and air metering (injector circuit)
3: Ignition system or misfire
4: Auxiliary emissions controls
5: Vehicle speed controls and idle control system
6: Computer output circuit
The third and the fourth number refer to the kind of specific problem the code relates to.
The P means the problem is from the powertrain section.
The 0 represents a generic code shared by all manufacturers.
The 3 represents the subsystem is the Ignition System.
The 01 represents that the cylinder number 1 has a misfire condition.
This could either mean that the dedicated ignition coil has worn out or the cylinder has suffered a leak.
However, these codes do not tell about the actual problem. Instead, they are like symptoms of these problems. For instance, a wiped out alternator will set off a number of 5 codes in other systems with no problem. It is up to you to make the connections and diagnose the root cause.
Types of Codes
The codes can be broadly classified into the following types:
These codes are live codes that malfunction and cause the indicator light to be turned on. For the MIL to be turned on, the code setting conditions have to occur for more than two operations of the vehicle.
These codes mean that the sensors have failed or detected a problem once. If they fail again, the MIL or the Check Engine Light will be turned on.
How to Use an OBD2 Scanner
Using the OBD2 scanner is quite simple. It involves the following steps:
Locate the DLC. The Diagnostic Link Connector in your vehicle is a 16-pin triangular shaped connector, located near the steering assembly on the left side of the dash. It is usually hidden behind a plastic panel that can easily be removed by hand. Sometimes it’s located lower in the footwell, close to where a driver’s knee or shin might be.
Turn the vehicle off.
Insert the OBD2 into the DLC.
Turn the car on, however, do not start the engine. The OBD2 will start communication with your computer.
You will see the screen displaying messages like “establishing data transmission link” and “searching for protocol”. However, if the screen is blank or does not light up, then reconnect it again for a better link. Your car may have a bad connector.
If the system does not work, then try checking your car cigarette lighter. Most systems use this circuit to power the device. If it does not work try for another connection.
Next, the scanner asks for the VIN (Vehicle Identification Number) as well as the model and the make of the car. The scanner might ask you to enter further specifications such as the engine type.
Next, find the menu once the device has started. Once you enter the menu select the Trouble Codes to open the codes menu.
The device will present you with a number of systems such as Powertrain, Body, etc. Select the one you want.
Next, you would see the pending codes as well as the active codes.
Pick the one you desire to see.
Check these codes with an official manual to see what the problem is.
How to Reset Your Check Engine Light
After you’ve done the repairs, or perhaps you do not want to see the light turned on again, you can easily turn the Check Engine Light off. The CEL off button is present on the main menu and the light will be turned off until the car has covered a certain amount of distance.
After resetting the CEL or MIL, the scanner allows you to check for the readiness of the vehicle. The PMC checks whether the fault has been corrected or not when you start driving the car around. You need to drive the vehicle around for a specific amount of time, which depends on the make and model of the car.
You can either correct the fault yourself or hire a mechanic to do it for you. The PCM will then check if the correct problem has been targeted. This can help you achieve efficiency in tuning and repairs.
Turn the OBD2 on again to check whether the car is ready or not.
View Data Menu:
Apart from the inspection menu, the tool has a data menu as well which allows you to view the data and numbers being read by the PCM.
This allows you to carefully monitor the oxygen sensor functionality, engine load, rpm, and temperatures. These potential trouble areas of the vehicle need proper monitoring to ensure the better life of the engine.
This information can further help you determine the problem with the vehicle. This allows you to see if you can solve it yourself or you need professional help.
Tips on Using an OBD2 Scanner
The data link connector is can be fragile, so ensure that you are gentle when you connect the scanner with the DLC. The 16 plugs in the cable are very delicate and fragile. They can be easily bent, so do not push too hard to connect it. Ensure the pin is in the right position before you proceed to the connection.
Do not start using a scanner with the engine running. The ignition should always be on electric power only, however, but the engine should not be running. That ensures the software does not get corrupted. Otherwise, you run the risk of damaging the software.
Carry the user’s manual with you. The manual for the OBD2 is very handy and can learn how to operate it and what the different codes mean. The best part about the manual is that it does not have to be printed. Instead, it can be easily downloaded online. This makes it easier to carry it around and to use it whenever needed.
Tips for Buying an OBD2 Scanner
If you wish to purchase an authentic version of the OBD2 Scanner, there are a few points you should consider first.
Check the compatibility of the device with your car. Is it compatible? Does it feature all the specs you need? You need to look at the latest technology as well. The OBD2 is very efficient and effective in displaying errors for various systems. This includes information about the service light system, airbag control, transmission, and engine specs, et cetera.
You should consider how user-friendly the device is. There is no point in buying a device you need a professional to use. Instead, choose one you can easily interact with.
Look at what kind of information it shows. Does it display all the information you need? Perhaps you need to monitor another specification. Look for these before you invest in a device.