how to read o2 sensor live data

How to read Live Data easily from OBD-II scanning devices?

If you are a car owner, you must have been facing unwanted errors in the vehicle. Have you ever tried to solve those errors by yourself? Does it seem a hard job to you to understand the error codes? If the answer is positive, then no worries, because today, I will bring you a detailed article on how to read live data accurately produced from the OBD2 scanner. In this article, I will elaborate on the factors behind yielding inaccurate live data and provide some valuable tips to read and interpret those live data without the help of any mechanic.  

What is Live Data?

Modern vehicles are filled with loads of Innovative technologies. There are so many car parts and insights that it is actually not possible to memorize correctly. The OBD2 scanner has been introduced into the automobile arena to satisfy the fact. The OBD2 scanner depends on many sensors, and it communicates with the sensors to operate a foolproof onboard diagnostic mechanism. The live data is on-screen, showcasing various fault codes and error mechanisms in the vehicle. This live data & information is capable of producing numerous fault codes, and each of the fault codes is capable of detecting the actual error place and position in the car’s system. The DTC scanner can scan the generic codes as well as the manufacturer-specific codes with freeze-frame, permanent DTCS, State OBD check, different modes of the OBD2 scanner, drive cycle mode, and many more related codes. 

How Does The OBD2 Technology Work?

The onboard diagnostic system or OBD2 system is mainly a self-sufficient program that enables it to produce error data. There is an OBD2 port in the main interface of the car. That port is mainly situated under the dashboard or near the driver’s seat and console. So basically, you need to connect the OBD2 scanner with the 16- pin port. After the car is attached to the OBD2 scanner, it starts to produce the error codes on the scanner’s screen. Nonetheless, The scanner scans the full portions of the car, and it finds the faulty location.

The OBD2 system is an extensive system installed and all the parts in the car. Each sensor is linked with the other, and it actuates the DTC OBD2 codes. Among this variety of sensors, some particular sensors are responsible for promoting the error codes. A self-sufficient OBD2 tool can almost identify all the fault data, including the short-term fuel trim, long-term fuel trim, Exact throttle position, engine coolant temperature, a mixture of the air-fuel, intake air temperature, RPM, and many more.

The more advanced tool you use there is a possibility of getting more information. Some OBD2 scanners show poor efficiency and performance. With that kind of shabby scene, you cannot scan all the parts of your car. So the first criteria are to choose the correct and authentic OBD2 scanner for the scanning purpose. 

What type of data is available from the OBD scanner?

There is a bunch of data and information produced from a smart and capable OBD2 scanner. Here I will enlist the group of data that are produced from the OBD,

The number of ignition cycles, Oxygen sensor (HO2S) test result that shows the amount of oxygen that remains in the combustion system, Illumination of The Check Engine light (CEL), The highlighting of the Malfunction Indicator Light (MIL), condition of the Freeze frame data, vehicle identification number (VIN), Emission readiness status (ERS), the position of the pedal, speed of the vehicle, airflow rate, RPM, coolant leakage, spark advance, and optimum temperature, etc. 

Importance of Live Engine Sensor Data

The engine is the most valuable part of a vehicle, and the possibility of an engine failure is always a high stake incident. If you regularly inspect the engine, it can be saved from an unwanted failure. The Live Engine Sensor Data is a perfect medium for knowing the actual condition of the engine regarding all other supportive parts of the vehicle. Here I am enlisting the Live Engine Sensor Data’s importance in a detailed manner. 

  • Shows Updated Situation

The prime advantage of the live sensor data is to inspect the real condition and positioning of the engine and its computerized systems. The main Computer system or the PCM is the prime coordinator and the commander of a car’s whole sensor and circuit system. Live data is always a blessing to know the actual situation of the vehicle’s internal parts.

  • Identify the exact faulty part

The other advantage of the Live data sensor is that it enables the auto mechanics to figure out the exact faulty part in the system and repair those parts. Fixing the parts in a to and fro manner may collapse the whole thing, and it may miss repairing the actual fault part in the vehicle. Any car parts, like the main engine, the oil control valve, air-fuel mix ratio, and emissions, might be affected.

  • Easy to locate

The luminescence of the check engine light is really a frustrating incident for most professionals. There are so many factors behind the Illumination of the check engine light. Sometimes it is really hard to find out the actual faulty location. In that case, the CEL comes to the rescue. It pinpoints the exact location where there are any sorts of inconsistencies. Then the mechanic could take steps based on that live data sensor.

  • Clears error codes automatically

There is another worth mentioning fact about the live data sensor is that it can eliminate the OBD2 code by itself. These live data sensors are harmonious with the Onboard diagnostic system, and combinedly, they can clear the fault codes. After the elimination of the fault codes, the check engine light must be turned off by itself. 

These are some of the brilliant advantages of live data sensors. They can operate among all the parts in a vehicle and sneak out of the trouble location, and by inspecting those data, the mechanic can repair the vehicle. 

How to Interpret OBD2 Live Sensor Data?

Before interpreting the live sensor data, you need to obtain the codes first. Here the OBD2 scanner comes to the rescue. After connecting the scanning tool with the OBD2 port, it will show some generic codes and a live data sensor. At first, the data will be in the form of some unknown codes, and after a while, the device will convert the codes into readable and adjustable formations. Then the live data sensor will show some fault information regarding the vehicle. You can use a certified app to read the data. Suppose the device only produces the codes but does not generate the fault location information. bad o2 sensor voltage chart

In that case, you need to use other apps to interpret the codes, or you can manually search the codes online to extract the actual meaning of that trouble code. Many of the parts could be affected or suffer internal damage. You can check and repair those faults by yourself or can seek help from a professional. Some of the apps are helpful in understanding the live data codes, and they are torque Pro, OBD Auto Doctor, in CarDoc Pro, EOBD Facile, dash, OBDeleven, and HobDrive. Some of these tremendous apps are absolutely free, and some of them need to be purchased. Of course, the purchased apps are more premium than the free ones. There is a chance of miscommunication in the free apps, so I suggest purchasing one of these apps and enjoying a smooth interpretation of the live data. 

What are the Fuel Trims?

The fuel trim is basically the computer’s adjustment of the engine combustion system’s basic air-fuel mix system. The oxygen sensor checks out the particular amount of oxygen in the combustion system. It also calculates the amount of left-out oxygen from the combustion. The fuel trims are mainly responsible for the emission of EPA standard gasses and fumes. If the fuel trims fail to monitor the combustion system, then there is a chance of bad emissions from the vehicle that may showcase black and white fumes. The engine’s emission depends on different variables like the throttle (RPM), engine temperature, the operating condition of the ECM, etc. And the smooth operation of all of these depends on the correct air-fuel mix.

If the air-fuel mix has deteriorated due to some unwanted reasons, then the overall structure of the emission collapses. If the sensors and the wirings tear or bend, the entire emission system faces a hard operation. Then the computer quickly makes necessary adjustments to settle the emission system. This adjustment can be termed the fuel trim. Aside from the variables operating the emission system, the factory software is based on the performance of a new engine. The fuel trims have been calculated in percentages. If it shows a positive sign, then there is ample fuel in the engine, and if it shows a negative result, then it needs some more fuel to even the air-fuel mix.  

What is Short Term Fuel Trim?

The short-time fuel trim (STFT) is involved with the main section of the air-fuel mix. If the ECM is showing a lower fuel, then the short-time fuel trim adjusts the combustion by adding some fuel into the system. If the ECM produces a rich fuel mix percentage, then the short-time fuel trim adjusts the section by leaking some fuel from the main engine. what should long term fuel trim be

What is LongTerm Fuel Trim

The long-time fuel trim (LTFT) is harmonious with the short-time fuel trim (STFT), and they simultaneously operate to adjust the actual air-fuel ratio in the main engine. The LTFT increases the quantity of the fuel if the ECM signals a low fuel level, and the LTFT decreases the actual ratio of the air-fuel mix if the ECM is showing a rich percentage of fuel. Short Term Fuel Trim typically fluctuates between -10.0% and 10.0%, and Long Term Fuel Trim levels typically fluctuate between -5.0% and 5.0%. In case you experience another feature apart from the LTFT and STFT, then there may have occurred another severe problem in the section of the air-fuel mix. Repair those faulty factors as soon as possible to avoid any further inconvenience.

Introducing OBD2 Live Data Codes

The air-fuel mix ratio is dependent on some parts and features of the main engine. Let us check some of the parts related to the air-fuel mix ratio. 

  • Engine Revolutions Per Minute (RPM)

The (RPM revolutions per minute) denotes how fast your car’s engine can operate. The RPM indicates the efficiency of a particular vehicle. It is mainly the number of rotations of the camshaft and the crankshaft in one minute. The RPM refers to how many times a piston goes up and down in a particular cylinder. The RPM is very necessary for the successful operation of the engine. If it fails to rotate the cam and crankshaft, the engine’s mileage plummets badly. A clue makes it pertinent how many RPMs a vehicle should produce. The car, truck, and bike RPM are 600 to 1000, 600, and  1000 to1500 rpm, respectively. If the RPM is hampered due to any surging, decreasing, or stumbling, then take necessary steps to repair the rpm as it is solely related to the engine mileage and efficiency.

  • A voltage of Oxygen Sensor 

The oxygen sensor is one of the prime sensors for detecting the actual amount of oxygen in the combustion chamber and in the fuel operating section. The fuel mix ratio depends on the amount of oxygen available in the system. The standard of the actual voltage of the oxygen sensor relies on 0.45 to 0.5 volts. If the voltmeter exceeds the value, then there is a serious fault in the oxygen sensor. Make it repaired by a professional mechanic. 

  • Intake Air Temperature

The name denotes the proceedings themselves. It is the sensor that controls the entry of the perfect temperature air into the system. If the air does not have the perfect temperature, then the engine’s operation may fail. Too much warm or too much cold air is not good for the air-fuel mix in the combustion chamber. Cold air is denser than warm air. As a result, it needs more warm air to maintain the air-fuel mix ratio in the combustion compartment of the engine. This particular sensor regulates the entry of the standard temperature air into the system.intake air temperature sensor

  • The Temperature of the Engine Coolant 

Many kinds of liquids work in the engine to make it alive. Such liquids are the engine fuel itself, the engine coolant, lubrication between different parts, Liquid control substances, etc. The ideal temperature of the engine coolant is about 200°F to 220°F. If the temperature increases or decreases, then the vehicle will fail to operate. If the temperature is below the average, the ECU incorporates more fuel into the engine to adjust the low temperature.

  • Ignition Timing

The ignition time refers to the timing of the sparks related to the piston top in a spark-ignition engine. It controls the exact timing of the spark plug when igniting the fuel. The ignition timing is related to the piston position and crankshaft angle and regulates each compression stroke. If the spark timing is not compatible with the engine, it may cause vibration, stumbling, and destruction, and it directly affects the engine’s longevity, power, and fuel consumption. The ignition key must be set up in the perfect position so that it can operate the vehicle quite easily. 

  • Mass Air Flow

This sensor mainly calculates the amount of air that enters the intake system of the combustion engine. An internal air temperature (IAT) sensor is typically incorporated within the MAF (mass airflow) sensor. There are various types of mass airflow sensors, but the most significant one is the hot wire sensor. They actually control the inflow of warm air into the system. This sensor is directly correlated with the shifting of the gear in the engine. And also reduces the chance of exhaust emission in the main system. The mass airflow sensor readings must be within the optimum level as given in the user’s manual. A bad airflow sensor in the main engine may impede the natural movement of the engine, and also it may face hard starting, dither under load, may run rough, or operate excessively rich.mass air flow sensor

  • Manifold Absolute Pressure sensor 

The ECU operates the MAP or the Manifold Absolute Pressure sensor to detect the actual engine load, and it evaluates the absolute air pressure (barometric pressure minus intake vacuum) in the intake manifold. The Manifold Absolute Pressure sensor behaves if there is something wrong with the fuel pressure, it can create an inappropriate fuel-air mix, an inconvenience in the combustion compartment, excessive consumption of fuel, a decrease in the fuel economy, and so on. The OBD2 scanner generates the optimum level for the Manifold Absolute Pressure, and if it exceeds the real value, it will sloth down the speed of the engine. This sensor is very much significant to making the balance within the engine.manifold absolute pressure sensor

How to Get Accurate OBD2 Live Data?

You probably have connected a smart OBD2 device with the vehicle, but suddenly you notice that it is not giving accurate data or information. Some internal factors may affect the device and produce faulty data. So before connecting the device with the car, check out some factors that should be considered, 

  • Compatibility of the Vehicle

The very first consideration is if the car is compatible with the latest OBD2 system. There are so many devices and scanners available in the market. Some of them are manufacturer-specific, which means they can only read the data on a particular car model. The wise thing to do is buy a universal generic OBD2 scanner that can read live data and error codes in any car brand. You can search for the compatible OBD2 scanner in the nearest shop, or it will be perfect if you check the scanners online. There you will find a wide version of OBD2 scanners that are of premium quality. You can also take suggestions from a professional on which scanner you should buy, as a low-quality scanner may not detect all the vehicle’s internal issues. 

  • Connection and communication

There are lots of types of obd2 scanners in the market. There are wireless Bluetooth OBD2 scanners, scanners with wires, and many other automatic scanners. Whichever scanner you choose, you make sure it easily complies with your vehicle. Some scanners don’t support the vehicle system as they can read only some particular codes in a specific model of car. So while choosing the scanner, you must also check the compatibility. If you choose the wireless scanning device, then you can automatically connect it without the help of any wire. And if you purchase the wired scanning device, just simply connect the device with the main OBD2 port located under the dashboard beside the steering wheel at the driver’s end. By clicking that scanner with the port, it will easily scan the car’s entire system, detect the fault codes, and record live data in a detailed manner. 

  • Absolute Temperature

An optimum temperature is a must for scanning the vehicle with an OBD2 scanner. The engine could not start easily in a cold temperature, and it may struggle to initiate the operation. So before you connect the OBD2 scanner, make sure that it catches up with the heat nicely. For heating, the engine starts the car and lets it be for some time. After a while, when the engine reaches a temperature of 180°F, connect the scanner and scan the whole system. Heating up the whole system can produce accurate OBD2 live data.


Extracting live data is not that easy as many of us do not know about the codes and the live data produced from a vehicle. The prerequisite for getting the latest and appropriate data out of a vehicle you need to choose a compatible scanner device. It is not always mandatory that the OBD2 scanner gives accurate live data; there may be some severe fault in the live data. Following the above article can minimize the overall chance of getting wrong live data. This article has briefly discussed the factor that Can affect the live data of the vehicle. Follow these above guidelines strictly to understand the live data correctly without the help of a professional.

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