How To Read Live Data On OBD2: A Comprehensive Guide

Do you want to understand how your car’s engine is performing in real-time? Reading live data on OBD2 is the key. This allows you to monitor various parameters, diagnose potential issues, and keep your vehicle running smoothly. At OBD2-SCANNER.EDU.VN, we empower you with the knowledge and tools to effectively interpret OBD2 live data, unlocking insights into your vehicle’s health and optimizing its performance. By understanding key parameters and using OBD2 scanners effectively, you gain valuable insights into your car’s performance and can address potential issues before they escalate, saving you time and money.

1. What Is OBD2 Live Data And Why Is It Important?

OBD2 live data refers to the real-time information your vehicle’s onboard computer (ECU) transmits about its various systems and sensors. This data is invaluable for diagnosing problems, monitoring performance, and ensuring your vehicle is running efficiently. According to the Society of Automotive Engineers (SAE), the OBD2 standard provides a standardized method for accessing this data, making it universally compatible across different makes and models.

1.1. Understanding The Significance Of Real-Time Vehicle Information

Real-time data provides a snapshot of your vehicle’s current operating conditions. This includes parameters such as engine RPM, vehicle speed, coolant temperature, and fuel trim.

1.2. Benefits Of Monitoring OBD2 Live Data

• Early Problem Detection: Identifies issues before they become major repairs.
• Performance Monitoring: Tracks engine performance under different conditions.
• Fuel Efficiency Optimization: Helps improve fuel economy by identifying inefficiencies.
• Diagnostic Accuracy: Provides precise data for accurate troubleshooting.
• Informed Maintenance: Enables proactive maintenance based on real-time data insights.

1.3. How Live Data Enhances Diagnostic Processes

Live data allows you to see how sensors and systems respond to changes in real-time. For example, you can monitor oxygen sensor readings while accelerating to ensure they are within the proper range, verifying the functionality of your car.

2. Essential Tools For Reading OBD2 Live Data

To read OBD2 live data, you’ll need the right tools. These tools range from basic code readers to advanced diagnostic scanners.

2.1. Overview Of OBD2 Scanners And Their Capabilities

OBD2 scanners connect to your vehicle’s OBD2 port (usually located under the dashboard) and allow you to access the data stored in the ECU. According to a study by Grand View Research, the automotive diagnostic scan tools market is expected to grow significantly, driven by the increasing complexity of vehicle systems.

2.2. Types Of OBD2 Scanners: From Basic To Advanced

• Basic Code Readers: These are entry-level tools that read and clear diagnostic trouble codes (DTCs). They often display limited live data.
• Mid-Range Scanners: Offer more comprehensive live data capabilities, including graphing and data logging.
• Advanced Diagnostic Scanners: Provide extensive live data parameters, bidirectional controls, and advanced diagnostic functions.

2.3. Smartphone Apps And Bluetooth OBD2 Adapters

Smartphone apps paired with Bluetooth OBD2 adapters offer a convenient and affordable way to access live data. Apps like Torque Pro and OBD Fusion provide a wide range of data parameters and customizable dashboards.

2.4. Key Features To Look For In An OBD2 Scanner

• Live Data Streaming: Ability to display real-time data from various sensors.
• Graphing: Visual representation of data trends over time.
• Data Logging: Recording data for later analysis.
• Code Reading And Clearing: Ability to read and clear DTCs.
• Compatibility: Ensure the scanner is compatible with your vehicle’s make and model.

3. Connecting Your OBD2 Scanner To Your Vehicle

Connecting your OBD2 scanner correctly is crucial for accurate data retrieval.

3.1. Locating The OBD2 Port In Your Vehicle

The OBD2 port is typically located under the dashboard on the driver’s side. Refer to your vehicle’s owner’s manual if you’re unsure of its exact location.

3.2. Establishing A Secure Connection

• Turn off the ignition before connecting the scanner.
• Plug the scanner firmly into the OBD2 port.
• Turn the ignition to the “ON” position but do not start the engine.
• Follow the scanner’s instructions to establish a connection.

3.3. Troubleshooting Connection Issues

• Ensure the scanner is fully plugged into the OBD2 port.
• Check the vehicle’s battery voltage. A low battery can cause connection problems.
• Verify the scanner is compatible with your vehicle.
• Try a different OBD2 port if available.

4. Navigating The OBD2 Scanner Interface

Understanding the scanner’s interface is essential for accessing and interpreting live data effectively.

4.1. Understanding Menu Options And Settings

Familiarize yourself with the scanner’s menu options, including “Live Data,” “Freeze Frame,” and “Diagnostic Trouble Codes.” Adjust settings such as units of measurement (e.g., Celsius or Fahrenheit) to your preference.

4.2. Selecting Parameters For Live Data Monitoring

Choose the parameters you want to monitor based on your diagnostic needs. Common parameters include engine RPM, coolant temperature, and fuel trim.

4.3. Customizing The Display For Optimal Viewing

Customize the display to show the most relevant data in an easy-to-read format. Many scanners allow you to create custom dashboards and graphs.

5. Key OBD2 Parameters And Their Meanings

Understanding the key OBD2 parameters is crucial for accurate diagnosis. Here are some of the most important ones:

5.1. Engine RPM (Revolutions Per Minute)

Engine RPM indicates how fast the engine’s crankshaft is rotating. Abnormal RPM readings can indicate issues with the engine’s idle control system, ignition system, or fuel delivery system.

5.2. Vehicle Speed Sensor (VSS)

The VSS measures the speed of the vehicle. Inaccurate VSS readings can affect transmission shifting, cruise control, and anti-lock braking systems (ABS).

5.3. Engine Coolant Temperature (ECT)

ECT measures the temperature of the engine coolant. Abnormal ECT readings can indicate problems with the thermostat, radiator, or coolant temperature sensor.

5.4. Intake Air Temperature (IAT)

IAT measures the temperature of the air entering the engine. High IAT readings can reduce engine performance and fuel efficiency.

5.5. Mass Air Flow (MAF)

MAF measures the amount of air entering the engine. An inaccurate MAF sensor can cause poor fuel economy, rough idling, and loss of power.

5.6. Oxygen Sensor Readings (O2S)

O2S readings indicate the amount of oxygen in the exhaust gas. These readings are crucial for monitoring the air-fuel ratio and catalytic converter efficiency.

5.7. Fuel Trim (Short Term And Long Term)

Fuel trim values indicate the adjustments the ECU is making to the air-fuel mixture. Positive values indicate the ECU is adding fuel, while negative values indicate it is reducing fuel.

5.8. Throttle Position Sensor (TPS)

TPS measures the position of the throttle plate. Inaccurate TPS readings can cause poor acceleration, erratic shifting, and stalling.

5.9. Manifold Absolute Pressure (MAP)

MAP measures the pressure in the intake manifold. High MAP readings can indicate vacuum leaks or issues with the intake system.

5.10. Ignition Timing Advance

Ignition timing advance refers to the angle at which the spark plug fires relative to the piston’s position. Incorrect timing can cause engine knocking, reduced power, and poor fuel economy.

6. Interpreting OBD2 Live Data: A Step-By-Step Guide

Interpreting live data involves understanding normal ranges, identifying anomalies, and correlating data with vehicle symptoms.

6.1. Understanding Normal Parameter Ranges

Each parameter has a normal range that varies depending on the vehicle’s make, model, and operating conditions. Refer to your vehicle’s service manual or online resources for specific ranges.

6.2. Identifying Abnormal Readings And Their Potential Causes

• High Engine RPM: Could indicate a vacuum leak, faulty idle air control valve, or incorrect throttle position.
• Low Coolant Temperature: Could indicate a stuck-open thermostat or faulty coolant temperature sensor.
• High Fuel Trim Values: Could indicate a vacuum leak, faulty oxygen sensor, or clogged fuel injector.
• Erratic Oxygen Sensor Readings: Could indicate a faulty oxygen sensor, exhaust leak, or catalytic converter issue.
• Abnormal MAF Readings: Could indicate a dirty or faulty MAF sensor, vacuum leak, or restricted air filter.

6.3. Correlating Live Data With Vehicle Symptoms

Match live data readings with the symptoms your vehicle is exhibiting. For example, if your vehicle is idling rough and the short-term fuel trim is high, you may have a vacuum leak.

6.4. Using Freeze Frame Data For Diagnostic Insight

Freeze frame data captures a snapshot of the OBD2 parameters when a DTC is triggered. This data can provide valuable clues about the conditions that caused the fault.

7. Advanced Techniques For Analyzing OBD2 Live Data

Advanced techniques include graphing, data logging, and comparing data under different operating conditions.

7.1. Graphing Live Data To Identify Trends

Graphing live data allows you to visualize trends and patterns over time. This can help identify intermittent issues or gradual degradation of components.

7.2. Data Logging For Comprehensive Analysis

Data logging involves recording live data over a period of time. This is useful for analyzing performance under different driving conditions and identifying subtle issues.

7.3. Comparing Data Under Different Operating Conditions

Compare live data readings under different operating conditions, such as idle, acceleration, and cruise. This can help identify issues that only occur under specific conditions.

7.4. Using Bidirectional Controls (If Available)

Some advanced scanners offer bidirectional controls, which allow you to command certain vehicle systems to perform specific actions. This can be useful for testing components and verifying their functionality.

8. Common OBD2 Diagnostic Trouble Codes (DTCs) And Live Data Interpretation

Understanding common DTCs and their corresponding live data can streamline the diagnostic process.

8.1. P0171 And P0174: System Too Lean (Bank 1 And Bank 2)

These codes indicate that the air-fuel mixture is too lean. Live data to check includes:

• Fuel Trim: High positive values indicate the ECU is adding fuel.
• MAF Sensor: Low readings may indicate a faulty MAF sensor.
• Oxygen Sensors: Erratic or low voltage readings.

8.2. P0300: Random Misfire Detected

This code indicates that the engine is misfiring randomly. Live data to check includes:

• Engine RPM: Fluctuations or drops in RPM.
• Misfire Counters: Increased misfire counts on specific cylinders.
• Oxygen Sensors: Lean or rich readings on the affected bank.

8.3. P0116: Engine Coolant Temperature Circuit Range/Performance

This code indicates an issue with the engine coolant temperature sensor. Live data to check includes:

• Coolant Temperature: Readings that are out of range or do not change as expected.
• Sensor Voltage: Abnormal voltage readings from the coolant temperature sensor.

8.4. P0420: Catalyst System Efficiency Below Threshold (Bank 1)

This code indicates that the catalytic converter is not functioning efficiently. Live data to check includes:

• Oxygen Sensors: Downstream oxygen sensor readings that are similar to upstream readings.
• Catalyst Temperature: Readings that are too low or inconsistent.

8.5. P0011: A Camshaft Position Timing – Over-Advanced Or System Performance (Bank 1)

This code indicates an issue with the camshaft timing. Live data to check includes:

• Camshaft Position Sensor: Readings that are inconsistent or out of range.
• Engine RPM: Fluctuations or rough idling.
• Ignition Timing Advance: Abnormal readings.

9. Real-World Examples Of Diagnosing Issues With OBD2 Live Data

Real-world examples illustrate how live data can be used to diagnose common vehicle problems.

9.1. Diagnosing A Vacuum Leak Using Fuel Trim Data

Scenario: A vehicle is idling rough and has poor fuel economy.

Live Data Analysis: The short-term and long-term fuel trim values are both high positive. This indicates the ECU is adding a significant amount of fuel to compensate for a lean condition.

Diagnosis: The high fuel trim values suggest a vacuum leak. Inspecting the intake manifold and vacuum lines reveals a cracked hose. Replacing the hose resolves the issue.

9.2. Identifying A Faulty MAF Sensor With Live Data

Scenario: A vehicle has a loss of power and hesitates during acceleration.

Live Data Analysis: The MAF sensor readings are lower than expected during acceleration. Additionally, the engine load calculation is inconsistent with the throttle position.

Diagnosis: The low MAF sensor readings indicate a faulty MAF sensor. Replacing the MAF sensor restores normal engine performance.

9.3. Diagnosing An Oxygen Sensor Issue With Live Data

Scenario: A vehicle has a check engine light and the code P0131 (O2 Sensor Circuit Low Voltage Bank 1 Sensor 1) is present.

Live Data Analysis: The oxygen sensor voltage for Bank 1 Sensor 1 is consistently low, hovering around 0.1 volts.

Diagnosis: The low voltage readings indicate a faulty oxygen sensor. Replacing the oxygen sensor resolves the issue.

10. Tips For Accurate And Effective OBD2 Live Data Analysis

Follow these tips for accurate and effective OBD2 live data analysis.

10.1. Regularly Update Your OBD2 Scanner Software

Keep your scanner’s software up to date to ensure compatibility with the latest vehicle models and access to the most accurate data.

10.2. Consult Your Vehicle’s Service Manual

Refer to your vehicle’s service manual for specific parameter ranges and diagnostic procedures.

10.3. Use High-Quality OBD2 Scanners And Adapters

Invest in high-quality scanners and adapters to ensure reliable data and accurate readings.

10.4. Practice And Familiarize Yourself With Different Vehicle Models

Practice using your OBD2 scanner on different vehicle models to become familiar with the variations in data parameters and diagnostic procedures.

10.5. Seek Professional Assistance When Needed

If you’re unsure about interpreting live data or diagnosing a complex issue, seek assistance from a qualified automotive technician.

11. The Future Of OBD2 Technology And Live Data

OBD2 technology is continually evolving, with advancements in data logging, wireless connectivity, and cloud-based diagnostics.

11.1. Advancements In OBD2 Data Logging And Storage

Newer OBD2 scanners offer enhanced data logging capabilities, allowing you to record and store vast amounts of data for comprehensive analysis.

11.2. Wireless OBD2 Connectivity And Cloud-Based Diagnostics

Wireless OBD2 adapters and cloud-based diagnostic platforms enable remote monitoring, data sharing, and access to advanced diagnostic tools.

11.3. Integration With Mobile Devices And IoT (Internet Of Things)

OBD2 data is increasingly integrated with mobile devices and IoT devices, providing real-time vehicle health monitoring and predictive maintenance capabilities.

11.4. Predictive Maintenance And Vehicle Health Monitoring

OBD2 live data is being used to develop predictive maintenance algorithms that can anticipate potential issues and recommend proactive maintenance.

12. Why Choose OBD2-SCANNER.EDU.VN For Your Diagnostic Needs

At OBD2-SCANNER.EDU.VN, we’re committed to providing you with the knowledge, tools, and support you need to effectively diagnose and maintain your vehicle.

12.1. Comprehensive Resources And Educational Materials

We offer a wide range of resources, including articles, tutorials, and guides, to help you understand OBD2 technology and interpret live data effectively.

12.2. Expert Support And Guidance

Our team of experienced automotive technicians is available to provide expert support and guidance, answering your questions and helping you troubleshoot complex issues.

12.3. High-Quality OBD2 Scanners And Accessories

We offer a curated selection of high-quality OBD2 scanners and accessories from leading brands, ensuring you have the tools you need for accurate and reliable diagnostics.

12.4. Commitment To Customer Satisfaction

We’re committed to your satisfaction. If you have any questions or concerns, please don’t hesitate to contact us. We’re here to help you get the most out of your OBD2 scanner and keep your vehicle running smoothly.

By understanding How To Read Live Data On Obd2, you can take control of your vehicle’s health and performance. Whether you’re a seasoned mechanic or a DIY enthusiast, mastering OBD2 live data analysis is a valuable skill that can save you time, money, and frustration. Remember to consult your vehicle’s service manual, use high-quality tools, and seek professional assistance when needed. With the right knowledge and tools, you can unlock the secrets of your vehicle’s ECU and keep it running at its best.

Ready to take control of your vehicle’s diagnostics? Contact us at OBD2-SCANNER.EDU.VN today. Our team is ready to assist you with expert advice, high-quality tools, and comprehensive resources to ensure you get the most out of your OBD2 scanner. Reach out to us at 123 Main Street, Los Angeles, CA 90001, United States, or connect via Whatsapp at +1 (641) 206-8880. Let us help you unlock the full potential of your vehicle’s diagnostic capabilities.

Frequently Asked Questions (FAQ)

1. What is OBD2?

OBD2 (On-Board Diagnostics II) is a standardized system used in vehicles to monitor and diagnose various engine and vehicle parameters. It provides access to real-time data and diagnostic trouble codes (DTCs) to help identify potential issues.

2. What is live data on OBD2?

Live data refers to the real-time information that your vehicle’s onboard computer (ECU) transmits about its various systems and sensors. This data includes parameters such as engine RPM, vehicle speed, coolant temperature, fuel trim, and oxygen sensor readings.

3. How do I access OBD2 live data?

To access OBD2 live data, you need an OBD2 scanner or a smartphone app paired with a Bluetooth OBD2 adapter. Connect the scanner to your vehicle’s OBD2 port (typically located under the dashboard) and follow the instructions to establish a connection.

4. What are the key parameters to monitor in OBD2 live data?

Key parameters to monitor include Engine RPM, Vehicle Speed Sensor (VSS), Engine Coolant Temperature (ECT), Intake Air Temperature (IAT), Mass Air Flow (MAF), Oxygen Sensor Readings (O2S), Fuel Trim, Throttle Position Sensor (TPS), Manifold Absolute Pressure (MAP), and Ignition Timing Advance.

5. How do I interpret OBD2 live data?

Interpreting live data involves understanding normal ranges, identifying anomalies, and correlating data with vehicle symptoms. Refer to your vehicle’s service manual or online resources for specific parameter ranges.

6. What are common OBD2 diagnostic trouble codes (DTCs)?

Common DTCs include P0171 and P0174 (System Too Lean), P0300 (Random Misfire Detected), P0116 (Engine Coolant Temperature Circuit Range/Performance), P0420 (Catalyst System Efficiency Below Threshold), and P0011 (Camshaft Position Timing – Over-Advanced).

7. How can fuel trim data help diagnose a vacuum leak?

High positive fuel trim values (both short-term and long-term) indicate that the ECU is adding a significant amount of fuel to compensate for a lean condition, which can be caused by a vacuum leak.

8. What does the MAF sensor reading indicate?

The Mass Air Flow (MAF) sensor measures the amount of air entering the engine. Low MAF sensor readings during acceleration can indicate a faulty MAF sensor.

9. How do oxygen sensor readings help diagnose catalytic converter issues?

If the downstream oxygen sensor readings are similar to the upstream readings, it can indicate that the catalytic converter is not functioning efficiently.

10. What are some tips for accurate and effective OBD2 live data analysis?

Regularly update your OBD2 scanner software, consult your vehicle’s service manual, use high-quality OBD2 scanners and adapters, practice and familiarize yourself with different vehicle models, and seek professional assistance when needed.

OBD2 Parameter Identifiers (PIDs) and Their Impact on Vehicle Operation

Parameter Identifiers (PIDs)	Vehicle Operation
Vehicle Operation
Engine RPM	Engine Revolutions Per Minute; abnormal readings can indicate issues with the engine’s idle control system, ignition system, or fuel delivery system.
Vehicle Speed	Speed of your Vehicle; inaccurate VSS readings can affect transmission shifting, cruise control, and anti-lock braking systems (ABS).
Engine Coolant Temperature	Coolant temperature is usually measured by a coolant temperature sensor confined to the vehicle’s engine that feeds information in the form of electrical current to the engine control unit or ECU; abnormal ECT readings can indicate problems with the thermostat, radiator, or coolant temperature sensor.
Engine Oil Temperature	Oil temperature is usually measured through thermocouples, thermistors, or RTD sensors. It would be best to control oil temperature because of its specific working range.
Ambient Air Temperature	Ambient Air Temperature is the temperature outside the passenger compartment and measured by a thermometric sensor mounted inside or near the front of the vehicle’s bumper.
Barometric Pressure	Barometric Pressure, also known as Atmospheric Pressure, is usually measured by a BARO sensor. The PCM uses the sensor’s information to adjust fuel trim and engine timing. Note: The average vehicle barometric pressure is 14.7 PSI at sea level.
Accelerator Pedal Position	Pedal positions on the driver’s side of your car floor control your vehicle’s power and speed, which are the accelerator, the foot brake, and the clutch. Each pedal is measured and controlled by individual sensors.
Relative Accelerator Pedal Position	A sensor evaluates the accelerator pedal position based on the output voltages to the pedal position. The vehicle may not always show 100% when placed on the floor. Note: Sensor may show the average value of the multiple position sensors depending on the vehicle.
Commanded Throttle Actuator	The throttle position requested by the ECM based on accelerator pedal position.
Relative Throttle Position	The Relative Throttle position compares the throttle position and the learned closed position. Carbon builds up over time, and other factors may affect throttle behavior. Adjustments to the throttle position are made to compensate for the changes in the previous throttle position.
Absolute Throttle Position	Also known as the actual position of the throttle and measured through its opening, which is 0% if completely closed or 100% if it is fully open.
Control Module Voltage	It is the voltage supplied to the engine control unit whose value is close enough to the voltage when the vehicle is running. Note: It is not the same as the battery voltage.
Hybrid Battery Pack Remaining Life	The remaining total charge percentage in the hybrid battery pack. Note: Standard OBD2 doesn’t show individual cell data.
Hybrid/EV Vehicle System Status	The following parameters of Hybrid Electronic Vehicle systems will show in your OBD2 Scanner: – HEV Charging State: Charge Sustaining Mode (CSM), a control system that maintains a constant State of Charge, or on a Charge Depletion Mode (CDM), a control system that targets lower current valued SOCs. – Non-PHEVs permanent Charge Sustaining Mode- HEV Battery voltage that ranges from 0V to 1024V- HEV Battery Current ranges from (- value means it is at charging state) -3300 Amps to 3300 Amps.
Calculated Engine Load Value	It is the calculated MAF sensor value of the current airflow in the engine divided by the peak airflow. Note: The altitude corrects peak airflow.
Absolute Load Value	It is the normalized percentage value of air mass per intake stroke. It is calculated by dividing air mass per intake stroke (g) by air mass per intake stroke at 100% throttle. Note: Values differ when your vehicle is idle, parking, or without accessories.
Driver’s Demand Engine – Percent Torque	It is the maximum available engine torque percentage value based on accelerator pedal position, cruise control, and transmission requested by the ECM. Note: Other external factors such as traction control and ABS won’t affect the values.
Actual Engine – Percent Torque	It is also known as Indicated Torque, whose parameters are shown as the current percentage of total available engine torque, net brake torque, and friction torque required to run the engine without load.
Engine Friction – Percent Torque	It is the maximum engine torque percentage value required to run a ‘fully equipped’ no-load engine, including internal engine components, fuel, water pump, air intake, alternator, exhaust, and emission control equipment.
Engine Reference Torque	It is a torque rating of the engine considered as 100% value for Actual Engine Percentage Torque and other parameters with percentage torque outputs. Note: Its value is constant and never changes over time.
Engine Percent Torque Data	A parameter used when changes in vehicle conditions can cause torque reference to change.
Auxiliary Input/Output	It is a composite data point that is capable of providing details of the following vehicle system status: – On or Off Status of Power Take Off and Glow Plug Lamp – Park/Neutral or Drive/Reverse Status of Automatic Transmission – Neutral/Clutch In or In Gear Status of Manual Transmission – 1 to 15 Status of Recommended Transmission Gear
Exhaust Gas Temperature (EGT)	It is measured by sensors installed on the following systems to guard the components from critical overheating: – Turbo Charger – Catalytic Converter – Diesel Particulate Filter – Components of the NOX reduction system
Engine Exhaust Flow Rate	It is the flow rate of the air and fuel mixture ignited using a spark plug. To calculate engine flow rate, exhaust temperature, volumetric efficiency, engine size, and flywheel RPM are required.
Exhaust Pressure	It is displayed as an absolute pressure value when the engine is on and roughly ambient atmospheric value when it is off. Note: Report data from one or two exhausts depends on vehicle configuration.
Manifold Surface Temperature	Temperature value of the exhaust manifold’s outer surface.
Timing Advance for #1 cylinder	It is a manufacturer-specific timing regarding the angle of the top dead center (TDC) and the time before the #1 cylinder should fire. Note: A positive value means delayed spark plug firing, and a negative value means the spark plug fires before #1 cylinder reaches the top.
Engine Run Time	It is a parameter report which measures the total run time of the following engine status: – Engine Run Time in Seconds – Engine Idle Time In Seconds – Engine Run Time when PTO is engaged
Run Time Since Engine Start	Total run time in seconds since the engine starts ignition.
Time Run with MIL On	Total Engine run time since the activation of the check engine light after a code is thrown. Note: This parameter is different from the total elapsed time. For example, when you have been driving your car for 3 months and your check engine light came on a month ago, the value of this parameter will start when the check engine light started to occur.
Distance Traveled while MIL is Activated	The total distance your vehicle has traveled since the check engine light activation. Note: This parameter will reset once codes are cleared, or your vehicle’s battery is disconnected.
Time since Trouble Codes Cleared	Total Engine run time since the codes were cleared by your OBD2 Scan tool or the battery is disconnected.
Distance Traveled Since Codes Cleared	Total distance covered of the vehicle since the codes were cleared by the OBD2 Scan tool or battery is disconnected. Note: This parameter will not reset even if clearing non-engine codes are done.
Warm-ups Since Codes Cleared	The total number of engine warm-up cycles after clearing codes or disconnecting the battery. Note: A warm-up cycle is achieved when the coolant temperature reaches at least 40 °F after startup and reaches at least 170 °F.

Data Point	Description
Fuel & Air
Fuel System Status	This data point shows the status of two fuel systems which run in Open and Closed Loop Mode. – Open Loop Modes means the engine computer uses pre-programmed air: fuel ratios to decide the amount of fuel to be injected. – Closed Loop Mode means that the ECM uses the O2 sensor feedback to adjust the air: fuel ratio to prevent too much air or gas condition.
Oxygen Sensor Voltage	This sensor measures the generated O2 voltage within the vehicle system. The generated voltage should be from 0.1 V to 0.9 V. If the reading is within this range, your O2 sensor is working properly.
Oxygen Sensor Equivalence Ratio	Also known as the Lambda sensor. In closed-loop mode, this sensor will inform the engine to adjust the fuel and air mixture. While in open-loop mode, the engine won’t listen to it.
Oxygen Sensor Current	This is the current that flows within the Oxygen sensor, which means that if the value is 0 mA, it has a well-balanced air: fuel ratio. If it has a positive current, it has a lean mixture (more air than required), and if it is a negative current, it has a rich mixture (less air than needed).
Short Term Fuel Trim	It involves on-the-spot changes the computer makes in response to the oxygen sensor. If the sensor reads a lean mixture, the computer compensates it by adding fuel, and if the oxygen sensor reads a rich mixture, the computer leans the fuel mixture out.
Long Term Fuel Trim	The percentage of ECM adjustments calculates the quantity of fuel to be injected into the cylinders to compensate for the changes over a longer period. Note: Changes in Long Term Fuel Trim only take seconds to update, and it is permanently stored in the ECM memory.
Commanded Equivalence Ratio	Command Equivalence Ratio (CER), also known as lambda, determines the air and fuel ratio requested by the ECM. Wide Range O2 Sensored Vehicles – CER is displayed in both open and closed loop mode. Conventional O2 Sensored Vehicles – CER is displayed in open loop mode. – 1.0 display in closed loop mode
Mass Air Flow Rate	Mass airflow rate is the value measured by a vehicle MAF sensor which should be within the range from 2 to 7 g/s at idle and rise to between 15 to 25 g/s at 2500 rpm. Note: If you want to ensure your vehicle’s airflow rate, refer to your manufacturer’s specifications.
Intake Air Temperature	Intake Air Temperature (IAT) is the value of the temperature that travels through the engine cylinders. There are 3 IAT sensors in a vehicle with different functions: – To measure the air that enters the engine. – To measure the climate control system of a vehicle. – To measure the ambient air temperature.
Intake Manifold Absolute Pressure	It is the Manifold Absolute Pressure (MAP) Sensor inside the intake. It is measured by a MAP Sensor which works with the intake air pressure to determine the amount of air and fuel to ignite the cylinders. – Running Engine: 18 – 20 “Hg intake manifold vacuum – Idle Engine: 0 – 20 20 “Hg intake manifold vacuum
Fuel Pressure (Gauge)	Fuel pressure value. Note: This is a gauge value – a value of 0 indicates atmospheric/ambient pressure
Fuel Rail Pressure	Pressure in the fuel rail displayed as a gauge value (0 psi/kPa means an atmospheric/ambient pressure reading)
Fuel Rail Pressure (Absolute)	Pressure in the fuel rail displayed as an absolute pressure value – when the fuel rail is not pressurized this data point will display ambient pressure – roughly 14.7 psi or 101.3 kPa
Fuel Rail Pressure (relative to manifold vacuum)	Fuel pressure value relative to the intake manifold
Alcohol Fuel %	The ethanol/alcohol content as measured by the engine computer in percentage. For example, an E85 blend would show 85% for alcohol fuel percentage
Fuel Level Input	Percent of maximum fuel tank capacity
Engine Fuel Rate	Near-instantaneous fuel consumption rate, expressed in Liters or Gallons per hourEngine fuel rate is calculated by the ECM using the volume of fuel used during the last 1000 msNote: engine fuel rate does not include fuel consumed by diesel aftertreatment systems
Cylinder Fuel Rate	The calculated amount of fuel injected per cylinder during the most recent intake stroke – displayed in mg/stroke
Fuel System Percentage Use	This parameter displays the % of total fuel usage for each cylinder bank – up to a maximum of four banks. This data point will display data for two separate fuel systems (e.g. diesel & CNG) if supported by the vehicle.
Fuel Injection Timing	The angle (in degrees) of crankshaft rotation before top dead center ( BTDC) at which the fuel injector begins to operate. A positive angle indicates injector operation before top dead center, while a negative angle indicates operation on the downstroke after TDC