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    Mastering Diagnostics #18: Calculated Load vs. Absolute Load

    Nov. 3, 2024
    Both these load PIDs hold tremendous value as they reflect the engine's breathability. Although they tell the same story, they tell it in two different languages.

    Motor Age Technical Editor, Brandon Steckler is back again with some more diagnostic nuggets from the driver’s seat. This time reflecting on the value of the frequently under-utilized PIDs, Calculate Load and Absolute Load.

    In this video Steckler reveals his regurgitated interpretation of the somewhat wordy SAE definition of each PID. Why?... So, techs will leverage them preliminarily in their driveability diagnostic approach.

    Both the Calculated Load (CALC_LOAD or ENG_LOAD) and Absolute Load (ABS_LOAD) PIDs hold value in the diagnostic evaluation of the engine’s breathing capability. Meaning they both tell a similar story, but in a different language.

    Calculated Load reflects how the engine is breathing during WOT at any point in time (regardless of elevation, engine temperature, air temperature, or rpm). This value represents available torque capacity, and it is compared to the engine’s maximum torque capacity (as in “100%”). The outcome is basically an expressed percentage value of maximum breathing capability.

    Absolute Load is based on the engine’s swept volume. For instance, a 3.0L engine is said to be 100% volumetrically efficient if it moves 3.0L liters of air in one engine cycle. If we turbo charge that same engine, it can move far more air (because it is being force-fed under pressurized induction from the turbo charger). That engine (under full boost) may reflect 190% Absolute Load but, that is the most it can breathe (meaning, 100% Calculated Load).

    Stick with Brandon in this video as he captures basic OBD2 global data from a scan tool from a normally functioning 2.3L turbocharged engine, and then when the turbo charger has been disabled. What do you expect to happen? Tune in to this episode of Mastering Diagnostics with Brandon Steckler and find out if your hypothesis is correct!

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    About the Author

    Brandon Steckler | Technical Editor | Motor Age

    Brandon began his career in Northampton County Community College in Bethlehem, Pennsylvania, where he was a student of GM’s Automotive Service Educational program. In 2001, he graduated top of his class and earned the GM Leadership award for his efforts. He later began working as a technician at a Saturn dealership in Reading, Pennsylvania, where he quickly attained Master Technician status. He later transitioned to working with Hondas, where he aggressively worked to attain another Master Technician status.

    Always having a passion for a full understanding of system/component functionality, he rapidly earned a reputation for deciphering strange failures at an efficient pace and became known as an information specialist among the staff and peers at the dealership. In search of new challenges, he transitioned away from the dealership and to the independent world, where he specialized in diagnostics and driveability. 

    Today, he is an instructor with both Carquest Technical Institute and Worldpac Training Institute. Along with beta testing for Automotive Test Solutions, he develops curriculum/submits case studies for educational purposes. Through Steckler Automotive Technical Services, LLC., Brandon also provides telephone and live technical support, as well as private training, for technicians all across the world.

    Brandon holds ASE certifications A1-A9 as well as C1 (Service Consultant). He is certified as an Advanced Level Specialist in L1 (Advanced Engine Performance), L2 (Advanced Diesel Engine Performance), L3 (Hybrid/EV Specialist), L4 (ADAS) and xEV-Level 2 (Technician electrical safety).

    He contributes weekly to Facebook automotive chat groups, has authored several books and classes, and truly enjoys traveling across the globe to help other technicians attain a level of understanding that will serve them well throughout their careers.  

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