Programmer vs Module – What is the Difference?

programmer vs module

What is the difference between a programmer and module? Programmer, Modules, and Chip Tuning Oh My!

(For the purpose of this explanation the term tune or tuning will be used to encompass any signal or communication that occurs between the vehicles computer and engine.)

We get this question a lot at Thoroughbred Diesel. What is the difference between a programmer and a module?

By installing a programmer or a module you are adding a new tune to your vehicle through these performance products. By adding a new tune to your diesel vehicle, you are simply modifying the signals that the vehicle’s computer (ECM) sends to the electrical components of the engine. New programmers come with tunes already installed on them. New tunes can be added to your vehicle when downloaded to your programmer/module from an usb cable and the use of the internet. However, if your truck has been updated you will sometimes need to also update the tuner so that the tunes on it will be more compatible with the updates. The difference between a programmer and a module/chip can be explained by the manor in which that signal is modified.


Programmers are installed or downloaded directly to the vehicle’s ECM through the data port under the dash. This new program or data modifies the ECM’s calibrations so that the original signals are changed to incorporate the desired effects created by the selected tune. This new signal is then sent out to the electrical components of the engine. Thoroughbred Diesel refers to this kind of tuning as Pre-ECM modifications.


Modules or chips can be installed in many different places on a diesel vehicle and placement usually varies greatly depending on the effect the module is intended to have. To explain it simply, a module is installed somewhere in between the ECM and at least one electrical component that the ECM communicates with. When the signal leaves the ECM it travels through its normal route until it reaches the module. At this point the signal enters the module, is modified by the computer elements inside of the modules, and then exits the module and continues on its path to the desired electrical component. We refer to this kind of tuning as Post-ECM Modifications. Some modules do not ever need to be updated due to the components that they effect. Therefore, they cannot be updated.


Sits on the ecm computer board itself instead of controlling ecm signals going to the motor (module)

Immediately changes and controls the ecm settings by flashing the computer (programmer)


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