The Tuner program is a general purpose ECM calibration editor that allows you to make a wide variety of calibration changes to your vehicle's ECM/PCM from an easy to use Windows environment. The program locates and displays the calibration parameters in standard engineering units so there's no need to work with or even understand hex and binary numbers.

With the addition of the appropriate ECM Definition File, the C.A.T.S. Tuner program supports a wide range of vehicles .

Each ECM Definition file is designed to give you access to the calibration parameters required to support major engine modifications, such as Cams, larger displacement (strokers), Injector size changes, etc.

Click on this link to view the Tuner User's Reference Manual for a detailed description of how to use all the features of this powerful program.

The example shown here is a type $42 ECM (1227747) used  in standard duty 87- 91 C/K Pickup Trucks and Vans. The ECM Definition Files for the next generation of PCMs are considerably larger and include transmission control functions.

Key calibration parameters, selected from a drop down menu, can be easily viewed and edited. 
  • ECM Switches  - off/on functions
  • ECM Constants - single value functions such as:
    • Injector Flow rate

    • Engine Displacement
    • EGR parameters 
  • Two and Three Dimension Tables 
    • All values in engineering units, (no Hex)

Typical 2D Table 

"Pump Shot" Vs. Differential TPS
(Added fuel for acceleration)
Changes to calibrations may be made on the table or the graph

Type $42 ECM Drop Down  Menu

(1227747 ECM)

Typical 3D Table (Main Spark)
Changes can be made on the table or the 3D graph by "clicking and dragging" a data point.
Main Spark Graph

The Tuner program is a Windows based utility developed to easily make changes to GM ECM/PCM engine and transmission control parameters. The program is designed to run on 32/64 bit Windows operating systems. (For more information on installing the program on a PC running Windows 7, 8 or 10 please see our FAQs page.)


Try our Tuner program free for 30 days. To purchase a copy of the program see the 'How To Order' page for details or click the 'Add to Cart' button. As soon as we receive your order we'll send you the information to register the program.

Additional ECM Definition files are available for $19.95 USD. See the 'ECM Definition Files' Page for a list of currently available ECM Definition Files.