Applying a Custom OS with RTT

Applying custom OS that includes RTT is similar to applying any other OS mod.

If you already have an existing VCM Enhancement applied to your vehicle and wish to use RTT, you will need to re-apply the VCM Enhancement with RTT from your stock GM OS.

CAUTION: Use these enhancements at your own risk. Modifications can result in permanent damage to vehicle components. Any modifications that change the vehicle's emissions from stock (most modifications do this) are not allowed by the EPA and are to be used for off-road applications only. Modifying or removing any emissions testing is illegal and subject to heavy fines. HP Tuners LLC is not liable for any type of damage caused by use of these enhancements. Use at your own risk!

To apply the enhancement to your PCM:

1. In VCM Editor, open the stock or existing tune read from the vehicle.
2. Select the OS tab. Enhancements that are available for the PCM's operating system will be listed under Code Modifications.

3. Apply the relevant modification by clicking the button.
4. Immediately save the file under a new name. DO NOT make any additional changes before saving the file. This is now your new "Base" file that must be used for all future tuning.
5. Close VCM Editor and then reopen it with the newly saved file. You should see that the operating system ID for the vehicle's PCM has changed from your original file.
6. For 2bar and 3bar enhancements only: The VE table will be full of invalid data. You *must* create a valid VE table before writing the file to the PCM.

NOTE: One strategy is to copy your previous VE table into the non-boost region and then copy and increase the last row of the VE table to the new boost area. It is important to start tuning on the rich side (higher numbers) and then work back to your desired AFR.

7. Save the file in the editor, you are now ready to write to the PCM.

IMPORTANT: The next step involves using the "Write Entire" option. Remember this option is not 100% recoverable on failure in some circumstances. Do NOT disconnect the battery if you have problems during this next step. Once this step is completed, you can use the normal "calibration only" write function for all tuning changes.

8. Connect to the vehicle and turn on ignition, wait 10 secs.
9. Still in VCM Editor with your file open, select Flash > Write Entire. The process takes approximately 2-4 minutes depending on vehicle type.
10. When the write is completed, turn off ignition and wait 30 secs.
11. Turn on ignition, wait 10 secs.
12. The PCM should display the new operating system ID.
13. At this point the PCM should now be running the new operating system and you can now use (much safer) calibration only writes for all future tuning changes.
14. For 2bar and 3bar enhancements only, remove the 1bar SAE Manifold Air Pressure PID and replace it with the appropriate 2 or 3 bar PID:
a. Open VCM Scanner and connect to the vehicle.
b. In the Channels list, right-click the Manifold Air Pressure (SAE) PID select Remove Channel.
c. Right-click in the Channels list and select Add Channel.
d. Go to the Engine > Airflow folder.
e. Choose either the Manifold Air Pressure - 2 bar or Manifold Air Pressure - 3 bar PID. Double-click to insert it into the table.

NOTE: If you don't do this, layouts that use MAP parameters will not function correctly.

15. For 1/2/3 bar Speed Density enhancements only:
Right-click the Mass Air Flow(SAE) PID and select Remove Channel.

NOTE: This removes the existing MAF PID. If you don't do this, layouts that use MAF parameters will not function correctly.

16. If you made any changes to the channel configuration in step 14 and/or step 15, click to save your changes.

You are now ready to select the RTT mode.