Vehicle Anti-Theft Systems (VATS) are designed to prevent car theft, but they can sometimes cause issues, especially when swapping engines or performing certain modifications. For users working with older General Motors vehicles, Tunercat Obdii software offers a solution to disable VATS directly through the engine control module (ECM). This guide provides a step-by-step walkthrough on how to disable VATS using TunerCat OBDII.
Disabling VATS with TunerCat OBDII: A Detailed Procedure
Here’s how to navigate TunerCat OBDII to effectively disable the VATS feature on compatible vehicles:
1. Load Your Calibration File and Access Code Patches
Begin by launching the TunerCat OBDII program on your computer. The first crucial step is to open the specific calibration file (.cal) associated with the vehicle you are working on. This file contains the operating parameters of the vehicle’s ECM. Once the file is loaded, locate the ‘Files’ menu at the top of the TunerCat OBDII interface. From this menu, select ‘Code Patches’. This action will open the ‘Code Patches’ screen, where pre-programmed software modifications are listed.
2. Apply the VATS Disable Code Patch
Within the ‘Code Patches’ screen, you should find the ‘VATS Disable’ patch. In most cases, this patch will be pre-selected or highlighted. To apply this patch, simply click on the ‘Apply’ button. After clicking ‘Apply’, verify that the box next to the ‘VATS Disable’ patch turns red. This color change visually confirms that the patch has been successfully applied to your calibration file. Once confirmed, click the ‘Exit’ button to close the ‘Code Patches’ screen and return to the main TunerCat OBDII interface.
3. Modify Calibration Options – Disable VATS Switches
Next, navigate to the ‘Switches’ menu located at the top of the TunerCat OBDII window. From the dropdown options, select ‘Calibration Options’. This section allows you to manually toggle various software switches that control different vehicle functions. In the ‘Calibration Options’ screen, carefully locate and uncheck the following switches. Unchecking these specific options is critical to effectively disabling the VATS system:
- VATS Enable
- VATS Auto Learn Enable
- Theft Relearn Password
- VATS Required to Run
- VATS Fail Enable Mode
- Clutch Interlock Enable (Manual Transmissions – if applicable)
By unchecking these boxes, you are directly deactivating the software components of the VATS within the ECM’s calibration settings.
4. Adjust Diagnostic Settings – Disable VATS Diagnostics
Proceed to the ‘Switches’ menu again, and this time select ‘Diagnostics’ from the dropdown list. The ‘Diagnostics’ screen allows you to configure which diagnostic trouble codes (DTCs) are reported by the ECM. To prevent VATS-related diagnostic issues after disabling the system, it’s important to disable the reporting of specific VATS DTCs. Uncheck the following diagnostic options:
- VATS Password Fail Diagnostic
- Starter Relay Diagnostic Enable
Disabling these diagnostic checks ensures that the ECM will not trigger error codes related to the VATS system after it has been disabled.
5. Configure System Parameters – Set VATS Type
Move to the ‘Constants’ menu at the top of the TunerCat OBDII interface. From the dropdown, select ‘System Parameters’. Within the ‘System Parameters’ settings, find the option labeled ‘VATS Type’. Set the ‘VATS Type’ value to ‘2’. This setting further configures the ECM to effectively bypass the VATS functionality.
6. Fine-tune Auxiliary Input Diagnostics – Disable Specific VATS DTCs
Go to the ‘Diagnostics’ menu and select ‘Auxiliary Input Diagnostics’. Scroll through the list of diagnostics until you locate the following DTCs related to the VATS system. These codes are often specific to VATS and should be disabled to prevent false positives or issues after VATS is disabled:
- Theft Deterrent Sys. Crank Signal (P1629)
- VATS Fuel Enable Circuit (P1630)
- VATS Learn Mode Active (P1631)
- VATS Fuel Disable Signal (P1632)
- VATS – Wrong Security Code (P1648)
- VATS – No Key/Code Programmed (P1649)
For each of these listed diagnostics, ensure they are unchecked and set to ‘No Error Reporting (Type X)’. This configuration prevents these specific VATS-related DTCs from being reported.
7. Configure Auxiliary Output Diagnostics – Disable Immobilizer DTC
Navigate to the ‘Auxiliary Output Diagnostics’ section within the ‘Diagnostics’ menu. Locate the diagnostic for:
- Immobilizer Key Not Programmed (P0633)
Similar to the auxiliary input diagnostics, set this diagnostic to be unchecked and configured for ‘No Error Reporting (Type X)’. This step is important for comprehensively disabling all aspects of VATS reporting and functionality.
8. Force Full Program When Flashing ECM
Important Note: When you are programming the ECM for the first time after applying the VATS Disable code patch, it is imperative to select the ‘Force Full Program’ option. This option is typically found within the ‘Setup’ menu of the WinFlash OBDII program (or similar flashing tool used with TunerCat). Performing a Force Full Program ensures that all the changes you’ve made with TunerCat OBDII, including the VATS disable settings, are correctly and completely written to the ECM. This step is crucial for the VATS disable to function as intended.
Conclusion
By following these steps within TunerCat OBDII, you can effectively disable the VATS on compatible GM vehicles. Remember to always double-check each setting and ensure you are working with the correct calibration file for your vehicle. Disabling VATS can be necessary for certain modifications or engine swaps, but always understand the implications and ensure all modifications are performed responsibly and legally. TunerCat OBDII provides a powerful tool for custom calibration and control over your vehicle’s ECM, and VATS disable is just one of its many capabilities.
