Case: When adding a car under the General Pool, there is no facility to apply the Car Cost Limit. Do we need to manually enter the car limit value?

Answer: Yes, that’s correct. The Car Cost Limit is not available when the asset type selected in Tools is under the General Pool.

Please refer to this guide for details on how to apply the Car Cost Limit via Tools: Applying "Car Cost Limit" for Depreciation

Alternative Option: 

If you prefer, you can add the Asset Depreciation Schedule directly in the Tax Form instead.
Before doing so, it’s recommended to run the “Migrate Depreciation” process first to ensure all relevant data is properly reflected in the tax form.

Add asset worksheet in Label P10 of an ITR, Business > Other > P10 > B 
 
When you add the Asset Worksheet, you need to select "Motor Vehicles" as the "Asset Type and click "Yes" to the "Apply car cost limit?"  option line item.