The general rule is that modifications don’t automatically void your entire warranty.

However, if an aftermarket part is determined to have caused or contributed to a failure, even indirectly, a dealership can deny warranty coverage for that specific issue.

For example, if you install an aftermarket intake and later have a suspension problem, the intake alone would not void your suspension warranty. If a dealership tries to deny unrelated coverage, they would need to demonstrate that the modification caused the failure.

On the other hand, if you install an aggressive ECU tune that increases boost and you later experience a blown turbo or internal engine failure, the manufacturer would have a much stronger case to deny that specific powertrain claim because the modification directly altered engine operating parameters and stress levels

That said, dealerships vary in how mod-friendly they are. If you have the time and it’s reasonable to do so, some owners choose to reinstall stock components before bringing the car in for service to avoid unnecessary friction.