How do you reset the tire pressure warning light on a VW Golf GTi?

All you need to do is check the tire pressure on all 5 tires, if it is correct then the light will turn off. Probably your problem is the spare tire. You can remove the spare tire by taking off the little plastic cap under the compartment in the trunk, towards the right side, very close to the back of the car. There is a tool to turn the nut that you will find under the round plastic cap (approx 3") and the spare tire will lower to the ground. I've had the TMPS turn on my car twice and it was always the spare tire. IMPORTANT: Make sure you are not missing the aluminum tire valve caps. Plastic replacements (or none) will cause the warning light to come on.