Have'nt used the car since December which there was no problems. Started it up today and the warning light came on it went out once then came back on again and stayed on for 15 min till I shut the car off. Have stock hydroboost system. Just installed new calipers, wheel cylinders & hoses last March and a new hrdrobooster in August. There are no visible leaks and the fluid level was good. I did not have the emergencey brake on either. The manual says there is a hydralic problem but it does not tell you what to check.