ASR light flashing

Hi fellows,
I need help with a VW Jetta 2000 1.8T 135000 km on it.When i start drive this car after sitting for a while,it start flashing the asr light and i cannot go faster than 40 miles.Than i just stop the car and start driving again and no more asr flashing.Have done a full scan on it and found no fault code.
any help please,

thanks