One problem related to service engine light on has been reported for the 2001 Saturn LS. The most recently reported issues are listed below.
On 3 separate occasions I was driving and went to accelerate to pass a vehicle when the vehicle lost power causing me to put the vehicle into neutral to restart it causing the service engine soon light to come on and the vehicle to have hard shifting. The result was due to the failure of the O2 sensor which I replaced once with Saturn that failed 2 years later and 2 others refurbished that were purchased from napa which the first failed 3 months after installation and the other a month after that one was replaced.