Beckman J-26 XP1 Error code 2

Hello I have a J-26 XP1 that spins up to about 1000 rpm then throws an error 2 code. Sometimes it works ok and will spin up to the 3500 rpm we need for a while then throws the error 2. I think this is a vacuum error code so I cleaned the rubber seal and now it seems ok but was hoping someone who has experienced this could give me any advice. Thanks