Most likely a RPM sensor error. Check to make sure your RPM lead is not running along side other radio system leads. If the error still continues, you probably have a bad rpm sensor. SpeedLow means the engine is not maintaining minimum RPM, typically a sensor problem but could be a pump issue as well. Watch the engine at idle, if RPMs drop off and pump voltage is jumping around trying to maintain, it is a bad pump... If RPMs are erratic or show zero at any point while engine is running the sensor is bad.