It sounds like the BICS system is waiting for another input. It could be the seat bar sensor, a pedal or handle out of neutral, or maybe even the engine speed sensor. If engine speed is not over about 500 rpm the machine will lock. Are there any fault codes being displayed? Follow all Safety and Maintenance Procedures as illustrated in the Operation and Maintenance Manuals for your machine! Remember to click ACCEPT if this info helps. Ask me more questions if necessary.