What was found
(CAN) DURING TAXI AT IDLE BEFORE TAKEOFF, THE OIL PRESSURE WENT TO 0. THE CREW ELECTED TO SHUT THE ENGINE DOWN BEFORE RETURNING TO THE RAMP. SUBSEQUENT TROUBLESHOOTING LED TO TIGHTENING THE CONNECTOR FOR THE OIL PRESSURE DIFFERENTIAL SWITCH AND REPLACING THE COCKPIT OIL PRESSURE INDICATOR. ALL OTHER CHECKS WERE SATISFACTORY AND THE ACFT WAS RETURNED TO SERVICE.