Details of the crash have not been made public but, in a press release on Monday, McLaren revealed Alonso's feedback has led to the installation of a new data sensor on the car.
"At the McLaren Technology Centre last week, Fernando met with his engineers and drove the simulator, to bring him up to date with the latest developments on the MP4-30 chassis and power unit," the statement said. "As part of that process he spent time with senior engineers, discussing the accident and reviewing the comprehensive data and analysis, all of which has been shared with the FIA.
"While there was nothing evident in the extensive car telemetry data, nor anything abnormal in the subsequent reconstructions and laboratory tests, Fernando recalls a sense of 'heavy' steering prior to the accident. Consequently, the team has fitted an additional sensor to the car, to increase our data capture."
McLaren also confirmed Alonso will travel with the team to Sepang. The Spaniard needs to pass a final test at the Malaysia circuit to be cleared to race.
"Fernando Alonso has been cleared to return to the McLaren cockpit at this weekend's Malaysian Grand Prix, subject of a final FIA assessment on Thursday. Since his Barcelona testing accident, Fernando has followed a rigorous, specialised training programme, designed and closely monitored by leading sports scientists, to ensure his safe and timely return to racing.