2011 Lexus IS 350 User Guide - Page 148

2-1. Driving procedures n If does not come on even after shifting the shift lever to S This may indicate a malfunction in the automatic transmission system. Have the vehicle inspected by your Lexus dealer immediately. (In this situation, the vehicle will operate as if the shift lever is in D.) n AI-SHIFT The AI-SHIFT automatically shifts the gear to the optimal position according to the driver performance and driving conditions. The AI-SHIFT automatically operates when the shift lever is in the D position. However, operating the "-" shift paddle switch will restrict the function's operation. (Shifting the shift lever to the S position cancels the function.) While in power mode, the engine speed may stay high while depressing the accelerator pedal and may remain high after releasing the accelerator pedal. This does not indicate a malfunction. 2 When driving CAUTION n When driving on slippery road surfaces Be careful of downshifting and sudden acceleration, as this could result in the vehicle skidding to the side or spinning. 155