i-Shift Function The i-SHIFT system is a system where the Transmission Control Module (TCM) determines the optimal condition based on the vehicle's change of wheel speed due to the operation of the accelerator and brakes, and then the actuator changes the vehicle speed. i-SHIFT system enables switchover between Auto mode and Manual mode. In the Auto mode, it automatically shifts gear appropriate for the driving condition, based on the shift transmission characteristics in the Transmission Control Module (TCM).In the Manual mode, changing gears is done manually by using the shift lever or the steering wheel shift switch. While driving, the gear range is shown in the speedometer, and if abnormalities or malfunctions occur, a warning is displayed in the i-SHIFT indicator of the gauge control module (tach) and the multi-information display.This technology didn't last as a lot of Honda owners struggled with it features and a lot of remedial work by Honda did dents it popularity and ultimately the technology has been withdrawn. But this thread is for people who still have Civic and Jazz with the i-Shift gearbox. System Components. The beauty of the i-shift system is it’s simplicity. The clutch and gearbox are very similar to a standard car - but not identical. Change Actuator The gear shift lever and cables are replaced with electric actuators mounted on the transmission case. Clutch Actuator The clutch pedal is replaced by a hydraulic actuator which connects to a standard clutch slave cylinder. Both actuators are controlled by the TCU (transmission control unit) which is fitted to the back of the clutch actuator. There are also some wiring harnesses and two clutch pipes. Operation Auto mode In the Auto mode, the indicator in the speedometer shows an ‘‘A'', and the REV indicator does not appear. Driving in auto mode is possible when the shift pattern in the shift lever is moved from ‘‘N'' to Driving Position after engine startup, and when ‘‘A/M'' is selected in the shift button. After selecting ‘‘A/M'' in the shift button, the shift lever normally returns to driving position. Based on the automatic gear-shifting map in the transmission control module (TCM), the clutch actuator and the transmission shift change actuator shifts gear from speed 1 to speed 6. Manual mode In the manual mode, the indicator in the speedometer shows the speed gear used and the speed while driving, and the REV indicator appears. When in the Auto mode, if ‘‘+'' or ‘‘−'' is selected in the shift button, reselecting ‘‘A/M'' enables driving in Manual mode. After selecting the shift pattern, the shift lever normally returns to driving position.In Manual mode, by operating the shift lever in the gear shift control module and the shift switch in the steering wheel, any speed gear can be selected. Neutral mode In the Neutral mode, the indicator in the gauge control module (speed) shows an ‘‘N'', and the REV does not appear.By selecting ‘‘N'' in the shift pattern, the shift lever is retained, and the transmission clutch changes to neutral condition. At this time, the speed gear for the transmission is not engaged. Furthermore, engine startup is possible only in Neutral mode. Reveres mode In the Reverse mode, the indicator in the gauge control module (speed) shows an ‘‘R'', and the REV does not appear. By selecting ‘‘R'' in the shift pattern, the shift lever is retained, and rollback becomes possible. Troubleshooting and handling tips Parts Replacement & Handling Many of the components on the I-SHIFT system are not dealer serviceable. The change actuator and clutch actuator must not be disassembled. The TCU is mounted to the clutch actuator and the two parts are not available separately. Brake fluid is used in the clutch actuator. If you order new parts you will see caps on the two fluid ports - these caps must be transferred to the faulty unit to prevent contamination of the other parts. Please note: analysis is not possible on units that have been disassembled or where the caps are not fitted to the fluid ports. i-Shift Learning The software in the TCU is constantly evolving. Each time the car is driven the parameters in the TCU will change to adapt to the vehicle characteristics and owners style. The TCU parameters are set before the car leaves the factory but as the car is used the values are tuned and improved upon. For this reason, you may find that owners’s comment that the way their car drives has improved since they first drove it - this is a feature of the system.