Functional Description

The A300 control unit monitors engine speed (terminal No. 21), injection signal (terminal No. 11), throttle position (terminal No. 7), road speed (terminal No. 8), kick-down signal (terminal No. 2), gear selector position (terminals No. 30, 28, 29, and 18), and program switch signal (terminals No. 14, 15, and 4). The A300 control unit electronic processing circuit compares this information with the A300 control unit program data. The A300 control unit then selects the correct gear and clutch engagement rate by controlling the shift valve solenoids and the hydraulic pressure regulator. The A300 control unit retards engine time during shifts by grounding terminal 24 for one second when shifting gears. This provides for a smoother shift.

The A4 check control module displays TRANSMISSION if a problem with the control system occurs. If a fault is detected, the transmission emergency problem turns on. Voltage to the Y300 transmission (terminal 1) is turned OFF and the vehicle can be driven only in third and reverse gears. NEUTRAL and PARK retain their functions.