Diagnosis - Aw-4: Description

The transmission electronic control system on the Aisin Warner 4 (AW4) controls transmission shift points and torque converter lock-up. Electronic control system consists of Transmission Control Unit (TCU), valve body solenoids, throttle position sensor, speed sensor, neutral safety switch and brake switch. On 1991 models, a POWER/COMFORT switch is mounted on the instrument panel. Switch is an automatic transmission mode selection switch which allows the driver to select different modes to change transmission upshift characteristics.