Section 70 (Automatic Transmission Diagnosis - 4L80-E (Gasoline)): Description: Notes
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The 4L80-E transmission uses 2 electric shift solenoids to control transmission upshifts and downshifts. In addition, a pressure control (force motor) solenoid controls hydraulic line pressure, and a Torque Converter Clutch (TCC) Pulse Width Modulated (PWM) solenoid is used to control fluid acting on converter clutch valve, which then controls TCC apply and release. Solenoids are turned on and off by a Vehicle Control Module (VCM).
VCM receives signals from various transmission sensors. Sensors include engine speed and throttle position, transmission speed, hydraulic pressure and transmission fluid temperature. VCM has on-board self-diagnostics to help identify any parts or circuits which may need further testing.