Diagnosis - 4L60-E: Description

The 4L60-E transaxle uses 2 electric shift solenoids to control transmission upshifts and downshifts. In addition, a pressure control (duty-cycle motor) solenoid controls hydraulic line pressure, and a Torque Converter Clutch (TCC) solenoid controls TCC application. A 3-2 control solenoid modulates hydraulic pressure for the 2-4 band and 3-4 clutch to improve 3-2 downshift. Solenoids are turned on and off by the Powertrain Control Module (PCM).

The PCM receives signals from various transmission sensors. The sensors include engine speed and throttle position, transmission speed, hydraulic pressure and transmission fluid temperature. The PCM has on-board self-diagnostics to help identify any parts or circuits that may need further testing.