K 3500 Truck 4WD V8-5.7L VIN R (1998)
Torque Converter Clutch: Description and Operation
4L80-E Automatic Transmission
TORQUE CONVERTER CLUTCH SOLENOID VALVE
The VCM/PCM energizes the Torque Converter Clutch Pulse Width Modulated (TCC PWM) solenoid valve, which is located on the transmission
valve body. The TCC PWM solenoid valve acts on the TCC apply valve in order to control the torque converter clutch application.
The TCC PWM Sol. Valve is pulse width modulated by the VCM/PCM. This means that the VCM/PCM pulses the solenoid so that the hydraulic
pressure against the torque converter clutch modulates. This modulated pressure allows the TCC to slip slightly, thus keeping the TCC balanced just at
the point of engagement.
One diagnostic code is associated with the TCC PWM solenoid valve Code P1860, TCC solenoid circuit-electrical, detects a fault in the TCC circuit.
While Code P1860 is set, both fourth gear in hot mode and the TCC are inhibited. Shift adapts does not update and the MIL illuminates. Recovery can
occur on the next ignition cycle.
