Output
Electronic Component Description (Output)Torque Converter Clutch (TCC) Solenoid
The Torque Converter Clutch (TCC) solenoid is a normally closed, Pulse Width Modulated (PWM) solenoid used to control apply and release of the Torque Converter Clutch (TCC). The PCM/TCM operates the solenoid with a negative duty cycle at a fixed frequency of 42 Hz to control the rate of TCC apply/release. The solenoid's ability to ramp TCC apply and release pressures results in a smoother TCC operation.
When vehicle operating conditions are appropriate to apply TCC, the PCM/TCM immediately increases duty cycle to approximately 68%. The PCM/TCM then ramps duty cycle up to approximately 93% to achieve full TCC apply pressure. The rate at which the PCM/TCM increases duty cycle controls TCC apply. Similarly, the PCM/TCM also ramps down TCC solenoid duty cycle to control TCC release.
Some operating conditions prevent or enable the TCC apply under various conditions. Also, if the PCM/TCM receives a high voltage signal from the brake switch indicating that brake pedal is depressed, the PCM/TCM immediately releases the TCC.
The TCC solenoid resistance should measure between 10-11 ohms when measured at 20°C (68°F). The resistance would measure approximately 16 ohms at 150°C (300°F).
Pressure Control Solenoid
The Pressure Control (PC) solenoid is a precision electronic pressure regulator that controls transaxle line pressure. This control is based on flow of current through solenoid coil windings. As the flow of current is increased, the magnetic field which is produced by the coil moves the solenoid's plunger further away from the exhaust port. Opening the exhaust port decreases output fluid pressure regulated by the PC solenoid, which ultimately decreases line pressure.
The Powertrain Control Module (PCM) or Transaxle Control Module (TCM)controls the PC solenoid based on various inputs, including throttle position, transaxle fluid temperature, MAP, and gear state.
The PCM/TCM controls the PC solenoid on a positive duty cycle at a fixed frequency of 614 Hz. Duty cycle is defined as percent of time current is flowing through the solenoid coil during each cycle. A higher duty cycle provides a greater current flow through the solenoid. The high (positive) side of the PC solenoid electrical circuit at the PCM/TCM controls PC solenoid operation. The PCM/TCM provides a ground path. The PCM/TCM monitors average current and continuously varies the PC solenoid duty cycle to maintain the correct average current flow.
The resistance of the PC solenoid should measure between 3 - 5 ohms at 20°C (68°F).
Shift Solenoid: 1-2 and 2-3
Shift solenoids are two identical, electrical exhaust valves that control upshifts and downshifts in all forward gear ranges. These valves are normally open. These shift solenoids work together in a combination of ON and OFF sequences in order to control positions of 1-2, 2-3 and 3-4 shift valve trains. The PCM/TCM monitors numerous inputs to determine the appropriate solenoid state combination and transaxle gear for the vehicle operating conditions.
Important: The solenoid states are normally ON (1-2) and OFF (2-3) in the P, R, and N gears. However, these may change based on the vehicle speed and throttle position.
The PCM/TCM energizes the shift solenoid by providing a ground to the solenoid's electrical circuit. This sends current through the coil winding of the solenoid, thereby creating a magnetic field. The magnetic field repels the plunger inside the solenoid. This seats the solenoid metering ball against the fluid inlet port. This action provides an increase in fluid pressure at end of shift valves. This fluid pressure initiates an upshift by moving the shift valves. The resistance of the shift solenoids should measure between 19 - 24 ohmswhen measured at 20°C (68°F) and between 24 - 31 ohms when measured at 88°C (190°F). The shift solenoid should energize when voltage is greater than 7.5 volts and de-energize when voltage is less than 1 volt.
Oil Level Control Valve
The oil level control valve is located on the bottom of the case next to the fluid filter, and is designed to control the fluid level in the side cover. At low temperatures, the thermostatic element exerts little pressure on the thermostatic element plate allowing fluid to drain into the sump (left balloon). As the temperature of the fluid increases, the thermostatic element begins to apply pressure to the thermostatic element plate, thereby trapping fluid in the side cover (right balloon). This level of transaxle fluid is required in order to maintain the operation of the hydraulic system in the transaxle.
It should be noted that when checking the fluid level, it will be higher when the transaxle is cold. Conversely, the fluid level will drop when checked at operating temperatures. Thus, the fluid level of the transaxle must be checked when the fluid is at operating temperature.