Beretta V6-3100 3.1L VIN M SFI (1995)
Torque Converter Clutch Solenoid: Description and Operation
Torque Converter Clutch (TCC) Solenoid
PURPOSE
The Torque Converter Clutch (TCC) system uses two Powertrain Control Module (PCM) controlled solenoids for engagement; a Pulse Width
Modulated (PWM) solenoid valve, and an enable (apply) solenoid valve in the automatic transaxle to couple the engine flywheel to the input shaft
of the transaxle through the torque converter. This reduces the slippage losses in the converter, increasing fuel economy.
TCC OPERATION
For TCC to apply two conditions must be met:
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Internal transaxle fluid pressure must be correct. For information on internal transaxle operation, refer to Automatic Transaxle On-Vehicle
Service. Refer to Chart C-8A TCC Diagnosis will cover only the electrical operation of the TCC system. Under Computers and Control
System/System Diagnosis/Procedures/Diagnostic Charts/C Charts.
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The PCM grounds switches internally to turn "ON" solenoids in the transaxle. This moves check balls, which will allow the TCC to apply, if
the hydraulic pressure is correct as described above. The TCC "APPLY" solenoid controls the flow of transmission fluid to the TCC. The TCC
Pulse PWM solenoid varies the hydraulic pressure at the converter clutch regulator valve to make locking and unlocking of TCC smoother.
The PCM controls the TCC apply and PWM solenoids after looking at several parameters:
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Vehicle Speed Sensor (VSS). Speed must be above a certain value before the clutch can apply.
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Engine Coolant Temperature (ECT) sensor. Engine must be warmed up before clutch can apply.
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Throttle Position (TP) sensor. After the converter clutch applies, the PCM uses the information from the TP sensor to release the clutch when
the vehicle is accelerating or decelerating at a certain rate.
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The TCC brake switch, which opens a 12 volt signal to the PCM when the brake pedal is depressed.
