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Torque Converter Clutch Solenoid: Description and Operation
The purpose of the Transmission Converter Clutch (TCC) feature is to eliminate the power loss of the torque converter stage when the vehicle is in a cruise mode. The TCC system uses a solenoid operated valve to engage the TCC which couples the engine flywheel to the input shaft of the transmission through the torque converter. This reduces the slippage losses in the converter, which increases fuel economy. Another solenoid (pulse width modulator or PWM solenoid) is used to regulate fluid pressure to the TCC to "cushion" the apply of the clutch.
For the converter clutch to apply, at least two conditions must be met.
Internal transmission fluid pressure must be correct.
The PCM completes a ground circuit to energize the TCC solenoid in the transmission, which moves a check ball in the fluid line.
The PCM controls the TCC apply solenoid by looking at several sensors.
Engine must be in closed loop operation.
Vehicle Speed Sensor (VSS). Speed must be above a certain value before the clutch can apply.
Coolant Temperature Sensor (CTS). Engine must be warmed up before the clutch can apply.
The 4th gear switch is used as a input to the PCM. The PCM uses the switch signal for TCC engage and disengage points.
Throttle Position Sensor (TPS). After the converter clutch applies, the PCM uses the information ftom the TPS to release the clutch when the car is accelerating or decelerating at a certain rate.
Another switch used in the TCC circuit is a brake switch which opens the 12 volt supply to the TCC solenoid when the brake is
Torque Converter Clutch Solenoid: Testing and Inspection Checking TCC Solenoid
.DISCONNECT PCM GREEN CONNECTOR .FIND TCC SOLENOID WIRE FAOM PCM
(GREEN CONNECTOR -SEE SECTION 6E-AI .CHECK CONTINUITY BETWEEN PIN "D-
(ENGINE HARNESS! AND PCM !GREEN CONNECTOR) WIRING HARNESS PIN
TESTING IITCC" SOLENOID OPERATION IN THE
TRANS AXLE WITHOUT TRANSMISSION TEST BOX
LESS THAN 20 OR GREATER , THAN 50 OHMS
.CHECK INTERNAL TRANSAXLE WIRING HARNESS FOR OPENS OR GROUNDS
.IF WIRING HARNESS IS OK, REPLACE TCC SOLENOID
.IF THE TCC SOLENOID DOES NOT APPLY. CHECK JUMPER WIRE CONNECTIONS. IF NO SOLENOID APPLY STIll EXISTS. CHECK FOR THESE POSSIBLE CAUSES:
-LOOSE PINS IN TRANSAXLE CONNECTOR
-PINCHED OR BARE WIRE
-FOREIGN. MATERIAL IN SOLENOID
-LOOSE OR DEFECTIVE CONNECTORS AT SOLENOIDS
-INOPERATIVE SOLENOIDS, BROKEN COlL IN SOLENOIDS
Diagnostic Chart, TCC Solenoid (W/Out Test Hox)
Torque Converter Clutch Solenoid: Technical Service Bulletins Redesigned TCC Solenoid
TECHNICAL BULLETIN # 286
PWM solenoid changes
PWM Solenoid Changes
1994 and 1995 4T60-E units were upgraded to a redesigned TCC PWM solenoid assembly (P/N 8683535). The PCM controls the duty cycle
command to change lockup pressure. As always, the 4T60-E PWM solenoid remauls negative duty cycle controlled (the PCM controls the ground side of the solenoid circuit). In addition, models which previously did not use PWM controlled TCC were upgraded to PWM control for 1995.
Due to the changes made within the solenoid and circuits; it is imperative the correct solenoid be used for your application. Using the incorrect solenoid may result in TCC slip/shudder apply concerns.
Torque Converter Clutch Solenoid: Locations SSE & SSEI
~\ -CnUISE 1,1 L-- CONTROL
.VALVE -/ r -..
BRAKE SWITCH CONNECTORC1
Component Location View. Bebind lIP, Right of Steering Column
Behind LH side of IP, on brake pedal support