Component Diagnostic Charts (C-Charts) - Port Fuel Injection

Chart C-8A - Torque Converter Clutch:

Wiring Diagram for Torque Converter Clutch:

CHARTC-8A TORQUE CONVERTER CLUTCH (TCC) DIAGNOSIS


Circuit Description:

The purpose of the torque converter clutch feature is to eliminate the power loss of the transmission/transaxle converter when the vehicle is in a cruise condition. This allows the convenience of the automatic transmission/transaxle and the fuel economy of a manual transmission/transaxle.

Fused battery ignition is supplied to the TCC solenoid through the brake switch, and third gear apply switch. The ECM will engage TCC by grounding CKT 422 to energize the solenoid.


TCC will engage when:

Engine warmed up to above 65 degrees C
Vehicle speed above a calibrated value
Throttle position sensor output not changing, indicating a steady road speed
Third gear switch closed
Brake switch closed


Test Description: Numbers below refer to circled numbers on the diagnostic chart.


1 . Light "OFF" confirms torque third gear apply switch is open.

2. At 20-25 mph the torque third gear apply switch should close. Test light will come on and confirm battery supply and closed brake switch.

3. Grounding the diagnostic terminal with ignition "ON," engine "OFF," should energize the TCC solenoid by grounding CKT 422. This checks the capability of the ECM to supply a ground for the TCC solenoid.


4. Solenoids and relays are turned "ON" or "OFF" by the ECM internal electronic switches called "drivers." Each driver is part of a group of four called quad-drivers. Failure of one can damage any other driver within the set. Before replacing ECM be sure to check the coil resistance of all solenoids and relays controlled by the ECM. See ECM CHART C-1 for the solenoid(s) and relay(s) and the coil terminal identification. When checking TCC solenoid, be sure to raise drive wheels and run about 20-25 mph to close third gear apply switch.