Component Tests and General Diagnostics

Chart C-8:

Chart C-8 Wiring Diagram:

CIRCUIT DESCRIPTION:

The purpose of the torque converter clutch feature is to eliminate the power loss of the torque converter when the vehicle is in a cruise condition. This allows the convenience of the automatic and the fuel economy of a manual transaxle. The heart of the system is a solenoid located inside the transaxle which is controlled by the ECM.

When the solenoid coil is activated ("ON,") the torque converter clutch is applied which results in straight through mechanical coupling from the engine to the wheels. When the transaxle (TCC) solenoid is deactivated, the torque converter clutch is released which allows the torque converter to operate in the conventional manner (fluid coupling between engine and transaxle).


TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. A test light "ON" indicates battery voltage and continuity through the TCC solenoid is OK.

2. The vacuum hose on the throttle shaft pin increases the TPS signal so the TCC will engage, without excessive wheel speed. Without the hose, it would require more than 65 mph to engage the TCC.

3. Checks for vehicle speed sensor signal to the ECM. Voltage should vary from under 2 to over 6 volts.

4. Checks for 3rd and 4th gear signal to ECM. These signals will not prevent TCC engagement, but could cause a change in the engage and disengage speed points.

5. Solenoids 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."