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

Fig. 042 - WIRING DIAGRAM for Chart C-8 Transmission/Transaxle Converter Clutch. VIN 9:

CHART C-8

TRANSMISSION/TRANSAXLE CONVERTER CLUTCH (TCC)

3.8L TURBO "E & G" SERIES

The purpose of the automatic transmission [1][2]torque converter clutch feature is to eliminate the power loss of the torque converter stage when the vehicle is in a cruise condition. This allows the convenience of the automatic transmission and the fuel economy of a manual transmission. The heart of the system is a solenoid located inside the automatic transmission which is controlled by the ECM.
When the solenoid coil is activated ("ON"), the [1][2]torque converter clutch is applied which results in straight through mechanical coupling from the engine to transmission. When the transmission solenoid is deactivated, the torque converter clutch is released which allows the torque converter to operate in the conventional manner (fluidic coupling between engine and transmission).
The TCC will engage on a warm engine under given road load in 4th gear only.

Fig. 040 - Chart C-8 Transmission Converter Clutch.:

1. A test light on indicates battery voltage and continuity through the TCC solenoids 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 ECM. Voltage should vary from under 2 to over 9 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 a group of four called "Quad-Drivers". Failure of one can damage any other driver within the set.

Solenoid coil resistance must measure more than 20 ohms. Less resistance will cause early failure of the ECM "Driver". Using an ohmmeter, check the solenoid coil resistance of the following before installing a replacement ECM.
a. TCC Solenoid