Chart C-8 Transmission Converter Clutch: Vins 0, 2 & R

Fig. 105 - Wiring Diagram for Chart C-8 Transmission Converter Clutch. VIN 0, VIN 2, VIN R:

CHART C-8, TRANSMISSION CONVERTER CLUTCH (TCC)

Fig. 104 Chart C-8 Transmission Converter Clutch:

The purpose of the automatic transmission 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.
Fused battery ignition is supplied to the TCC solenoid through the brake switch, and transmission third gear apply switch. The ECM will engage TCC by grounding CKT 422 to energize the solenoid.
TCC will engage when:
- Vehicle speed above 45 mph
- Engine at normal operating temperature (above 70°C)
- Throttle position sensor output not changing, indicating a steady road speed.
- Transmission third gear switch closed
- Brake switch closed
1. Light off confirms transmission third gear apply switch is open.
2. At 30 mph the transmission third gear switch should close. Test light will come on and confirm battery supply and closed brake switch.
3. Grounding the diagnostic terminal with engine "OFF" should energize the TCC solenoid. This test checks the capability of the ECM to control the solenoid.
4. Solenoids are turned "ON" or "OFF" by the ECM internal electronic switches called "drivers". Each driver is part of 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.
Check TCC solenoid resistance as follows:
- Disconnect TCC at transmission.
- Connect ohmmeter between transmission connector opposite harness connector Terminal "A" and "D".
- Raise drive wheels.
- Run engine in drive about 30 MPH to close third gear apply switch.
- Replace the TCC solenoid and ECM if resistance measures less than 20 ohms when switch is closed.