Firenza L4-121 2.0L VIN K TBI (1987)
Fig. 016 Wiring Diagram for C-8A-2 125C Transmission Converter Clutch (TCC)
CHART C-8A-2
125C TRANSMISSION CONVERTER CLUTCH (TCC)
2.0L (VIN 1) "J" SERIES
FUEL INJECTION (TBI)
Circuit Description: The purpose of the automatic transmission torque converter clutch 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 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 (73 km/h).
Engine at normal operating temperature (above 70 degrees C, 156 degrees F).
Throttle position sensor output not changing, indicating a steady road speed.
Transmission third gear switch closed.
Brake switch closed.
Test Description: Numbers below refer to circled numbers on Diagnostic Chart
Chart C-8A-1 125C Transmission Converter Clutch (TCC) 1987; VIN K (2.0L) VIN R (2.5L) VIN U (2.5L)
1.
Light "OFF" confirms transmission third gear apply switch is open.
2.
At 48 km/h (30 mph), the transmission third gear switch should close. Test light will come on and confirm battery supply, and close 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.
Check TCC solenoid resistance as follows:
1.
Disconnect TCC at transmission.
2.
Connect ohmmeter between transmission connector, opposite harness connector terminal "A" and "D".
3.
Raise drive wheels.
4.
Run engine in drive about 48 km/h (30 mph) to close third gear apply switch.
5.
Replace the TCC solenoid, and ECM, if resistance measures less than 20 ohms, when switch is closed.
Diagnostic Aids:
An engine coolant thermostat that is stuck open, or opens at too low a temperature, may result in an inoperative TCC.
Chart C-8A-1 125C Transmission Converter Clutch: Vins K, R & U
