Grand Prix V6-191 3.1L (1989)
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 3rd and 4th
gears. TCC will engage when:
^
Engine warmed up
^
Vehicle speed above a calibrated value (about 28 mph 45 km/h)
^
Throttle position sensor output not changing, indicating a steady road speed
^
Brake switch closed
Test Description:
Numbers below refer to circled numbers on the diagnostic chart.
1.
This test checks the functional operation of the TCC circuit.
2.
This test checks the TCC control driver in the ECM.
3.
This test will confirm that there is B + to terminal "A".
4.
This test confirms that the ECM has the ability to turn the TCC "ON".
Diagnostic Aids:
The "Scan" tool only indicates when the ECM has turned "ON" the TCC driver, and this does not confirm that the TCC has engaged. To determine if
TCC is functioning properly, engine rpm should decrease when the "Scan" indicates the TCC driver has turned "ON."
