Chart C-8A, Torque Converter Clutch Electrical Diagnosis - 1992 5.7L PFI Y Body: Notes

Fig 1: Chart C-8A, TCC Circuit Diagram (1992 5.7L PFI Y Body)

Courtesy of GENERAL MOTORS CORP.

When solenoid coil is activated, TCC is applied which results in a straight through mechanical coupling from engine to wheels. When solenoid coil is deactivated, TCC is released which allows torque converter to operate in conventional manner. ECM turns on TCC when engine coolant temperature is greater than 149°F (65°C). TPS not changing and vehicle speed is greater than a specified value.

NOTE: Test numbers refer to test numbers in diagnostic chart.

This test confirms 12 volt supply as well as continuity of TCC circuit.
Grounding diagnostic test terminal with engine off should energize TCC solenoid.
TCC solenoid resistance must measure more than 20 ohms. Using an ohmmeter, check solenoid coil resistance of all ECM controlled solenoids and relays before installing a replacement ECM. Replace any solenoid or relay that measures less than 20 ohms.