K 1500 Truck 4WD V6-262 4.3L VIN Z (1993)
Torque Converter Clutch (TCC) Solenoid Circuit
Circuit Description:
The TCC solenoid is a normally open exhaust valve. The PCM activates the solenoid by grounding CKT 422 with an internal quad-driver.
The PCM continually monitors the TCC circuit for either low or high voltage depending on the commanding state of the circuit. A DTC will set if
a fault is detected.
For example: If command TCC solenoid "ON," the voltage on that circuit should drop when the solenoid is grounded, if the voltage stays up for 2
seconds, a DTC will set. If the TCC solenoid is "OFF," the voltage on the circuit should remain higher if the voltage drops for 2 seconds, a DTC
will set.
Test Description:
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This test checks for a shorted, internal transmission harness or TCC solenoid.
2. This test checks power supply to the TCC solenoid.
3. This test checks CKT 422 for a short to ground.
4. This test checks the PCM ability to control the TCC solenoid.
Diagnostic Aids:
Check all connections at the transmission pass-thru connector.
If OK, refer to 'PCM Intermittent Diagnostic Trouble Codes or Performance" or "Symptom Diagnosis".
Some slight TCC slip is normal.
