P1864

WITH 4L60-E AUTOMATIC TRANSMISSION

DTC P1864 Torque Converter Clutch (TCC) Solenoid Circuit - Electrical Diagnostic Chart:

Torque Converter Clutch (TCC) Solenoid Circuit - Electrical Wiring Schematic:

CIRCUIT DESCRIPTION
The Torque Converter Clutch (TCC) solenoid is an electrical device used in conjunction with the TCC Pulse Width Modulation (PWM) solenoid to control fluid acting on the TCC converter clutch valve, which then controls TCC apply and release. This solenoid is attached to the transmission case assembly extending into the pump cover. The Vehicle Control Module-A (VCM-A) monitors Throttle Position (TP) voltage, vehicle speed and other inputs to determine when to energize the TCC solenoid. Ignition voltage is supplied directly to the TCC solenoid. The VCM-A controls the solenoid by providing the ground path through CKT 422. DTC Type (D).

DTC P1864 WILL SET WHEN
- The VCM-A commands the TCC solenoid "ON", and the voltage stays high (B+) for two seconds.
- The VCM-A commands the solenoid "OFF", and the voltage remains low (zero volts) for two seconds.

ACTION TAKEN (VCM-A will default to)
- No TCC.
- No fourth gear in hot mode.
- Freeze adapts.

DTC P1864 WILL CLEAR DEFAULT ACTION WHEN
The fault condition(s) no longer exist and the ignition switch is cycled "OFF" for five seconds, then "ON".

DTC P1864 WILL PASS WHEN
- VCM-A commands TCC solenoid "ON" and voltage drops to 0 volts.
or
- VCM-A commands TCC solenoid "OFF" and voltage increases to (B+).
- The VCM-A turns "OFF" the Malfunction Indicator Lamp with reported passes (if applicable).

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This test checks the VCM-A's ability to control the solenoid
2. This test checks power supply to the TCC solenoid.

DIAGNOSTIC AIDS
Check all connections at the transmission wiring connector assembly.
If OK, refer to Intermittents.
Some slight TCC slip is normal.
An open in the ignition feed circuit will cause multiple DTC(s) to set.
A short to ground in the TCC circuit may also cause a DTC PO742 to set. If the TCC circuit is shorted to ground, the TCC will hydraulically engage in D2.