P1864

DTC P1864 TCC Solenoid Electrical (1 Of 2):

DTC P1864 TCC Solenoid Electrical (2 Of 2):

TCC Solenoid:

CIRCUIT DESCRIPTION
The Torque Converter Clutch Solenoid Valve (TCC Sol. Valve) is an electrical device used with the TCC PWM Sol. Valve in order to control the fluid acting on the Torque Converter Clutch (TCC) valve. The TCC valve controls TCC application and release. The solenoid is a normally-open, ON/OFF device. The TCC Sol. Valve attaches to the transmission case assembly extending into the pump cover. The Vehicle Control Module (VCM) monitors the Throttle Position (TP) voltage, the vehicle speed, and other inputs in order to determine when to energize the TCC Sol. Valve. The TCC Sol. Valve receives ignition voltage on circuit 1020. The VCM controls the solenoid by providing the ground path through circuit 422.

When the VCM detects a continuous open or a short to ground in the TCC Sol. Valve circuit or in the TCC Sol. Valve, then DTC P1864 sets. DTC P1864 is a type A DTC.

CONDITIONS FOR SETTING THE DTC

^ The system voltage is 10-17 volts.
^ The engine is running.
^ The VCM commands first gear only.
^ All of the above conditions are met for 5 seconds and either of the following fail conditions occurs for 5 seconds:

- The VCM commands the solenoid ON and the voltage remains high (B+).
- The VCM commands the solenoid OFF and the voltage remains low (0 volt).

ACTION TAKEN WHEN THE DTC SETS

^ The VCM inhibits TCC engagement.
^ The VCM inhibits 4th gear if the transmission is in hot mode.
^ The VCM freezes shift adapts from being updated.
^ The VCM commands maximum line pressure.
^ The VCM illuminates the Malfunction Indicator Lamp (MIL).

CONDITIONS FOR CLEARING THE MIL/DTC

^ The VCM turns OFF the MIL after three consecutive ignition cycles without a failure reported.
^ A scan tool can clear the DTC from the VCM history. The VCM clears the DTC from the VCM history if the vehicle completes 40 warm-up cycles without a failure reported.
^ The VCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the VCM.

DIAGNOSTIC AIDS

^ Inspect the wiring for poor electrical connections at the VCM. Inspect the wiring for poor electrical connections at the transmission 20-way connector. Look for the following conditions:

- A bent terminal
- A backed out terminal
- A damaged terminal
- Poor terminal tension
- A chafed wire
- A broken wire inside the insulation

^ When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change.
^ With the TCC engaged, the TCC slip speed should be -20 to +20 RPM.
^ A short to ground in the TCC Sol. Valve circuit may also set a TCC Stuck On DTC P0742.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic chart.

4. This Step tests for voltage to the solenoid.
6. This Step tests the ability of the VCM and wiring to control the ground circuit.
8. This Step tests the resistance of the TCC Sol. Valve and the Automatic Transmission Wiring Harness Assembly.