P0740

Electrical Diagram:

CIRCUIT DESCRIPTION

The Torque Converter Clutch Solenoid Valve (TCC Sol. Valve) is an electrical device that is used with the Torque Converter Clutch Pulse Width Modulation Solenoid Valve (TCC PWM Sol. Valve) in order to control TCC apply and release. The TCC Sol. valve attaches to the transmission case assembly extending into the pump cover. The TCC Sol. Valve receives ignition voltage through circuit 339. The Powertrain Control Module (PCM) controls the solenoid by providing the ground path on circuit 422. The PCM monitors the Throttle Position (TP) voltage, the vehicle speed and other inputs in order to determine when to energize the TCC Sol. Valve. When the PCM detects a continuous open or a short to ground in the TCC Sol. Valve circuit or in the TCC Sol. Valve, then DTC P0740 sets. DTC P0740 is a type A DTC.


CONDITIONS FOR SETTING THE DTC

^ The system voltage is 10-18 volts.

^ The engine speed is greater than 450 RPM for 8 seconds.

^ Not in fuel cutoff.

^ All of the above conditions are met for 5 seconds and either of the following fail conditions occurs for 5 seconds:

- The PCM commands the solenoid ON and the voltage input remains high (B+).

- The PCM commands the solenoid OFF and the voltage input remains low (0.0 volt).

ACTION TAKEN WHEN THE DTC SETS

^ The PCM illuminates the Malfunction Indicator Lamp (MIL).

^ The PCM inhibits TCC engagement.

^ The PCM inhibits 4th gear if the transmission is in hot mode.

^ The PCM freezes shift adapts from being updated.

^ DTC P0740 stores in PCM history.

CONDITIONS FOR CLEARING THE MIL/DTC

^ The PCM turns OFF the MIL after three consecutive trips without a failure reported.

^ A scan tool can clear the DTC from the PCM history. The PCM clears the DTC from the PCM history if the vehicle completes 40 warm-up cycles without a failure reported.

^ The PCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the PCM.

DIAGNOSTIC AIDS

^ Inspect the at the PCM, the transmission 20-way connector and all other circuit connecting points 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

- Moisture intrusion

- Corrosion

^ 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 +30 RPM.

TEST DESCRIPTION

The numbers below refer to the step numbers on the diagnostic table.

4. This step tests for voltage to the solenoid.

6. This step tests the ability of the PCM and the wiring to control the ground circuit.

8. This step tests the resistance of the TCC Sol. Valve and the Automatic Transmission Wiring Harness Assembly.