For 1990-2009 cars

### DTC P0740 - TCC Solenoid Control Circuit Low Voltage

### Circuit Description

The torque converter clutch (TCC) solenoid is used to apply and release TCC. The TCC can be applied in all forward gears. The powertrain control module (PCM) controls TCC by pulse width modulating (PWM) an internal driver that pulls the solenoid circuit to ground. When the TCC solenoid is commanded ON, circuit grounded, the TCC is applied, which works opposite to all other 4 transaxle solenoids. The TCC solenoid circuit is monitored for low and high voltage faults. DTC P0740 sets when the TCC solenoid is commanded OFF, PWM Off-time, and the feedback voltage at the PCM is low.

### DTC Parameters

DTC P0740 will set if TCC solenoid feedback voltage is less than 1.25 volts with TCC solenoid commanded OFF when:

• | The condition exists for longer than 100 milliseconds (2001)*.

• | The condition exists for longer than 100 milliseconds, solenoid is turned OFF for 1 minute, then condition exists again for longer than 100 milliseconds (2000).

• | The fuel pump relay is commanded ON.

DTC P0740 diagnostic runs continuously with fuel pump relay commanded ON and TCC solenoid commanded OFF.

DTC P0740 is a type D DTC.

*Applicable to vehicles built after June 2000.

### Diagnostic Aids

To locate an intermittent problem, use scan tool to command TRANS. SOLENOID POWER ON, while monitoring the TCC SOLENOID - LOW VOLT or TCC SOLENOID - OPEN test. When a fault, open or short to ground exists, the scan tool will display TEST FAIL for both tests.

The tests will fail only when the device is being commanded OFF and the voltage at the PCM is low. The tests update every 100 milliseconds whenever the ignition is turned ON and the device is being commanded OFF via the scan tool or PCM.

The TCC solenoid resistance: 3.8-7.2 ohms

Nominal value: 4.5 ohms at 68°F