Code P0740, Torque Converter Clutch: Notes

The Torque Converter Clutch (TCC) eliminates loss of power to torque converter when cruise control is engaged. This allows convenience of automatic and fuel economy of a manual transaxle. The main components of system are 2 PCM controlled solenoids located inside transaxle.

TCC is applied when TCC apply solenoid coil is activated (on) resulting in a straight through mechanical coupling from engine to wheels. TCC is released when TCC apply solenoid coil is deactivated (off) allowing torque converter to operate in conventional manner (fluid coupling between engine and transaxle). TCC PWM solenoid is used to vary hydraulic pressure to converter clutch regulator valve, allowing a smoother engagement of converter clutch.

Code P0740 will set when the following conditions are present.

• TP sensor throttle angle greater than 10 percent.
• Vehicle is in 3rd or 4th gear.
• VSS signal greater than 35 MPH for a 10 second minimum.
• TCC is commanded on by PCM.
• Engine RPM/vehicle speed ratio indicates TCC is not locked.
• All conditions exist for over 10 seconds.
  NOTE: Test numbers refer to numbers on diagnostic chart.

1. Determines whether fault is caused by a bad solenoid or control circuit.
2. Checks availability of battery voltage.
3. Checks PCM's ability to pulse PWM solenoid on and off.