Torque Converter Lock-Up

Torque Converter Lock-Up

When the gearbox is in 4th or 5th gear, and the ATCU registers a high vehicle speed combined with a small throttle angle, the ATCU will lock the torque converter. This will enable maximum power to be transmitted to the road wheels. When this occurs, the ATCU (C0932) provides a PWM signal to the Lock-Up solenoid (C0243) on a U wire. The solenoid (C0243) is earthed via the ATCU (C0932) on an SB wire. For more details on torque converter lock-up, refer to the Automatic Gearbox – Jatco section of the System Description and Operation Workshop manual.

Shift Interlock

When the ignition switch is in the 'ignition' position and the selector lever is in the 'Park', the ATCU (C0932) provides a feed to the shift interlock solenoid (C0268) on a GW wire locking the selector lever in the 'Park' position. When the brake pedal is pressed, the brake pedal switch (C0652) provides a feed to the ATCU (C0932) on a GR wire. Sensing the brake pedal has been pressed the ATCU withdraws the feed to the shift interlock solenoid, releasing the selector lever.

The shift interlock solenoid (C0268) is earthed on a B wire.

Diagnostic Socket

If the ATCU detects a failure in an associated component, a fault code will be stored in its memory. TestBook or T4 can be used via the diagnostic socket to retrieve these fault codes to identify the cause of the failure. The diagnostic socket (C0040) is connected to the ATCU (C0932) by a K wire.