Shift Interlock: Description and Operation

Automatic Transmission Shift Lock Control Description and Operation

With WHB

The automatic transmission shift lock control system is a safety device that prevents an inadvertent shift out of PARK. The driver must press the brake pedal before moving the shift lever out of the PARK position.

The IPC controls the voltage to the shift lock control solenoid through the shift lock control solenoid control circuit. The following conditions must be met before the IPC will supply voltage to the shift lock solenoid:

* The ignition is in the ON position.
* The IPC determines the brake pedal is applied according the brake pedal switch.

Since the shift lock control solenoid is permanently grounded, the IPC supplies voltage to the automatic transmission shift lock control solenoid, mechanically unlocking the shift lever allowing the driver to move the shift lever out of the PARK position as the solenoid energizes. When the brake pedal is not applied, the IPC turns the control voltage output of the shift lock control solenoid OFF, de-energizing the shift lock control solenoid. The de-energized solenoid mechanically locks the shift lever from going into the PARK position.

Without WHB

The stop lamp switch controls the shift lock solenoid by providing battery voltage to the shift lock control solenoid when the brake pedal is pressed. Ground is provided to the solenoid when the shift lever is in the park position.