Automatic Transmission Shift Lock Control System
The automatic transmission shift lock control system is a safety device that
prevents an inadvertent shift out of PARK when the engine is running. The driver must
press the brake pedal before moving the shift lever out of the PARK position. The
system consists of the following components:
• | The automatic transmission shift lock control solenoid |
• | The body control module (BCM) |
• | The powertrain control module (PCM) |
The BCM controls the voltage to the shift lock control solenoid through the
shift lock control solenoid controlled voltage circuit. The following conditions must
be met before the BCM will supply voltage to the shift lock control solenoid:
• | The ignition is in the ON position. |
• | The PCM sends a class 2 message to the BCM indicating the transmission
is in the PARK position. |
• | The BCM determines the brake pedal is not applied according to the stop
lamp switch. |
When the ignition is in the ON position, the ignition 1 fuse supplies
voltage to the automatic transmission shift lock control solenoid as the BCM supplies
a ground to the control circuit, mechanically locking the shift lever in the PARK
position as the solenoid energizes. When the brake pedal is applied, the BCM turns
the ground of the control circuit OFF, de-energizing the shift lock control solenoid.
The de-energized solenoid releases the mechanical lock allowing the driver to move
the shift lever out of the PARK position. When the transmission is out of the PARK
position, the shift lock control solenoid remains de-energized.