Diagnostic Aids

Use a scan tool to verify there are no brake pedal position sensor and/or transmission internal mode switch (IMS) DTCs set that could cause the BCM not to provide battery voltage to the A/T shift lock solenoid.
If the automatic transmission shift lock control circuit is shorted to battery positive voltage, the A/T shift lock solenoid will be inoperative. The vehicle will shift out of PARK without depressing the brake pedal.