GM Service Manual Online
For 1990-2009 cars only
TCC Brake Pedal Switch: The scan displays Applied/Released. This parameter indicates the state of the brake switch circuit. Applied indicates a B+ voltage input when the brake switch is closed and the brake pedal is applied. Released indicates a zero voltage input when the brake switch is open and the brake pedal is released. When the brake pedal is applied, the torque converter clutch (TCC) brake pedal switch energizes the shift lock relay in order to disengage the shift lock. The TCC brake pedal switch also sends signals to the PCM, the cruise control servo and the ABS EBCM.

Transmission Range: The scan tool displays Park or Neutral when the transmission is in Park or Neutral and Reverse, Drive, Second or Low when the transmission is operating in forward or reverse gears.