GM Service Manual Online
For 1990-2009 cars only
Ignition Voltage: This parameter indicates the ignition positive voltage at the electronic brake control module (EBCM).

PNP Switch: This parameter indicates the range selection of 3 speed or 4 speed automatic transmission equipped vehicles. The parameter will display Park/Neutral for the Park or Neutral position of the gear selector. The parameter will display In Gear for the Reverse, Drive, or Low positions of the gear selector.

Starter Switch: This parameter displays Cranking when the PCM is receiving a signal indicating that the engine starter motor is cranking. The scan tool will display Released when the ignition is on and when the engine is running.