GM Service Manual Online
For 1990-2009 cars only
Battery 1: The scan tool displays 0-20 Volts. The scan tool displays the voltage as received on the battery positive voltage circuit of the BCM.

Crank Request Signal: The scan tool displays Yes/No. The scan tool displays No until the ignition is placed into the START position, then Yes is displayed.

GEN F-Terminal Signal: The scan tool displays 0-100%. The scan tool displays the percentage of the field current.

GEN L-Terminal Signal: The scan tool displays Voltage/No Voltage. The scan tool displays Voltage until the engine is running, then displays No Voltage when the engine is running.

GEN L-Terminal Signal Command: The scan tool displays On/Off. The scan tool displays Off until the engine is running, then displays On when the engine is running.

Ignition Accessory Signal: The scan tool displays Volts. The scan tool displays the voltage as received on the ignition accessory circuit to the ECM/PCM.

Ignition 1 Signal: The scan tool displays 0-20 Volts. The scan tool displays the voltage as received on the ignition 1 circuit to the ECM/PCM.

Power Mode: The scan tool displays Off/Accy./Run/Crank. The scan tool displays the current status of the transmission range switch.

Starter Relay Command: The scan tool displays On/Off. The scan tool displays Off until the ignition is placed into the START position, then ON is displayed while the engine is cranking.