GM Service Manual Online
For 1990-2009 cars only
Battery Charger: The scan tool displays On/Off. The scan tool displays On when the engine is OFF and battery voltage is greater than 13.5 Volts.

Battery Current: The scan tool displays the estimated current draw upon the battery as calculated by the module.

Battery State: The scan tool displays Low Voltage/Normal/High Voltage. The scan tool displays Low Voltage below 9.0 Volts and returns to Normal when battery voltage returns to above 9.5 Volts. High Voltage is displayed above 16.0 Volts and returns to Normal when battery voltage returns to below 15.5 Volts.

Battery Temperature: The scan tool displays an estimated battery temperature in °C. The module calculates the battery temperature by utilizing either the outside air temperature sensor or the intake air temperature sensor and comparing it against engine run times and ignition cycle times.

Battery Voltage: The scan tool displays a voltage. The scan tool displays the battery voltage as calculated by the module or received as a class 2 message.

Battery Voltage Sense: The scan tool displays the battery voltage as received on a dedicated power and ground circuit. This signal is highly accurate and is sent out as a class 2 message.

Crank Request: The scan tool displays Yes/No. The scan tool displays Yes when the ignition is placed in the Start position and a battery voltage is received by the PCM.

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.

Clutch Start Switch: The scan tool displays On/Off. The scan tool displays On when the clutch is depressed.

Fast Idle for Generator: The scan tool displays Yes when Idle boost has been requested due to high system current draw.

GEN L-Terminal Signal: The scan tool displays On/Off. The scan tool displays Off until the engine is running, then the PCM supplies a 5.0 V signal to turn ON the regulator, then On is displayed.

GEN L-Terminal Signal Command : The scan tool displays On/Off. The scan tool displays Off until the engine is running, then the PCM supplies a PWM signal to turn ON the regulator, then On is displayed.

GEN L-Terminal Signal Command (RVC Data): The scan tool display the PWM signal percentage that the module is requesting the ECM to control the generator L-terminal

GEN F-Terminal Signal: The scan tool displays 0-100%. The scan tool displays the percentage of generator On time, the higher the percentage the greater the generator output.

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

Load Shed: The scan tool displays No unless the module has entered one of the load shed states.

PNP Switch: The scan tool displays P-N/R-D-L. The scan tool displays P-N when the transmission is in the Park (P) or Neutral (N) position.

Running State of Charge: The scan tool displays the calculated battery state of charge while the engine is running.

Start Up State of Charge: The scan tool displays the calculated battery state of charge prior to engine start up.

Starter Disabled: The scan tool displays Yes/No. The scan tool displays No unless the VTD receives improper key information, then Yes will be displayed and starting will be disabled.

Starter Motor Status: The scan tool displays Turning/Not Turning. The scan tool displays Turning during cranking until a run flag is received by the PCM.

Starter Relay Circuit Status: The scan tool displays Fault/OK/Invalid State. The scan tool displays Fault until the ignition is placed into the Start position then OK is displayed.

Starter Relay Command: The scan tool displays On/Off. The scan tool displays On when the PCM has received all of the requirements for starting the engine.