GM Service Manual Online
For 1990-2009 cars only
Battery Voltage: The scan tool displays 0-30 volts. The voltage measured between the modules battery positive voltage circuit and ground circuit.

Engine Run: This parameter displays if engine is ON or OFF.

Exhaust Valve Command: This parameter displays if the exhaust flow control solenoid is being commanded ON or OFF.

Power Mode: This parameter displays what position has been selected by the ignition switch, (Run, Accessory, Crank, Retained Accessory Power, or Off).

System Enabled: This parameter displays Yes or No. Yes indicates the Exhaust Flow Control system has been enabled. No indicates the system is disabled

System Mode Status: This parameter displays Normal or Comp. Normal indicates exhaust flow is bypassing the mufflers less frequently and at higher engine RPMs. Comp indicates exhaust flow is bypassing the mufflers more frequently and at lower engine RPMs

Throttle Position: This parameter displays the angle of the throttle position (TP) sensor in percent. This information is calculated by the control module using the signal from the throttle position sensor. The scan tool will display a low percentage when the throttle plates are closed. The scan tool will display a high percentage when the throttle plates are fully open.

Vehicle Speed: This parameter indicates the vehicle speed calculated by the control module based on an input from the vehicle speed sensor (VSS).