GM Service Manual Online
For 1990-2009 cars only
Battery 1: The scan tool displays 0-19 volts. The battery voltage as monitored by the ECM.

Coolant Gauge Position: The scan tool displays 0-100%. The BCM receives a serial data message from the PCM/ECM regarding the engine coolant temperature and converts the data to percentage.

Driver Door Switch: The scan tool displays High or Low. The state of the driver door switch as commanded by the BCM.

ECT: The scan tool displays -40 to +151°C (-40 to +304°F). The ECM monitors the voltage at the signal circuit of the engine coolant temperature sensor. The voltage is inversely proportional to the engine coolant temperature.

Engine Oil Life Left (3.0L): The scan tool displays 0-100%. The ECM calculates the remaining engine oil life.

Engine Oil Life Remaining (2.2L): The scan tool displays 0-100%. The PCM calculates the remaining engine oil life.

Engine Speed: The scan tool displays 0-9999 RPM. Engine speed is computed by the ECM. It should remain close to desired idle under various engine loads with the engine idling.

Fuel Gauge Position: The scan tool displays 0-100%. The BCM calculates the amount of fuel remaining in the tank based on the serial data messages from the ECM/PCM regarding fuel level.

Fuel Level: The scan tool displays the amount of fuel left in Gallons or Liters. The ECM/PCM calculates the amount of fuel remaining in the tank based on the input from the fuel level sensor.

Fuel Level Sensor (3.0L): The scan tool displays the state of the fuel level in Volts. The ECM monitors the signal circuit of the fuel level sensor and displays the current voltage.

Key in Ignition: The scan tool displays Yes or No. The state of the key in ignition switch as commanded by the BCM.

Liftgate Ajar Switch: The scan tool displays High or Low. The state of the liftgate switch as monitored by the BCM.

Low Brake Fluid: The scan tool displays Yes or No. The state of the brake fluid level switch as commanded by the BCM.

Low Coolant: The scan tool displays Yes or No. The state of the coolant level switch as commanded by the BCM.

Low Oil Pressure: The scan tool displays Yes or No. The state of the engine oil pressure sensor as commanded by the ECM.

Low Oil Pressure Switch: The scan tool displays Open or Closed. The state of the engine oil pressure switch as commanded by the ECM.

Oil Life Reset Switch: The scan tool displays High or Low. The BCM calculates the remaining engine oil life.

Pass Door Switches: The scan tool displays High or Low. The state of the passenger door switches as monitored by the BCM.

Software Date-Day: The scan tool displays the day the software was created for the BCM installed in the vehicle.

Software Date-Month: The scan tool displays the month the software was created for the BCM installed in the vehicle.

Software Date-Year: The scan tool displays the year the software was created for the BCM installed in the vehicle.

Software ID: The scan tool displays a numeric value. The identification of the BCM software installed in the vehicle.

Vehicle Speed: The scan tool displays 0-255 km/h (0-155 mph). The ECM/PCM monitors the signal circuit of the vehicle speed sensor.