GM Service Manual Online
For 1990-2009 cars only
Ambient Air Temp Sensor: The scan tool displays voltage. This is the ambient air temperature sensor voltage as monitored by the body control module (BCM). The BCM converts the sensor voltage to a temperature value and sends the information via GMLAN serial data circuit to the instrument panel cluster (IPC) for display.

Battery Voltage : The scan tool displays Normal or Out of Range. This is the state of the battery voltage as monitored by the BCM.

Battery Voltage Signal: The scan tool displays 0-19V. This is the voltage measured at the battery positive voltage circuit of the BCM.

Battery Voltage Signal: The scan tool displays 0-19V. This is the voltage measured at the battery positive voltage circuit of the IPC.

Cruise Control Active: The scan tool displays Yes or No. This is state of the cruise control switch signal as monitored by the engine control module (ECM).

DIC Information Switch: The scan tool displays Active or Inactive. This is the state of the driver information center (DIC) information switch as monitored by the IPC.

DIC Switch: The scan tool displays Menu/Reset. This is the DIC switch inputs as monitored by the BCM via GMLAN serial data. The BCM is responsible for driving DIC displays via GMLAN.

DIC Switch Input: The scan tool displays voltage. This is the DIC switch input as monitored by the IPC.

Driver Door Ajar Sw: The scan tool displays Door Closed or Door Ajar. This is the state of the driver door ajar switch as monitored by the BCM.

Door Ajar Switch:: The scan tool displays Door Closed or Door Ajar. This is the state of the passenger door ajar switch as monitored by the BCM.

ECT Sensor: 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 Remaining: The scan tool displays 0-100%. The ECM calculates the remaining engine oil life.

Engine Oil Pressure Switch: The scan tool displays Ok or Low. This is the status of the engine oil pressure switch signal as monitored by the ECM.

Engine Speed: The scan tool displays 0-8000 RPM. The engine speed is computed by the ECM from the ignition reference input. It should remain close to the desired idle under various engine loads.

Fuel Level Sensor: The scan tool displays 0-5 volts. The ECM monitors the signal circuit of the fuel level sensor and the fuel data is sent via the GMLAN to the IPC for display.

Fuel Pump Relay Command: The scan tool displays On or Off. The state of the fuel pump as commanded by the ECM.

Fuel Tank Level Remaining: The scan tool displays 0-100%. The ECM calculates the amount of fuel remaining in the tank based on the input from the fuel level sensor signal circuit.

Hazard Lamp Switch: The scan tool displays On or Off. The BCM monitors the hazard lamp switch circuit . When the hazard switch is turned Off the signal is displayed as Off.

Headlamp Off Switch: The scan tool displays On or Off. This is the status of the headlamp-off switch as monitored by the BCM.

Headlamp On Switch: The scan tool displays On or Off. This is the status of the headlamp-on switch as monitored by the BCM.

High Beam Relay Command: The scan tool displays On or Off. The state of the high beam relay as commanded by the BCM.

High Beam Select Switch: The scan tool displays Active or Inactive. The state of the high beam switch as monitored by the BCM.

Hood Ajar Switch: The scan tool displays Closed or Ajar. This is the status of the hood ajar switch as monitored by the BCM.

Ignition 1 input: The scan tool displays Active or Inactive. The scan tool displays Active when voltage is present at the ignition 1 input of the IPC.

Ignition 1 Signal: The scan tool displays 9-16V. This is the voltage present at the ignition 1 voltage circuit of the ECM.

Ignition Accessory Signal: The scan tool displays On or Off. The scan tool displays On when voltage is present at the ignition accessory signal circuit of the ECM.

Ignition Switch Accessory Signal: The scan tool displays Active or Inactive. The scan tool displays Active when voltage is present at the ignition accessory switch signal circuit of the BCM.

Ignition Mode Switch: The scan tool displays 9-16V. The state of the ignition switch circuit as monitored by the BCM.

Key In Ignition Cylinder Switch: The scan tool displays Yes or No. This is the status of the key-in-ignition cylinder switch as monitored by the BCM. When the key is in the ignition cylinder, the scan tool displays On.

Left Turn Signal Switch: The scan tool displays Active or Inactive. The state of left turn signal switch input detected by the BCM. The indicator turns on when the switch is closed.

Liftgate Ajar Switch: The scan tool displays Closed or Ajar. This is the status of the liftgate ajar switch as monitored by the BCM.

Low Beam Relay Command: The scan tool displays On or Off. The state of the low beam relay as commanded by the BCM.

Menu Switch: The scan tool displays Off or On. This is the status of the DIC menu switch as monitored by the IPC.

MIL Command: The scan tool displays On or Off. This is the commanded state of the malfunction indicator lamp (MIL) by the ECM. The MIL should be On in the IPC when scan tool displays MIL Command is On.

MIL Requested by DTC: The scan tool displays Yes or No. This is the state where the MIL is commanded On by an ECM diagnostic trouble code.

Non-Driven Wheel Speed: The scan tool displays 0-255 km/h (0-155 mph). This is the vehicle non-driven wheel speed as monitored by the ECM.

Park Brake Switch: The scan tool displays Active or Inactive. The state of the park brake switch as monitored by the BCM.

Passenger Seat Belt Indicator Command: The scan tool displays On or Off. The state of the passenger seat belt indicator as commanded by the BCM.

Park Lamp Relay Cmd: The scan tool displays On or Off. The state of the park lamp relay as commanded by the BCM.

Park Lamp Switch: The scan tool displays On or Off. This is the status of the park lamp switch as monitored by the BCM.

Reduced Engine Power: The scan tool displays Active or Inactive. This is the state of the Reduced Engine Power indicator as commanded by the ECM. The IPC receives a GMLAN serial data message from the ECM requesting the display of the indicator in the DIC.

Reset Switch: The scan tool displays Active or Inactive. This is the status of the DIC reset switch as monitored by the IPC.

Right Turn Signal Switch: The scan tool displays Active or Inactive. The state of right turn signal switch input detected by the BCM. The indicator turns on when the switch is closed.

Security Indicator Command: The scan tool displays On or Off. This is the commanded state of the security indicator lamp by the BCM. The security indicator should be On in the IPC when scan tool displays Security Indicator Command is On.

Traction Control Status: The scan tool displays Active or Inactive. This is the state of the traction control as commanded by the ECM.

Vehicle Speed Sensor: The scan tool displays 0-255 km/h (0-155 mph). This is the vehicle speed as calculated by the ECM.