GM Service Manual Online
For 1990-2009 cars only
ABS Lamp: The scan tool displays On/Off. This is the state of the ABS indicator as commanded by the instrument panel cluster (IPC).

Air Bag Lamp: The scan tool displays On/Off. This is the state of the air bag indicator as commanded by the sensing and diagnostic module (SDM).

Brake Lamp: The scan tool displays On/Off. This is the state of the brake lamp as commanded by the IPC.

Change Engine Oil Command: The scan tool displays On/Off. The engine control module (ECM) monitors the engine oil life and the scan tool displays on or off as determined by the ECM.

Change Oil Now Command: The scan tool displays On/Off. The powertrain control module (PCM) monitors the engine oil life and the scan tool displays on or off as determined by the PCM.

Coolant Hot Lamp: The scan tool displays On/Off. The IPC receives a serial data class 2 message from the PCM indicating the state of the engine coolant temperature.

Cruise Control Active: The scan tool displays Yes/No. This is state of the cruise control as determined by the ECM/PCM.

Display Odometer Switch: The scan tool displays Yes/No. The DIC monitors the display odometer switch. A closed switch is displayed as On.

Display Backlighting Level: The scan tool displays 0-100%. This is the current level of the display backlighting as controlled from the dimmer switch.

ECT Sensor: The scan tool displays -40 to +151°C (-40 to +304°F). The PCM/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 Hot Lamp Command: The scan tool displays On/Off. This is the status of the engine coolant temperature indicator as commanded by the PCM.

Engine Oil Life Remaining: The scan tool displays 0-100%. The scan tool displays the engine oil life remaining as calculated by the PCM.

Engine Oil Level Switch: The scan tool displays Ok/Low. The PCM monitors the signal circuit of the engine oil level switch, where an open switch is displayed as Low (low engine oil level).

Engine Oil Pressure Sensor: The scan tool displays engine oil pressure in kPa or psi. The ECM monitors the engine oil pressure sensor signal circuit and calculates the current oil pressure of the engine.

Engine Oil Pressure Sensor: The scan tool displays engine oil pressure in 0-5 V. The ECM monitors the engine oil pressure sensor signal circuit and calculates the current oil pressure of the engine based on the sensor voltage.

Engine Oil Pressure Switch: The scan tool displays Ok/Low. The PCM monitors the signal circuit of the engine oil pressure switch, where a closed switch is displayed as low engine oil pressure.

Engine Oil Temperature Calculated: The scan tool displays engine oil pressure in Celsius or Fahrenheit. This is the current engine oil temperature as calculated by the ECM.

Engine Speed: The scan tool displays 0-9999 RPM. Engine speed is computed by the PCM/ECM from the 3X reference input. It should remain close to desired idle under various engine loads with the engine idling.

Engine Speed Circuit Status: The scan tool displays Ok/Fault/Fault/Invalid State. This is the state of the engine speed signal circuit as determined by the PCM.

Engine Speed Circuit Status: The scan tool displays Ok/Incomplete/Short to GND/Open/Short to B+. This is the state of the engine speed signal circuit as monitored by the ECM.

Fog Lamp: The scan tool displays On/Off. This is the state of the fog lamp indicator as commanded by the IPC

Fuel Level Sensor: The scan tool displays 0-5 volts. The scan tool displays the voltage at the signal circuit of the fuel level sensor as calculated by the PCM/PCM.

Fuel Tank Level Remaining: The scan tool displays 0-100%. The PCM/ECM calculates the amount of fuel remaining in the tank based on the signal circuit of the fuel level sensor. The IPC receives a class 2 message from the PCM/ECM indicating the fuel level percent.

Fuel Switch: The scan tool displays On/Off. This is the state of the driver information center (DIC) fuel switch. A closed switch is displayed as On.

Gage Switch: The scan tool displays On/Off. This is the state of the DIC gage switch. A closed switch is displayed as On.

Generator Lamp Command: The scan tool displays On/Off. This is the state of the generator indicator as determined by the PCM. The PCM disables the generator under certain conditions to ease starting or engine load.

High Beam Lamp: The scan tool displays On/Off. This is the state of the high beam indicator as commanded by the IPC.

Ignition 1 Signal: The scan tool displays 0-19 volts. This is the voltage at the ignition 1 input of the PCM/ECM.

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

Key In Ignition: The scan tool displays Yes/No. The body control module (BCM) monitors the ignition key alarm switch, where a closed switch is displayed as Yes (key is in the ignition).

Km/h Lamp and MPH Lamp: The scan tool displays On/Off. Vehicle information is displayed in Km/h or mph as selected from the IPC.

Left Turn Signal: The scan tool displays On/Off. This is the state of the left turn signal indicator. The IPC receives a class 2 message indicating the status of the left turn signal.

Low Brake Fluid: The scan tool displays On/Off. This is the state of the low brake fluid indicator as commanded by the IPC. The IPC receives a serial data class 2 message indicating the status of the brake fluid.

Low EOP Indicator Command: The scan tool displays On/Off. This is the status of the engine oil pressure indicator as commanded by the ECM.

Low EOP Lamp Command: The scan tool displays On/Off. This is the status of the engine oil pressure indicator as commanded by the PCM.

Low Engine Oil Level Lamp Command: The scan tool displays On/Off. This is the status of the engine oil level indicator as commanded by the PCM.

Low Oil Pressure: The scan tool displays On/Off. This is the state of the low oil pressure indicator as commanded by the IPC. The IPC receives a serial data class 2 message from the PCM indicating the status of the engine oil pressure.

MIL Circuit History: The scan tool displays Ok/Open/Short/Invalid State. This is the state of the malfunction indicator lamp (MIL) circuit as monitored by the PCM.

MIL Circuit Status: The scan tool displays Ok/Incomplete/Short GND/Open/Short B+. This is the status of the MIL circuit as monitored by the ECM.

MIL Command: The scan tool displays On/Off. This is the commanded state of the MIL by the PCM/ECM. The MIL should be On when scan tool indicates the MIL command is on.

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.

Odometer: The scan tool displays miles (kilometers). This is the total vehicle accumulated miles as calculated by the PCM/ECM.

Options Switch: The scan tool displays On/Off. This is the state of the DIC options switch. A closed switch is displayed as On in the scan tool.

Reset Switch: The scan tool displays On/Off. This is the state of the DIC reset switch. A closed switch is displayed as On in the scan tool.

Right Turn Signal: The scan tool displays On/Off. This is the state of the right turn signal indicator. The IPC receives a class 2 message indicating the status of the right turn signal.

Switch Backlight Level: The scan tool displays percent (%). This is the state of the switch backlighting as controlled from the dimming switch.

Upshift Lamp: The scan tool displays On/Off. This is the state of the upshift indicator as commanded by the PCM.

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

VSES Active Lamp: The scan tool displays On/Off. This is the state of the vehicle stability enhancement system (VSES) indicator as commanded by the IPC. The IPC receives a serial data class 2 message indicating the status of the VSES.