GM Service Manual Online
For 1990-2009 cars only
1-4 Shift (Manual Trans Only): The scan tool displays On/Off. This is the status of the manual transmission range as determined by the engine control module (ECM).

ABS Telltale: The scan tool displays On/Off. This is the state of the ABS telltale as commanded by the instrument panel cluster (IPC).

Adjust Display Down Switch: The scan tool displays Inactive/Active. This is the state of the head-up display (HUD) Display Down Switch. Active is displayed when switch is selected.

Adjust Display Up Switch: The scan tool displays Inactive/Active. This is the state of the HUD Display Up Switch. The scan tool displays Inactive/Active.

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

Average Fuel Economy: The scan tool displays Liters (Gallons). This is the average fuel economy information as calculated by the ECM.

Average Speed: The scan tool displays Km/h (mph). This is the average vehicle speed information as calculated by the IPC in miles travelled per hour of ignition-on time.

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

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

Brake Fluid Level Switch: The scan tool displays On/Off. This is status of brake fluid level switch as monitored by the IPC

Brake Warning Indicator Command: The scan tool displays Off/On. This is the state of the brake warning indicator as commanded by the IPC.

Change Engine Oil Indicator: The scan tool displays On/Off. This is the state of the change engine oil indicator as commanded by the IPC. The IPC receives a class 2 message from the ECM indicating the engine oil life.

Cruise Control Active: The scan tool displays Inactive/Active. This is the state of the cruise control switch as determined by the ECM.

Dim Down Switch: The scan tool displays Inactive/Active. The scan tool displays the state of the Dimmer Down Switch as commanded by the IPC.

Dim Up Switch: The scan tool displays Inactive/Active. The scan tool displays the state of the Dimmer Up Switch as commanded by the IPC.

Dome Lamp Switch: The scan tool displays On/Off. The IPC receives a class 2 message from the body control module (BCM) indicating the dome lamp switch status.

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.

ECT: The scan tool displays °Celcius (°Fahrenheit). The IPC displays the engine coolant temperature as determined by the ECM. The ECM sends a class 2 message to the IPC indicating the engine coolant temperature.

Engine Oil Level Switch: The scan tool displays Ok/Low. The ECM monitors the engine oil level switch. The IPC receives a serial data message from the ECM indicating the engine oil level.

Engine Oil Life: The scan tool displays 0-100%. This is the engine oil life index as calculated by the ECM.

Engine Oil Pressure Sensor: The scan tool displays kPa or psi. The scan tool displays the current engine oil pressure as calculated by the ECM.

Engine Oil Pressure: The scan tool displays kPa (psi). The scan tool displays the IPC engine oil pressure information. The IPC receives a class 2 message from the IPC indicating the engine oil pressure.

English Metric Status: The scan tool displays English or Metric. The scan tool displays vehicle information in English or Metric system as selected from the IPC.

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

Engine Speed Circuit Status: The scan tool displays SHORT GND/OPEN, INCOMPLETE, SHORT B+, OK. This is the status of the engine speed signal circuit as monitored by the ECM.

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

Engine Speed Signal: The scan tool displays 0-9999 RPM. Engine speed is computed by the IPC via a discrete input from the ECM.

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

Fuel Gage Select Sw: The scan tool displays Released/Depressed. This is the state of the fuel gage select switch as controlled from the switch.

Fuel Level: The scan tool displays 0-100%. The IPC displays the approximate value of fuel remaining in the gas tank. The ECM calculates the amount of fuel in the gas tank based on the fuel level sensors and sends the information via class 2 to the IPC.

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

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

Fuel Range: The scan tool displays Km/h (mph). The IPC displays the approximate range of the fuel remaining in the gas tank. The ECM calculates the distance of the remaining fuel in the gas tank based on the fuel level sensor information.

Fuel Tank Level Remaining: The scan tool displays the approximate value of fuel remaining in the gas tank in liters or gallons. The ECM calculates the amount of fuel remaining in the tanks based on the signal circuits of the fuel level sensors.

Gage Switch: The scan tool displays Inactive/Active. This is the status of the gage switch as determined by the IPC.

Headlamps On Indicator: The scan tool displays On/Off. This is the status of the headlamps indicator as determined by the IPC. The IPC illuminates the indicator when the park lamps are ON.

High Beam Indicator Command: The scan tool displays On/Off. This is the status high beam indicator as determined by the IPC. The IPC receives a class 2 message from the BCM indicating the high beam status.

Ignition Accessory Signal: The scan tool displays Off/On. The scan tool displays the ignition accessory signal status of the ECM.

Ignition 1 Signal: The scan tool displays Volts. The scan tool displays the ignition 1 input voltage to the ECM.

Inst. Fuel Economy: The scan tool displays Liters (Gallons). This is the Inst. Fuel Economy information as calculated by the ECM.

Language: The scan tool displays English, French, German, Italian, Spanish or Japanese. This is the language selected for the HUD.

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

LF Tire Pressure: The scan tool displays kPa (psi). This is the left front tire pressure information received class 2 by the IPC from the tire pressure module.

Low Engine Oil Level Indicator Command: The scan tool displays On/Off. This is the state of the low engine oil indicator as determined by the IPC. The IPC receives a class 2 message indicating the engine oil level.

Low EOP Indicator Command: The scan tool displays On/Off. This is the state of the low engine oil pressure (EOP) indicator as determined by the IPC. The IPC receives a class 2 message from the ECM indicating the engine oil pressure.

Low Tire Press. Lamp: The scan tool displays On/Off. This is the state of the low tire pressure lamp as commanded by the IPC.

Low Traction Lamp Command: The scan tool displays On/Off. This is the state of the low traction lamp as commanded by the IPC.

LR Tire Pressure: The scan tool displays kPa (psi). This is the left rear tire pressure information received class 2 by the IPC from the tire pressure module.

MIL Circuit Status: The scan tool displays SHORT GND/OPEN, INCOMPLETE, SHORT B+, OK. The scan tool will display the status of the malfunction indicator lamp (MIL) circuit as commanded by the ECM.

MIL Command: The scan tool displays Off/On. This is the commanded state of the MIL by the ECM. The malfunction indicator lamp should be ON when the scan tool indicates the MIL Command is ON.

Navigation Present: The scan tool displays Present/Notpresent. This is the state of the vehicle navigation system as determined by the IPC.

Non - Driven Wheel Speed: The scan tool displays Km/h (miles). This is the vehicle non-driven wheel speed as determined by the ECM.

Odometer: The scan tool displays kilometers or miles. This is the total accumulated miles of the vehicle as calculated by the ECM.

Odometer: The scan tool displays kilometers or miles. This is the total accumulated miles of the vehicle as displayed by the IPC.

Options Switch: The scan tool displays Inactive/Active. This is the state of the driver information center (DIC) Option Switch as detected by the IPC.

Page Switch: The scan tool displays Inactive/Active. This is the state of the HUD page switch detected by the IPC.

Park Brake Switch: The scan tool displays Released/Applied. This is the state of the park brake switch as detected by the IPC.

Park Lamps Signal: The scan tool displays On/Off. This is the state of the park lamps signal as detected by the IPC.

Rear Fog Indicator Command: The scan tool displays On/Off. This is the state of the rear fog indicator as detected by the IPC.

Reset Switch: The scan tool displays Inactive/Active. This is the state of the DIC reset switch as detected by the IPC.

RF Tire Pressure: The scan tool displays kPa (psi). This is the right front tire pressure information received class 2 by the IPC from the tire pressure module.

RR Tire Pressure: The scan tool displays kPa (psi). This is the right rear tire pressure information received class 2 by the IPC from the tire pressure module.

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

Seat Belt Indicator Command: The scan tool displays On/Off. This is the state of the seat belt indicator as determined by the SDM.

Security Indicator Command: The scan tool displays On/Off. The IPC receives a class 2 message from the BCM requesting the illumination of the security indicator.

Skip Shift Lamp Command: The scan tool displays On/Off. This is the state of the skip shift indicator as determined by the ECM. The IPC receives a class 2 message requesting illumination.

Trip Odometer A/B Switch: The scan tool displays On/Off. This is the state of the trip odometer A/B switch of the IPC.

Trip Odometer A: The scan tool displays kilometers (miles). This is the total accumulated kilometers (miles) of Trip Odometer A as displayed by the IPC.

Trip Odometer B: The scan tool displays kilometers (miles). This is the total accumulated kilometers (miles) of Trip Odometer B as displayed by the IPC.

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

Vehicle Speed Signal: The scan tool displays 0-255 km/h (0-155 mph). The IPC calculates the vehicle speed signal via a discrete input from the ECM.

Windshield Washer Fluid Switch: The scan tool displays Low Fluid/Ok. This is the state of the windshield washer fluid as detected by the IPC via discreet input.