GM Service Manual Online
For 1990-2009 cars only
Battery Voltage: Scan tool displays 0-19 volts. This is the voltage measured at the battery positive voltage circuit of the body control module (BCM).

Battery Voltage: Scan tool displays 0-19 volts. This is the voltage measured at the battery positive voltage circuit of the instrument panel cluster (IPC).

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

Change Engine Oil Indicator Command: The scan tool displays On/Off. This is the state of the indicator as commanded by the power train control module (PCM). The IPC receives the engine oil life information via the serial data circuit from the PCM.

Cruise Control Active: The scan tool displays No/Yes. This is the status of the cruise control switch as detected by the PCM or ECM.

Current Gear: The scan tool displays P/N/1st/2nd/3rd/4th/5th/Reverse. The scan tool displays the current transmission range as provided by the ECM.

DIC Information Switch: The scan tool displays Off/On. This is the status of the DIC information switch as monitored by the IPC.

ECT Sensor: The scan tool displays -40 to +151°C (-40 to +304°F). The PCM or 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 Hot Lamp as determined by the IPC. The IPC receives a class 2 serial data message from the ECM indicating that the engine is hot.

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

Engine Oil Life Remaining: The scan tool displays 0-100%. The PCM or ECM calculates the remaining engine oil life.

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

Engine Oil Pressure Switch: The scan tool displays Ok/Low. The scan tool displays the current engine oil pressure as calculated by the PCM.

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

Engine Speed: The scan tool displays 0-9999 RPM. The Engine speed is computed by the PCM or 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/Invalid State. This is the status of the engine speed signal circuit as detected by the PCM.

Fuel Switch: The scan tool displays Inactive/Active. This is the status of the DIC fuel switch signal as monitored by the instrument panel cluster (IPC).

Fuel Level: The scan tool displays Percent (%). The 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 ECM indicating the fuel level percent.

Fuel Tank Level Remaining: The scan tool displays Liters (Gallons). The 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 ECM indicating the fuel level percent.

Fuel Tank Level Remaining: The scan tool displays Percent (%). The PCM 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 indicating the fuel level percent.

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

Gauge Switch: The scan tool displays Inactive/Active. This is the status of the DIC gauge switch signal as monitored by the IPC.

Generator Lamp Command: The scan tool displays On/Off. The PCM disables the generator under certain conditions to ease starting or engine load.

Headlamp Off Switch: The scan tool displays Inactive/Active. This is the status of the headlamp off switch as monitored by the BCM.

Ignition 0 Signal: The scan tool displays On/Off. The scan tool displays the state of the ignition 0 input to the ECM.

Ignition 1 Signal: The scan tool displays On/Off. The scan tool displays the state of the ignition 1 input to the ECM.

Ignition 1 Signal: The scan tool displays 0-19 volts. This is the voltage measured at the ignition 1 signal circuit of the PCM.

Key in Ignition: The scan tool displays Inactive/Active. This is the status of the key-in-ignition switch as monitored by the BCM. When the key is in the ignition cylinder, the scan tool displays On.

LF Door Ajar Switch: The scan tool displays Closed/Ajar. This is the state of the left front door ajar switch as monitored by the BCM.

Left Rear Door Ajar Switch: The scan tool displays Closed/Ajar. This is the state of the left rear door ajar switch as monitored by the BCM.

Low Engine Oil Level Indicator Command: The scan tool displays On/Off. This is the state of the indicator as commanded by the IPC. The IPC receives a serial data message from the PCM requesting the display of the indicator.

Low EOP Indicator Command: The scan tool displays On/Off. This is the state of the indicator as determined by the IPC. The IPC receives a serial data message from the PCM/ECM requesting the display of the indicator.

MIL Command: The scan tool displays On/Off. This is the state of the MIL indicator as commanded by the PCM/ECM.

MIL Circuit History: The scan tool displays Ok/Open/Short/Invalid State. This is the history of the MIL circuit as monitored by the PCM.

MIL Circuit Status: The scan tool displays Fault/Indeterminate/Ok. This is the status of the MIL circuit as monitored by the ECM.

Outside Air Temp.: The scan tool displays numeric counts. This is the status of the outside air temperature sensor as monitored by the IPC.

Outside Air Temp. Raw: The scan tool displays Fahrenheit or Celsius. This is the raw outside air temperature as monitored by the IPC.

Outside Air Temp. Filtered: The scan tool displays Fahrenheit or Celsius. This is the filtered outside air temperature as monitored by the IPC.

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

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

RF Door Ajar Switch: The scan tool displays Closed/Ajar. This is the state of the right front door ajar switch as monitored by the BCM.

Right Rear Door Ajar Switch: The scan tool displays Closed/Ajar. This is the state of the right rear door ajar switch as monitored by the BCM.

Select Switch: The scan tool displays Off/On. This is the status of the DIC select switch as monitored by the IPC.

Trunk Open Switch: The scan tool displays Closed/Open. This is the state of the trunk open switch as monitored by the BCM.

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.