GM Service Manual Online
For 1990-2009 cars only

The Scan Tool Data Definitions list contains a brief description of all of the engine related parameters that are available on the scan tool. The list is arranged in alphabetical order. A given parameter may appear in any one of the data lists. In some cases the parameter may appear more than once, or in more than one data list in order to group certain related parameters together.

A/C High Side Pressure: This parameter displays the voltage from the A/C high side pressure sensor signal circuit to the control module.

Actual EGR Position: This parameter displays the actual exhaust gas recirculation (EGR) position as commanded by the control module.

Ambient Air Temperature: This parameter displays the temperature of the outside air based on input to the control module from the ambient air temperature sensor.

APP Sensor 1 and Sensor 2: This parameter displays the actual voltage of the APP sensor 1 and sensor 2 signal circuits as measured by the control module.

APP Sensors: This parameter displays the actual percentage of the combined APP sensor 1 and 2 signal circuits as measured by the control module.

BARO: This parameter displays the barometric pressure. The control module uses the manifold absolute pressure sensor to determine the barometric pressure. The control module uses the barometric pressure for fuel control to compensate for altitude differences.

Change Engine Oil Indicator Command: This parameter displays the control module commanded state of the change engine oil indicator.

Crank Request Signal: This parameter displays the control modules commanded state of the starter relay.

Cruise Active: This parameter displays the status of the cruise control system as determined by the control module.

Cruise Cancel Switch: This parameter displays the state of the cruise cancel switch input to the control module .

Cruise Control Switch: This parameter displays the state of the cruise control switch input to the control module .

Cruise On/Off Switch: This parameter displays the state of the on/off switch input to the control module. The scan tool will display On when the cruise ON/OFF switch is on. The scan tool will display OFF when the cruise ON/OFF switch is OFF.

Cruise Release Brake Pedal Switch: This parameter displays the state of the cruise brake pedal switch input to the control module .

Cruise Resume/Accel. Switch: This parameter displays the state of the Resume/Accel switch input to the control module When the cruise control switch is in the on position and the Resume/Accel switch is activated, the scan tool displays Active. When the Resume/Accel switch is released the scan tool displays Inactive.

Cruise Set/Coast Switch: This parameter displays the state of the Set/Coast switch input to the control module from the cruise control system. When the cruise control switch is in the on position and the Set/Coast switch is activated, the scan tool displays Active. When the Set/Coast switch is released the scan tool displays Inactive.

Decel. Fuel Cut Off: This parameter displays the status of the operating mode of the control module used to turn off the fuel injectors during certain deceleration conditions.

Desired EGR Position: This parameter displays the desired EGR position as commanded by the control module.

Desired Idle Speed: This parameter displays the desired engine idle speed as commanded by the control module.

Desired Torque ABS/TCS: This parameter displays the desired torque as commanded by the control module.

Distance Since DTC Cleared: This parameter displays the mileage that has elapsed since the DTC cleared.

ECT Sensor: This parameter displays the temperature of the engine coolant based on input to the control module from the engine coolant temperature (ECT) sensor.

EGR Closed Pintle Position: This parameter displays the exhaust gas recirculation (EGR) valve position in percent of range when commanded closed by the control module.

EGR Duty Cycle: This parameter displays the percentage of the commanded state of the EGR valve by the control module.

EGR Feedback: This parameter displays the actual EGR pintle position in volts based on input to the control module from EGR sensor.

EGR Flow Test Count: This parameter displays the number of EGR flow test samples collected during the current ignition cycle.

Engine Load: This parameter displays the calculated engine load in percent based on inputs to the control module from various engine sensors.

Engine Oil Level Switch: This parameter displays the state of the engine oil level switch input to the control module.

Engine Oil Pressure Sensor: This parameter displays the state of the oil pressure sensor input to the control module.

Engine Oil Temperature: This parameter displays the temperature of the engine oil based on input to the control module from the engine oil temperature sensor.

Engine Run Time: This parameter displays the time elapsed since the engine was started.

Engine Speed: This parameter displays the speed of the engine crankshaft rotation from information received from the crankshaft position (CKP) sensor.

EVAP Duty Cycle: This parameter displays the on-time or duty cycle of the evaporative emission (EVAP) canister purge solenoid commanded by the control module. Zero percent indicates no purge. One hundred percent indicates full purge.

Fan Relay 1 and Relay 2: This parameter displays the control module commanded state of the cooling fans.

Fuel Level: This parameter displays the fuel level gage position in percent of range as commanded by the control module.

Fuel Level Sensor Left Tank: This parameter displays the voltage in range based on input to the control module from the fuel level sensor in the left side fuel tank.

Fuel Level Sensor Right Tank: This parameter displays the voltage in range based on input to the control module from the fuel level sensor in the right side fuel tank.

Fuel Pump: This parameter displays the control modules commanded state of the fuel pump relay control circuit.

Fuel Tank Level Remaining: This parameter displays the fuel level in liters as commanded by the control module.

Fuel Tank Pressure Sensor (If Equipped): This parameter displays the voltage signal received by the control module from the fuel tank pressure (FTP) sensor.

Fuel Trim Learn: This parameter displays Enabled when conditions are appropriate for enabling long term fuel trim corrections. This indicates that the long term fuel trim is adapting continuing amounts of short term fuel trim. If the scan tool displays Disabled, then long term fuel trim will not respond to changes in short term fuel trim.

HO2S Sensor 1 and Sensor 2: This parameter displays the voltage output from the heated oxygen sensors (HO2S) to the control module. A lower voltage indicates a lean exhaust, while a higher voltage indicates a rich exhaust.

HO2S Heater Sensor 1 and Sensor 2: This parameter displays the percentage of the HO2S heaters commanded by the control module.

HO2S Heater Sensor 1 and Sensor 2: This parameter displays the HO2S heaters commanded On or Off by the control module.

IAT Sensor: This parameter displays the temperature of the air entering the air induction system based on input to the control module from the intake air temperature (IAT) sensor.

Ignition 1: This parameter displays voltage input to the control module by the ignition 1 voltage circuit.

Ignition Accessory Relay: This parameter displays the control modules commanded state of the ignition accessory relay.

Injector PWM Bank 1: This parameter displays the average pulse width of the fuel injectors as determined by the control module.

Knock Detected Cyl. 1-4: This parameters displays the number of times the control module detects activity from the knock sensor for the cylinder.

Knock Retard: This parameter indicates the amount of spark advance the control module removes from the ignition control (IC) spark advance in response to the signal from the knock sensors.

KS Active Counter: This parameters displays the number of times the control module detects activity from the knock sensor.

Long Term FT: This parameter displays the percentage commanded Long Term Fuel Trim correction by the control module.

Long Term FT: This parameter displays the counts commanded Long Term Fuel Trim correction by the control module.

Low Engine Oil Level Indicator Command: This parameter displays the control modules commanded state of the low engine oil level indicator.

Low Oil Pressure Warning: This parameter displays the control modules commanded state of the low oil pressure warning lamp.

MAF Sensor: This parameter displays the air flow from the MAF sensor signal to the control module.

Main Relay: This parameter displays the control modules commanded state of the main relay.

MAP Sensor: This parameter displays the vacuum signal from the MAP sensor to the control module.

MAP Sensor: This parameter displays the signal voltage from the MAP sensor to the control module.

Mileage at First Failure: This parameter displays the total number of Km/miles that the control module detected since the first DTC failure.

Misfire Current Cyl. 1-4: This parameter displays the number of misfires that have been detected during the last 200 cylinder firing events. The counters may normally display some activity, but the activity should be nearly equal for all of the cylinders, and in low numbers.

Purge Learned Memory B1: This parameter displays the learned minimum value of the EGR valve as recorded by the control module during the last learn procedure.

Reduced Engine Power: This parameter displays the status of the operating mode of the control module used to reduce engine power to prevent catalytic converter or engine damage or due to a Throttle Actuator Control (TAC) system failure.

Short Term FT : This parameter displays the short-term correction to the fuel delivery by the control module in response to the oxygen sensor. If the oxygen sensor indicates a lean air/fuel mixture, the control module will add fuel increasing the short term fuel trim above 0. If the oxygen sensor indicates a rich air/fuel mixture, the control module will reduce fuel decreasing the short term fuel trim below 0.

Short Term FT: This parameter displays the short-term correction to the fuel delivery by the control module in response to the oxygen sensor. If the oxygen sensor indicates a lean air/fuel mixture, the control module will add fuel increasing the short term fuel trim above 0. If the oxygen sensor indicates a rich air/fuel mixture, the control module will reduce fuel decreasing the short term fuel trim below 0.

Spark: This parameter displays the amount of spark advance the control module is commanding on the ignition control circuits. The control module determines the desired advance.

Start Up ECT: This parameter displays the temperature of the engine coolant on start up based on input to the control module from the ECT sensor.

Starter Relay Status: This parameter displays the control modules commanded state of the starter relay.

Torque Delivered: Represents the pulse width modulation (PWM) signal which indicates the percent of available torque the engine is delivering to the drive wheels. The EBTCM monitors the traction control torque signal to ensure that the PCM is responding properly to the traction control desired torque signal.

Total Knock Retard: This parameter indicates the amount of total spark advance the control module removes from the ignition control (IC) spark advance in response to the signal from the knock sensors.

Total Misfire Current Counter: This parameter displays the total number of cylinder firing events that the control module detected as misfires for the last 200 crankshaft revolution sample period.

TP Angle: This parameter displays the percent of throttle opening as calculated by the control module using information from the two TP sensors.

TP Indicated Angle: This parameter displays the actual TP angle indicated by the control module using information from the two TP sensors.

TP Sensor 1 and Sensor 2: This parameter displays the voltage in range based on input to the control module the control module from the TP sensor 1 and sensor 2.

Vehicle Speed Sensor: This parameter displays the speed of the vehicle as calculated by the control module from information received from the vehicle speed sensor (VSS).