GM Service Manual Online
For 1990-2009 cars only

The Engine Scan Tool Data Definitions contains a brief description of all engine related parameters 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.

5-Volt Reference 1, 2, or 3 Circuit Status: This parameter will display OK if the circuit is good or Fault if a short to ground, short to B+, or open circuit is present.

A/C Disengage 1-8 History: The parameter displays the last 8 air conditioning (A/C) compressor disengages in order from 1 to 8 with 8 being the most recent. There are about 8 possible causes for the A/C compressor to disengage.

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

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

A/C Off for WOT: This parameter displays whether the control module is commanding the A/C compressor clutch relay off for wide open throttle (WOT).

A/C Pressure Disable: This parameter displays whether the A/C pressure is out of range for normal operation as determined by the control module.

A/C Relay Circuit Status: This parameter displays the state of the air conditioning (A/C) clutch relay control circuit. The parameter displays Fault if the A/C clutch relay control circuit is open, shorted to ground, or shorted to voltage. The parameter displays Incomplete until the circuit has been commanded ON.

A/C Relay Command: This parameter displays the commanded state of the A/C clutch relay control circuit. The scan tool will display ON or OFF. ON indicates the A/C clutch relay control circuit is being grounded by the control module, allowing voltage to the A/C compressor clutch. OFF indicates the A/C clutch relay is not being commanded on by the control module.

A/C Request Signal: This parameter displays the state of the air conditioning (A/C) request input to the control module from the heating, ventilation, and air conditioning (HVAC) controls. The scan tool will display Yes or No. Yes indicates the control module is receiving a request from the HVAC system to ground the A/C clutch relay control circuit, engaging the A/C compressor clutch. No indicates the control module is not receiving a request from the HVAC system to ground the A/C clutch relay control circuit.

Actual Fuel Rail Pressure: This parameter displays the fuel rail pressure as calculated by the control module using the signal from the fuel rail pressure (FRP) sensor. The actual fuel rail pressure is a range of values indicating a low pressure when the fuel rail pressure is low to a high pressure when the fuel rail pressure is high.

Air Flow Calculated: This parameter displays the air flow of the engine as calculated by the control module using information from the manifold absolute pressure (MAP) sensor. The scan tool will display a range of values indicating a high air flow when MAP pressure is high and a low air flow when MAP pressure is low. This value is listed in grams per second (g/s).

Air Fuel Ratio: This parameter displays the air to fuel ratio based on the oxygen sensor inputs. The control module uses the fuel trims to adjust fueling in order to attempt to maintain an air fuel ratio of 14.7:1.

APP Indicated Angle: This parameter displays the angle of the accelerator pedal as calculated by the control module using the signals from the accelerator pedal position (APP) sensors. The accelerator pedal position indicated angle is a range of values indicating a low percentage when the accelerator pedal is not depressed to a high percentage when the accelerator pedal is fully depressed.

APP Sensor 1: This parameter displays the voltage signal sent to the control module from APP sensor 1 of the APP sensor assembly. APP sensor 1 is a range of values indicating a low voltage when the accelerator pedal is not depressed to a high voltage when the accelerator pedal is fully depressed.

APP Sensor 1 and 2: This parameter displays the results of a control module test that compares the signals from the APP sensors 1 and 2 . The scan tool will display Agree or Disagree. Agree indicates that APP sensor 1 and APP sensor 2 voltages correspond to the same accelerator pedal position. Disagree indicates that APP sensor 1 and APP sensor 2 voltages correspond to different accelerator pedal positions.

APP Sensor 2: This parameter displays the voltage signal sent to the control module from APP sensor 2 of the APP sensor assembly. APP sensor 2 is a range of values indicating a low voltage when the accelerator pedal is not depressed to a high voltage when the accelerator pedal is fully depressed.

APP Sensors: This parameter displays the average of the accelerator pedal position (APP) sensors as calculated by the throttle actuator control (TAC) module. The APP average is a range of values indicating a low number when the accelerator pedal is not depressed to a high number when the accelerator pedal is fully depressed. This value is listed in percent.

Aux. Vac. Pump Relay Circuit Status: This parameter shows the state of the auxiliary vacuum pump circuit status. The parameter displays the vacuum pump relay short to ground test status.

Aux. Vac. Pump Relay Command: This parameter shows the state of the auxiliary vacuum pump relay. The scan tool shows either commanded on or off.

Average Injector PWM: This parameter indicates the average base pulse width modulation (PWM) or average ON time of the fuel injectors in milliseconds. When the engine load is increased, the injector pulse width will increase.

BARO: This parameter displays the barometric pressure that is received from the BARO Sensor that is integrated within the ECM, in kPa.

BARO Sensor: This parameter shows the Barometric Pressure in volts.

Boost Pressure Sensor: This parameter shows the Turbo Charger Boost sensor voltage.

Boost Pressure Sensor: This parameter shows the TC Boost pressure in kPa.

Brake Booster Pressure Sensor: This parameter shows the brake booster pressure in kPa.

Brake Pedal Signal Status: This parameter displays the serial data message of the brake signal from the electronic brake and traction control module (EBTCM).

Calc. TWC Temp: Calculated catalytic converter temperature.

Calculated ECT-Closed Loop Fuel Control: This parameter shows the calculated temp used for closed loop control.

Calculated ECT-Thermostat Diagnosis: This parameter shows the calculated temp for thermostat diagnosis.

Catalyst Monitor Complete This Ignition: This parameter shows the Catalyst Monitoring Status for this cycle. The scan tool reads yes/no.

Catalyst Monitor Enabled This Ignition: This parameter states if the catalyst monitoring has been enabled for this cycle. The scan tool reads yes/no.

Catalytic Converter Protection Active: This parameter displays the state of the Catalytic Converter Protection mode.

CKP Active Counter: This parameter displays an incrementing counter when the control module receives a signal from the crankshaft position sensor (CKP).

CKP Resync Counter: This parameter displays the number of times the control module has to resynchronize the CKP sensor.

Commanded A/F Equivalence Ratio: This parameter displays the ratio of air to fuel as calculated by the control module based on various sensor inputs. The scan tool will display a lower air fuel ratio when a richer air to fuel mixture is commanded. The scan tool will display a higher air fuel ratio when a leaner air to fuel mixture is commanded. In closed loop operation the air fuel ratio should normally be around 14.2-14.7 to 1.

CMP Sensor: This parameter will read zero unless there is a fault with the CAM sensor. Then the value will increase to 255 and stop.

Cold Startup: This parameter displays whether the engine meets the conditions for a cold startup during the present ignition cycle. The scan tool displays Yes when the conditions for a cold startup are met during this ignition cycle. The scan tool displays No when the conditions for a cold startup are not met during the present ignition cycle. Conditions for a cold startup require the coolant temperature and the intake air temperature to be below a predetermined temperature and within a certain range of each other. These conditions must occur after the engine was warmed up to a specific temperature during the previous ignition cycle.

Control Module Voltage Signal: This parameter shows the control module voltage.

Cooling Fan Motor Command: This parameter shows the Percent (PWM) Duty Cycle that the cooling fan motor is commanded. The scan tool reads this in percent.

CPP Switch: This parameter displays the current state of the clutch pedal as determined by the control module.

Cruise Control Active: This parameter displays the status of the cruise control system as determined by the control module. The scan tool will display Yes when the cruise control system is in control of vehicle speed. The scan tool will display No when the cruise control system is not operating.

Cycles Of Misfire Data: This parameter displays the number of cylinder firing events that were recorded as misfires as determined by the control module.

Cylinder 1 IC Circuit Status: This parameter displays the current diagnostic state of the output driver for the ignition control circuit. The scan tool will display OK if the circuit is operating correctly. The scan tool will display Fault if there is an open, short to ground, or a short to voltage on the circuit.

Cylinder 2 IC Circuit Status: This parameter displays the current diagnostic state of the output driver for the ignition control circuit. The scan tool will display OK if the circuit is operating correctly. The scan tool will display Fault if there is an open, short to ground, or a short to voltage on the circuit.

Cylinder 3 IC Circuit Status: This parameter displays the current diagnostic state of the output driver for the ignition control circuit. The scan tool will display OK if the circuit is operating correctly. The scan tool will display Fault if there is an open, short to ground, or a short to voltage on the circuit.

Cylinder 4 IC Circuit Status: This parameter displays the current diagnostic state of the output driver for the ignition control circuit. The scan tool will display OK if the circuit is operating correctly. The scan tool will display Fault if there is an open, short to ground, or a short to voltage on the circuit.

Cylinder 1 Injector Circuit Status: This parameter displays the current diagnostic state of the output driver for the injector control circuit. The scan tool will display OK if the circuit is operating correctly. The scan tool will display Fault if there is an open, short to ground, or a short to voltage on the circuit.

Cylinder 2 Injector Circuit Status: This parameter displays the current diagnostic state of the output driver for the injector control circuit. The scan tool will display OK if the circuit is operating correctly. The scan tool will display Fault if there is an open, short to ground, or a short to voltage on the circuit.

Cylinder 3 Injector Circuit Status: This parameter displays the current diagnostic state of the output driver for the injector control circuit. The scan tool will display OK if the circuit is operating correctly. The scan tool will display Fault if there is an open, short to ground, or a short to voltage on the circuit.

Cylinder 4 Injector Circuit Status: This parameter displays the current diagnostic state of the output driver for the injector control circuit. The scan tool will display OK if the circuit is operating correctly. The scan tool will display Fault if there is an open, short to ground, or a short to voltage on the circuit.

Cylinder 1-4 Knock Retard: This parameter displays the knock retard as commanded by the control module for cylinders 1-4. Each cylinder is controlled individually based on both knock sensor signal inputs.

Decel. Fuel Cutoff: This parameter displays the status of the operating mode used to turn off the fuel injectors during certain deceleration conditions. When the scan tool displays Active, the control module has turned off the fuel injectors. When the scan tool displays Inactive, the fuel system is operating normally.

Desired Exh. CMP: This parameter displays the desired exhaust camshaft position, as determined by the control module. The scan tool will display a higher value for more advanced exhaust valve timing, such as at high load or speed conditions. The scan tool will display a lower value for a less advanced exhaust valve timing, such as at idle.

Desired Fuel Rail Pressure: This parameter displays the desired fuel rail pressure as calculated by the control module. This value is calculated based on engine speed, engine load, and sensor inputs. The scan tool will display a higher value at higher engine speeds and loads, and a lower value at idle.

Desired HO2S 1: This parameter displays the desired heated oxygen sensor (HO2S) lambda value as commanded by the control module.

Desired HO2S 1: This parameter displays the desired heated oxygen sensor (HO2S) voltage as commanded by the control module.

Desired Idle Speed: This parameter displays the engine idle speed in RPM commanded by the control module. The control module compensates for various engine loads in order to maintain the desired engine RPM at idle. This parameter is not valid unless the engine is running.

Desired Int. CMP: This parameter displays the desired intake camshaft position, as determined by the control module. The scan tool will display a higher value for more advanced intake valve timing, such as at high load or speed conditions. The scan tool will display a lower value for a less advanced intake valve timing, such as at idle.

Desired TC Boost: This parameter displays the desired turbocharger boost pressure as determined by the control module.

Distance Since DTC Cleared: This parameter displays the distance accumulated since an emission diagnostic trouble code was cleared. The scan tool will display increasing distance as the vehicle is driven.

EC Ignition Relay Circuit Status: This parameter displays the status of the output driver for the EC ignition relay control circuit. The scan tool will display OK if the circuit is operating correctly. The scan tool will display Fault if there is an open, short to ground or a short to voltage on the circuit.

EC Ignition Relay Command: This parameter displays the commanded state of the EC ignition relay control circuit. The scan tool will display ON or OFF. ON indicates the EC ignition relay control circuit is being grounded by the control module, allowing voltage to the ignition system. OFF indicates the EC ignition relay is not being commanded on by the control module.

EC Ignition Relay Feedback Signal: This parameter displays the voltage signal sent to the control module from the engine control ignition relay. The scan tool will display battery voltage when the engine is running. The scan tool will display no voltage when the relay is OFF.

ECT Sensor: This parameter displays the temperature of the engine coolant based on the input from the engine coolant temperature (ECT) sensor. When the coolant temperature is low, the scan tool will display a low temperature. When the coolant temperature is high, the scan tool will display a high temperature.

Engine Load: This parameter displays the engine load in percent based on inputs to the control module from various engine sensors. The scan tool will display a low percentage when the engine is at idle with little or no load. The scan tool will display a high percentage when the engine is running at a high RPM under a heavy load.

Engine Off EVAP Test Conditions Met: This parameter displays Yes if the conditions for running the Engine Off EVAP diagnostic are met.

Engine Off Time: This parameter displays the time elapsed since the engine was shut off.

Engine Oil Life Remaining: This parameter displays the amount engine oil life remaining before requiring an oil change based on calculations by the control module. The scan tool will display lower values as the engine oil life approaches 0 miles.

Engine Oil Pressure Switch: This parameter displays the state of the engine oil pressure as determined by the control module. The control module monitors the engine oil pressure switch to determine if the engine oil pressure is sufficient. The scan tool will display low when the engine oil pressure is below a predetermined value.

Engine Oil Temperature Calculated: This parameter displays the temperature of the engine oil as calculated by the control module using a signal from the engine oil temperature sensor. The engine oil temperature sensor has a range of values indicating a low value when the oil temperature is low to a high value when the oil temperature is high.

Engine Run Time: This parameter displays the time elapsed since the engine was started. The scan tool will display the time in hours, minutes and seconds. The engine run time will reset to zero when the engine stops running.

Engine Speed: This parameter displays the speed of the crankshaft as determined by the control module using an input from the CKP sensor. The scan tool will display a high value at high engine speeds and a low value at low engine speeds.

EVAP Fault History: This parameter displays the result of the evaporative emission (EVAP) system diagnostic. The scan tool displays NO FAULT, EXCESS VACUUM, PURGE VALVE LEAK, SMALL LEAK, or WEAK VACUUM. The EVAP Fault History indicates the status of EVAP system diagnostics performed by the control module.

EVAP Monitor Complete This Ignition: This parameter displays the diagnostic monitor completion status during the current driving/monitoring cycle.

EVAP Monitor Enabled This Ignition: This parameter displays the diagnostic monitor enable status during the current driving/monitoring cycle.

EVAP Purge Solenoid Circuit Status: This parameter displays the status of the output driver for the evaporative emission purge solenoid control circuit. The scan tool will display OK if the circuit is operating correctly. The scan tool will display Fault if there is an open, short to ground or a short to voltage on the circuit.

EVAP Purge Solenoid Command: This parameter displays the on-time or duty cycle of the EVAP purge solenoid commanded by the control module expressed as a percent. The scan tool will display a high percentage when the control module is commanding the EVAP purge solenoid to be open a large amount . The scan tool will display a low percentage when the control module is commanding the EVAP purge solenoid to be open a small amount. The scan tool will display 0 when the control module is commanding the EVAP purge solenoid closed.

EVAP Vent Solenoid Circuit Status: This parameter displays the status of the output driver for the evaporative emission vent solenoid control circuit. The scan tool will display OK if the circuit is operating correctly. The scan tool will display Fault if there is an open, short to ground or a short to voltage on the circuit.

EVAP Vent Solenoid Command: This parameter displays the state of the EVAP vent solenoid commanded by the control module expressed as Venting or Not Venting. The scan tool will display Venting when the control module is commanding the EVAP vent solenoid to be open . The scan tool will display Not Venting when the control module is commanding the EVAP vent solenoid to be closed.

Exh. CMP Active Counter: This parameter displays an incrementing counter when the control module receives a signal from the camshaft position (CMP) sensor.

Exh. CMP Angle: This parameter displays the degrees of advanced exhaust camshaft angle related to crankshaft position as determined by the control module based on input from the exhaust CMP sensor. The scan tool will display a higher value for a more advanced exhaust camshaft position. The scan tool will display a lower value when the exhaust camshaft is not being advanced, such as at idle.

Exh. CMP Command: This parameter displays the exhaust camshaft position in percent of range as commanded by the control module.

Exh. CMP Solenoid Circuit Status: This parameter displays the state of the exhaust camshaft actuator solenoid control circuit. The parameter displays Fault if the camshaft actuator solenoid control circuit is open, shorted to ground, or shorted to voltage. The parameter displays Incomplete until the circuit has been commanded ON.

Exh. CMP Variance: This parameter displays in degrees, the difference between the desired exhaust camshaft position and the actual exhaust camshaft position.

FC Circuit Status: This parameter displays the status of the output driver for the cooling fan relay control circuit. The scan tool will display OK, Incomplete, Short B+, Short Gnd, or Open. The scan tool will display OK if the circuit is operating correctly. The scan tool will display a fault if there is an open, short to ground, or a short to voltage on the circuit.

FRP Regulator Command: This parameter displays the portion of the high fuel pressure pump stroke that delivers fuel to the fuel rail. The scan tool will display a higher value for a higher commanded pressure, and a lower value for a lower commanded pressure.

Fuel Level Sensor: This parameter displays the approximate fuel level in the fuel tank as a voltage. The control module calculates this level using the signal from the sensor used to monitor the fuel level in the fuel tank. The scan tool will display a low reading when the fuel level in the tank is low or near empty. The scan tool will display a high reading when the fuel level in the tank is high or near full.

Fuel Pump Relay Circuit Status: This parameter displays the status of the output driver for the fuel pump relay control circuit. The scan tool will display OK if the circuit is operating correctly. The scan tool will display Fault if there is an open, short to ground or a short to voltage on the circuit.

Fuel Pump Relay Command: This parameter displays the commanded state of the fuel pump relay control circuit. The fuel pump relay should be ON when the scan tool indicates the Fuel Pump Relay Command is On. The fuel pump relay should be OFF when the scan tool indicates the Fuel Pump Relay Command is Off.

Fuel Rail Pressure Sensor: This parameter displays the voltage signal sent to the control module from the sensor used to monitor the pressure inside the fuel rail. The scan tool will display a low voltage when the pressure in the fuel rail is low. The scan tool will display a high voltage when the pressure in the fuel rail is high.

Fuel Tank Level Remaining: This parameter displays the amount of fuel remaining in the fuel tank as a percentage. The control module calculates this level using the signal from the sensor used to monitor the fuel level in the fuel tank. The scan tool will display a low reading when the fuel level in the tank is low or near empty. The scan tool will display a high reading when the fuel level in the tank is high or near full.

Fuel Tank Level Remaining: This parameter displays the approximate fuel level in the fuel tank as calculated by the control module based on the input from the fuel level sensor. The scan tool will display a low value when the fuel level in the tank is low or near empty. The scan tool will display a high value when the fuel level in the tank is high or near full.

Fuel Tank Pressure Sensor: This parameter displays the fuel tank pressure as calculated based on a signal sent to the control module from the fuel tank pressure (FTP) sensor. The scan tool will display a low value when the pressure in the fuel tank is low or a vacuum. The scan tool will display a high value when the pressure in the fuel tank is high.

Fuel Tank Pressure Sensor: This parameter displays the voltage signal sent to the control module from the sensor used to monitor the pressure inside the fuel tank. The scan tool will display a low voltage when the pressure in the fuel tank is high. The scan tool will display a high voltage when the pressure in the fuel tank is low or in a vacuum.

Fuel Tank Rated Capacity: This parameter displays the rated maximum quantity of fuel the fuel tank will hold. This is calibrated in the control module to match the vehicle.

Fuel Trim Learn: This parameter indicates if the control module is adjusting long term fuel trim in response to the short term fuel trim. The scan tool displays Enabled or Disabled. When conditions are appropriate for enabling long term fuel trim corrections, the scan tool displays Enabled.

Fuel Trim System Test State: This parameter indicates the status of the Fuel Trim System Test. The scan tool will display Disabled, Enabled, Monitoring, or Run Purge Test.

Fuel Volatility:  This parameter indicates the rate the fuel can be vaporized in the cylinder as calculated by the control module. The scan tool will display HIGH when the fuel volatility is high. The scan tool will display LOW when the fuel volatility is low.

HO2S 1: The scan tool displays a range of 0-1,106 mV.

HO2S 1 Heater Circuit Status: This parameter displays the diagnostic state of the output driver for the heater control circuit of oxygen sensor 1. The scan tool will display OK if the circuit is operating correctly. The scan tool will display Fault if there is an open, short to ground, or a short to voltage on the circuit.

HO2S 1 Heater Command: This parameter displays the commanded state of the heater control circuit for oxygen sensor 1. The oxygen sensor 1 heater should be on when the scan tool indicates the HO2S 1 Heater Command is On. The oxygen sensor 1 heater should be off when the scan tool indicates the HO2S 1 Heater Command is Off.

HO2S 1 or 2 Heater Command: This parameter displays the commanded state of the heater control circuit as commanded by the control module.

HO2S 1 or 2 Sensing Element: This parameter displays the resistance of the sensing element within the control module. The front sensors are normally regulated to 80 ohms. The rear sensors are normally regulated between 20-300 ohms which depends on temperature.

HO2S 2: The scan tool displays a range of 0-1,106 mV.

HO2S 2 Heater Circuit Status: This parameter displays the status of the output driver for the HO2S Heater Sen. 2. The scan tool will display OK if the circuit is operating correctly. The scan tool will display Fault if there is an open, short to ground, or a short to voltage on the circuit.

HO2S 2 Heater Command: This parameter displays the commanded state of the heater control circuit for oxygen sensor 2. The oxygen sensor 1 heater should be on when the scan tool indicates the HO2S 2 Heater Command is ON. The oxygen sensor 2 heater should be OFF when the scan tool indicates the HO2S 2 Heater Command is OFF.

HO2S Heater Monitor Complete This Ignition: This parameter displays the diagnostic monitor completion status during the current driving/monitoring cycle.

HO2S Heater Monitor Enabled This Ignition: This parameter displays the diagnostic monitor enable status during the current driving/monitoring cycle.

HO2S Sensor 1 Module Signal: This parameter displays the voltage of the HO2S control transistor, which is internal to the control module.

HO2S/O2S Monitor Complete This Ignition: This parameter displays the diagnostic monitor completion status during the current driving/monitoring cycle.

HO2S/O2S Monitor Enabled This Ignition: This parameter displays the diagnostic monitor enable status during the current driving/monitoring cycle.

IAT Sensor: The scan tool displays a range of -40 to +150°C (-40 to +302°F). The engine control module (ECM) converts the resistance of the intake air temperature (IAT) sensor to degrees.

IAT Sensor 2: This parameter displays the temperature of the air after the turbocharger and the charge air cooler, before it enters the intake manifold. Intake air temp is used by the ECM to adjust fuel delivery and spark timing according to incoming air density.

Ignition 0 Signal: This parameter displays On when the control module detects a voltage at the ignition 0 input terminal.

Ignition 1 Signal: This parameter displays the voltage measured at the ignition 1 circuit of the control module. Voltage is applied to the control module when the ignition switch is in the ignition 1 position.

Ignition Off Time: This parameter displays the time elapsed since the ignition was last turned off. The scan tool will display the time in hours, minutes, and seconds.

Initial Brake Apply Signal: This parameter displays the state of the brake pedal that is transmitted over the serial data circuit from the electronic brake control module (EBCM).

Inj. 1 Disabled Due to Misfire: This parameter displays the status of the fuel injector driver by the control module. The scan tool will display YES if the fuel injector is being disabled due to a misfire detection. The scan tool will display NO if the fuel injector is not being disabled by the control module due to a misfire.

Inj. 2 Disabled Due to Misfire: This parameter displays the status of the fuel injector driver by the control module. The scan tool will display YES if the fuel injector is being disabled due to a misfire detection. The scan tool will display NO if the fuel injector is not being disabled by the control module due to a misfire.

Inj. 3 Disabled Due to Misfire: This parameter displays the status of the fuel injector driver by the control module. The scan tool will display YES if the fuel injector is being disabled due to a misfire detection. The scan tool will display NO if the fuel injector is not being disabled by the control module due to a misfire.

Inj. 4 Disabled Due to Misfire: This parameter displays the status of the fuel injector driver by the control module. The scan tool will display YES if the fuel injector is being disabled due to a misfire detection. The scan tool will display NO if the fuel injector is not being disabled by the control module due to a misfire.

Injector 1-4 Command: This parameter displays the amount of fuel injector ON time or pulse width as commanded by the control module.

Intake Manifold Pressure: This parameter displays the pressure difference between the MAP and the barometric pressure (BARO). The scan tool will display a higher value during high vacuum conditions, such as idle or deceleration. The scan tool will display a lower value during low vacuum conditions, such as wide open throttle or high load cruising.

Int. CMP Active Counter: This parameter displays an incrementing counter when the control module receives a signal from the camshaft position (CMP) sensor.

Int. CMP Angle: This parameter displays the actual intake camshaft position in degrees.

Int. CMP Command: This parameter displays the intake camshaft position in percent of range as commanded by the control module.

Int. CMP Solenoid Circuit Status: This parameter displays the state of the intake camshaft actuator solenoid control circuit. The parameter displays Fault if the camshaft actuator solenoid control circuit is open, shorted to ground, or shorted to voltage. The parameter displays Incomplete until the circuit has been commanded ON. This parameter may not change if the scan too is used to command the CMP solenoid ON.

Int. CMP Variance: This parameter displays in degrees, the difference between the desired intake camshaft position and the actual intake camshaft position.

Knock Detected Cyl. 1: This parameter displays the status of each cylinder for knock detection by the control module. The scan tool will display YES if a knock condition has been detected related to that cylinder combustion event. The scan tool will display NO if there is no knock condition detected related to that cylinder combustion event.

Knock Detected Cyl. 2: This parameter displays the status of each cylinder for knock detection by the control module. The scan tool will display YES if a knock condition has been detected related to that cylinder combustion event. The scan tool will display NO if there is no knock condition detected related to that cylinder combustion event.

Knock Detected Cyl. 3: This parameter displays the status of each cylinder for knock detection by the control module. The scan tool will display YES if a knock condition has been detected related to that cylinder combustion event. The scan tool will display NO if there is no knock condition detected related to that cylinder combustion event.

Knock Detected Cyl. 4: This parameter displays the status of each cylinder for knock detection by the control module. The scan tool will display YES if a knock condition has been detected related to that cylinder combustion event. The scan tool will display NO if there is no knock condition detected related to that cylinder combustion event.

Knock Retard: The scan tool displays degrees. This parameter indicates the amount of spark the ECM is removing from ignition control (IC) spark advance in response to the signal from the knock sensors. The traction control system desired torque signal from the electronic brake and traction control module (EBTCM) may cause knock retard to display a value more than 0.0 degrees if traction control is active.

KS 1 or 2 Signal: This parameter displays the voltage input to the control module from the knock sensor (KS).

Long Term FT: The scan tool displays percentage. The ECM derives the long term fuel trim from the short term fuel trim value. The long term fuel trim represents a long term correction of fuel delivery. A value of 0 percent indicates that fuel delivery requires no compensation in order to maintain the ECM commanded air/fuel ratio. A negative value significantly below 0 percent indicates that the fuel system is rich and the ECM is reducing the fuel delivery. A positive value significantly more than 0  percent indicates that a lean condition exists and the ECM compensates by adding fuel. Fuel trim values at maximum authority indicates an excessively rich or lean system.

Loop Status: Closed loop indicates that the ECM is controlling fuel delivery according to oxygen sensor voltage. In open loop, the ECM ignores the oxygen sensor voltage and bases the amount of fuel to be delivered on throttle position (TP) sensor, ECT, and mass air flow (MAF) sensor inputs only.

LT FT Idle/Decel.: This parameter displays the commanded Long Term Fuel Trim correction by the control module for idle and deceleration conditions.

MAF Sensor: The scan tool displays a range of 0.0-655 g/s. The MAF is the MAF input frequency converted to grams of air per second. This indicates the amount of air entering the engine.

MAF Sensor: The scan tool displays a range of 0-65,535 Hz. The MAF sensor is a hot wire type air flow sensor. The ECM converts current draw needed by the MAF to keep the hot wires at a constant into a frequency signal. The scan tool displays this frequency in a hertz signal.

MAP Sensor: The MAP sensor measures the change in the intake manifold pressure which results from engine load and speed changes. As the intake manifold pressure increases, the air density in the intake also increases and additional fuel is required. The scan tool displays a range of 0-255 kPa. The MAP sensor measures the absolute pressure in the intake manifold.

MAP Sensor: The MAP sensor measures the change in the intake manifold pressure which results from engine load and speed changes. As the intake manifold pressure increases, the air density in the intake also increases and additional fuel is required. The scan tool displays a range of 0-5 volts. The MAP sensor measures the absolute pressure in the intake manifold.

MIL Circuit Status: This parameter displays the status of the output driver for the malfunction indicator lamp (MIL) control circuit. The scan tool will display OK if the circuit is operating correctly. The scan tool will display Fault if there is an open, short to ground or a short to voltage on the circuit.

MIL Command: This parameter displays the commanded state of the MIL control circuit. The malfunction indicator lamp should be ON when the scan tool indicates the MIL Command is ON. The malfunction indicator lamp should be OFF when the scan tool indicates the MIL Command is OFF. The control module will command the MIL On when the ignition is ON with the engine OFF in order to perform a bulb check.

MIL Requested by DTC: This parameter indicates the reason the control module illuminated the MIL. The scan tool will display YES when the MIL is requested as a result of an A or B type DTC. The scan tool will display NO if the MIL is illuminated for another reason, such as transmission DTCs.

Misfire Current Cyl. 1-4: The scan tool displays 0-255 counts. The display shows 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.

Misfire History Cyl. 1-4: The scan tool range is 0-255 counts. This parameter indicates the total level of misfire that has been detected on each cylinder. The misfire history counters will not update or show any activity until a misfire or DTC P0300 has become active. The misfire history counter will update every 200 cylinder firing events.

Moderate Brake Apply Signal: This parameter displays the state of the brake pedal that is transmitted over the serial data circuit from the electronic brake control module (EBCM).

PNP Switch: This parameter displays whether the transmission range selector is in Park or Neutral.

Post Inj. Cyl. 1-4 Command: This parameter displays the amount of fuel injector ON time or pulse width as commanded by the control module for catalyst heating.

Power Enrichment: Scan tool displays ACTIVE or INACTIVE. ACTIVE displayed indicates that the ECM has detected conditions appropriate to operate in Power Enrichment mode. The ECM will command Power Enrichment mode when a large increase in throttle position and load is detected. While in Power Enrichment, the ECM will increase the amount of fuel delivered by entering Open Loop and increasing the injector pulse width. This is done to prevent a possible sag or hesitation from occurring during acceleration.

Reduced Engine Power: The scan tool displays Active or Inactive. The scan tool displays Active when the ECM receives a signal from the TAC module that a throttle actuator control system fault is occurring. The ECM limits the engine power.

Short Term FT: The scan tool displays percentage. The short term fuel trim represents a short term correction to fuel delivery by the ECM in response to the amount of time the fuel control oxygen sensor voltage spends above or below the 450 mV threshold. If the oxygen sensor voltage mainly remains less than 450 mV, indicating a lean air/fuel mixture, short term fuel trim increases into the positive range above 0 percent. The ECM adds fuel. If the oxygen sensor voltage stays mainly above the threshold, the short term fuel trim decreases below 0 percent into the negative range. The ECM reduces the fuel delivery in order to compensate for the indicated rich condition. Under certain conditions such as an extended idle and a high ambient temperature, the canister purge may cause the short term fuel trim to read in the negative range during normal operation. The fuel trim values at maximum authority may indicate an excessively rich or lean system.

Spark: The scan tool displays a range of -64 to +64°. The scan tool displays the amount of degrees the ECM commands. The ECM computes the desired spark advance using the following: (1) ECT, (2) engine speed (RPM), (3) load, (4) vehicle speed. The ECM adjusts the timing. A negative (-) value indicates degrees before top dead center (BTDC) or spark advance; a positive value indicates degrees after top dead center (ATDC) or spark retard.

Start Up ECT: Indicates the engine coolant temperature at engine start up. The scan tool displays a range of -40 to +150°C (-40 to +302°F). The scan tool displays the engine ECT at the time the engine was started. The ECM uses start-up ECT for certain DTCs.

Start Up IAT: Indicates the IAT at the time that the vehicle was started. The scan tool range is -40 to +150°C (-40 to +302°F). This parameter indicates the ambient air temperature at start-up.

Stop Lamp Pedal Switch: This parameter displays the position of the stop lamp pedal switch input to the control module.

System Power Mode: This parameter displays the position of the ignition switch.

TAC Forced Engine Shutdown: This parameter indicates the status of throttle actuator control (TAC) by the control module. The scan tool will display YES if the engine has been shut down due to a throttle control fault. The scan tool will display NO if the engine has not been shut down due to a throttle control fault.

TAC Motor: This parameter indicates the status of the throttle actuator control (TAC) motor driver by the control module. The scan tool will display Enabled if TAC motor operation is allowed. The scan tool will display Disabled if the TAC motor is disabled.

TC Bypass Solenoid Circuit Status: This parameter displays the diagnostic state of the output driver for the turbocharger bypass solenoid. The scan tool will display OK if the circuit is operating correctly. The scan tool will display Fault if there is an open, short to ground, or a short to voltage on the circuit.

TC Bypass Solenoid Command: This parameter shows the state of the turbocharger bypass solenoid. The scan tool shows either commanded on or off.

TC Wastegate Solenoid Circuit Status: This parameter displays the diagnostic state of the output driver for the turbocharger wastegate solenoid. The scan tool will display OK if the circuit is operating correctly. The scan tool will display Fault if there is an open, short to ground, or a short to voltage on the circuit.

TCC/Cruise Brake Pedal Switch: This parameter displays the position of the torque converter clutch (TCC) brake pedal switch input to the control module. The scan tool displays Applied, Released, or Invalid.

TCS Torque Delivered Signal: 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 ECM is responding properly to the traction control desired torque signal.

TCS Torque Request Signal: Represents the PWM signal from the EBTCM. The EBTCM reduces the traction control desired torque signal pulse width when a drive wheel slippage situation is detected. The ECM monitors the traction control desired torque signal and reduces drive wheel slippage as necessary by retarding spark timing.

Total Fuel Trim Average: This parameter displays the overall fuel trim from the idle/decel cell and the cruise/accel cell.

Total Knock Retard: This parameter indicates how much ignition spark timing is being retarded due to all control systems monitored by the control module. The scan tool will display a high value during extreme conditions such as high temperatures and antilock braking. The scan tool will display a lower value during lighter driving conditions.

Total Misfire: The scan tool range is 0-255 counts. This parameter indicates the total level of misfire that has been detected on each cylinder. The misfire history counters will not update or show any activity until a misfire or DTC P0300 has become active. The misfire history counter will update every 200 cylinder firing events.

TP Desired Angle: The scan tool displays 0-100 percent. The ECM indicates the desired throttle angle commanded by the vehicle operator. The scan tool indicates the desired throttle angle commanded by the vehicle operator.

TP Indicated Angle: This parameter displays the angle of the TP in percent. This information is calculated by the control module using the signals from the throttle position sensors. The scan tool will display a low percentage when the throttle plate is closed. The scan tool will display a high percentage when the throttle plate is fully open.

TP Sensor 1: This parameter displays the voltage signal sent to the control module from the sensor used to monitor the position of the throttle plates. This parameter is for sensor 1 of the TP sensor assembly. The scan tool will display a low voltage when the throttle plates are at rest. The scan tool will display a high voltage when the throttle plates are fully open.

TP Sensor 1 Learned Minimum: This parameter displays the learned minimum value of TP sensor 1 as recorded by the control module on start-up for the ignition cycle.

TP Sensor 2: This parameter displays the voltage signal sent to the control module from the sensor used to monitor the position of the throttle plates. This parameter is for sensor 2 of the TP sensor assembly. The scan tool will display a high voltage when the throttle plates are at rest. The scan tool will display a low voltage when the throttle plates are fully open.

TP Sensor 2 Learned Minimum: This parameter displays the learned minimum value of TP sensor 2 as recorded by the control module on start-up for the ignition cycle.

TP Sensors 1 and 2: This parameter displays the results of a control module test that compares the signals from the TP sensors 1 and 2 . The scan tool will display Agree when the signal from TP sensor 1 corresponds with the signal from TP sensor 2. The scan tool will display Disagree when the signal from TP sensor 1 conflicts with the signal from TP sensor 2.

Vehicle Speed Sensor: This parameter indicates the vehicle speed as calculated by the control module based on a signal from the vehicle speed sensor (VSS). The scan tool will display a higher value at higher vehicle speeds, and a lower value at lower vehicle speeds.

Volumetric Efficiency: This parameter displays the calculated volumetric efficiency of the engine as calculated by the control module.

Warm Ups Since DTC Cleared: This parameter indicates the number of warm up cycles that have occurred since DTCs were cleared. The scan tool will display higher counts as more warm up cycles have occurred since the DTCs were cleared.

Wastegate Solenoid Command: This parameter shows the Percent (PWM) Duty Cycle that the wastegate solenoid is commanded. The scan tool reads this in percent.

Wide Open Throttle: This parameter indicates the throttle status commanded by the control module. The scan tool will display YES if the vehicle throttle is commanded to wide open. The scan tool will display NO if the vehicle throttle is commanded to an amount less than 100 percent.