Part 1
Scan Tool Data DefinitionsThe Engine Scan Tool Data Definitions contains a brief description of all engine related parameters available on the scan tool. The list is 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: This parameter displays the voltage sensed on the 5-volt reference 1 circuit at the control module.
5-Volt Reference 2: This parameter displays the voltage sensed on the 5-volt reference 2 circuit at the control module.
A/C Disengage (1-8) History: The scan tool displays the last 8 reasons why the A/C system was disengaged.
A/C High Side Pressure Sensor Volts: This parameter displays the voltage signal sent to the control module from the A/C high side pressure sensor. The A/C high side pressure sensor has a range of values indicating a low refrigerant pressure when the voltage is low to a high refrigerant pressure when the voltage is high. This parameter also displays kPa and psi.
A/C High Side Pressure Sensor kPa (psi): This parameter displays the kPa (psi) signal sent to the control module from the A/C high side pressure sensor. The A/C high side pressure sensor has a range of values indicating a low refrigerant pressure when the kPa is low to a high refrigerant pressure when the kPa (psi) is high.
A/C Off for Wide Open Throttle (WOT): This parameter indicated the throttle status commanded by the control module. The scan tool will display YES if the vehicle throttle is commanded to wide open and the A/C will turn off. The scan tool will display NO if the vehicle throttle is commanded to an amount less than 100 percent and the A/C is operating normal.
A/C Pressure Disable: This parameter displays the state of the air conditioning (A/C) compressor cycling switch as determined by the control module. The scan tool will display Yes or No. Yes indicated the A/C system has enough refrigerant to close the A/C cycling switch, allowing the A/C compressor to engage. No indicates the A/C refrigerant system has low pressure and the A/C compressor switch is opened.
A/C Relay Command: This parameter displays the commanded state of the air conditioning (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.
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).
Ambient Air Temperature: This parameter displays the ambient, outside, air temperature as calculated by the control module.
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 sensors. The accelerator pedal position (APP) 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. The accelerator pedal position (APP) 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 Indicated Position: This parameter displays the angle of the APP sensor 1 as calculated by the control module using the signals from the APP sensor 1. APP sensor 1 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 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 indicated 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 2 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 Sensors 2 Indicated Position: This parameter displays the angle of the accelerator pedal as calculated by the control module using the signals from the accelerator pedal position sensors. The accelerator pedal position (APP) 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 full depressed.
APP Sensors: This parameter displays the angle of the accelerator pedal as calculated by the control module using the signals from the accelerator pedal position sensors. The accelerator pedal position (APP) 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 full depressed.
BARO (Gasoline): This parameter displays the barometric pressure as calculated by the control module using the signal from the manifold absolute pressure (MAP) sensor measured when the ignition is turned on with the engine not running. The control module will update the barometric pressure during wide-open throttle (WOT) conditions. The scan tool will display a low value when the barometric pressure is low and a high value when the barometric pressure is high.
BPP Circuit Signal: This parameter displays the state of the brake pedal position switch as determined by the brake pedal switch. The scan tool will display Applied when the brake pedal is depressed, and Released when the brake pedal is not depressed.
Calculated. TWC Temp. Bank 1/Calculated. TWC Temp. Bank 2: This parameter displays the catalytic converter temperature as calculated by the control module.
Catalytic Converter Protection Active: This parameter indicates the status of the control module for catalytic converter protection. The scan tool will indicate YES if the control module is adjusting fuel and ignition quantity and timing to protect the catalytic converter from damage. The scan tool will indicate No if the control module is in normal fuel and ignition control mode.
CKP Active Counter: This parameter displays an incrementing counter when the control module receives a signal from the crankshaft position (CKP) sensor.
CKP Resync Counter: This parameter displays the number of times the control module has to resynchronize the CKP sensor.
CKP Sensor: This parameter displays the engine speed as calculated by the control module using the signal from the CKP sensor.
CMP Active Counter: This parameter displays an incrementing counter when the control module received a signal from the camshaft position (CMP) sensor.
CMP Angle: The scan tool displays 0-25 °. The scan tool will display the actual commanded cam degrees retard.
CMP Sensor: This parameter displays the number of times the signal voltage from the camshaft position (CMP) sensor changed from high to low. The scan tool will display these transitions as counts.
CMP Variance: The scan tool displays 0-25°. The scan tool will display the difference in degrees between the desired and actual cam angle.
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 the 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.
Commanded Air Fuel 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.
Crank Request Signal: This parameter displays the state of the crank request input to the control module from the ignition switch. The scan tool will display YES when the ignition switch is in the Crank position. The scan tool will display No when the ignition switch is in any other position.
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.
Cruise Disengage History 1-8: The Scan tool displays the last 8 cruise control Disengage in order from 1 to 8. There are 46 possible caused for the cruise control to disengage.
Cruise On/Off Switch: The scan tool displays Off/On. When the cruise control module is enabled, the scan tool displays On.
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 On. When the Resume/Accel switch is released the scan tool displays Off.
Cruise Set/Coast Switch: This parameter displays the state of the Set/Coast switch input to the control module. When the cruise control switch is in the on position and the Set/Coast switch is activated, the scan tool displays On. When the Set/Coast switch is released the scan tool displays Off.
Cycles Of Misfire Data: This parameter displays the number of cylinder firing events that were recorded as misfires as determined by the control module.
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 Camshaft Position (CMP): The scan tool displays 0-25°. The scan tool will display the desired cam phase angle.
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.
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 indicated the EC ignition relay control circuit is being grounded by the control module, allowing voltage to other control module circuits and systems. OFF indicated 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.
ECM in VTD Fail Enable:The scan tool displays Yes or No: The scan tool displays Yes if the powertrain interface module (PIM) and the control module lose communications with each other after the PIM sends the correct password. The scan tool displays No if the PIM is communicating the correct password to the ECM.
ECT: This parameter displays the temperature of the engine coolant based on a voltage input from the engine coolant temperature (ECT) sensor to the control module. The scan tool will display a low value when the coolant temperature is low and a high value when the coolant temperature is high.
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 Time: This parameter displays the time elapsed since the engine was last started. The scan tool will display the time in hours, minutes and seconds. The engine off time will reset to zero and start counting up every 24 hours.
Engine Oil Level Switch: This parameter displays the state of the engine oil level switch as determined by the control module. The scan tool will display OK or Low. OK indicates that the engine oil level is not too low for safe operation of the engine. Low indicates the engine oil level is abnormally low and has closed the engine oil level switch.
Engine Oil Pressure: This parameter displays the pressure of the engine oil as calculated by the control module using a signal from the engine oil pressure (EOP) sensor. The scan tool will display oil pressure when the engine is running. The engine oil pressure sensor has a range of values indicating a low value when the oil pressure is low to a high value when the oil pressure is high.
Engine Oil Pressure Sensor: The scan tool displays 0 to 5 volts. The ECM monitors the engine oil pressure sensor signal circuit where a low voltage indicates low pressure.
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 as soon as the engine stops running.
Engine Speed: This parameter displays the speed of the crankshaft as calculated by the control module based on inputs from the Crankshaft Position (CKP) Sensor. The scan tool will display the engine speed in revolutions per minute (RPM).
EVAP Fault History: This parameter displays the result of the evaporative emission (EVAP) system diagnostic as determined by the control module. The scan tool will display various messages, depending on the result of the test.
EVAP Purge Solenoid Command: This parameter displays the commanded state of the EVAP purge solenoid control circuit. The scan tool will display 0-100%. A high value indicates the purge solenoid control circuit is being commanded more by the control module, opening the EVAP purge solenoid. A low value indicates the purge solenoid is being commanded on less by the control module.
EVAP Vent Solenoid Command: This parameter displays the commanded state of the EVAP vent solenoid control circuit. The scan tool will display venting or not venting. Not venting indicates the purge solenoid control circuit is being commanded ON by the control module, closing the EVAP vent solenoid. Venting indicates the vent solenoid is not being commanded by the control module, allowing the solenoid to remain open.
Fuel Level Sensor: This parameter displays the voltage from the signal produced by the sensor used to monitor the fuel level inside the fuel tank. The scan tool will display a low voltage reading when the fuel level in the tank is low or near empty. The scan tool will display a high voltage reading when the fuel level in the tank is high or near full.
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 indicated the Fuel Pump Relay Command is Off.
Fuel Tank Level Remaining: This parameter displays the amount of fuel remaining in all of the fuel tanks of the vehicle as a percentage. The control module calculates this level using the signals from the sensors used to monitor the fuel level in the fuel tanks. The scan tool will display a low reading when the total fuel level in the vehicle 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 Pressure: 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 value 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: The scan tool displays Liters or gallons. This parameter displays the fuel tank capacity as determined by the calibrations of the vehicle.
Fuel Tank Remaining: This parameter displays the remaining percentage of fuel in the tank.
Fuel Trim Cell: This parameter displays the fuel trim cell as calculated by the control module based on many sensor inputs. The fuel trim cell indicates which cell is currently active.
Fuel Trim Learn: The scan tool displays Enabled or Disabled. When conditions are appropriate for enabling long term fuel trim corrections, the scan tool displays Enabled. If the scan tool displays Disabled, then long term fuel trim will not respond to changes in short term fuel trim.
Fuel Volatility: This parameter indicates the rate the fuel can be vaporized in the cylinder as calculated by the control module. The scan tool displays Low, Moderate, or High. The scan tool will display High when the fuel volatility is High. The scan tool will display Low when the fuel volatility is Low.
Generator L-Terminal Signal Command: This parameter displays if the control module is allowing the generator to operate. The scan tool displays On if the generator is allowed to operate. The scan tool displays Off if the control module is disabling the generator.
Generator F-Terminal Signal Command: This parameter displays if the commanded state of the generator by the control module. A High value indicated a high charging command, and a low value indicated a low charging command.