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Part 1



Scan Tool Data Definitions

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
- This parameter displays the voltage sensed on the 5-volt reference 1 circuit at the control module. The scan tool will display a higher value at higher voltage. The scan tool will display a lower value at lower voltage.

5-Volt Reference 1 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.

5-Volt Reference 2
- This parameter displays the voltage sensed on the 5-volt reference 2 circuit at the control module. The scan tool will display a higher value at higher voltage. The scan tool will display a lower value at lower voltage.

5-Volt Reference 2 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 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.

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
- Outside temperature at any given altitude expressed in degrees.

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 Indicated Position
- This parameter displays the angle of the APP sensor 1 as calculated by the control module using the signal 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 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 Sensor 2 Indicated Position
- This parameter displays the angle of the APP sensor 2 as calculated by the control module using the signal from the APP sensor 2. APP sensor 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.

BARO
- This parameter displays the barometric pressure as calculated by the control module using the signal from the 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.

BPP 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.

Calc. TWC Temp
- Calculated catalytic converter temperature.

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.

CKP Sensor
- This parameter displays the RPM that the control module is using for crankshaft position sensing.

CMP Sensor
- This parameter displays the speed of the engine as calculated by the signal from the camshaft position (CMP) sensor, shown in RPM.

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.

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 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 IC 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 IC 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 IC 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 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.

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 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 exhaust 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.

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 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.
The scan tool displays OK or Low. This parameter displays whether or not sufficient engine oil pressure is present.

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.
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 ECM.

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 a Venting or Not Venting. The scan tool will display a venting when the control module is commanding the EVAP vent solenoid to be open. The scan tool will display a 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 sensors. 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 Indeterminate until the circuit has been commanded ON.

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

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 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 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 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 Cell
- This parameter displays the fuel trim cell number as calculated by the control module based on engine speed and load inputs. The scan tool will display a lower number as conditions are nearer to idle, and a higher value as conditions approach maximum engine speed and maximum load.

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
- This parameter displays the current through the control module when the heated oxygen sensor (HO2S) 1 heater is commanded ON by the control module. HO2S 1 Heater Current is a range of values indicating a low current when the heater circuit resistance is high to a high current when the heater circuit resistance is low.

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

HO2S 2 Heater
- This parameter displays the current through the control module when the HO2S 2 heater is commanded ON by the control module. HO2S 2 Heater Current is a range of values indicating a low current when the heater circuit resistance is high to a high current when the heater circuit resistance is low.

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 Sensor 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.

Hot Open Loop
- This parameter indicates the status of the fuel delivery system. The scan tool will display Active if the fuel system is running in open loop due to a temperature concern. The scan tool will display Inactive if the fuel system is operating normally.

IAT Sensor
- The scan tool displays °C. The engine control module (ECM) converts the resistance of the intake air temperature (IAT) sensor to degrees in the same manner as the ECT sensor. Intake air temp is used by the ECM to adjust fuel delivery and spark timing according to incoming air density.
The scan tool displays a range of -40 to +150°C (-40 to +302°F). The ECM converts the resistance of the intake air temperature sensor to degrees. The ECM uses the IAT in order to adjust fuel delivery and spark timing according to incoming air density.

Ignition Accessory Signal
- This parameter displays the state of the ignition 0 input to the control module from the ignition switch. The scan tool will display ON when the ignition switch is in the ignition accessory position. The scan tool will display OFF when the ignition switch is in any other position.

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.

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.

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