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 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.

4WD Low Signal
- This parameter displays the state of the transfer case based on the signal from the four wheel drive (4WD) low switch. The scan tool will display Enabled or Disabled. Enabled indicates the transfer case is in 4WD low gear and the 4WD low switch is closed, completing the low signal circuit. Disabled indicates the transfer case is not in 4WD low gear and the 4WD low switch is open.

4WD Signal
- This parameter displays the state of the transfer case based on the signal from the front axle indicator switch. The scan tool will display Enabled or Disabled. Enabled indicates the front axle is locked in four wheel drive and the front axle indicator switch is closed, supplying voltage to the controller on the axle switch signal circuit. Disabled indicates the transfer case is not in four wheel drive and the front axle indicator switch is open.

5 Volts 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 Volts 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.

A/C Compressor Cycling Switch
- 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 Normal or Low Pressure. Normal indicates the A/C system has enough refrigerant to close the A/C compressor cycling switch, allowing the A/C compressor to engage. Low Pressure indicates the A/C refrigerant system has low pressure and the A/C compressor cycling switch is open.

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 Fuel 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.

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 Indicated Pressure
- This parameter displays the Secondary Air Injection (AIR) system pressure above barometric pressure as calculated based on a signal sent to the control module from the sensor used to monitor the pressure inside the AIR injection system. The scan tool will display a low value when the pressure in the AIR system pressure is low. The scan tool will display a high value when the pressure in the AIR system is high.

AIR Pressure Sensor
- This parameter displays the voltage signal sent to the control module from the sensor used to monitor the pressure inside the AIR injection system. The scan tool will display a low voltage when the pressure in the AIR system is high. The scan tool will display a high voltage when the pressure in the AIR system is low.

AIR Pressure Sensor
- This parameter displays the actual AIR system pressure as calculated based on a signal sent to the control module from the sensor used to monitor the pressure inside the AIR injection system. The scan tool will display a low value when the pressure in the AIR system is low. The scan tool will display a high value when the pressure in the AIR system is high.

AIR Pressure Sensor Variance
- This parameter displays the difference between the desired AIR pressure calculated by the control module and the actual AIR pressure. The scan tool will display a higher value if the difference is large, and a lower value if the difference is small.

AIR Pump Relay Circuit Status
- This parameter displays the status of the output driver for the AIR pump relay control circuit. The scan tool will display OK , Indeterminate, Short B+, Short Gnd, or Open. OK indicates that no circuit faults are detected during the current test. The different faults will indicates that a short or open circuit/component exists, electronically disconnecting the circuit/component from the control module.

AIR Pump Relay Command
- This parameter displays the commanded state of the secondary air injection (AIR) pump relay control circuit. The scan tool will display ON or OFF. ON indicates the AIR pump relay control circuit is being grounded by the control module, allowing voltage to the AIR pump. OFF indicates the AIR pump relay is not being commanded on by the control module.

AIR Solenoid Circuit Status
- This parameter displays the status of the output driver for the AIR solenoid control circuit. The scan tool will display OK , Incomplete, Short B+, Short Gnd, or Open. OK indicates that no circuit faults are detected during the current test. The different faults will indicates that a short or open circuit/component exists, electronically disconnecting the circuit/component from the control module.

AIR Solenoid Command
- This parameter displays the commanded state of the AIR solenoid control circuit. The scan tool will display ON or OFF. ON indicates the AIR solenoid control circuit is being grounded by the control module, opening the AIR solenoid and allowing vacuum to the shutoff or combination valve(s). OFF indicates the AIR solenoid is not being commanded on 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
- This parameter displays the average of the 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 counts.

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 (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.

BARO (Gasoline)
- This parameter displays the voltage signal received by the control module 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 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.

Catalytic Converter Protection Active
- This parameter indicates the status of the control module control 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 a 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.

Clutch Pedal Switch
- This parameter displays the current state of the clutch pedal as determined by the control module.

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

CMP Sensor
- This parameter displays the engine speed as calculated by the control module using the signal from the CMP sensor.

CMP Sensor - High To Low
- This parameter displays the number of times the signal voltage from the camshaft position (CMP) sensor changes from high to low. The scan tool will display these transitions as counts.

CMP Sensor - Low To High
- This parameter displays the number of times the signal voltage from the camshaft position (CMP) sensor changes from low to high. The scan tool will display these transitions as counts.

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.

Coolant Level Switch
- This parameter displays the level of engine coolant as determined by the control module. The control module determines the level of the coolant using the signal from a switch used to monitor the engine coolant level. The scan tool will display low when the engine coolant level is low. The scan tool will display OK when the coolant level is correct.

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 Inhibit Signal Command
- This parameter displays the commanded state of the cruise inhibit signal circuit. The scan tool will display On when the control module is inhibiting cruise control operation. The scan tool will display Off when the control module is allowing cruise control operation.

Current Gear
- This parameter displays the transmission gear commanded by the control module. The scan tool will display 1 when the control module has commanded first gear regardless of the gear selector position. The scan tool will display up to 6 depending upon which gear is commanded and what transmission is in the vehicle. The scan tool will display 9 if the transmission gear is not known.

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 1-8 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 EGR Position
- This parameter displays the position of the exhaust gas recirculation (EGR) valve commanded by the control module. The scan tool will display 0 percent when the control module is commanding the EGR valve closed.

Desired IAC Airflow
- This parameter displays the desired airflow in the idle air control (IAC) passage as calculated 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.

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.

DTC Set This Ignition
- This parameter displays if a diagnostic trouble code (DTC) set during the current ignition cycle. The scan tool will display YES if a DTC is stored this ignition cycle.

EC Ignition Relay Circuit Status
- This parameter displays the status of the output driver for the engine control (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 other control module circuits and systems. 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.

ECM Reset
- The scan tool displays Yes or No. This parameter indicates when the internal ECM resets. The scan tool displays YES when an internal ECM reset occurred. The scan tool displays NO under the normal operating conditions.

ECT Sensor
- 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.

EGR Learned Minimum Position
- This parameter displays the voltage from the EGR valve that the control module uses to determine that the EGR valve is closed. The voltage displayed will be the closed position of the EGR pintle learned by the control module.

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

EGR Position Sensor
- This parameter displays the voltage signal received from the EGR valve position sensor by the control module. The scan tool will display a lower value when the EGR valve is closed, and a higher value when the EGR valve is open.

EGR Position Sensor
- This parameter displays EGR valve position as calculated by the control module based on an input from the EGR valve position sensor. The scan tool will display a lower value when the EGR valve is closed, and a higher value when the EGR valve is open.

EGR Position Variance
- This parameter displays the difference between the desired EGR valve position calculated by the control module and the actual EGR position input from the EGR valve position sensor. The scan tool will display a higher value if the difference is large, and a lower value if the difference is small.

EGR Solenoid Circuit Status
- This parameter displays the status of the output driver for the EGR 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.

EGR Solenoid Command
- This parameter displays the duty cycle commanded by the control module for the EGR valve. The scan tool will display a high percentage when the EGR valve is commanded open. The scan tool will display a low percentage when the EGR valve is commanded closed.

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 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 Life Remaining
- This parameter displays the amount of engine oil life remaining before requiring an oil change. This number is calculated by the control module based on many inputs and is displayed as a percent. The lower the percentage, the sooner the next oil change will be required.

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

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 Purge Solenoid Circuit Status
- This parameter displays the diagnostic state of the output driver for the evaporative emission purge solenoid control circuit as determined by the control module. The scan tool will display OK if the circuit is operating correctly. The scan tool will display the appropriate fault if there is an open, short to ground or a short to voltage on the circuit. The scan tool will display Incomplete if the diagnostic has not completed.

EVAP Test Result
- The scan tool displays No Result, Passed, Aborted, Fail-DTC P0440, Fail-DTC P0442, Fail-DTC P0446, or Fail-DTC P1441. The scan tool displays PASS if the control module determines that the EVAP test has passed.

EVAP Test State
- The scan tool displays Waiting For Purge, Test Running, or Test Completed. This parameter indicates the state of the EVAP service bay test.

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.

EVAP Vent Solenoid Circuit Status
- This parameter displays the diagnostic state of the output driver for the evaporative emission vent solenoid control circuit as determined by the control module. The scan tool will display OK if the circuit is operating correctly. The scan tool will display the appropriate fault if there is an open, short to ground or a short to voltage on the circuit. The scan tool will display Incomplete if the diagnostic has not completed.