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.

A/C Off For WOT
- The scan tool displays YES or NO. Indicates whether A/C is commanded OFF due to wide open throttle (WOT).

A/C Pressure Disable
- The scan tool displays YES or NO. Indicates whether A/C is commanded OFF due to excessive or insufficient pressure.

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 that the A/C clutch relay control circuit is being grounded by the control module, allowing voltage to the A/C compressor clutch. OFF indicates that 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 that 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 that 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 14.2-14.7 to 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 sensors. The 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 accelerator pedal position (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 Circuit Status
- This parameter displays the diagnostic state of the APP sensor 1 circuit. The scan tool will display OK or Fault. OK indicates that no circuit faults are detected during the current test. Fault indicates that a short or open circuit/component exists.

APP Sen. 1 and 2
- This parameter displays the results of a control module test that compares the signals from the accelerator pedal position (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 accelerator pedal position (APP) sensor 2 of the APP sensor assembly. The APP sensor 2 is a range of values indicating a high voltage when the accelerator pedal is not depressed to a low voltage when the accelerator pedal is fully depressed.

APP Sensor 2 Circuit Status
- This parameter displays the diagnostic state of the APP sensor 2 circuit. The scan tool will display OK or Fault. OK indicates that no circuit faults are detected during the current test. Fault indicates that a short or open circuit/component exists.

BARO
- This parameter displays the barometric pressure as calculated by the control module using the signal from the sensor measured when the ignition is turned ON or with the engine running.

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

CKP Active Counter
- The crankshaft position (CKP) active counter displays whether the PCM is receiving the pulses from the CKP sensor.

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 speed of the engine as calculated by the signal from the camshaft position (CMP) sensor.

Crank Request
- This parameter displays whether the ignition switch has been cycled to the crank position requesting the control module to activate the starter relay.

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 1-8 History
- The parameter displays the last 8 cruise control disengages in order from 1 to 8, with 8 being the most recent. There are about 33 possible causes for the cruise control to disengage.

Cruise On/Off Switch
- This parameter displays the state of the cruise control on/off switch input to the control module.

Cruise Resume/Accel. Switch
- This parameter displays the state of the cruise controls resume/accel switch position input to the control module.

Cycles of Misfire Data
- The scan tool displays a range of 0-100. The powertrain control module (PCM) counts the number of misfire tests during 200 engine revolutions.

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 can 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 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 Feedback Signal
- This parameter displays the voltage available at the EC ignition relay pin of the control module.

ECT Sensor
- The powertrain control module (PCM) applies 5 volts to the engine coolant temperature (ECT) sensor circuit. The sensor is a thermistor which changes internal resistance as the engine temperature changes. When the sensor is cold, internal resistance high, the PCM senses a high signal voltage and interprets the voltage as a cold engine. As the sensor warms, internal resistance decreases, the voltage signal decreases and the PCM interprets the lower voltage as a warm engine.

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
- The PCM calculates engine oil life based upon the number of engine revolutions seen and operating conditions such as calculated oil temperature. Pressing the oil life monitor reset switch will return the displayed engine oil life to 100 percent.

Engine Oil Pressure Switch
- This parameter displays OK or low.

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
- The powertrain control module (PCM) computes engine speed from the ignition reference pulses. The engine speed should remain close to desired idle under various engine loads with the engine idling.

EVAP Fault History
- This parameter displays the result of the EVAP System diagnostic. The scan tool displays NO FAULT, EXCESS VACUUM, PURGE VALVE LEAK, SMALL LEAK, NO TEST RESULT, or WEAK VACUUM. The EVAP Fault History indicates the status of EVAP system diagnostics performed by the PCM.

EVAP Purge Solenoid Command
- This parameter displays the on-time or duty cycle of the evaporative emission (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 Command
- The scan tool displays Venting or Not Venting. The evaporative emission (EVAP) canister vent valve is normally open. The powertrain control module (PCM) commands the EVAP canister vent valve closed, during testing of the EVAP system.

FC Relay 1 Command
- Indicates the commanded state of the FC Relay. The scan tool displays ON or 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 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 Pressure Sensor
- The scan tool displays mm/Hg and in H2O vacuum or pressure.

Fuel Trim Cell
- The powertrain control module (PCM) determines from the manifold absolute pressure (MAP) and RPM inputs which fuel trim cell to operate the engine in. The fuel trim cell displayed on the scan tool is the cell that the engine is operating under.

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 form enabling long term fuel trim corrections, the scan tool displays Enabled.

Gen F-Terminal Signal
- Represents the field terminal input from the generator. The field PWM duty cycle indicates generator output level. A higher duty cycle indicates a higher generator output. The PCM uses the generator F terminal signal in order to adjust spark and idle air control (IAC) to compensate for variances in engine load caused by the generator.

Generator L-Terminal Signal
- The scan tool displays Voltage/No Voltage.

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

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