The Engine Scan Tool Data Definitions contain 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 more than once or in more than one data list in order to group certain related parameters together.

3X Crank Sensor: The scan tool displays 1600-10,000 RPM. This signal is calculated from the 7X pulses and is fed to the PCM by the ignition control module. This is used by the PCM to calculate RPM at engine speeds above 1600 RPM and to initiates injector pulses.

24X Crank Sensor: The scan tool displays 0-1600 RPM. Displays the engine speed calculated from the 24X reference signal PCM input. Should nearly match engine speed up to approximately 1,600 RPM limit.

1-2 Sol.: The scan tool displays OK, Fault or Invalid state. These parameters describe the condition of the control circuit.

2-3 Sol.: The scan tool displays OK, Fault or Invalid state. These parameters describe the condition of the control circuit.

Abuse Management: The scan tool displays Active or Inactive. Active indicates the PCM is commanding protection against abnormal driveline conditions. For further information refer to Automatic Transaxle Diagnosis.

A/C High Side Pressure: The scan tool displays 0.00-5.00 volts. Represents the A/C refrigerant pressure sensor signal. The amount of pressure indicates the amount of load that the A/C compressor is placing on the engine. The PCM uses this information to adjust idle and to control the cooling fans.

A/C Relay: The scan tool displays OK, Fault or Invalid state. These parameters describe the condition of the control circuit.

A/C Request: The scan tool displays Yes or No. Indicates the state of the A/C request input circuit from the HVAC controls. The PCM uses the A/C request signal to determine whether A/C compressor operation is being requested.

Actual EGR Position: The scan tool displays 0-100 percent. Represents the actual position of the EGR pintle in percent. 0 percent displayed indicates a fully extended pintle (EGR valve closed).

Air/Fuel Ratio: The scan tool displays 0.0 to 25.5. Air fuel ratio indicates the PCM commanded value. In closed loop, air fuel ratio should normally be around 14.2-14.7. A lower air fuel ratio indicates a richer commanded mixture, which may be seen during Power Enrichment or TWC Protection modes. A higher air fuel ratio indicates a leaner commanded mixture. This can be seen during Decel Fuel Mode.

Air Active Test Inhibit: The scan tool displays Yes or No. This test will not run because the conditions for setting have not been obtained.

Air Active Test Air Injection: The scan tool displays Yes or No. The AIR Active Test has the PCM turn on the air pump specifically for diagnostic purposes.

Air Diagnostic Complete: The scan tool displays Yes or No. When all the passive and active tests have been completed

Air Passive Test 1 Passed: The scan tool displays Yes or No. AIR Passive Test 1 is being performed during regular AIR pump operation. When it passes Test 1, it will run AIR Passive Test 2.

Air Passive Test 2 Fail: The scan tool displays Yes or No. If either AIR Passive Test 1 or 2 fails or is inconclusive, the diagnostic will proceed to the AIR Active Test.

Air Passive Test Passed: The scan tool displays Yes or No. Indicates that both AIR Passive Test 1 and 2 have passed and no further action is needed.

Air Passive Test Inhibit: The scan tool displays Yes or No. This test will not run because the conditions for setting have not been obtained.

Air Passive Test In Progress: The scan tool displays Yes or No. Displays the AIR Passive Tests are in progress.

Air Pump Relay: The scan tool displays OK/Fault/Invalid state. The scan tool displays ON/OFF. These parameters describe the condition of the control circuit.

Air Solenoid: The scan tool displays OK/Fault/Invalid state. The scan tool displays ON/OFF . These parameters describe the condition of the control circuit.

BARO: The scan tool displays 10-105 kPa/0.00-5.00 volts. The barometric pressure reading is determined from the MAP sensor signal monitored during key up and wide open throttle (WOT) conditions. Barometric pressure is used to adjust fuel delivery and spark advance to compensate for altitude changes.

Brake Switch: The scan tool displays APPLIED or RELEASED. Indicates the brake pedal position. When the brake pedal is depressed a signal voltage is sent to the PCM.

Cam Signal Present: The scan tool displays Yes or No. If the PCM does not receive a cam signal from the ignition control module the scan tool displays NO.

Commanded A/C: The scan tool displays ON or OFF. Represents the PCM commanded state of the A/C compressor clutch relay driver circuit. The A/C compressor clutch should be engaged when Commanded A/C displays ON.

Commanded Fuel Pump: The scan tool displays ON or OFF. Indicates the PCM commanded state of the fuel pump relay control circuit.

Commanded Gen: The scan tool displays ON or OFF. OFF displayed indicates that the PCM has commanded the generator control circuit OFF.

Cruise Mode: The scan tool displays ON or OFF. Represents the state of the Cruise Status Input from the cruise control module. Cruise Engaged should not display YES unless the vehicle is operating in a cruise control mode.

Cruise Inhibited: The scan tool displays ON or OFF. The scan tool displays OK/Fault/Invalid state in ODD. On or OK displayed indicates that the PCM is commanding the cruise control module to inhibit cruise control operation. This should display ON or OK at idle.

Current Gear: The scan tool displays 0-4. The scan tool display the gear that the transmission is in.

Cycles of Misfire Data: The scan tool displays counts from 0-99. The number showing represents the number of times the PCM has checked for misfires.

Cyl. 1-6 Circuit History: The scan tool displays OK, Stuck Low (open) or Stuck High. These parameters describe the condition of each injector control circuit. If a fault is detected the scan tool will list which the fault type with the corresponding cylinder.

Cyl. 1-6 Circuit Status: The scan tool displays OK, Stuck Low (open) or Stuck High. These parameters describe the condition of each injector control circuit.

Decel Fuel Mode: The scan tool displays ACTIVE or INACTIVE. ACTIVE is displayed if the PCM has detected conditions appropriate to operate in Deceleration Fuel Mode. The PCM will command deceleration fuel mode when a sudden decrease in throttle position has been detected while the vehicle is traveling over 25 mph. While in Deceleration Fuel mode, the PCM will decrease the amount of fuel delivered by entering Open Loop and decreasing the injector pulse width.

Desired EGR Position: The scan tool displays 0-100 percent. Represents the EGR pintle position that the PCM is commanding. Desired EGR position should stay close to actual EGR position.

Desired Idle Speed: The scan tool displays 0-3187 RPM. Represents the idle speed that is commanded by the PCM. The PCM will compensate for various engine loads based on engine coolant temperature to keep the engine at the desired idle speed.

Driver Module 1 / 2 / 3 / 4 Status: The scan tool displays Enabled, Off-High Volts, Off High Temp or Invalid state. This parameter describes the internal PCM driver module condition. This module controls all the relays/solenoids listed below the driver module parameter in the scan tool Output Driver Data List up to the next driver module.

ECT: The scan tool displays -40-151°C (-40-304°F). The engine coolant temperature (ECT) sensor is mounted in the coolant stream. The PCM applies 5 volts to the ECT sensor circuit. The sensor is a thermistor which changes internal resistance as temperature changes. When the sensor is cold (internal resistance high), the PCM monitors a high signal voltage and interprets it 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.

EGR Closed Valve Pintle Position: The scan tool displays 0.0-5.0 volts. Represents the learned voltage that the PCM uses to determine whether or not the EGR valve is fully closed (0 percent pintle position). If the desired EGR position is 0 percent and a difference of more than 0.4 volt between EGR Feedback and EGR closed valve pintle position is detected, DTC P1406 will set.

EGR Duty Cycle: The scan tool displays 0-100 percent. Represents the EGR valve driver PWM signal from the PCM. A duty cycle of 0 percent indicates that no EGR flow is being commanded; a 100 percent duty cycle indicates maximum EGR flow commanded.

EGR Feedback: The scan tool displays 0.00-5.00 volts. Indicates the EGR pintle position sensor signal voltage being monitored by the PCM. A low voltage indicates a fully extended pintle (closed valve); a voltage near 5 volts indicates a fully retracted pintle (open valve)

EGR Flow Test Count: The scan tool displays 0-255. Indicates the number of EGR flow test samples collected during the current ignition cycle. The maximum number of samples allowed is 1 during normal operation. If the PCM battery feed has been disconnected or a DTC P0401 has been cleared, several EGR flow test samples will be allowed during the next ignition cycle. This is to allow repair verification during a single ignition cycle.

EGR Position Error: The scan tool displays 0-100 percent. Indicates the difference between desired EGR position and actual EGR position currently being monitored by the PCM. If the EGR position error reaches an unacceptable level, DTC P1406 will set.

Engine Load: The scan tool displays 0-100 percent. Engine load is calculated by the PCM from engine speed and MAF sensor readings. Engine load should increase with an increase in RPM or air flow.

Engine Oil Level: The scan tool displays OK or Low. Indicates the oil level as determined by the engine oil level sensor.

Engine Oil Life: The scan tool displays Percents. Indicates how much oil life is left until the next recommended oil change.

Engine Oil Pressure: The scan tool displays OK/Low/High. Indicates the oil pressure as determined by the oil sending unit.

Engine Run Time: The scan tool displays 00:00:00 to 99:99:99 Hrs:Min:Sec. Indicates the time elapsed since the engine was started. If the engine is stopped, ENGINE RUN TIME will be reset to 00:00:00.

Engine Speed: The scan tool displays 0-9999 RPM. Engine speed is computed by the PCM from the 3X reference input. It should remain close to desired idle under various engine loads with engine idling

EVAP Canister Purge: The scan tool displays 0-100 percent. Represents the PCM commanded PWM duty cycle of the EVAP Purge valve. Zero percent displayed indicates no purge. 100 percent displayed indicates full purge.

EVAP Fault History: The scan tool displays NO FAULT, EXCESS VACUUM, PURGE VALVE LEAK, SMALL LEAK or WEAK VACUUM. The EVAP Fault History indicates the status of the EVAP system diagnostics performed by the PCM.

EVAP Purge Solenoid: The scan tool displays OK, Fault or Invalid state. These parameters describe the condition of the control circuit.

EVAP Vent Solenoid:  The scan tool displays Open or Closed. The scan tool displays OK/Fault/Invalid state in EVAP. The scan tool displays Open and OK when the PCM commands the EVAP system to purge. The scan tool will show Closed when the system is not purging.

Fans High Speed: The scan tool displays ON or OFF. Represents the PCM commanded state of both fans.

Fans Low Speed: The scan tool displays ON or OFF. Represents the PCM commanded state of both fans.

Fan Control Relay 1: The scan tool displays OK, Fault or Invalid state. These parameters describe the condition of the control circuit.

Fan Control Relay 2 and 3: The scan tool displays OK, Fault or Invalid state. These parameters describe the condition of the control circuit.

Fuel Level: The scan tool displays 0-100 percent. The scan tool displays in percentage the amount of fuel in the fuel tank.

Fuel Pump CKT. History: The scan tool displays OK, Stuck Low (open) or Stuck High. These parameters describe the condition of the fuel pump control circuit.

Fuel Pump CKT. Status: The scan tool displays OK, Stuck Low (open) or Stuck High. These parameters describe the condition of the fuel pump control circuit. If a fault is detected the scan tool will list which the fault type.

Fuel Tank Pressure: The scan tool displays in 0-5.00 volts or (-32 to 32 inches/H2O). This parameter indicates the pressure\vacuum inside of the fuel tank. A negative value indicates a vacuum. A positive value indicates a pressure.

Fuel Trim Cell: The scan tool displays 0-9. Fuel trim cell is dependent upon engine speed and MAF sensor readings. A plot of RPM vs. MAF is divided into 10 cells. 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, FUEL TRIM LEARN will display Enable. This indicates that the Long Term FT is responding to Short Term FT. If the Fuel Trim Learn displays Disable, Long Term FT will not respond to changes in Short Term FT.

Generator PWM: The scan tool displays in Percents. The PCM Input Field (F) terminal from the alternator provides a PWM signal to the PCM.

Hot Mode: The scan tool displays ON or OFF. On displayed indicates that the PCM has detected conditions appropriate for transaxle hot mode operation. The PCM determines this base on transaxle fluid temperature. While in Hot Mode, transaxle shift points may be altered, 4th gear disabled, and the TCC forced On in 2nd gear.

Hot Open Loop: The scan tool displays Active or Inactive. When in Hot Open Loop the Hot Light comes on and the Air/Fuel mixture becomes rich to cool the internal engine temperature.

HO2S Sensor1: The scan tool displays READY or NOT READY. Indicates the status of the fuel control exhaust oxygen sensor. The scan tool will indicate that the exhaust oxygen sensors are ready when the PCM detects a fluctuating HO2S voltage sufficient to allow closed loop operation. This will not occur unless the exhaust oxygen sensors are warmed up.

HO2S Sensor 1:  The scan tool displays 0-1132 mV. Represents the fuel control exhaust oxygen sensor output voltage. Should fluctuate constantly within a range between 10 mV (lean exhaust) and 1000 mV (rich exhaust) while operating in Closed Loop.

HO2S Sensor 2: The scan tool displays 0-1132 mV. Represents the fuel control exhaust oxygen sensor output voltage. Should fluctuate constantly within a range between 10 mV (lean exhaust) and 1000 mV (rich exhaust) while operating in Closed Loop.

HO2S XCounts: The scan tool displays 0-255. Indicates the number of times the HO2S 1 signal has crossed the 450 mV bias voltage during a 1 second interval. A HO2S 1 signal that almost never crosses the bias voltage could indicate a fuel trim problem, a faulty HO2S 1 circuit, or a faulty HO2S 1.

IAC Position: The scan tool displays 0-255. Displays the commanded position of the idle air control pintle in counts. A larger number of counts means that more air is being commanded through the idle air passage. IAC position should respond fairly quickly to changes in engine load to maintain desired idle RPM.

IAT: The scan tool displays -40-151°C (-40-304°F). The PCM converts the resistance of the intake air temperature sensor to degrees. The PCM uses intake air temperature (IAT) to adjust fuel delivery and spark timing according to incoming air density. IAT is also compared to ECT at startup to identify cold starts for the HO2S heater and the EVAP diagnostics.

Ignition 1: The scan tool displays 0-25.5 volts. Represents the system voltage measured by the PCM at its ignition feed.

Ignition Mode: The scan tool displays BYPASS or IC. Indicates the commanded state of the bypass signal output from the PCM. When BYPASS is displayed, the ignition control module is controlling the spark advance at a fixed 10 degrees BTDC (Bypass mode). IC displayed indicates that the PCM has requested control of the spark advance (IC mode). The ignition control module determines the correct operating mode based on the level of voltage that the PCM applies to the ignition control module bypass circuit. The PCM provides 5 volts to the ignition control module bypass circuit when conditions are appropriate for PCM control of spark timing (IC mode). If the PCM does not apply 5 volts to the bypass circuit, or if the ignition control module does not receive it, the module will control spark timing.

Injector Pulse Width: The scan tool displays 0-1000 msec. Indicates the amount of time the PCM is commanding each injector ON during each engine cycle. A longer injector pulse width will cause more fuel to be delivered. Injector pulse width should increase with increased engine load.

Knock Retard: The scan tool displays 0.0-25.5 degrees. Indicates the amount of spark the PCM is removing from IC spark advance in response to the signal from the knock sensors.

Long Term Fuel Trim: The scan tool displays -10 percent to 10 percent. Long Term FT is derived from the Short Term FT value and represents a long-term correction of fuel delivery. A value of 0 percent indicates that fuel delivery requires no compensation to maintain the PCM commanded air/fuel ratio. A negative value significantly below 0  percent indicates that the fuel system is rich and fuel delivery is being reduced (decreased injector pulse width). A positive value significantly more than 0 percent indicates that a lean condition exists and the PCM is compensating by adding fuel (increased injector pulse width). Because Long Term FT tends to follow Short Term FT; a value in the negative range due to canister purge at idle should not be considered unusual. The PCMs maximum authority to control Long Term FT allows a range between -10 percent and +10 percent. Fuel trim values at or near maximum authority may indicate an excessively rich or lean system.

Loop Status:  The scan tool displays OPEN or CLOSED. Closed Loop indicates that the PCM is controlling fuel delivery according to oxygen sensor voltage. In Open Loop, the PCM ignores the oxygen sensor voltage and bases the amount of fuel to be delivered on TP sensor, engine coolant, and MAF sensor inputs only.

MAF: The scan tool displays 0.0 to 512 g/s. MAF (mass air flow) is the MAF Input Frequency converted to grams of air per second. This indicates the amount of air entering the engine.

MAF Frequency: The scan tool displays 0-32000 Hz. The mass air flow sensor input signal to the PCM is a frequency which varies from around 3000 Hz at idle to above 7000 Hz at wide-open throttle. The PCM converts this frequency signal to grams per second to be displayed on the scan tool as MAF.

MAP: The scan tool displays 10-105 kPa/0.00 to 4.97 volts. The manifold absolute pressure (MAP) sensor measures the change in the intake manifold pressure from engine load, EGR flow, and speed changes. As intake manifold pressure increases, intake vacuum decreases resulting in a higher MAP sensor voltage and kPa reading. The MAP sensor signal is used to monitor intake manifold pressure changes during the EGR flow test, to update the BARO reading, and as an enabling factor for many of the diagnostics.

MIL:  The scan tool displays ON or OFF. Indicates the PCM commanded state of the malfunction indicator lamp.

MIL: The scan tool displays OK, Fault or Invalid state. These parameters describe the condition of the control circuit.

Misfire Current Cylinder 1-6: The scan tool displays 0-198 Counts. The misfire current counters indicate the number of cylinder firing events detected as possible misfires on each cylinder during the last 200 crankshaft revolutions. The number that the counters display are twice the actual number of misfire events detected. The counters may normally display some activity, but the activity should be very low and nearly equal for all the cylinders.

Misfire History Cylinder 1-6: The scan tool displays 0-65535 Counts. The misfire history counters indicate the total level of misfire that has been detected on each cylinder. The number that the counters display are twice the actual number of misfire events detected. The misfire history counters will not update or show any activity until a misfire DTC (P0300) has become active. The Misfire History counters will be updated every time a 200 crankshaft revolution misfire test failure is detected.

Non-Volitile Memory: The scan tool displays Pass or Fail. Indicates the condition of the PCMs random access memory.

Power Enrichment: The scan tool displays ACTIVE or INACTIVE. ACTIVE displayed indicates that the PCM has detected conditions appropriate to operate in Power Enrichment mode. The PCM will command Power Enrichment mode when a large increase in throttle position and load is detected. While in Power Enrichment, the PCM 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.

Short Term Fuel Trim : The scan tool displays -10 percent to 10 percent. Short Term FT represents a short-term correction to fuel delivery by the PCM 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 has mainly remained less than 450 mV, indicating a lean air/fuel mixture, Short Term FT will increase into the positive range above 0 percent and the PCM will add fuel. If the oxygen sensor voltage stays mainly above the threshold, Short Term FT will decrease below 0 percent into the negative range while the PCM reduces fuel delivery to compensate for the indicated rich condition. Under certain conditions such as extended idle and high ambient temperatures, canister purge may cause Short Term FT to read in the negative range during normal operation. The PCMs maximum authority to control fuel trim allows a range between -10 percent and +10 percent. Fuel trim values at maximum authority may indicate an excessively rich or lean system.

Spark: The scan tool displays -64 degrees to 64 degrees. Displays the spark timing being commanded by the PCM on the IC circuit. 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. Because the ignition control module sets spark advance at a fixed value of 10 degrees BTDC while operating in Bypass mode, the displayed Spark advance only reflects true spark timing when the PCM has commanded IC mode.

Start-Up ECT: The scan tool displays -40-151°C (-40-304°F). Indicates the engine coolant temperature at the time that the vehicle was started. Used by the HO2S diagnostic to determine if the last startup was a cold start.

Start-Up IAT: The scan tool displays -40-151°C (-40-304°F). Indicates the intake air temperature at the time that the vehicle was started. Used by the HO2S diagnostic to determine if the last startup was a cold start.

TCC Engaged: The scan tool displays Engaged or Disengaged. Indicates the command state of the transaxle torque convertor clutch.

TCC Sol.: The scan tool displays OK, Fault or Invalid state. These parameters describe the condition of the control circuit.

Total Misfire Current Count: The scan tool displays 0-99. Indicates the total number of cylinder firing events that were detected as being misfires during the last 200 crankshaft revolution sample period.

Total Misfire Failures : The scan tool displays 0-65535 Counts. Indicates the number of 200 crankshaft revolution sample periods during which the level of misfire was sufficiently high to report a failure.

Total Misfire Passes : The scan tool displays 0-65535 Counts. Indicates the number of 200 crankshaft revolution sample periods during which the level of misfire was sufficiently low to report a pass.

TP Angle: The scan tool displays 0-100 percent. TP angle is computed by the PCM from the TP sensor voltage. TP angle should display 0 percent at idle and 100 percent at wide open throttle.

TP Sensor : The scan tool displays 0-5 volts to 5.00 volts. The voltage being monitored by the PCM on the TP sensor signal circuit.

Transmission Range: The scan tool displays PARK/NEUTRAL, REVERSE, DRIVE 4, DRIVE 3, DRIVE 2, or LOW. Transmission range represents the decoded status of the four inputs from the transaxle range switch assembly. The combination of transaxle range inputs indicates the position of the transaxle manual valve.

TR Switch P / A / B / C: The scan tool displays HIGH or LOW. The TR switch A/B/C display represents the states of the four inputs from the transaxle range switch. HIGH displayed indicates a B+ voltage signal being monitored at the PCM, LOW displayed indicates a grounded input signal. The combination of transaxle range inputs indicates the position of the transaxle manual valve.

TWC Protection: The scan tool displays ACTIVE or INACTIVE. ACTIVE displayed indicates that the PCM has detected conditions appropriate to operate in TWC Protection mode. This is determined based on engine load and engine coolant temperature. While in TWC Protection, the PCM will decrease Air/Fuel ratio to a value that depends on mass air flow (higher mass airflow = lower Air/Fuel ratio).

Vehicle Speed: The scan tool displays 0-255 km/h, 0-155 mph. The vehicle speed sensor signal is converted into mph and km/h for display.

VTD Fuel Disable: The scan tool displays ACTIVE or INACTIVE. The Theft Deterrent Fuel Enable circuit is an input from the vehicle theft deterrent system that signals the PCM to enable the injectors if the proper signal is received. The scan tool will normally display INACTIVE. If the vehicle theft deterrent system does not sent the correct theft deterrent fuel enable signal to the PCM, the display will switch to ACTIVE and the fuel system may be disabled.