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 High Side Pressure: The scan tool range is 0.00-5.00 volts. This parameter indicates the A/C high side pressure sensor input to the PCM.

A/C Relay Command: The scan tool displays ON or OFF. This parameter displays the powertrain control module (PCM) commanded state of the A/C clutch control relay. When the scan tool displays ON, the A/C clutch should be engaged.

A/C Request Signal: The scan tool displays Yes or No. The A/C Request Signal displays the state of the A/C request input circuit from the heating, ventilation, and air conditioning (HVAC) controls. The powertrain control module (PCM) uses the A/C request signal in order to determine whether the A/C compressor operation is being requested.

Air Flow Calculated: The calculated air flow is a calculation based on manifold absolute pressure (MAP). The calculation is used in several diagnostics to determine when a sufficient engine load has been achieved to run the diagnostic.

Air Fuel Ratio: The scan tool displays the ratio of the air to fuel. A typical ratio is about 14.7:1.

APP Average: The scan tool displays 0-125 counts. The throttle actuator control (TAC) module takes the voltages from the 3 accelerator pedal position (APP) sensors, averages the readings, and converts the readings into counts. The scan tool displays the average. The average is different on every vehicle.

APP Indicated Angle: The scan tool displays 0-100 percent. The scan tool displays the accelerator pedal position (APP) in percentage. When the APP is at rest, the display shows 0 percent. When the APP is fully depressed, the display shows 100 percent.

APP Sensor 1: The scan tool displays 0-5 volts. When the accelerator pedal is at 0 percent (pedal at rest), the display shows less than 1.1 volt. When the accelerator pedal is at 100 percent (pedal fully depressed), the display shows more than 2.0 volts.

APP Sensor 2: The scan tool displays 5-0 volts. When the accelerator pedal is at 0 percent (pedal at rest), the display shows more than 3.9 volts. When the accelerator pedal is at 100 percent (pedal fully depressed), display shows less than 3.0 volt.

APP Sen. 1 and 2 Disagree: The scan tool displays Agree or Disagree. When the throttle actuator control (TAC) module receives a signal voltage from accelerator pedal position (APP) sensor 1 not in proper relationship to APP sensor 2, the scan tool displays Disagree . The scan tool displays Agree under the normal operating conditions.

BARO: The scan tool displays a range of 10-105 kPa and 0.00-5.00 volts. The barometric pressure reading is determined from the manifold absolute pressure (MAP) sensor signal. The powertrain control module (PCM) monitors the MAP signal during key up or wide-open throttle (WOT) conditions. The barometric pressure compensates for altitude differences.

Camshaft Actual Angle: The scan tool displays 0-25 °.The scan tool will display the actual commanded cam degrees retard.

Camshaft Desired Angle: The scan tool displays 0-25 °.The scan tool will display the desired cam phase angle.

Camshaft Angle Variance: The scan tool displays 0-25 °.The scan tool will display the difference in degrees between the desired and actual cam angle.

Camshaft Actuator Solenoid Command: The scan tool displays 0-100 percent. The scan tool will display in percentage the amount of cam phase retard .

CKP Active Counter: The crankshaft position (CKP) active counter displays whether the PCM is receiving the pulses from the ignition module.

CMP Active Counter: The camshaft position (CMP) active counter displays the activity sent to the PCM from the CMP sensor. The counter will continually increment while the engine is running.

CMP Resync Counter: The camshaft position (CMP) resync counter displays the number of times the PCM had to resync with the CMP sensor.

Crank Request Signal: The scan tool displays Yes or No. Yes is displayed when the key is in the Crank position.

Cruise Control Active: The cruise display indicates if the PCM is allowing cruise operation. The PCM has the ability to disable the cruise control under certain conditions.

Cruise Disengage History 1-8: The Scan tool displays the last 8 cruise control disengages in order from 1 to 8. There are 20 possible causes for the cruise control to disengage. Refer to in Cruise Control for descriptions.

Cruise On/Off Switch: The scan tool displays Yes/No. When the cruise control module is enabled, the scan tool displays Yes.

Cruise Release Brake Pedal Switch: When the brake pedal is applied, the brake switch sends a signal to the PCM to disengage the TCC and disable cruise control.

Cruise Release Clutch/TCC Pedal Switch--Range Applied/Unapplied: When the brake pedal is applied, the torque converter clutch (TCC) brake switch sends a signal to the PCM to disengage the TCC and disable cruise control.

Cruise Resume/Accel: The scan tool displays On or Off. 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: The scan tool displays On or Off. 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.

Current Gear: The scan tool displays 0-4. The scan tool displays which gear the transmission is in. An illegal transmission position displays 9.

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.

Desired Fan Speed:  The PCM commands the desired fan speed. The PCM compensates for various engine loads based on engine coolant temperature in order to keep the fan at the desired speed.

Desired Idle Speed: Scan Tool Range 0-3187 RPM. The powertrain control module (PCM) commands the desired idle speed. The PCM compensates for various engine loads based on engine coolant temperature (ECT) in order to keep the engine at the desired speed.

ECT Sensor: The scan tool displays a range of -39 to +140°C (-38 to +284°F). 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: The scan tool displays a range of 0-100 percent . The PCM calculates the engine load from engine speed and mass air flow (MAF) sensor readings. The engine load increases with an increase in RPM or airflow.

Engine Oil Level Switch: The scan tool displays OK or Low. This parameter indicates when the engine oil level is low. The scan tool displays Low when the powertrain control module (PCM) detects the engine oil level is low.

Engine Oil Life Remaining: The scan tool displays 0-100 percent . This display represents the engine oil life index that is calculated and maintained by the powertrain control module (PCM).

Engine Oil Pressure Sensor: The engine oil pressure sensor sends an input to the PCM to indicate what the engine oil pressure value is.

Engine Oil Pressure Temperature: The engine oil temperature sensor sends an input to the PCM to indicate what the engine oil temperature value is.

Engine Run Time: The scan tool displays Hours, Minutes, Seconds. This displays the amount of engine run time for the current ignition cycle. When you cycle the ignition OFF, the timer resets to zero.

Engine Speed: The scan tool displays a range of 0-10,000 RPM. 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.

Engine Torque:  This display indicates the amount of available engine torque.

EVAP Purge Solenoid Command: The scan tool displays a range of 0-100 percent. The powertrain control module (PCM) supplies a pulse width modulated (PWM) duty cycle to control the evaporative emission (EVAP) purge solenoid valve. 0 percent indicates no purge and 100 percent indicates full purge.

EVAP Test Abort Reason: The scan tool displays Not Aborted, Lost Enable, Small Leak, Veh. Not at Rest. This parameter indicates the reason the EVAP system test was aborted.

EVAP Test Result: The scan tool displays No Result, Aborted, Passed, Failed-DTC P0440, Failed-DTC P0442, Failed-DTC P0446, Failed-DTC P1441. This parameter indicates the results of the EVAP system tests.

EVAP Test State: The scan tool displays Wait For Purge, Test Running, Test Complete. This parameter indicates the state of the EVAP Service Bay Test.

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.

Fail Counter: The scan tool displays the number of times a diagnostic failed.

Fan Speed: The scan tool displays the fan speed in RPM.

Fuel Tank Pressure Sensor: The scan tool displays -32.7 to +13.96 mm/Hg ( -17.4 to +7.5 inch 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 Tank Pressure Sensor: The scan tool displays 0-5.0 volts. The scan tool displays in voltage the pressure inside of the fuel tank.

Fuel Trim Cell: The scan tool displays a range of 0-23. 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 Level Sensor: The scan tool displays 0-5.00 volts. The scan tool displays below 1.0 volt for an empty tank, and close to 2.5 volts for a full tank.

Fuel Pump Relay Command: The scan tool displays On/Off. Indicates the PCM command of the fuel pump relay.

Generator F- Terminal Signal: The scan tool displays Active or Inactive. The scan tool displays inactive if the powertrain control module (PCM) does not detect a correct voltage on the F-terminal circuit. The scan tool displays active under normal operating conditions.

Generator L- Terminal Signal: The scan tool displays Active or Inactive. The scan tool displays inactive if the powertrain control module (PCM) does not detect a correct voltage on the L-terminal circuit. The scan tool displays active under normal operating conditions.

HO2S Bank 1 Sensor 1 and Sensor 2: The scan tool displays a range of 0-1,106 mV. The heated oxygen sensor (HO2S) bank 1 and bank 2 sensor 1 parameter represents the fuel control exhaust oxygen sensor output voltage. The voltage fluctuates constantly within a range between 10 mV, and 1,000 mV, while operating in Closed Loop.

HO2S 1 Heater Command: The scan tool displays On/Off. Indicates the PCM command of the HO2S 1 heater.

HO2S 2 Heater Command: The scan tool displays On/Off. Indicates the PCM command of the HO2S 2 heater.

IAT Sensor: The scan tool displays a range of -39 to +140°C (-38 to +284°F). The powertrain control module (PCM) converts the resistance of the intake air temperature (IAT) sensor to degrees. The PCM uses the IAT in order to adjust fuel delivery and spark timing according to incoming air density.

Ignition 1 Signal: The scan tool displays 0-25.5 volts. The ignition 1 represents the system voltage measured by the powertrain control module (PCM) at the ignition feed circuit.

Injector PWM: The scan tool displays 0-999.9 mS. Indicates the base pulse width modulation (PWM) or ON time of the fuel injectors in milliseconds. When the engine load is increased, the injector pulse width will increase.

Injector 1-6 Command: The scan tool displays 0-999.9 mS. Indicates the PCM command on the fuel injectors. The higher the number the longer the PCM is commanding the fuel injectors ON.

Knock Retard: The scan tool displays a range of 0-16 degrees. Knock retard indicates the amount of spark the powertrain control module (PCM) removes from the ignition control (IC) spark advance in response to the signal from the knock sensors.

Long Term FT: The scan tool displays percentage. The powertrain control module (PCM) derives the long term fuel trim from the short term fuel trim value. The long term fuel trim represents a long term correction of fuel delivery. A value of 0 percent indicates that fuel delivery requires no compensation in order to maintain the PCM commanded air/fuel ratio. A negative value significantly below 0 percent indicates that the fuel system is rich and the PCM is reducing the fuel delivery. A positive value significantly more than 0  percent indicates that a lean condition exists and the PCM compensates by adding fuel. Fuel trim values at maximum authority indicates an excessively rich or lean system.

Loop Status: The scan tool displays Open or Closed. Closed Loop indicates that the powertrain control module (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 throttle position (TP) sensor, engine coolant, and mass air flow (MAF) sensor inputs only.

MAP Sensor: The scan tool displays a range of 10-105 kPa and 0.00-5.0 volts. The manifold absolute pressure (MAP) sensor measures the absolute pressure in the intake manifold.

Med. Resolution Resync Counter: The scan tool displays 0-255 counts. The medium resolution resync counter displays the number of times the PCM had to resync the crankshaft position (CKP) sensor.

MIL Command: The scan tool displays On or Off. The scan tool indicates if the powertrain control module (PCM) has commanded the malfunction indicator lamp (MIL) ON.

Misfire Current Cyl. #1 - #6: The scan tool displays a range of 0-255 counts. The misfire current counters increment at a rate according to the number of possible misfires the powertrain control module (PCM) detects on each cylinder during the last 200 cylinder firing events. The counters may normally display some activity, but the activity should be nearly equal for all the cylinders.

Misfire History Cyl. #1 - #6: The scan tool displays a range of 0-65,535 counts. The misfire history counters display the total level of misfire that has been detected on each cylinder. The misfire history counters will not update or show any activity until a misfire DTC P0300 has become active. The misfire history counters will update every 200 cylinder firing events.

Number of DTCs--Range 0-255: The number of current DTCs indicates the total number of current diagnostic trouble codes (DTCs) set. These current DTCs set does not necessarily mean that the malfunction indicator lamp (MIL) is illuminated.

PCM in VTD Fail Enable: The PCM displays Yes or No. The scan tool displays Yes if the body control module (BCM) and the powertrain control module (PCM) lose communications with each other after the BCM sends the correct password. The scan tool displays No if the BCM is communicating the correct password to the PCM.

Power Enrichment: The scan tool displays Active/Inactive. The scan tool indicates when power enrichment mode is active (moderate to heavy acceleration). Helpful in diagnosing DTC P1171.

Reduced Engine Power: The scan tool displays Active or Inactive. The scan tool displays Active when the PCM receives a signal from the TAC module that a throttle actuator control system fault is occurring. The PCM limits the engine power.

Short Term FT: The scan tool displays percentage. The short term fuel trim represents a short term correction to fuel delivery by the powertrain control module (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 mainly remains less than 450 mV, indicating a lean air/fuel mixture, short term fuel trim increases into the positive range above 0 percent. The PCM adds fuel. If the oxygen sensor voltage stays mainly above the threshold, the short term fuel trim decreases below 0 percent into the negative range. The PCM reduces the fuel delivery in order to compensate for the indicated rich condition. Under certain conditions such as an extended idle and a high ambient temperature, the canister purge may cause the short term fuel trim to read in the negative range during normal operation. The fuel trim values at maximum authority may indicate an excessively rich or lean system.

Spark: The scan tool displays a range of -64 degrees to +64 degrees. The scan tool displays the amount of degrees the powertrain control module (PCM) commands the spark advance on the ignition control (IC) circuit. The PCM computes the desired spark advance using the following: 1. Engine coolant temperature (ECT) 2. Engine speed (RPM), 3. Load 4. Vehicle speed The PCM adjusts the timing.

Start Up ECT: The scan tool displays a range of -39 to +140°C (-38 to +284°F). The scan tool displays the engine coolant temperature (ECT) at the time the engine was started. The powertrain control module (PCM) uses start-up ECT for certain diagnostic trouble codes (DTCs).

Starter Relay Command: The scan tool displays ON, or OFF. This parameter indicates the PCM commanded state of the starter relay control circuit.

TCC Enable Solenoid Command: The scan tool displays Enabled or Disabled. The scan tool displays Enabled when the electrical system supplies a voltage to the torque converter clutch (TCC) enable solenoid.

TP Desired Angle: The scan tool displays 0-100 percent. The powertrain control module (PCM) indicates the desired throttle angle commanded by the vehicle operator.

TP Indicated Angle: The scan tool displays 0-100 percent. The throttle position (TP) indicated angle displays in percentage the amount of throttle opening.

TP Sensors 1 and 2: The scan tool displays Yes or No. When the throttle actuator control (TAC) module receives a signal voltage from one of the throttle position sensors not in proper relationship to the other, the scan tool displays YES. The scan tool displays NO under normal operating conditions.

TP Sensor 1: The scan tool displays 0-100 percent. The scan tool displays the amount of throttle opening in percentage. Closed throttle displays 0 percent and wide open throttle displays near 100 percent.

TP Sensor 1: The scan tool displays 0-5 volts. The scan tool displays the amount of throttle opening in volts. Closed throttle displays about 1 volt and wide open throttle displays above 3.5 volts.

TP Sensor 2: The scan tool displays 0-100 percent. The scan tool displays the amount of throttle opening in percentage. Closed throttle displays 0 percent and wide open throttle displays near 100 percent.

TP Sensor 2: The scan tool displays 5-0 volts. The scan tool displays the amount of throttle opening in volts. Closed throttle displays about 4 volts and wide open throttle displays below 1.5 volts.

Traction Control Signal: The scan tool display Active / Inactive. This parameter indicates the status of the traction control system.

TR Switch: The scan tool displays High/Low. A transaxle mounted switch is used as an input to let the PCM know what position the gear select lever is in. The scan tool status will switch from High to Low as different combinations are met. In Park, PRNDL P and A will be Low and B and C will be High.

TWC Temperature Calculated: Represents the calculated temperature of the catalytic converter. Useful for determining if the Catalyst Monitor Test has run.

Vehicle Speed Sensor: The scan tool displays km/h and mph. The vehicle speed sensor signal is converted into km/h and mph for display on the scan tool.

VTD Fuel Disable: The scan tool displays Active/Inactive. If the powertrain control module (PCM) has not received the correct password from the body control module (BCM), the PCM disables the fuel system and the scan tool displays Active. The scan tool displays Inactive under normal operating conditions.

VTD Password: The scan tool displays OK, or Incorrect. This parameter indicates the validity of the vehicle theft deterrent password.

VTD Auto Learn Timer: The scan tool displays Active/Inactive. The auto learn timer is the indication if the vehicle theft deterrent (VTD) system is in the learn mode and has not timed out.

VTD Fuel Disable Until Ignition Off: The scan tool displays Yes or No. With the ignition ON and a vehicle theft deterrent (VTD) code present, the scan tool displays Yes.