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 Clutch Feed Back Signal
- The scan tool displays relay On or relay OFF. This parameter displays the signal received from the A/C clutch to the PCM to indicate the A/C clutch relay is ON or OFF.

A/C Compressor Cycling Switch
- The scan tool displays Low Pressure or Normal. This parameter displays the state of the A/C compressor cycling switch. The A/C compressor cycling switch is a normally closed switch.

A/C Relay Command
- The scan tool displays ON or OFF. This parameter displays the 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 Sec. High Pressure Switch
- The scan tool displays High Pressure or Normal. This parameter displays the state of the A/C secondary high pressure switch. The A/C secondary high pressure switch is normally open.

A/C Request Signal
- The scan tool displays Yes or No. The A/C Request 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 Pump Relay Command
- The scan tool displays ON or OFF. The scan tool displays ON when the PCM grounds the AIR pump relay control circuit. The scan tool displays OFF when the PCM disables the ground circuit.

APP Average
- The scan tool displays 0-125 counts. The TAC Module takes the voltages from the 3 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 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 Sensor 3
- The scan tool displays 5-0 volts. When the accelerator pedal is at 0 percent (pedal at rest), display shows more than 3.2 volts. When the accelerator pedal is at 100 percent (pedal fully depressed), display shows less than 3.5 volts.

APP Sensor 1
- The scan tool displays 0-100 percent. When the accelerator pedal is at rest, display shows 0 percent. When the accelerator pedal is fully depressed, display shows 100 percent. This percentage indicates to the TAC Module the actual pedal position.

APP Sensor 2
- The scan tool displays 0-100 percent. When the accelerator pedal is at rest, display shows 0 percent. When the accelerator pedal is fully depressed, display shows 100 percent. This percentage indicates to the TAC Module the actual pedal position

APP Sensor 3
- The scan tool displays 0-100 percent. When the accelerator pedal is at rest, display shows 0 percent. When the accelerator pedal is fully depressed, display shows 100 percent. This percentage indicates to the TAC Module the actual pedal position.

APP Sen. 1 and 2 Disagree
- The scan tool displays Agree or Disagree. When the TAC module receives a signal voltage from 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.

APP Sen. 1 and 3 Disagree
- The scan tool displays Agree or Disagree. When the TAC module receives a signal voltage from APP Sensor 1 not in proper relationship to APP Sensor 3, the scan tool displays Disagree. The scan tool displays Agree under the normal operating conditions.

APP Sen. 2 and 3 Disagree
- The scan tool displays Agree or Disagree. When the TAC module receives a signal voltage from APP Sensor 2 not in proper relationship to APP Sensor 3, the scan tool displays Disagree. The scan tool displays Agree under the normal operating conditions.

Auxiliary Fan Request
- The scan tool displays On or Off. The scan tool displays On when the PCM grounds the auxiliary fan relay control circuit. The scan tool displays Off when the PCM disables the ground circuit.

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

CMP Sensor-High to Low
- The scan tool displays 0-65,535 counts. The counts increment as the PCM detects the camshaft position (CMP) sensor signal voltage going from high to low.

CMP Sensor-Low to High
- The scan tool displays 0-65,535 counts. The counts increment as the PCM detects the CMP signal voltage going from low to high.

Cold Start Up
- The scan tool displays Yes or No. A cold start-up is when the engine coolant temperature (ECT) rises above a predetermined temperature during an ignition cycle. The next ignition cycle the ECT should be below a predetermined temperature. Also the ECT and the intake air temperature (IAT) are less than 50° C (122° F) and are within 3° C (5° F) of each other at start-up. When the above is true, the scan tool displays Yes.

Coolant Level Switch
- The scan tool displays OK or Low. This parameter indicates when the engine coolant level is low. The scan tool displays Low when the PCM detects the engine coolant level is low.

Cruise Control Active
- The scan tool displays Yes or No. When the cruise control switch is on and the set/coast switch is activated, the scan tool displays yes. When the cruise control switch is ON and the set/coast switch is released, the scan tool displays No.

Cruise On/Off Switch
- The scan tool displays On or Off. When you activate the cruise control switch, the scan tool displays ON. The switch, when in the ON position, sends a signal voltage to the Throttle Actuator Control (TAC) Module. This allows all other functions of the Cruise Control. When you turn off the cruise control switch, the scan tool displays OFF.

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
- 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 PCM counts the number of misfire tests during 200 engine revolutions.

Desired EGR Position
- The scan tool displays 0-100 percent. This parameter displays the desired position of the EGR pintle as requested by the PCM. This parameter should be very close to Actual EGR position.

Desired EGR Position
- The scan tool displays 0-5.0 volts. The commanded EGR is the EGR pintle position commanded by the PCM.

Desired Idle Speed
- The scan tool displays a range of 0-3,187 RPM. The PCM commands the desired idle speed. The PCM compensates for various engine loads based on ECT in order to keep the engine at the desired speed.

DTC Set This Ignition
- The scan tool displays Yes or No. This parameter indicates if a diagnostic trouble code (DTC) set during the current ignition cycle.

ECT Sensor
- The scan tool displays a range of -39°C to +140°C (-38°F to +284°F). The PCM applies 5.0 volts to the 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.

EGR Closed Valve Pintle Position
- The scan tool displays 0-5.0 volts. This display represents the voltage that the PCM uses in order to determine whether or not the EGR valve is closed. The voltage displayed will be the closed position of the EGR pintle learned by the PCM.

EGR Position Sensor
- The scan tool displays 0-5 volts. This parameter displays the actual EGR pintle position in voltage.

EGR Position Sensor
- The scan tool displays a range of 0-100 percent. The PCM supplies a pulse width modulated (PWM) duty cycle to control the exhaust gas recirculation (EGR) valve. Zero percent indicates no EGR flow. One hundred percent indicates full EGR flow.

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 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 PCM.

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

EVAP Test Result
- The scan tool displays if the EVAP test has passed or failed. The scan tool displays pass when the PCM determines that the EVAP diagnostic has passed. The scan tool displays fail when the PCM determines that the EVAP diagnostic has failed.

EVAP Vent Solenoid Command
- The scan tool displays Venting or Not Venting. The EVAP canister vent valve is normally open. The PCM commands the EVAP canister vent valve closed, during testing of the EVAP system.

Fuel Level Sensor
- The scan tool displays 0-5 volts. The scan tool displays below 1 volt for an empty tank, and close to 2.5 volts for a full tank.

Fuel Tank Level Remaining
- The scan tool displays in liters or gallons the amount of fuel remaining in the fuel tank.

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

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

Fuel Tank Rated Capacity
- The scan tool displays the capacity of the fuel tank in liters or gallons.

Fuel Trim Cell
- The scan tool displays a range of 0 to 23. The 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
- The scan tool displays Enabled or Disabled. When conditions are appropriate for enabling long term fuel trim corrections, the scan tool displays Enabled. This indicates that the long term fuel trim is responding to the short term fuel trim. If the scan tool displays Disabled, then long term fuel trim will not respond to changes in short term fuel trim.

Generator F Terminal Signal Command
- The scan tool displays 0-100 percent. The display shows generator F terminal duty cycle in percent from 0-100 percent. The generator is able to produce the desired voltage by varying the duty cycle of the field current.

Generator L Terminal Signal Command
- The scan tool displays On or Off. The scan tool displays Off if the PCM does not detect a correct voltage on the L-terminal circuit. The scan tool displays On under normal operating conditions.

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

IAT Sensor
- The scan tool displays a range of -39°C to +140°C (-38°F to +284°F). The PCM converts the resistance of the intake air temperature 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 PCM at the ignition feed circuit.

Inj. PWM Average Bank 1 and Bank 2
- The scan tool displays a range of 0-1,000 milliseconds. The injector average indicates the amount of time the PCM commands each injector ON during each engine cycle. A longer injector pulse width causes more fuel to be delivered. The injector pulse width increases with an increased engine load.

Knock Retard
- The scan tool displays a range of 0.0 degrees-16 degrees. Knock retard indicates the amount of spark the PCM removes from the ignition control (IC) spark advance in response to the signal from the knock sensors.

Long Term FT Avg. Bn1 and Bn2
- The scan tool displays percentage. This parameter indicates the average of all long term fuel trim cells. The short term fuel trim cells are rated, for the amount of which they are used. For example, an idle cell is rated higher than a wide open cell. If a fueling malfunction occurs in the idle cell and the wide open cell, the average would be more affected by the idle cell than the wide open cell. A negative value significantly below 0 percent indicates that the fuel system is rich and fuel delivery is being reduced. A positive value significantly more than 0 percent indicates that a lean condition exists and the PCM compensates by adding fuel. When the average of the cells reach a predetermined high or low, a fuel trim DTC sets.

Long Term FT Bank 1 and Bank 2
- The scan tool displays percentage. The 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.