Engine Data 1

Engine Speed - Range 0-16384 Revolutions Per Minute (RPM): The VCM computes the Engine Speed from the fuel control reference input. The speed should remain close to the desired idle under the various engines loads with the engine idling.

Desired Idle - Range 0-3187 Revolutions Per Minute (RPM): The VCM commands the desired IAC. The VCM compensates for various engine loads in order to maintain the desired idle speed.

Start Up Engine Coolant Temperature (ECT) - Range -40°-215°C (-40°-419°F): When the engine is started, the VCM records the engine coolant temperature. The VCM uses the recorded temperature in order to calculate the time to a Closed Loop.

Engine Coolant Temperature (ECT) - Range -40°-215°C (-40°-419°F): The Engine Coolant Temperature (ECT) sensor is mounted in the intake manifold. The ECT sends the engine temperature information to the VCM. The VCM supplies 5 volts to the ECT sensor circuit. The sensor is a thermistor which changes the internal resistance as the temperature changes. When the sensor is cold, meaning the internal resistance is high, the VCM monitors a high voltage signal. The VCM interprets the high voltage signal as a cold engine. As the sensor warms, meaning the internal resistance decreases, the voltage signal decreases. The VCM interprets the lower resistance as a warm engine.

Startup Intake Air Temperature (IAT) - Range (-40°-151°C): The VCM converts the resistance of the Intake Air Temperature (IAT) sensor to degrees. The VCM uses the intake air temperature in order to adjust the fuel delivery and the spark timing according to the incoming air density.

Intake Air Temperature (IAT) - Range (-40°-151°C): The VCM converts the resistance of the Intake Air Temperature (IAT) sensor to degrees. The VCM uses the intake air temperature in order to adjust the fuel delivery and the spark timing according to the incoming air density.

Intake Air Temperature (IAT) Sensor - (0.0-5.0 Volts): The VCM converts the resistance of the Intake Air Temperature (IAT) sensor to degrees. The VCM uses the intake air temperature in order to adjust the fuel delivery and the spark timing according to the incoming air density.

Air Fuel Ratio - Range (0.0:1-25.5:1): The air to fuel ratio is based on the Oxygen sensor (HO2S) inputs. The VCM uses the fuel trim to adjust the fueling of the engine in order to maintain an air fuel ratio of 14.7:1. A lower number indicates a richer air fuel mixture. A higher number indicates a leaner mixture.

Idle Air Control (IAC) Position - Range (0-255) Counts: The scan tool displays in counts the Idle Air Control (IAC) pintle position commanded from the VCM. The greater the number of counts, the greater the command idle speed (air passages opened) is. The idle air control should respond fairly quickly to the changes in the engine load in order to maintain the desired idle RPM.

Desired IAC - Range (0-255) Counts: The desired IAC indicates the desired IAC position based on a command from the VCM.

Throttle Position Sensor (TPS)- Range (0.0-5.0 Volts): The VCM uses the Throttle Position in order to determine the amount of throttle demanded by the operator of the vehicle. The TP sensor reads between 0.36-0.96 volts at idle to above 4.0 volts at Wide Open Throttle (WOT).

Throttle Position Sensor (TPS) Angle - Range (0-100%): The VCM computes the TPS angle from the TPS signal voltage input. The TPS angle should read 0% at idle. At 0%, the TPS voltage will read below 0.90 volts. The TPS angle should read 100% at Wide Open Throttle (WOT).

Manifold Absolute Pressure (MAP) - Range (10 kPa-104 kPa): The Manifold Absolute Pressure (MAP) sensor measures the change in the intake manifold pressure from the engine load and the speed changes. As the intake manifold pressure increases, the air density in the intake manifold also increases. Additional fuel is required.

Manifold Absolute Pressure (MAP) Sensor - Range (0.0-5.0 Volts): The MAP sensor produces a low signal voltage when the manifold pressure is low. A low manifold pressure means a high vacuum. The MAP sensor produces a high signal voltage when the manifold pressure is high. A high manifold pressure means a low vacuum. With the ignition ON and the engine stopped, the manifold pressure equals the atmospheric pressure causing the signal voltage to be high. The VCM uses this information as an indication of the vehicles altitude. This information is referred to as the BARO. Comparison of this BARO reading with a known good vehicle with the same sensor is a good way to check accuracy of a suspect sensor. The readings should read the same ±0.4 volts.

Barometric Pressure Sensor (BARO) - Range (0 kPa-62 kPa): The VCM determines the displayed BARO reading from the MAP sensor at the ignition ON and the engine OFF and the WOT conditions. The BARO reading displayed represents the barometric pressure. The VCM uses the displayed BARO readings in order to compensate for the altitude differences.

Barometric Pressure Sensor (BARO) - Range (0.0-5.0 Volts): The BARO represents a measurement of the barometric air pressure. This measurement is determined by using the Manifold Air Pressure (MAP) sensor in order to determine the manifold vacuum. Since the barometric air pressure depends on the altitude, the measurement may vary from 100 kPa (sea level) to 60 kPa (14,000 ft).

Ignition 1 - Range (0.0-25.5 Volts): The Ignition 1 indicates the voltage of the ignition system input to the VCM.

Engine Speed - Range 0-16384 Revolutions Per Minute (RPM): The VCM computes the Engine Speed from the fuel control reference input. The speed should remain close to the desired idle under the various engines loads with the engine idling.

Long Term Fuel Trim (FT) Bank 1 - Percentage of Compensation Required: The Long Term Fuel Trim (FT) is derived from the short term fuel trim value. The VCM uses the Long Term Fuel Trim for the long-term correction of the fuel delivery. A value of 128 counts equals 0%, which indicates that the fuel delivery system requires no compensation to maintain a 14.7:1 air to fuel ratio. A value below 128 counts means that the fuel system is too rich and the fuel delivery is being reduced, therefore decreasing fuel injector pulse width. A value above 128 counts indicates that a lean condition exists. The VCM compensates by adding fuel and increasing the fuel injector pulse width.

Long Term Fuel Trim (FT) Bank 1 - Range (0-255) Counts: The Long Term Fuel Trim (FT) is derived from the short term fuel trim value. The VCM uses the Long Term Fuel Trim for the long-term correction of the fuel delivery. A value of 128 counts equals 0%, which indicates that the fuel delivery system requires no compensation to maintain a 14.7:1 air to fuel ratio. A value below 128 counts means that the fuel system is too rich and the fuel delivery is being reduced, therefore decreasing fuel injector pulse width. A value above 128 counts indicates that a lean condition exists. The VCM compensates by adding fuel and increasing the fuel injector pulse width.

Long Term Fuel Trim (FT) Bank 2 - Percentage of Compensation Required: The Long Term Fuel Trim (FT) is derived from the short term fuel trim value. The VCM uses the Long Term Fuel Trim for the long-term correction of the fuel delivery. A value of 128 counts equals 0%, which indicates that the fuel delivery system requires no compensation to maintain a 14.7:1 air to fuel ratio. A value below 128 counts means that the fuel system is too rich and the fuel delivery is being reduced, therefore decreasing fuel injector pulse width. A value above 128 counts indicates that a lean condition exists. The VCM compensates by adding fuel and increasing the fuel injector pulse width.

Long Term Fuel Trim (FT) Bank 2 - Range (0-255) Counts: The Long Term Fuel Trim (FT) is derived from the short term fuel trim value. The VCM uses the Long Term Fuel Trim for the long-term correction of the fuel delivery. A value of 128 counts equals 0%, which indicates that the fuel delivery system requires no compensation to maintain a 14.7:1 air to fuel ratio. A value below 128 counts means that the fuel system is too rich and the fuel delivery is being reduced, therefore decreasing fuel injector pulse width. A value above 128 counts indicates that a lean condition exists. The VCM compensates by adding fuel and increasing the fuel injector pulse width.

Short Term Fuel Trim (FT) Bank 1 - Percentage of Compensation Required: The short term fuel trim was formerly called the fuel integrator. The short term fuel trim represents a short-term correction to the fuel delivery by the VCM in response to the amount of time the HO2S voltage spends above or below the 450 mV threshold. An HO2S voltage reading below 450 mV indicates a lean air to fuel mixture. If the HO2S voltage has mainly been below the 450 mV threshold, the short term fuel trim increases in order to tell the VCM to add fuel. If the HO2S voltage stays mainly above the 450 mV threshold, the VCM reduces the fuel delivery in order to compensate for the indicated rich condition.

Short Term Fuel Trim (FT) Bank 1 - Range (0-255) Counts: The short term fuel trim was formerly called the fuel integrator. The short term fuel trim represents a short-term correction to the fuel delivery by the VCM in response to the amount of time the HO2S voltage spends above or below the 450 mV threshold. An HO2S voltage reading below 450 mV indicates a lean air to fuel mixture. If the HO2S voltage has mainly been below 450 mV threshold, the short term fuel trim increases in order to tell the VCM to add fuel. If the HO2S voltage stays mainly above the 450 mV threshold, the VCM reduces the fuel delivery in order to compensate for the indicated rich condition.

Short Term Fuel Trim (FT) Bank 2 - Percentage of Compensation Required: The short term fuel trim was formerly called the fuel integrator. The short term fuel trim represents a short-term correction to the fuel delivery by the VCM in response to the amount of time the HO2S voltage spends above or below the 450 mV threshold. An HO2S voltage reading below 450 mV indicates a lean air to fuel mixture. If the HO2S voltage has mainly been below 450 mV threshold, the short term fuel trim increases in order to tell the VCM to add fuel. If the HO2S voltage stays mainly above the 450 mV threshold, the VCM reduces the fuel delivery in order to compensate for the indicated rich condition.

Short Term Fuel Trim (FT) Bank 2 - Range (0-255) Counts: The short term fuel trim was formerly the fuel integrator. The short term fuel trim represents a short-term correction to the fuel delivery by the VCM in response to the amount of time the HO2S voltage spends above or below the 450 mV threshold. An HO2S voltage reading below 450 mV indicates a lean air to fuel mixture. If the HO2S voltage has mainly been below 450 mV threshold, the short term fuel trim increases in order to tell the VCM to add fuel. If the HO2S voltage stays mainly above the 450 mV threshold, the VCM reduces the fuel delivery in order to compensate for the indicated rich condition.

Fuel Trim (FT) Cell Bank 1 - Range (0-22) Cell: The Fuel Trim Cell is dependent upon the engine speed and the MAP sensor readings. Engine RPM and MAP sensor readings are broken into a plot of 22 different cells. The Fuel Trim Cell indicates which cell is currently active.

Fuel Trim (FT) Cell Bank 2 - Range (0-22) Cell: The Fuel Trim Cell is dependent upon the engine speed and the MAP sensor readings. Engine RPM and MAP sensor readings are broken into a plot of 22 different cells. The Fuel Trim Cell indicates which cell is currently active.

Knock Sensor (KS) Activity - Range (0-255) Counts: The Knock Sensor activity indicates the amount of spark knock that is detected by the VCM.

Knock Sensor (KS)- Range (0.0-5.0 Volts): The Knock Sensor indicates the amount of engine knock which is detected in volts.

Spark - Range (-96° to -255°): The spark advance is a display of the spark advance calculation which the VCM is programming into the ignition system. The VCM computes the desired spark advance using data such as the engine temperature, RPM, engine load, vehicle speed, and the operating mode.

Knock (KS) Retard - Range (0.0-90°): The KS Retard indicates the amount of spark advance which is being removed in order to diminish the spark knock.

Camshaft Position (CMP) Retard - Degrees: The camshaft position (CMP) retard indicates the difference between the camshaft position sensor (CMP) and the crankshaft position sensor (CKP) in degrees.

Engine Run Time - Range (0:00:00-18:12:15) Hours: Minutes: Seconds: The Engine Run Time is a measure of how long the engine has run during this ignition cycle. When the engine stops running, the timer resets to zero.

Engine Data 2

Engine Speed - Range 0-16384 Revolutions Per Minute (RPM): The VCM computes the Engine Speed from the fuel control reference input. The speed should remain close to the desired idle under the various engines loads with the engine idling.

Desired Idle - Range 0-3187 Revolutions Per Minute (RPM): The VCM commands the desired IAC. The VCM compensates for various engine loads in order to maintain the desired idle speed.

EVAP Duty Cycle - Range (0-100%): The EVAP duty cycle indicates the EVAP duty cycle that the VCM is commanding.

EVAP Canister Purge- OFF/ON: The EVAP Canister Purge pulls a small vacuum on the entire evaporative emission system. The scan tool displays if the EVAP Canister Purge Solenoid Valve is currently Off or On. When the scan tool displays ON, the small vacuum is being applied.

Air Fuel Ratio - Range (0.0:1-25.5:1): The air to fuel ratio is based on the Oxygen sensor (HO2S) inputs. The VCM uses the fuel trim to adjust the fueling of the engine in order to maintain an air fuel ratio of 14.7:1. A lower number indicates a richer air fuel mixture. A higher number indicates a leaner mixture.

Exhaust Gas Recirculation (EGR) Duty Cycle - (0%-100%): The EGR duty cycle determines a percentage of time the EGR valve is being opened and closed.

Actual Exhaust Gas Recirculation (EGR) Position - Range (0-100%): The actual EGR position indicates the actual EGR position in a percentage.

Desired Exhaust Gas Recirculation (EGR) Position - Range (0-199.9%): The desired EGR position indicates the desired EGR position in a percentage.

Exhuast Gas Recirculation (EGR) Sensor - Range (0.00-5.00 Volts): The EGR sensor indicates the actual EGR position in a voltage.

Air Fuel Ratio - Range (0.0:1-25.5:1): The air to fuel ratio is based on the Oxygen sensor (HO2S) inputs. The VCM uses the fuel trim to adjust the fueling of the engine in order to maintain an air fuel ratio of 14.7:1. A lower number indicates a richer air fuel mixture. A higher number indicates a leaner mixture.

Ignition 1 - Range (0.0-25.5 Volts): The Ignition 1 indicates the voltage of the ignition system input to the VCM.

Idle Air Control (IAC) Position - Range (0-255) Counts: The scan tool displays in counts the Idle Air Control (IAC) pintle position commanded from the VCM. The greater the number of counts, the greater the command idle speed (air passages opened) is. The idle air control should respond fairly quickly to the changes in the engine load in order to maintain the desired idle RPM.

Desired IAC - Range (0-255) Counts: The desired IAC indicates the desired IAC position based on a command from the VCM.

Engine Coolant Temperature (ECT) - Range -40°-215°C (-40°-419°F): The Engine Coolant Temperature (ECT) sensor is mounted in the intake manifold. The ECT sends the engine temperature information to the VCM. The VCM supplies 5 volts to the ECT sensor circuit. The sensor is a thermistor which changes the internal resistance as the temperature changes. When the sensor is cold, meaning the internal resistance is high, the VCM monitors a high voltage signal. The VCM interprets the high voltage signal as a cold engine. As the sensor warms, meaning the internal resistance decreases, the voltage signal decreases. The VCM interprets the lower resistance as a warm engine.

Start Up Engine Coolant Temperature (ECT) - Range -40°-215°C (-40°-419°F): When the engine is started, the VCM records the engine coolant temperature. The VCM uses the recorded temperature in order to calculate the time to a Closed Loop.

Intake Air Temperature (IAT) - Range (-40°-151°C): The VCM converts the resistance of the Intake Air Temperature (IAT) sensor to degrees. The VCM uses the intake air temperature in order to adjust the fuel delivery and the spark timing according to the incoming air density.

Camshaft Position (CMP) Retard - Degrees: The camshaft position (CMP) retard indicates the difference between the camshaft position sensor (CMP) and the crankshaft position sensor (CKP) in degrees.

Spark Control - Range (Advance/Retard): The Spark Control indicates if the VCM is commanding the spark advance or the spark retard.

Power Enrichment - Range (Yes/No): The Power Enrichment indicates if the Power Enrichment mode is active.

Brake Switch - Range (Open/Closed): The Brake Switch indicates the status of the brake switch. This is a normally open switch. When the brake pedal is depressed, the brake switch is then closed.

Transmission Range (TR) Switch: The Transmission Range switch indicates the current drive gear.

A/B/C Range - Range (On/Off): The A/B/C Range indicates the current state of the transmission range switch.

Vehicle Speed- km/h - MPH - Range (0-255): The Vehicle Speed is displayed in km/h or MPH and indicates how fast the drive wheels are turning.

Decel Fuel Mode - Range (Yes/No): The Decel Fuel Mode indicates if the VCM is in a Decel Fuel Mode.

1-2 Solenoid (Off/On): The scan tool will determine the status of the electronic solenoids in the automatic transmission. By determining the status of the solenoids, the correct gear state can also be determined.

2-3 Solenoid (Off/On): The scan tool will determine the status of the electronic solenoids in the automatic transmission. By determining the status of the solenoids, the correct gear state can also be determined.

3-2 Downshift Solenoid (Off/On): The scan tool will determine the status of the electronic solenoids in the automatic transmission. By determining the status of the solenoids, the correct gear state can also be determined.

Torque Converter Clutch (TCC) Enable - Range (Yes/No): The TCC enable indicates the status of the TCC enable output.

Torque Converter Clutch (TCC) Duty Cycle- Range (0%-100%): The TCC duty cycle indicates the how often the vehicle is reaching a TCC lockup.

Torque Converter Clutch (TCC) Slip Speed - RPM: The TCC slip speed will be displayed on the scan tool based on the RPM of the engine and the amount of slip in a lockup condition.

Cruise Mode - Range (Yes/No): The Cruise Mode indicates if the driver has requested the cruise control. If the cruise control has been requested or engaged, yes will be displayed. If the cruise is not being requested or disengaged, no will be displayed.

Engine Run Time - Range (0:00:00-18:12:15) Hours: Minutes: Seconds: The Engine Run Time is a measure of how long the engine has run during this ignition cycle. When the engine stops running, the timer resets to zero.

Engine Data 3

Engine Speed - Range 0-16384 Revolutions Per Minute (RPM): The VCM computes the Engine Speed from the fuel control reference input. The speed should remain close to the desired idle under the various engines loads with the engine idling.

Desired Idle - Range 0-3187 Revolutions Per Minute (RPM): The VCM commands the desired IAC. The VCM compensates for various engine loads in order to maintain the desired idle speed.

Idle Air Control (IAC) Position - Range (0-255) Counts: The scan tool displays in counts the Idle Air Control (IAC) pintle position commanded from the VCM. The greater the number of counts, the greater the command idle speed (air passages opened) is. The idle air control should respond fairly quickly to the changes in the engine load in order to maintain the desired idle RPM.

Desired IAC - Range (0-255) Counts: The desired IAC indicates the desired IAC position based on a command from the VCM.

Injector Pulse Width Modulated Average (Inj. PWM) Bank 1 - Range (0-499 ms): The Injector average Bank 1 indicates the injector on time that the VCM is commanding.

Injector Pulse Width Modulated Average (Inj. PWM) Bank 2 - Range (0-499 ms): The Injector average Bank 2 indicates the injector on time that the VCM is commanding.

Engine Load - Range (0-100%): The Engine Load is based on the Manifold Absolute Pressure. The higher the percentage, the greater the load the engine is under.

Mass Air Flow Sensor (MAF) Frequency (Hertz): The VCM converts the Mass Air Flow (MAF) sensor input signal into grams per second or hertz. The MAF indicates the amount of air entering the engine.

Mass Air Flow Sensor (MAF) - Range 0-512 g/s: The VCM converts the Mass Air Flow (MAF) sensor input signal into grams per second. The MAF indicates the amount of air entering the engine.

Throttle Position Sensor (TPS)- Range (0.0-5.0 Volts): The VCM uses the Throttle Position in order to determine the amount of throttle demanded by the operator of the vehicle. The TP sensor reads between 0.36-0.96 volts at idle to above 4.0 volts at Wide Open Throttle (WOT).

Throttle Position Sensor (TPS) Angle - Range (0-100%): The VCM computes the TPS angle from the TPS signal voltage input. The TPS angle should read 0% at idle. At 0%, the TPS voltage will read below 0.90 volts. The TPS angle should read 100% at Wide Open Throttle (WOT).

Manifold Absolute Pressure (MAP) - Range (10 kPa-104 kPa): The Manifold Absolute Pressure (MAP) sensor measures the change in the intake manifold pressure from the engine load and the speed changes. As the intake manifold pressure increases, the air density in the intake manifold also increases. Additional fuel is required.

Manifold Absolute Pressure (MAP) Sensor - Range (0.0-5.0 Volts): The MAP sensor produces a low signal voltage when the manifold pressure is low. A low manifold pressure means a high vacuum. The MAP sensor produces a high signal voltage when the manifold pressure is high. A high manifold pressure means a low vacuum. With the ignition ON and the engine stopped, the manifold pressure equals the atmospheric pressure causing the signal voltage to be high. The VCM uses this information as an indication of the vehicles altitude. This information is referred to as the BARO. Comparison of this BARO reading with a known good vehicle with the same sensor is a good way to check accuracy of a suspect sensor. The readings should read the same ±0.4 volts.

Barometric Pressure Sensor (BARO) - Range (0 kPa-62 kPa): The VCM determines the displayed BARO reading from the MAP sensor at the ignition ON and the engine OFF and the WOT conditions. The BARO reading displayed represents the barometric pressure. The VCM uses the displayed BARO readings in order to compensate for the altitude differences.

Barometric Pressure Sensor (BARO) - Range (0.0-5.0 Volts): The BARO represents a measurement of the barometric air pressure. This measurement is determined by using the Manifold Air Pressure (MAP) sensor in order to determine the manifold vacuum. Since the barometric air pressure depends on the altitude, the measurement may vary from 100 kPa (sea level) to 60 kPa (14,000 ft).

EVAP Duty Cycle - Range (0-100%): The EVAP duty cycle indicates the EVAP duty cycle that the VCM is commanding.

Exhaust Gas Recirculation (EGR) Duty Cycle - (0%-100%): The EGR duty cycle determines a percentage of time the EGR valve is being opened and closed.

Actual Exhaust Gas Recirculation (EGR) Position - Range (0-100%): The actual EGR position indicates the actual EGR position in a percentage.

Desired Exhaust Gas Recirculation (EGR) Position - Range (0-199.9%): The desired EGR position indicates the desired EGR position in a percentage.

Exhuast Gas Recirculation (EGR) Sensor - Range (0.00-5.00 Volts): The EGR sensor indicates the actual EGR position in a voltage.

Camshaft Position (CMP) Retard - Degrees: The camshaft position (CMP) retard indicates the difference between the camshaft position sensor (CMP) and the crankshaft position sensor (CKP) in degrees.

Air Conditioning (A/C) Request - Range (Yes/No): The A/C Request indicates if the driver has requested the A/C.

Air Conditioning (A/C) Relay - Range (Yes/No): The A/C Relay indicates the state of the A/C relay control circuit.

Engine Run Time - Range (0:00:00-18:12:15) Hours: Minutes: Seconds: The Engine Run Time is a measure of how long the engine has run during this ignition cycle. When the engine stops running, the timer resets to zero.

HO2S Data

Engine Speed - Range 0-16384 Revolutions Per Minute (RPM): The VCM computes the Engine Speed from the fuel control reference input. The speed should remain close to the desired idle under the various engines loads with the engine idling.

Desired Idle - Range 0-3187 Revolutions Per Minute (RPM): The VCM commands the desired IAC. The VCM compensates for various engine loads in order to maintain the desired idle speed.

Pre HO2S (Not Ready/Ready): The scan tool will display the current state of the HO2S system.

Post HO2S (Not Ready/Ready): The scan tool will display the current state of the HO2S system.

HO2S BN 1 Sen. 1 - Range (0-1107mV): The HO2S BN 1 Sen. 1 indicates the activity of the HO2S (Bank 1 Sensor 1).

HO2S BN 1 Sen. 2 - Range (0-1107mV): The HO2S BN 1 Sen. 2 indicates the activity of the HO2S (Bank 1 Sensor 2).

HO2S BN 2 Sen. 1 - Range (0-1107mV): The HO2S BN 2 Sen. 1 indicates the activity of the HO2S (Bank 2 Sensor 1).

HO2S BN 1 Sen. 3 - Range (0-1107mV): The HO2S BN 1 Sen. 3 indicates the activity of the HO2S (Bank 1 Sensor 3).

Air Fuel Ratio - Range (0.0:1-25.5:1): The air to fuel ratio is based on the Oxygen sensor (HO2S) inputs. The VCM uses the fuel trim to adjust the fueling of the engine in order to maintain an air fuel ratio of 14.7:1. A lower number indicates a richer air fuel mixture. A higher number indicates a leaner mixture.

HO2S Xcounts Bn 1 - Range (0-255): The HO2S Xcounts Bn 1 indicates the number of times that the HO2S (Bank 1 Sensor 1) crosses a threshold.

HO2S Xcounts Bn 2 - Range (0-255): The HO2S Xcounts Bn indicates the number of times that the HO2S (Bank 2 Sensor 1) crosses a threshold.

Rich/Lean Bn 1 - (Rich/Lean): The Rich/Lean Bn 1 indicates the condition of the exhaust gases in bank 1.

Rich/Lean Bn 2 - (Rich/Lean): The Rich/Lean Bn 2 indicates the condition of the exhaust gases in bank 2.

Loop Status - Range (Open/Close): The Loop Status indicates what mode of operation the VCM is in.

Closed (CL) Since Restart - Range (Yes/No): The Closed (CL) Since Restart indicates if the system has gone into a Closed Loop operation since the driver started the engine.

Idle Air Control (IAC) Position - Range (0-255) Counts: The scan tool displays in counts the Idle Air Control (IAC) pintle position commanded from the VCM. The greater the number of counts, the greater the command idle speed (air passages opened) is. The idle air control should respond fairly quickly to the changes in the engine load in order to maintain the desired idle RPM.

Desired IAC - Range (0-255) Counts: The desired IAC indicates the desired IAC position based on a command from the VCM.

Mass Air Flow Sensor (MAF) - Range 0-512 g/s: The VCM converts the Mass Air Flow (MAF) sensor input signal into grams per second. The MAF indicates the amount of air entering the engine.

Long Term Fuel Trim (FT) Bank 1 - Percentage of Compensation Required: The Long Term Fuel Trim (FT) is derived from the short term fuel trim value. The VCM uses the Long Term Fuel Trim for the long-term correction of the fuel delivery. A value of 128 counts equals 0%, which indicates that the fuel delivery system requires no compensation to maintain a 14.7:1 air to fuel ratio. A value below 128 counts means that the fuel system is too rich and the fuel delivery is being reduced, therefore decreasing fuel injector pulse width. A value above 128 counts indicates that a lean condition exists. The VCM compensates by adding fuel and increasing the fuel injector pulse width.

Long Term Fuel Trim (FT) Bank 1 - Range (0-255) Counts: The Long Term Fuel Trim (FT) is derived from the short term fuel trim value. The VCM uses the Long Term Fuel Trim for the long-term correction of the fuel delivery. A value of 128 counts equals 0%, which indicates that the fuel delivery system requires no compensation to maintain a 14.7:1 air to fuel ratio. A value below 128 counts means that the fuel system is too rich and the fuel delivery is being reduced, therefore decreasing fuel injector pulse width. A value above 128 counts indicates that a lean condition exists. The VCM compensates by adding fuel and increasing the fuel injector pulse width.

Long Term Fuel Trim (FT) Bank 2 - Percentage of Compensation Required: The Long Term Fuel Trim (FT) is derived from the short term fuel trim value. The VCM uses the Long Term Fuel Trim for the long-term correction of the fuel delivery. A value of 128 counts equals 0%, which indicates that the fuel delivery system requires no compensation to maintain a 14.7:1 air to fuel ratio. A value below 128 counts means that the fuel system is too rich and the fuel delivery is being reduced, therefore decreasing fuel injector pulse width. A value above 128 counts indicates that a lean condition exists. The VCM compensates by adding fuel and increasing the fuel injector pulse width.

Long Term Fuel Trim (FT) Bank 2 - Range (0-255) Counts: The Long Term Fuel Trim (FT) is derived from the short term fuel trim value. The VCM uses the Long Term Fuel Trim for the long-term correction of the fuel delivery. A value of 128 counts equals 0%, which indicates that the fuel delivery system requires no compensation to maintain a 14.7:1 air to fuel ratio. A value below 128 counts means that the fuel system is too rich and the fuel delivery is being reduced, therefore decreasing fuel injector pulse width. A value above 128 counts indicates that a lean condition exists. The VCM compensates by adding fuel and increasing the fuel injector pulse width.

Short Term Fuel Trim (FT) Bank 1 - Percentage of Compensation Required: The short term fuel trim was formerly called the fuel integrator. The short term fuel trim represents a short-term correction to the fuel delivery by the VCM in response to the amount of time the HO2S voltage spends above or below the 450 mV threshold. An HO2S voltage reading below 450 mV indicates a lean air to fuel mixture. If the HO2S voltage has mainly been below the 450 mV threshold, the short term fuel trim increases in order to tell the VCM to add fuel. If the HO2S voltage stays mainly above the 450 mV threshold, the VCM reduces the fuel delivery in order to compensate for the indicated rich condition.

Short Term Fuel Trim (FT) Bank 1 - Range (0-255) Counts: The short term fuel trim was formerly called the fuel integrator. The short term fuel trim represents a short-term correction to the fuel delivery by the VCM in response to the amount of time the HO2S voltage spends above or below the 450 mV threshold. An HO2S voltage reading below 450 mV indicates a lean air to fuel mixture. If the HO2S voltage has mainly been below 450 mV threshold, the short term fuel trim increases in order to tell the VCM to add fuel. If the HO2S voltage stays mainly above the 450 mV threshold, the VCM reduces the fuel delivery in order to compensate for the indicated rich condition.

Short Term Fuel Trim (FT) Bank 2 - Percentage of Compensation Required: The short term fuel trim was formerly called the fuel integrator. The short term fuel trim represents a short-term correction to the fuel delivery by the VCM in response to the amount of time the HO2S voltage spends above or below the 450 mV threshold. An HO2S voltage reading below 450 mV indicates a lean air to fuel mixture. If the HO2S voltage has mainly been below 450 mV threshold, the short term fuel trim increases in order to tell the VCM to add fuel. If the HO2S voltage stays mainly above the 450 mV threshold, the VCM reduces the fuel delivery in order to compensate for the indicated rich condition.

Short Term Fuel Trim (FT) Bank 2 - Range (0-255) Counts: The short term fuel trim was formerly the fuel integrator. The short term fuel trim represents a short-term correction to the fuel delivery by the VCM in response to the amount of time the HO2S voltage spends above or below the 450 mV threshold. An HO2S voltage reading below 450 mV indicates a lean air to fuel mixture. If the HO2S voltage has mainly been below 450 mV threshold, the short term fuel trim increases in order to tell the VCM to add fuel. If the HO2S voltage stays mainly above the 450 mV threshold, the VCM reduces the fuel delivery in order to compensate for the indicated rich condition.

Fuel Trim (FT) Cell Bank 1 - Range (0-22) Cell: The Fuel Trim Cell is dependent upon the engine speed and the MAP sensor readings. Engine RPM and MAP sensor readings are broken into a plot of 22 different cells. The Fuel Trim Cell indicates which cell is currently active.

Fuel Trim (FT) Cell Bank 2 - Range (0-22) Cell: The Fuel Trim Cell is dependent upon the engine speed and the MAP sensor readings. Engine RPM and MAP sensor readings are broken into a plot of 22 different cells. The Fuel Trim Cell indicates which cell is currently active.

Engine Coolant Temperature (ECT) - Range -40°-215°C (-40°-419°F): The Engine Coolant Temperature (ECT) sensor is mounted in the intake manifold. The ECT sends the engine temperature information to the VCM. The VCM supplies 5 volts to the ECT sensor circuit. The sensor is a thermistor which changes the internal resistance as the temperature changes. When the sensor is cold, meaning the internal resistance is high, the VCM monitors a high voltage signal. The VCM interprets the high voltage signal as a cold engine. As the sensor warms, meaning the internal resistance decreases, the voltage signal decreases. The VCM interprets the lower resistance as a warm engine.

Start Up Engine Coolant Temperature (ECT) - Range -40°-215°C (-40°-419°F): When the engine is started, the VCM records the engine coolant temperature. The VCM uses the recorded temperature in order to calculate the time to a Closed Loop.

Ignition 1 - Range (0.0-25.5 Volts): The Ignition 1 indicates the voltage of the ignition system input to the VCM.

Engine Run Time - Range (0:00:00-18:12:15) Hours: Minutes: Seconds: The Engine Run Time is a measure of how long the engine has run during this ignition cycle. When the engine stops running, the timer resets to zero.

Misfire Data

Engine Speed - Range 0-16384 Revolutions Per Minute (RPM): The VCM computes the Engine Speed from the fuel control reference input. The speed should remain close to the desired idle under the various engines loads with the engine idling.

Desired Idle - Range 0-3187 Revolutions Per Minute (RPM): The VCM commands the desired IAC. The VCM compensates for various engine loads in order to maintain the desired idle speed.

Misfire Current Cyl. #1: The scan tool will display the number of current cylinder misfires.

Misfire Current Cyl. #2: The scan tool will display the number of current cylinder misfires.

Misfire Current Cyl. #3: The scan tool will display the number of current cylinder misfires.

Misfire Current Cyl. #4: The scan tool will display the number of current cylinder misfires.

Misfire Current Cyl. #5: The scan tool will display the number of current cylinder misfires.

Misfire Current Cyl. #6: The scan tool will display the number of current cylinder misfires.

Engine Speed - Range 0-16384 Revolutions Per Minute (RPM): The VCM computes the Engine Speed from the fuel control reference input. The speed should remain close to the desired idle under the various engines loads with the engine idling.

Desired Idle - Range 0-3187 Revolutions Per Minute (RPM): The VCM commands the desired IAC. The VCM compensates for various engine loads in order to maintain the desired idle speed.

Misfire History Cyl. #1: The scan tool will display the number of history cylinder misfires.

Misfire History Cyl. #2: The scan tool will display the number of history cylinder misfires.

Misfire History Cyl. #3: The scan tool will display the number of history cylinder misfires.

Misfire History Cyl. #4: The scan tool will display the number of history cylinder misfires.

Misfire History Cyl. #5: The scan tool will display the number of history cylinder misfires.

Misfire History Cyl. #6: The scan tool will display the number of history cylinder misfires.

Idle Air Control (IAC) Position - Range (0-255) Counts: The scan tool displays in counts the Idle Air Control (IAC) pintle position commanded from the VCM. The greater the number of counts, the greater the command idle speed (air passages opened) is. The idle air control should respond fairly quickly to the changes in the engine load in order to maintain the desired idle RPM.

Desired IAC - Range (0-255) Counts: The desired IAC indicates the desired IAC position based on a command from the VCM.

Ignition 1 - Range (0.0-25.5 Volts): The Ignition 1 indicates the voltage of the ignition system input to the VCM.

Rich/Lean Bn 1 - (Rich/Lean): The Rich/Lean Bn 1 indicates the condition of the exhaust gases in bank 1.

Rich/Lean Bn 2 - (Rich/Lean): The Rich/Lean Bn 2 indicates the condition of the exhaust gases in bank 2.

Brake Switch - Range (Open/Closed): The Brake Switch indicates the status of the brake switch. This is a normally open switch. When the brake pedal is depressed, the brake switch is then closed.

Decel Fuel Mode - Range (Yes/No): The Decel Fuel Mode indicates if the VCM is in a Decel Fuel Mode.

Power Enrichment - Range (Yes/No): The Power Enrichment indicates if the Power Enrichment mode is active

Transmission Range (TR) Switch: The Transmission Range switch indicates the current drive gear.

Torque Converter Clutch (TCC) Forced Off (No/Yes): The scan tool will display the status of the TCC based on the command of the VCM.

Torque Converter Clutch (TCC) Enable - Range (Yes/No): The TCC enable indicates the status of the TCC enable output.

Vehicle Speed- km/h - MPH - Range (0-255): The Vehicle Speed is displayed in km/h or MPH and indicates how fast the drive wheels are turning.

Cruise Mode - Range (Yes/No): The Cruise Mode indicates if the driver has requested the cruise control. If the cruise control has been requested or engaged, yes will be displayed. If the cruise is not being requested or disengaged, no will be displayed.

EVAP Data

Manifold Absolute Pressure (MAP) - Range (10 kPa-104 kPa): The Manifold Absolute Pressure (MAP) sensor measures the change in the intake manifold pressure from the engine load and the speed changes. As the intake manifold pressure increases, the air density in the intake manifold also increases. Additional fuel is required.

Manifold Absolute Pressure (MAP) Sensor - Range (0.0-5.0 Volts): The MAP sensor produces a low signal voltage when the manifold pressure is low. A low manifold pressure means a high vacuum. The MAP sensor produces a high signal voltage when the manifold pressure is high. A high manifold pressure means a low vacuum. With the ignition ON and the engine stopped, the manifold pressure equals the atmospheric pressure causing the signal voltage to be high. The VCM uses this information as an indication of the vehicles altitude. This information is referred to as the BARO. Comparison of this BARO reading with a known good vehicle with the same sensor is a good way to check accuracy of a suspect sensor. The readings should read the same ±0.4 volts.

Throttle Position Sensor (TPS)- Range (0.0-5.0 Volts): The VCM uses the Throttle Position in order to determine the amount of throttle demanded by the operator of the vehicle. The TP sensor reads between 0.36-0.96 volts at idle to above 4.0 volts at Wide Open Throttle (WOT).

Throttle Position Sensor (TPS) Angle - Range (0-100%): The VCM computes the TPS angle from the TPS signal voltage input. The TPS angle should read 0% at idle. At 0%, the TPS voltage will read below 0.90 volts. The TPS angle should read 100% at Wide Open Throttle (WOT).

Fuel Level - Range (% ): The scan tool will display the percentage of fuel in the fuel tank.

Fuel Level Sensor - (0.0-2.9 Volts): The scan tool will display the voltage coming from the Fuel Level Sensor which will vary from .39 volts to 2.9 volts.

Fuel Tank Pressure - (in. H2O): Tank pressure will be shown on the scan tool which also is used in determining the correct fuel level inside the fuel tank.

Weak Vacuum Test - (Not Run/Fail): The scan tool will show the status of the diagnostic test.

Small Leak Test - (Not Run/Fail): The scan tool will show the status of the diagnostic test.

Purge Leak Test - (Not Run/Fail): The scan tool will show the status of the diagnostic test.

Excess Vacuum Test - (Not Run/Fail): The scan tool will show the status of the diagnostic test.

EVAP Canister Purge- OFF/ON: The EVAP Canister Purge pulls a small vacuum on the entire evaporative emission system. The scan tool displays if the EVAP Canister Purge Solenoid Valve is currently Off or On. When the scan tool displays ON, the small vacuum is being applied.

EVAP Vent Solenoid - (Closed/Open): The scan tool will show the status of the EVAP Vent Solenoid.

EVAP Duty Cycle - Range (0-100%): The EVAP duty cycle indicates the EVAP duty cycle that the VCM is commanding.

Engine Run Time - Range (0:00:00-18:12:15) Hours: Minutes: Seconds: The Engine Run Time is a measure of how long the engine has run during this ignition cycle. When the engine stops running, the timer resets to zero.