HO2S Data

Engine Speed - Range 0 - 16384 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 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 too will display the current state of the HO2S system.

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

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

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

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

HO2S BN 1 Sen. 3 - Range (0 - 1107 mV): 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/Fuel Ratio indicates the calculated air to fuel ratio that the VCM is commanding.

HO2S Crosscounts 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 Crosscounts 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.

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

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 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.

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

Long Term Fuel Trim FT Bn 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 (0% indicates that the fuel delivery 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, decreased injector pulse width. A value above 128 counts indicates that a lean condition exists. The VCM compensates by adding fuel, increased injector pulse width.

Long Term Fuel Trim FT Bn 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 (0% indicates that the fuel delivery 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, decreased injector pulse width. A value above 128 counts indicates that a lean condition exists. The VCM compensates by adding fuel, increased injector pulse width.

Long Term Fuel Trim FT Bn 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 (0% indicates that the fuel delivery 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, decreased injector pulse width. A value above 128 counts indicates that a lean condition exists. The VCM compensates by adding fuel, increased injector pulse width.

Long Term Fuel Trim FT - Bn 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 (0% indicates that the fuel delivery 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, decreased injector pulse width. A value above 128 counts indicates that a lean condition exists. The VCM compensates by adding fuel, increased injector pulse width.

Short Term Fuel Trim FT - Bn 1 - Percentage of Compensation Required: 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. A 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 threshold, the VCM reduces the fuel delivery in order to compensate for the indicated rich condition.

Short Term Fuel Trim FT - Bn 1 - Range (0 - 255): 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. A 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 threshold, the VCM reduces the fuel delivery in order to compensate for the indicated rich condition.

Short Term Fuel Trim FT Bn 2 - Range (0 - 255): 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. A 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 threshold, the VCM reduces the fuel delivery in order to compensate for the indicated rich condition.

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

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

ECT - Range -40° - 215°C (-40° - 419°F): The Engine Coolant Temperature (ECT) sensor is mounted in the intake 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 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 condition of the ignition 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.