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 Speed-Range (03187 RPM): The VCM commands the desired IAC. The VCM compensates for various engine loads in order to maintain the desired idle speed.

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 Position-Range (0-255) Counts: The desired IAC indicates the desired IAC position.

Throttle Position (TP) Sensor-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).

TP Angle-Range (0-100%): The VCM computes the TP Angle from the TP signal voltage input. The TP Angle should read 0% at idle. AT 0%, the TP voltage will read below 0.90 volts. The TP Angle should read 100% at Wide Open Throttle.

Start Up ECT-Range -40°-215°C (-40°-19°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.

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.

ECT Sensor-Range (0.0-5.0 Volts): 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.

Loop Status-Range (Open Loop/Closed Loop): The scan tool indicates whether the vehicle is in an open or closed loop state. The VCM uses HO2S information for determining fuel delivery during closed loop.

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.

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.

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 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).

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.

Closed Loop Since Restart-Range (Yes/No): The Closed Loop Since Restart indicates whether or not the vehicle has been in a closed loop state.

Air Fuel Ratio-Range (0.0:1-25.5:1): The scan tool indicates the VCM calculated air to fuel ratio. The typical air to fuel ratio is 14.7:1.

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 vehicle's 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 volt.

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.

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.

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

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

Engine Load-Range (0-100%): The VCM determines the engine load based upon the engine speed and MAF sensor readings. Engine Load increases with any increase in RPM and/or airflow.

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 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. 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-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 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. 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.

Fuel Trim Cell-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.

Fuel Trim Enable-Range (ON/OFF): The Fuel Trim Enable indicates the state of the fuel trim (Enable/Disabled) that the VCM is commanding. Fuel trim will be disabled when the vehicle is not in closed loop, malfunction codes related to fuel trim are set, large amounts of purge vapor are injested by the engine, or additional diagnostics that temporarily affect fuel trim operation are active.

Inj. PWM Avg. Bank 1-Range (0-499 ms): The Inj. Avg. Bank 1 indicates the injector on time that the VCM is commanding.

Inj. PWM Avg. Bank 2-Range (0-499 ms): The Inj. Avg. Bank 2 indicates the injector on time 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.

EVAP Duty Cycle-Range (0-100%): The scan tool indicates the EVAP duty cycle that the VCM is commanding. The EVAP duty cycle is a pulse modulated signal which is translated into a direct percentage of the maximum commandable state.

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

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

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

Brake Switch-Range (Open/Closed): The Brake Switch indicates the status of the brake switch. Milage Since DTC Clear-Range (Km/Mi): The scan tool indicates the total distance the vehicle has traveled since the DTCs were cleared.

Powertrain DTC Set-Range (Yes/No): The scan tool indicates whether a Powertrain DTC has set.

DTC Set this Ignition-Range (Yes/No): The scan tool indicates whether or not any DTC has set during the current ignition cycle.

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.