Oxygen Sensor Data

O2S Data

02S 1 - Range 0 - 1132 mV: The Oxygen Sensor (02S 1) represents the exhaust oxygen sensor output voltage. This voltage will fluctuate constantly within a range between 100 mV (lean exhaust) to 900 mV (rich exhaust) when operating in Closed Loop.

HO2S 2 - Range 0-1132 mV: The Rear Heated Oxygen Sensor (HO2S 2) represents the exhaust oxygen output voltage beyond the catalytic converter. This voltage will remain inactive or appear lazy within a range of 100 mV (lean exhaust) and 900 mV (rich exhaust) when the system is operating in Closed Loop.

Engine Speed - Range 0-16384 RPM: Engine Speed is computed by the PCM from the fuel control reference input. It should remain close to desired idle under various engine loads with the engine idling. Desired Idle - Range 0-3187 RPM: The idle speed that is commanded by the PCM. The PCM will compensate for various engine loads to keep the engine at the desired idle speed.

ECT - Range -40°C - 151°C (-40°F - 304°F): The Engine Coolant Temperature (ECT) sensor sends engine temperature information to the PCM. The PCM supplies 5 volts to the engine coolant temperature sensor circuit. The sensor is a thermistor which changes internal resistance as temperature changes. When the sensor is cold (internal resistance high), the PCM monitors a high voltage which it interprets as a cold engine. As the sensor warms (internal resistance decreases), the voltage signal will decrease and the PCM will interpret the lower voltage as a warm engine.

IAT - Range -40°C - 151°C (-40°F - 304°F): The PCM converts the resistance of the Intake Air Temperature (IAT) sensor to degrees in the same manner as the ECT sensor. Intake air temp is used by the PCM to adjust fuel delivery and spark timing according to incoming air density.

MAP - Range 11 - 105 kPa, 0 - 5.0 Volts: The Manifold Absolute Pressure (MAP) sensor measures the change in the intake manifold pressure which results from engine load and speed changes. As the intake manifold pressure increases, the air density in the intake also increases and additional fuel is required.

BARO - Range 11-105 kPa, 0 - 5.0 Volts: The Barometric Pressure (BARO) sensor measures the change in the intake manifold pressure which results from altitude changes. This value is updated at ignition ON and also at Wide Open Throttle (WOT).

TP Sensor - Range 0 - 5.0 Volts: The Throttle Position (TP) sensor is used by the PCM to determine the amount of throttle demanded by the operator of the vehicle. The TP sensor will read between .36-.96 volt at idle to above 4 volts at Wide Open Throttle (WOT).

TP Angle - Range 0 - 100%: Throttle Position (TP) angle is computed by the PCM from the TP sensor voltage input. TP angle will auto zero to 0% at idle (TP voltage below 0.90 volt) and read 100% at Wide Open throttle (WOT).

Fuel Trim Cell - Range 0 - 22: Fuel Trim Cell is dependent upon engine speed and MAP sensor readings. A plot of RPM vs. MAP is broken down into 22 cells. Fuel Trim Cell indicates which cell is currently active.

FT Index - Range 0 - 255 (-100% to 100%): Fuel Trim (FT) Index represents average Long Term Fuel Trim for certain cells which are used in determining DTC P0171 and P0172.

Short Term FT - Range 0 - 255 (-100% to 100%): Short Term Fuel Trim (FT) represents a short term correction to fuel delivery by the PCM in response to the amount of time the oxygen sensor voltage spends above or below the 450 mV threshold. If the oxygen sensor has mainly been below 450 mV, indicating a lean air/fuel mixture, short term fuel trim will increase to tell the PCM to add fuel. If the oxygen sensor voltage stays mainly above the threshold, the PCM will reduce fuel delivery to compensate for the indicated rich condition.

Long Term FT, Range 0 - 255 (-100% to 100%): The Long Term Fuel Trim (FT) is derived from the short term fuel trim value. The Long Term Fuel Trim (FT) is used for the long term correction of the fuel delivery. A value of the 128 counts (0%) indicates that the fuel delivery requires no compensation in order 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. The PCM is decreasing the injector pulse width. A value above 128 counts indicates that a lean condition exists for which the PCM is compensating.

Short Term FT - Average - Range 0 - 255 (-100% to 100%): Short Term Fuel Trim (FT) Average is derived from the short term fuel trim from all of the cells. The PCM then takes all of the values and then creates one average value.

Long Term FT Average - Range 0 - 255 (-100% to 100%): Long Term Fuel Trim (FT) Average is derived from the long term fuel trim from all of the cells. The PCM then takes all of the values and then creates one average value.

Lean/Rich Transition - Range 0 - 255 counts: The PCM counts the number of times the Oxygen Sensor (O2S 1) goes from a low voltage (lean exhaust) to a high voltage (rich exhaust) within a 100 second period.

Rich/Lean Transition - Range 0 - 255 counts: The PCM counts the number of times the Oxygen Sensor (025 1) goes from a high voltage (rich exhaust) to a low voltage (lean exhaust) within a 100 second period.

Lean/Rich Avg. - Range 0 - 249 mS counts: The PCM takes the Lean/Rich transition times following the completion of the data collection period. Then the PCM averages the transition time from the total transition times.

Rich/Lean Avg. - Range 0 - 249 mS: The PCM takes the Rich/Lean transition value following the completion of the data collection period. Then the PCM divides the value with the 100 second period. Rich/Lean to Lean/Rich Ratio Sen. 1 - Range 0:1-15.93:1: The Rich/Lean average is divided by the Lean/Rich average in order to find the Oxygen Sensor (025 1) ratio.

Calc. Air Flow - Range 0 - 512 grams/second: The calculated air flow is a calculation based on manifold absolute pressure. The calculation is used in several diagnostics to determine when to run.

LOAD - Range 0 - 100%: Indicates engine load based on manifold absolute pressure. The higher the percentage, the more load the engine is under.

Loop Status - Range Open/Closed: Closed Loop is displayed indicating that the PCM is controlling fuel delivery according to the Oxygen Sensor (025 1) voltage as close to an air/fuel ratio of 14.7 to 1 as possible.

# of Curr. DTCs - Range 0 - 255: The # of Curr. 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.

Engine Run Time - Range 0:00:00-18:12:15 hours:minutes:seconds : A measure of how long the engine has been running. When the engine stops running, the timer is reset to zero.