EGR/EVAP Data

Engine Speed - Range 0-16384: Prom the fuel control reference input, the PCM computes the Engine Speed. The engine speed should remain close to the desired idle under the various engine loads with the engine idling.

Desired Idle - Range 0-3187 RPM: The PCM commands the idle speed. The PCM compensates for the various engine loads in order 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 the engine temperature information to the PCM. The PCM supplies 5 volts to the engine coolant temperature sensor circuit. The sensor is a thermistor. The thermistor changes the internal resistance as the temperature changes. When the sensor is cold indicating the internal resistance is high, the PCM monitors a high voltage. The PCM interprets as a cold engine. As the sensor warms indicating that the internal resistance is decreasing, the voltage signal decreases. The PCM interprets the lower voltage as a warm engine.

IAT - Range -40°C-151°C (-40°F-3O4°F): The PCM converts the resistance of the Intake Air Temperature (IAT) sensor to degrees in the same mode as the ECT sensor. The PCM muses the intake air temperature in order to adjust the fuel delivery and the spark timing according to the incoming air density.

MAP - Range 11-105 kPa, 0.0-5.0 Volts: The Manifold Absolute Pressure (MAP) sensor measures the change in the intake manifold pressure. The change in the intake manifold pressure results from engine load changes and speed changes. As the intake manifold pressure increases, the air density in the intake also increases. 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 the altitude changes. This value updates when the ignition is turned ON and at Wide Open Throttle (WOT).

TP Sensor - Range 0.0-5.0 Volts: The PCM uses the Throttle Position (TP) sensor in order to determine the amount of the throttle demanded by the vehicle's operator. The TP sensor reads between 0.36-0.96 volt at idle to above 4 volts at Wide Open Throttle (WOT).

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

O2S 1 - Range 0-1132 mV: The Oxygen Sensor (O2S 1) represents the exhaust oxygen sensor output voltage. This voltage fluctuates constantly within a range of 100 mV (lean exhaust) to 900 mV (rich exhaust) when operating in a 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.

IAC Position - Range 0-255 Counts: The scan tool displays the PCM command for the Idle Air Control (IAC) pintle position in counts. The higher the number of counts, the greater the commanded idle speed reads. The Idle Air Control responds to changes in the engine load in order to maintain the desired idle RPM.

Fuel Trim Cell - Range 0-22: A Fuel Trim Cell depends upon the engine speed and the MAP sensor readings. RPM vs. MAP is broken down into 22 fuel trim cells. The Fuel Trim Cell indicates which cell is currently active.

Short Term FT - Range 0-255 (-100% to 100%): The Short Term Fuel Trim represents a short term correction of the fuel delivery. The correction is in response to the amount of time the oxygen sensor voltage is above or below 450 mV. An oxygen sensor voltage below 450 mV indicates a lean air to fuel mixture. If the oxygen sensor has mainly read below 450 mV, the short term fuel trim will increase in order to tell the PCM to add fuel. If the oxygen sensor voltage stays mainly above the threshold, the PCM will reduce the fuel delivery in order 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.

Delta MAP Change - Range -20 to 20 kPa: The amount of MAP change the PCM sensed from the beginning of the diagnostic until the end. Used to calculate the difference in the actual MAP change and the expected MAP change to determine the Decel EWMA value.

EGR Decel Filter- Range -10 to 10 kPa: The EGR Decel Filter is an average kPa difference between the expected MAP kPa change the PCM expected to see when the diagnostic ran and the actual MAP kPa change that was seen. The EGR Decel Filter value should always be near -3. Whenever the EGR Decel Filter value becomes more positive (towards 0), then the EGR system is becoming restricted.

Desired EGR Position - Range 0 to 100%: The desired EGR position is the commanded EGR position. The PCM calculates the desired EGR position. The higher the percentage, the longer the PCM is commanding the EGR valve ON.

EGR Actual - Range 0 to 100%: The PCM monitors the results of its commands through a feedback signal. The EGR valve sends a voltage signal back to the PCM. The signal represents the actual EGR pintle position. The EGR pintle position should remain close to the desired EGR position.

EGR Decel Trip Sample Counter - Range 0 to 255 Counts: Displays the number of test that have been run for DTC P0401. Once the counter reaches 255, the number will stop until a battery disconnect or an EGR DTC has been cleared.

EVAP Solenoid - Range 0%-100%: When energized, the EVAP Solenoid allows the fuel vapor to flow from the EVAP canister to the engine. The EVAP Solenoid is normally closed. The EVAP solenoid is pulse width modulated by the PCM. The EVAP Solenoid reads 0% when closed to 100% when fully opened.

EVAP Vent Solenoid - Range ON/OFF: The EVAP Vent Solenoid allows fresh outside air to the EVAP canister during purge mode. The EVAP vent Solenoid allows the diagnostic to pull a vacuum on the fuel tank by closing the vent solenoid.

Fuel Level Sensor - Range 0%-100%: The Fuel Level Sensor monitors the fuel level in the tank. The fuel level sensor monitors the rate of change of the air pressure in the EVAP System. Several of the Enhanced EVAP System diagnostics are dependent upon the correct fuel level.

Fuel Tank Pressure - Range 0.0-5.0 Volts: The fuel tank pressure sensor measures the difference between the pressure or the vacuum in the fuel tank and the outside air pressure. When the air pressure in the fuel tank equals the outside air pressure, the output voltage of the sensor is 1.3 to 1.7 volts.

Number of Current DTCs - Range 0-255: Indicates the total number of current Diagnostic Trouble Codes (DTCs) set. Does not necessarily mean the Malfunction Indicator Lamp (MIL) is illuminated.

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 been running. When the engine stops running, the timer resets to zero.