Misfire Data

Misfire Data Definitions Engine Speed - Range 0-16384: From 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 Speed- 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.

Engine Coolant Temperature (ECT) - Range -40°C to 215°C (-40°F to 419°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 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.

Intake Air Temperature (IAT) - Range -40°C to 215°C (-40°F to 419°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 uses the intake air temperature in order to adjust the fuel delivery and the spark timing according to the incoming air density.

Manifold Absolute Pressure (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.

Barometric Absolute Pressure (BARO) - Range 11-105 kPa: The Barometric Pressure (BARO) sensor measures the change in the intake manifold pressure which results from the altitude changes. The BARO updates when the ignition is turned ON and at Wide Open Throttle (WOT).

Throttle Position (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).

Misfire Current Cyl. 1 Range 0-255 Counts: The misfire cur. #1 indicates the number of current misfires that are present in cylinder #1. The misfire cur. 1 increments only when the misfire is current. Misfire

History Cyl. 1 - Range 0-255 Counts: The Misfire Hist. #1 indicates the number of misfires that have occurred after the PCM has counted 195 current misfires. After 195 total misfires, the current misfire counter adds the misfires to the history misfire counter. If 1 cylinder is misfiring, the misfire current counter will count 195 misfires before adding the misfires to the history counter. If 2 cylinders are misfiring, the misfiring current counters add to the history counters after 97 misfires.

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

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

Base Pulse Width Modulation (PWM) Cyl. 1 - Range 0-999.9 mS: The base PWM Cyl. 1 indicates the base Pulse Width Modulation (PWM) or the ON time of the cylinder 1 injector in milliseconds. When the engine load increases, the injector pulse width increases.

Total Misfire Current Count - Range 0-255 Counts: The Total Misfire indicates the total number of misfires that have been detected in all cylinders after 100 engine cycles. One cycle equals the completion of a 4 stroke cycle. The total misfire only increments during a steady state cruise conditions.

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 engine resets to 0.

Number of Current Diagnostic Trouble Code (DTC)s - 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.