For 1990-2009 cars

The Transmission and the Engine Scan Tool Data Definitions contains a brief description of all transmission and engine related parameters available on the scan tool. The list is arranged in the alphabetical order.

Air Conditioning: The parameter will indicate ON whenever the A/C Idle-Up signal is received by the PCM from the A/C compressor cONtrol module. This will allow the PCM to adjust the engine idle to maintain acceptable engine performance.
BARO: The scan tool range 0-125 kPa. The barometric pressure (BARO) sensor measures the changes in atmospheric pressure. This parameter will read approximately 95 to 105 kPa at sea level.
Battery Voltage: This parameter indicates battery positive voltage inputted from the Main Relay to the PCM.
Closed Throttle Switch: This parameter will read CLOSED when the throttle valve is CLOSED, and OPEN when the throttle valve is OPEN. The CLOSED throttle Switch parameter is a calculated valve. The PCM uses the information from the TP sensor voltage in order to determine whether the throttle is OPEN or CLOSED.
Current Gear: Displays 1,2 or 3. This parameter indicates the current command state of the shift solenoid valves.
Desired Idle Speed: The Desired Idle Speed is a PCM internal parameter which indicates the PCM requested idle speed. If the engine is not running, this number indicated is not valid.
Electrical Load Signal: The scan tool displays YES/NO if there is electrical current.
Engine Speed: The scan tool range is 0-10,000 RPM. The PCM computes Engine speed from the ignitiON reference pulses. The Engine speed should remain close to desired idle under various engine loads with the engine idling.
ECT: The Scan tool range is 80°C-90°C (176F-194°F). The ECT sensor is a thermistor which changes internal resistance as temperature changes. When the sensor is cold (internal resistance high), the PCM monitors a high signal voltage and interprets the voltage as a cold engine. As the sensor warms (internal resistance decreases), the voltage signal decreases and the PCM interprets the lower voltage as a warm engine.
Engine Coolant Fan: The scan tool will indicate ON/OFF, whenever a signal is recieved by the PCM from the Engine Coolant Fan. The PCM will adjust when the Engine Coolant Fan will run ON/OFF.
Engine Load: The scan tool range is 10% to 18%. This parameter indicates engine load based on manifold absolute pressure. The higher the percentage, the more load the engine is under.
Fuel Cutoff Signal: When the fuel is being cut, output signal to the fuel injector is stopped, the parameter should read ON, but when fuel is not in the cut off mode the parameter should read off.
Fuel Pump: This parameter indicates that the PCM is turning on the fuel pump by turning on the fuel pump relay. The PCM will turn the fuel pump relay ON for three seconds when the ignition is turned on and turn the fuel pump relay on continuously when receiving reference pulses from the ignition module.
IAC Duty Cycle: The scan tool range is 17 to 30%. This scan tool parameter indicates the opening of the bypass air passage in terms of percentage. The opening of the bypass air passage determines the amount of air flowing through the bypass air passage and is controlled by the IAC motor.
IAT: The scan tool range is -40°C to 120°C (-40°F to 250°F). The PCM converts the resistance of the intake air temperature sensor to degrees. The PCM uses the intake air temperature (IAT) in order to adjust fuel delivery and spark timing according to incoming air density.
Loop Status: The scan tool displays Open Loop or Closed Loop. Closed Loop indicates that the PCM is cONtrolling fuel delivery according to oxygen sensor voltage. Open Loop indicates that the PCM ignores the oxygen sensor voltage and bases the amount of fuel to be delivered ON the TP sensor, the ECT sensor, and MAP sensor inputs.
MAP: The scan tool range is 0-125 kPa/0.0-5.0 volts. The manifold absolute pressure (MAP) sensor measures the change in the intake manifold pressure from engine load, and speed changes. As intake manifold pressure increases, the intake vacuum decreases resulting in a higher kPa reading.
Monitor Shift Sol. 1: The scan tool displays ON/OFF, when the PCM energizes the shift solenoid 1, line pressure is relieved and the 2-3 shift valve does not operate.
Monitor Shift Sol. 2: The scan tool displays ON/OFF, when the PCM engergizes the shift solenoid 2, line pressure is relieved and the 1-2 shift valve does not operate.
PNP: The scan tool displays P-N when the transmission is in Park or Nuetral, and R-D-L when the transmission is operating in forward or reverse gears.
Shift Solenoid 1: The scan tool displays ON/OFF. This parameter indicates the status of the 1-2 solenoid valve. When the transmission is in FIRST gear, the scan tool should display ON. When the transmission is in SECOND or THIRD gear, the scan tool should display OFF.
Shift Solenoid 2: The scan tool displays ON/OFF. This parameter indicates the status of the 2-3 solenoid valve. When the transmission is in FIRST gear, the scan tool should display ON. When the transmission is in SECOND or THIRD gear, the scan tool should display OFF.
Throttle Position Level: The scan tool will display 0 level until the throttle is taken off the idle position.
TP Sensor: The scan tool displays 0-5 volts. The scan tool displays the amount of throttle opening in volts. Closed throttle displays about 1 volt and wide open throttle displays about 3.5 volts.
TP Angle: The scan tool displays 0 to 100%. The scan tool displays the amount of throttle opening in percentage. Closed throttle displays 0% and wide open throttle displays near 100%.
Transmission Range: The scan tool displays Park/Reverse/Neutral/Drive/Drive 2/Low/Invalid. The scan tool displays the decoded position of the transmission range switch (PRNDL). This information is then sent to the Instrument Panel Cluster (IPC) and is displayed to the operator.
Vehicle Speed: The scan tool range is 0-200 km/h/0-125 MPH. This parameter displays the vehicle speed. The Powertrain Control Module (PCM) receives reference pulses from the Vehicle Speed Sensor (VSS) and converts them into km/h and MPH for display.