For 1990-2009 cars
Engine Coolant Temperature Sensor: The scan tool displays -40 to +151°C ( -40 to +304°F). The Engine Coolant Temperature (ECT) sensor is mounted in the coolant stream. The ECM applies 5 volts to the ECT sensor circuit. The sensor is a thermistor which changes internal resistance as the temperature changes. When the sensor is cold (internal resistance high), the ECM monitors a high signal voltage and interprets it as a cold engine. As the sensor warms and internal resistance decreases, the voltage signal decreases and the ECM interprets the lower voltage as a warm engine.
Fan Control Relay 1 Command: Engine Control Module (ECM) controls cooling fan relay ON/OFF.
Fan Control Relay 2 and 3 Command: Engine Control Module (ECM) controls cooling fan relay ON/OFF.
Circuit State of the Fan Control Relay 1: This parameter displays the state of the drive circuit.
Circuit State of the Fan Control Relay 2 and 3: This parameter displays the state of the drive circuit.
5-Volt Reference 1: This parameter displays the voltage that the 5-volt reference 1 circuit of the control module senses. The scan tool will display a high value, when the voltage is higher. The scan tool will display a low value, when the voltage is lower.
5-Volt Reference 2: This parameter displays the voltage that the 5-volt reference 2 circuit of the control module senses. The scan tool will display a high value, when the voltage is higher. The scan tool will display a low value, when the voltage is lower.
5-Volt Reference 1 or 2 Circuit Status: This parameter displays the diagnostic state of the output driver of the 5-volt reference circuit. The scan tool will display OK or Fault. OK indicates that no circuit faults are detected during the current test. Fault indicates that a short or open circuit/component exists, electronically disconnecting the circuit/component from the control module.
Engine Load: This parameter displays the engine load in percent based on inputs to the control module form various engine sensors. The scan tool will display a low percentage when the engine is at idle with little or no load. The scan tool will display a high percentage when the engine is running at a high RPM under a heavy load.
Calculated Engine Oil Temperature: This parameter displays the temperature of the engine oil as calculated by the control module according to a signal from the engine oil temperature sensor. The engine oil temperature sensor has a range of values indicating a low value when the oil temperature is low, and a high value when the oil temperature is high.
Engine Oil Temperature Sensor: This parameter displays the temperature of the engine oil as calculated by the control module according to a signal from the engine oil temperature sensor. The engine oil temperature sensor has a range of values indicating a low value when the oil temperature is low, and a high value when the oil temperature is high.
Engine Running Time: This parameter displays the time elapsed since the engine started. The scan tool will display the time in hours, minutes and seconds. The engine running time will reset to zero when the engine stops running.
Engine Speed: This parameter displays the speed of the crankshaft as determined by the control module according to the input from the Crankshaft Position (CKP) Sensor. The scan tool will display a high value at high engine speed and a low value at low engine speed.
Hot Open Loop: This parameter indicates the status of the fuel delivery system. The scan tool will display Active if the fuel system is running in open loop due to a temperature concern. The scan tool will display Inactive if the fuel system is operating normally.
Intake Air Temperature Sensor: This parameter displays the temperature of the air entering the engine as calculated by the control module based on the input from the intake air temperature sensor. The scan tool will display a low value when the air temperature is low, and a high value when the air temperature is high.
Ignition 1 Signal: This parameter displays the voltage measured at the ignition 1 circuit of the control module. Voltage is applied to the control module when the ignition switch is in the ignition 1 position. The scan tool will display a low value when the voltage is low. The scan tool will display a high value when the voltage is higher.
Knock Retard: This parameter indicates the amount of spark advance the control module removes from the Ignition control (IC) spark advance in response to the signal from the knock sensors.
Spark: This parameter displays the spark timing being commanded by the control module on the IC circuit. The scan tool will display a negative value if the spark timing is before top dead cent (BTDC) or spark advance; the scan tool will display a positive value if the spark timing is after top dead center (ATDC) or spark retard. Because the ignition control module sets spark advance at a fixed value BTDC while operating in bypass mode, the displayed spark advance only reflects true spark timing when the PCM has commanded IC mode.
Start Up Engine Coolant Temperature: This parameter indicates the ECT at engine start up as calculated by the control module based on the signal from the ECT sensor. The scan tool will display a higher value on a warmer engine, and a lower value on a colder engine.
Calculated ECT -- Closed Loop Fuel Control: The scan tool under the control of the closed loop fuel displays -39 to +140°C (-38 to +284°F). The voltage applied to the ECM input by the sensor is converted to a temperature value.
Calculated ECT -- Thermostat Diagnosis: When diagnosing the thermostat, the scan tool displays -39 to +140°C (-38 to +284°F). The voltage applied to the ECM input from the sensor is converted to a temperature value.
Start Up IAT: This parameter indicates the IAT at engine start up as calculated by the control module based on the signal from the IAT sensor. The scan tool will display a higher value during warmer underhood temperatures, and a lower value during colder underhood temperatures.
Transmission Oil Temperature Sensor: This parameter displays the temperature of transmission oil temperature as calculated by the control module according to a signal from the transmission oil temperature sensor. The transmission oil temperature sensor has a specific range of values indicating a low value when the oil temperature is low, and a high value when the oil temperature is high.
Total Knock Retard Value: This parameter indicates the ignition spark timing being retarded due to all control systems monitored by the control module. The scan tool will display a high value during extreme conditions such as high temperatures and antilock braking. The scan tool will display a lower value under light loads driving.
Vehicle Speed Sensor: This parameter indicates the vehicle speed as calculated by the control module based on a signal form the vehicle speed sensor VSS). The scan tool will display a higher value at higher vehicle speed, and a lower value at lower vehicle speed.
Volumetric Efficiency: This parameter displays the calculated volumetric efficiency of the engine as calculated by the control module.