Scan Tool Data Definitions Part 2

Fuel Level : This parameter displays the approximate fuel level in the fuel tank as calculated by the control module based on inputs from the fuel level sensors. The scan tool will display a low value when the fuel level in the tank is low or near empty. The scan tool will display a high value when the fuel level in the tank is high or near full.

Fuel Level Sensor: This parameter displays the voltage received by the control module from the sensor used to monitor the fuel level inside the fuel tank. The scan tool will display a low voltage when the fuel level in the tank is low or near empty. The scan tool will display a high voltage reading when the fuel level in the tank is high or near full.

Fuel Pump Relay Command: This parameter displays the commanded state of the fuel pump relay control circuit. The fuel pump relay should be on when the scan tool indicates the Fuel Pump Relay Command is On. The fuel pump relay should be off when the scan tool indicates the Fuel Pump Relay Command is OFF.

Fuel Tank Level Remaining: This parameter displays the amount of fuel remaining in the fuel tank as measured in liters or gallons. The control module determines the amount of fuel remaining in the tank by using information from the fuel level sensor(s). The scan tool will display a higher value with a full fuel tank, and a lower value with an empty fuel tank.

Fuel Tank Pressure Sensor: This parameter displays the voltage signal sent to the control module from the sensor used to monitor the pressure inside the fuel tank. The scan tool will display a low voltage when the pressure in the fuel tank is high. The scan tool will display a high voltage when the pressure in the fuel tank is low or in a vacuum.

Fuel Tank Pressure Sensor: This parameter displays the fuel tank pressure as calculated based on a signal sent to the control module from the fuel tank pressure (FTP) sensor. The scan tool will display a low value when the pressure in the fuel tank is low or a vacuum. The scan tool will display a high value when the pressure in the fuel tank is high.

Fuel Trim Cell: This parameter displays the fuel trim cell number as calculated by the control module based on engine speed and load inputs. The scan tool will display a lower number as conditions are nearer to idle, and a higher value as conditions approach maximum engine speed and maximum load.

Fuel Trim Learn: This parameter indicated if the control module is being commanded to adjusting long term fuel trim in response to the short term fuel trim. The scan tool displays Enabled or Disabled. When fuel trim is being learned because of an external command, the scan tool displays Enabled. Under normal conditions the scan tool displays Disabled.

Genr F-Terminal Signal: This parameter indicates the generator field duty cycle as commanded by the voltage regulator or control module. The scan tool will display a higher value for a higher commanded generator output, and a lower value for a lower commanded generator output.

Generator L-Terminal Signal Command: This parameter indicates whether the control module is allowing the generator to operate. The control module can disable the generator under certain conditions. The scan tool will YES if the control module is allowing generator operation, while NO indicates that the control module is not allowing generator operation.

HO2S Bank 1 Sensor 1: This parameter indicates the heated oxygen sensor (HO2S) bank 1 sensor 1 output voltage as measured by the control module. The scan tool value fluctuates constantly while operating in Closed Loop. The scan tool will display a higher value during rich running conditions, and a lower value during leaner running conditions.

HO2S Bank 1 Sensor 2: This parameter indicates the heated oxygen sensor (HO2S) bank 1 sensor 2 output voltage as measured by the control module. The scan tool value fluctuates constantly while operating in Closed Loop. The scan tool will display a higher value during rich running conditions, and a lower value during leaner running conditions. The post-catalyst HO2S output voltage will fluctuate slowly over a longer period of time, compared to the fuel control oxygen sensor s. This is due to the oxygen storage capacity of an efficiently operating catalyst.

HO2S Bank 2 Sensor 1: This parameter indicates the heated oxygen sensor (HO2S) bank 2 sensor 1 output voltage as measured by the control module. The scan tool value fluctuates constantly while operating in Closed Loop. The scan tool will display a higher value during rich running conditions, and a lower value during leaner running conditions.

HO2S Heater Bn 1 Sen. 1: This parameter displays the current through the control module when the bank 1 sensor 1 HO2S heater is commanded ON by the control module. HO2S Heater Bn 1 Sen. 1 is a range of values indicating a low current when the heater circuit resistance is high to a high current when the heater circuit resistance is low.

HO2S Heater Bn 1 Sen. 2: This parameter displays the current through the control module when the bank 1 sensor 2 HO2S heater is commanded ON by the control module. HO2S Heater Bn 1 Sen. 2 is a range of values indicating a low current when the heater circuit resistance is high to a high current when the heater circuit resistance is low.

HO2S Heater Bn 2 Sen. 1: This parameter displays the current through the control module when the bank 2 sensor 1 HO2S heater is commanded ON by the control module. HO2S Heater Bn 2 Sen. 1 is a range of values indicating a low current when the heater circuit resistance is high to a high current when the heater circuit resistance is low.

HO2S Heater Bn 1 Sen. 1: This parameter displays the duty cycle of the HO2S Heater when commanded by the control module. HO2S Heater Bn 1 Sen. 1 is a range of values indicating a low percentage when the heater circuit is commanded ON less to a high percentage when the heater circuit is commanded ON more.

HO2S Heater Bn 1 Sen. 2: This parameter displays the duty cycle of the HO2S Heater when commanded by the control module. HO2S Heater Bn 1 Sen. 2 is a range of values indicating a low percentage when the heater circuit is commanded ON less to a high percentage when the heater circuit is commanded ON more.

HO2S Heater Bn 2 Sen. 1: This parameter displays the duty cycle of the HO2S Heater when commanded by the control module. HO2S Heater Bn 2 Sen. 1 is a range of values indicating a low percentage when the heater circuit is commanded ON less to a high percentage when the heater circuit is commanded ON more.

IAC Position: This parameter displays the commanded position of the IAC motor by the control module. The scan tool will display a lower value if the valve is being commanded closed. The scan tool will display a higher value when the valve is commanded open.

IAT 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, such as battery voltage, when the voltage is higher.

Injector PWM Bank 1 Average: This parameter indicates the average commanded ON time for each injector on Bank 1 by the control module. The scan tool will display a larger value for a longer injector commanded ON time, causing more fuel to be delivered to the cylinders. The scan tool will display a smaller value for a shorter injector commanded ON time, causing less fuel to be delivered to the cylinders.

Injector PWM Bank 2 Average: This parameter indicates the average commanded ON time for each injector on Bank 2 by the control module. The scan tool will display a larger value for a longer injector commanded ON time, causing more fuel to be delivered to the cylinders. The scan tool will display a smaller value for a shorter injector commanded ON time, causing less fuel to be delivered to the cylinders.

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 sensor(s). the scan tool displays a high value for a large amount of spark retard, and a low value for a small amount of spark retard.

Long Term FT Avg. Bn1: This parameter is calculated by the control module based on the Short Term FT value. The Long Term FT bank 1 is used for the long term correction of the fuel delivery in bank 1. The scan tool will a high value for a large amount of long term fuel correction, and 0% for no long term fuel trim correction. The scan tool will display a negative value when fuel system is running too rich and fuel is being removed from the combustion event. The scan tool will display a positive value if the fuel system is running lean and fuel is being added to the combustion event.

Long Term FT Avg. Bn2: This parameter is calculated by the control module based on the Short Term FT value. The Long Term FT bank 2 is used for the long term correction of the fuel delivery in bank 1. The scan tool will a high value for a large amount of long term fuel correction, and 0% for no long term fuel trim correction. The scan tool will display a negative value when fuel system is running too rich and fuel is being removed from the combustion event. The scan tool will display a positive value if the fuel system is running lean and fuel is being added to the combustion event.

Long Term FT Bank 1: This parameter is calculated by the control module based on the Short Term FT value. The Long Term FT bank 1 is used for the long term correction of the fuel delivery in bank 1. The scan tool will a high value for a large amount of long term fuel correction, and 0% for no long term fuel trim correction. The scan tool will display a negative value when fuel system is running too rich and fuel is being removed from the combustion event. The scan tool will display a positive value if the fuel system is running lean and fuel is being added to the combustion event.

Long Term FT Bank 2: This parameter is calculated by the control module based on the Short Term FT value. The Long Term FT bank 2 is used for the long term correction of the fuel delivery in bank 1. The scan tool will a high value for a large amount of long term fuel correction, and 0% for no long term fuel trim correction. The scan tool will display a negative value when fuel system is running too rich and fuel is being removed from the combustion event. The scan tool will display a positive value if the fuel system is running lean and fuel is being added to the combustion event.

MAF Sensor: This parameter indicates the quantity calculated by the control module based on a signal from the Mass Airflow (MAF) Sensor. The scan tool will display a high value at high engine speeds, and a low value at low engine speeds.

MAF Sensor: This parameter indicates the frequency signal received from the mass airflow (MAF) sensor by the control module. The scan tool will display a high value at high engine speeds, and a low value at low engine speeds.

Main Injection Timing: Indicates the current timing of the main injection pulse as calculated by the control module. The scan tool will display a higher value for a main injection event farther from TDC (Top Dead Center). The Scan tool will display a lower value for a main injection event closer to TDC.

MAP Sensor: This parameter indicates the manifold absolute pressure inside the engine as calculated by the control module based on the signal from the manifold absolute pressure (MAP) sensor. The scan tool will display a higher value wide open throttle, and a lower value at idle.

MAP Sensor: This parameter indicates the voltage signal received by the control module from the manifold absolute pressure (MAP) sensor. The scan tool displays a low voltage at idle, and a high voltage at wide open throttle. Barometric pressure and altitude can effect these values.