Scan Tool Data Definitions Part 1

SCAN TOOL DATA DEFINITIONS

The Engine Scan Tool Data Definitions contains a brief description of all engine related parameters available on the scan tool. The list is arranged in alphabetical order. A given parameter may appear in any one of the data lists. In some cases, the parameter may appear more than once or in more than one data list in order to group certain related parameters together.

24X Crank Sensor: This parameter displays the speed of the crankshaft as calculated from the medium resolution engine speed signal by the control module. A high RPM indicates a high engine speed. A low RPM indicates a low engine speed.

5-Volts Reference 1: This parameter displays the voltage sensed on the 5-volt reference 1 circuit at the control module. The scan tool will display a higher value at higher voltage. the scan tool will display a lower value at lower voltage.

5-Volts Reference 2: This parameter displays the voltage sensed on the 5-volt reference 2 circuit at the control module. The scan tool will display a higher value at higher voltage. the scan tool will display a lower value at lower voltage.

A/C High Side Pressure: This parameter displays the voltage signal sent to the control module from the A/C high side pressure sensor. The A/C high side pressure sensor has a range of values indicating a low refrigerant pressure when the voltage is low to a high refrigerant pressure when the voltage is high.

A/C Relay Command: This parameter displays the commanded state of the air conditioning (A/C) clutch relay control circuit. The scan tool will display ON or OFF. ON indicates the A/C clutch relay control circuit is being grounded by the control module, allowing voltage to the A/C compressor clutch. OFF indicates the A/C clutch relay is not being commanded on by the control module.

Air Fuel Ratio: This parameter displays the ratio of air to fuel as calculated by the control module based on various sensor inputs. The scan tool will display a lower air fuel ratio when a richer air to fuel mixture is commanded. The scan tool will display a higher air fuel ratio when a leaner air to fuel mixture is commanded. In closed loop operation the air fuel ratio should normally be around 14.2-14.7 to 1.

Air Pump Relay Command: This parameter displays the commanded state of the secondary air injection (AIR) pump relay control circuit. The scan tool will display ON or OFF. ON indicates the AIR pump relay control circuit is being grounded by the control module, allowing voltage to the AIR pump. OFF indicates the AIR pump relay is not being commanded on by the control module.

Air Solenoid Command: This parameter displays the commanded state of the secondary air injection (AIR) solenoid control circuit. The scan tool will display ON or OFF. ON indicates the AIR solenoid control circuit is being grounded by the control module, opening the AIR solenoid and allowing vacuum to the shutoff or combination valve(s). OFF indicates the AIR solenoid is not being commanded on by the control module.

BARO: This parameter displays the barometric pressure as calculated by the control module using the signal from the manifold absolute pressure (MAP) sensor measured when the ignition is turned on with the engine not running. The control module will update the barometric pressure during wide-open throttle (WOT) conditions.

CMP Sensor: This parameter displays the speed of the engine as calculated by the control module using the signal from the camshaft position (CMP) sensor. The scan tool will display a higher value as engine speed is increased. the scan tool will display a lower value as the engine speed is decreased.

Commanded Gear: This parameter displays the transmission gear commanded by the control module. The scan tool will display P/N when the transmission is commanded to park or neutral. The scan tool will display R when the transmission is commanded to reverse. The scan tool will display 1-5 when the transmission is commanded into a specific low gear.

Crank Request Signal: This parameter displays the state of the crank request input to the control module from the ignition switch. The scan tool will display Yes when the ignition switch is in the Crank position. The scan tool will display No when the ignition switch is in any other position.

Cruise Control Active: This parameter displays the status of the cruise control system as determined by the control module. The scan tool will display Yes when the cruise control system is in control of vehicle speed. The scan tool will display No when the cruise control system is not operating.

Cruise Inhibit Signal Command: This parameter displays the commanded state of the cruise inhibit signal circuit. The scan tool will display On when the control module is inhibiting cruise control operation. The scan tool will display Off when the control module is allowing cruise control operation.

Cycles Of Misfire Data: This parameter displays the number of cylinder firing events that were recorded as misfires as determined by the control module. the scan tool will display a high value as misfire events increase. The scan tool will display a lower value when there are fewer misfire events.

Desired EGR Position: This parameter displays the position of the exhaust gas recirculation (EGR) valve commanded by the control module. The scan tool will display 0 percent when the control module is commanding the EGR valve closed. The scan tool will display a higher percentage when the EGR valve is commanded open.

Desired idle speed: This parameter displays the engine idle speed in RPM as commanded by the control module. The control module compensates for various engine loads in order to maintain the desired engine speed at idle. This parameter is not valid unless the engine is running.

ECT Sensor: This parameter displays the temperature of the engine coolant calculated by the control module, based on the input from the engine coolant temperature sensor. When the coolant temperature is low, the scan tool will display a low temperature. When the coolant temperature is high, the scan tool will display a high temperature.

EGR Position Sensor: This parameter displays the voltage signal received from the exhaust gas recirculation (EGR) valve position sensor by the control module. The scan tool will display a lower value when the EGR valve is closed, and a higher value when the EGR valve is open.

EGR Position Sensor: This parameter displays EGR valve position as calculated by the control module based on an input from the exhaust gas recirculation (EGR) valve position sensor. The scan tool will display a lower value when the EGR valve is closed, and a higher value when the EGR valve is open.

Engine Load: This parameter displays the engine load in percent based on inputs to the control module from 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.

Engine Oil Level Switch: This parameter displays the status of the engine oil level switch as determined by the control module. The control module uses this information to turn on the low engine oil lamp if the engine oil level remains approximately 1 quart low for a sufficient amount of time. The scan tool will display Low when the engine oil level is low. The scan tool will display OK when the engine oil level is correct.

Engine Oil Pressure Switch: This parameter displays the state of the engine oil pressure as determined by the control module. The control module monitors the engine oil pressure switch to determine if the engine oil pressure is sufficient. The scan tool will display low when the engine oil pressure is below a predetermined value. The scan tool will display OK when the engine oil pressure is adequate.

Engine Run Time: This parameter displays the time elapsed since the engine was started. The scan tool will display the time in hours, minutes and seconds. The engine run 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 using an input from the Crankshaft Position (CKP) Sensor. The scan tool will display a high value at high engine speeds and a low value at low engine speeds.

EVAP Purge Solenoid Command: This parameter displays the on-time or duty cycle of the evaporative emission (EVAP) purge solenoid commanded by the control module expressed as a percent. The scan tool will display a high percentage when the control module is commanding the EVAP purge solenoid to be open a large amount. The scan tool will display a low percentage when the control module is commanding the EVAP purge solenoid to be open a small amount. The scan tool will display 0 when the control module is commanding the EVAP purge solenoid closed.

EVAP Test Abort Reason: This parameter displays the reason the EVAP test was aborted by the control module. The scan tool will display various messaged to indicate the reason the last test failed to complete.

EVAP Test Result: This parameter displays the result of the EVAP test performed by the control module. The scan tool will display various messaged to indicate the final result of the test.

EVAP Test State: This parameter displays the status of the EVAP test performed by the control module. The scan tool will display various messaged to indicate the current status of the test. The scan tool will display Wait For Purge, Test Running, or Test Complete.

EVAP Vent Solenoid Command: This parameter displays the state of the evaporative emission (EVAP) vent solenoid commanded by the control module. The scan tool will display a venting when the control module is commanding the EVAP vent solenoid to be open. The scan tool will display a not venting when the control module is commanding the EVAP vent solenoid to be closed.

Extended Travel Brake Pedal Switch: This parameter displays the state of the brake pedal as determined by the extended travel brake pedal switch. The scan tool will display Applied when the brake pedal is depressed greater than approximately 40 percent of the total travel.

FC Relay 1 Command: This parameter displays the commanded state of the cooling fan relay 1 control circuit. The cooling fan relay 1 should be on when the scan tool indicates the FC Relay 1 Command is On. The cooling fan relay 1 should be off when the scan tool indicates the FC Relay 1 Command is Off.

FC Relay 2 Command: This parameter displays the commanded state of the cooling fan relay 2 control circuit. The cooling fan relay 2 should be on when the scan tool indicates the FC Relay 2 Command is On. The cooling fan relay 2 should be off when the scan tool indicates the FC Relay 2 Command is Off.

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.