Scan Tool Data Definitions

The Scan Tool Data Definitions list contains a brief description of all of the engine related parameters that are 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.

5 Volt Reference 1: This parameter displays the output voltage from the 5-volt reference circuit from the control module. This parameter only supports one 5-volt reference output from the control module.
A/C High Side Pressure Sensor: This parameter displays the voltage from the A/C high side pressure sensor signal circuit to the control module.
A/C High Side Pressure Sensor: This parameter displays the pressure from the A/C high side pressure sensor signal circuit to the control module.
A/C Relay Command: This parameter displays the state of the air conditioning (A/C) clutch relay control circuit as commanded by the control module.
A/C Request Signal: This parameter displays the state of the air conditioning (A/C) request input to the control module from the heating, ventilation, and air conditioning (HVAC) controls.
Air Flow Calculated: This parameter displays the calculated air flow into the engine that is based on manifold absolute pressure. The calculation is used in several diagnostics to determine when to run the diagnostics.
Air Fuel Ratio: This parameter displays the air to fuel ratio based on the oxygen sensor inputs. The ECM uses the fuel trims to adjust fueling in order to attempt to maintain an air fuel ratio of 14.7:1.
BARO: This parameter displays the barometric pressure. The control module uses the manifold absolute pressure sensor to determine the barometric pressure. The control module uses the barometric pressure for fuel control to compensate for altitude differences.
Catalytic Converter Protection Active: This parameter displays if the control module is commanding catalytic converter protection.
CMP Active Counter: This parameter displays the CMP active counts. If the control module does not detect a signal from the CMP sensor, the counter will not increment.
Coolant Hot Lamp (If Equipped): This parameter displays the control modules commanded state of the hot mode lamp.
Decel Fuel Cutoff: This parameter displays the status of the operating mode of the control module used to turn off the fuel injectors during certain deceleration conditions.
Desired EGR Position: This parameter displays the desired EGR position as commanded by the control module.
Desired IAC Position: This parameter displays the desired IAC position as commanded by the control module.
Desired Idle Speed: This parameter displays the desired engine idle speed as commanded by the control module.
ECT Sensor: This parameter displays the temperature of the engine coolant based on input to the control module from the engine coolant temperature (ECT) sensor.
Engine Load: This parameter displays the calculated engine load in percent based on inputs to the control module from various engine sensors.
EGR Flow Test Count: This parameter displays the number of EGR flow test samples collected during the current ignition cycle.
EGR Learned Minimum: This parameter displays the learned minimum value of the EGR valve as recorded by the control module during the last learn procedure.
EGR Position Sensor: This parameter displays the EGR pintle position in percent of range as commanded by the control module.
EGR Position Sensor: This parameter displays the actual EGR pintle position in volts.
EGR Position Variance: This parameter displays the difference between the actual command of the EGR valve to the desired position of the EGR valve.
EGR Solenoid Command: This parameter displays the state of the control circuit for EGR solenoid as commanded by the control module.
Engine Load: This parameter displays the calculated engine load in percent based on inputs to the control module from various engine sensors.
Engine Run Time: This parameter displays the time elapsed since the engine was started.
Engine Speed: This parameter displays the speed of the engine crankshaft rotation from information received from the crankshaft position (CKP) sensor.
EVAP Purge Solenoid Command (If Equipped): This parameter displays the on-time or duty cycle of the EVAP canister purge solenoid commanded by the control module. Zero percent indicates no purge. One hundred percent indicates full purge.
EVAP Vent Solenoid Command (If Equipped): This parameter displays the state of the control circuit for evaporative emission (EVAP) vent solenoid as commanded by the control module.
Fail Counter: This parameter displays the number of times a DTC failed.
Fans High Speed: This parameter displays the control module commanded state of the fan relay control circuit.
Fans Low Speed: This parameter displays the control module commanded state of the fan relay control circuit.
Fuel Level to Cluster: This parameter displays the fuel level gage position in percent of range as commanded by the control module.
Fuel Level Sensor: This parameter displays the voltage signal received by the control module from the fuel level sensor.
Fuel Level Sensor: This parameter displays the percentage signal received by the control module from the fuel level sensor.
Fuel Pump Relay Command: This parameter displays the control modules commanded state of the fuel pump relay control circuit.
Fuel Tank Pressure Sensor (If Equipped): This parameter displays the pressure/vacuum inside the fuel tank. A negative value indicates a vacuum, while a positive value indicates a pressure.
Fuel Tank Pressure Sensor (If Equipped): This parameter displays the voltage signal received by the control module from the fuel tank pressure (FTP) sensor.
Fuel Trim Cell: This parameter displays what fuel trim cell that is currently active.
Fuel Trim Learn: This parameter displays Enabled when conditions are appropriate for enabling long term fuel trim corrections. This indicates that the long term fuel trim is adapting continuing amounts of short term fuel trim. If the scan tool displays Disabled, then long term fuel trim will not respond to changes in short term fuel trim.
O2S/HO2S 1: This parameter displays the voltage output from the HO2S to the control module. A lower voltage indicates a lean exhaust, while a higher voltage indicates a rich exhaust.
O2S/HO2S 1 Ready: This parameter displays that the HO2S 1 is at operating temperature.
O2S/HO2S 2: This parameter displays the voltage output from the HO2S to the control module. A lower voltage indicates a lean exhaust, while a higher voltage indicates a rich exhaust.
IAC Position: This parameter displays the ECM command for the idle air control (IAC) pintle position in counts. The higher the number of counts, the greater the commanded idle speed reads. The idle air control responds to changes in the engine load in order to maintain the desired idle RPM.
IAT Sensor: This parameter displays the temperature of the air entering the air induction system based on input to the control module from the intake air temperature (IAT) sensor.
Ignition 1 Signal: This parameter displays On when the control module detects a voltage at the ignition 1 input terminal.
IMT Valve Command (If Equipped): This parameter displays the control modules commanded state of the IMRC solenoid.
Injector PWM: This parameter displays the average pulse width of the fuel injectors as determined by the control module.
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.
KS Active Counter: This parameters displays the number of times the control module detects activity from the knock sensor.
Long Term FT: This parameter displays the commanded Long Term Fuel Trim correction by the control module.
Long Term FT Avg.: This parameter displays percentage. This parameter indicates the average of the long term fuel trim cells The long fuel trim cells are rated, or weighted for the amount of which they are used. For example, the control module rates an idle cell higher then a wide open cell. If a fueling malfunction occurs in the idle cell and the wide open, the idle cell would effect more than the wide open cell. If the oxygen sensor indicates a lean air/fuel mixture, the control module will add fuel increasing the long term fuel trim above 0. If the oxygen sensor indicates a rich air/fuel mixture, the control module will reduce fuel decreasing the long term fuel trim below 0.
Long Term FT Average: This parameter displays the average Long Term Fuel Trim correction by the control module.
Loop Status: This parameter displays the state of the fuel control system as commanded by the control module. Closed Loop operation indicates that the control module is controlling the fuel delivery based off the oxygen sensors input signal. In Open Loop operation the control module ignores the oxygen sensor input signal and bases the amount of fuel to be delivered on other sensor inputs.
Low Fuel Lamp Command (If Equipped): This parameter displays the control modules commanded state of the low fuel lamp.
MAP Sensor: This parameter displays the pressure from the manifold absolute pressure (MAP) sensor to the control module.
MAP Sensor: This parameter displays the signal voltage from the manifold absolute pressure (MAP) sensor to the control module.
MIL Command: This parameter displays the commanded state of the malfunction indicator lamp (MIL) control circuit by the control module.
Mileage Since First Failure: This parameter displays the mileage that has elapsed since the first emission failure.
Mileage Since Last Failure: This parameter displays the mileage that has elapsed since the last emission failure.
Misfire Current Cyl. 1-4: This parameter displays the number of misfires that have been detected during the last 200 cylinder firing events. The counters may normally display some activity, but the activity should be nearly equal for all of the cylinders, and in low numbers.
Misfire History Cyl. 1-4: The misfire history counters display the total level of misfire that has been detected on each cylinder. The misfire history counters will not update or show any activity until a misfire DTC P0300 has become active. The misfire history counters will update every 200 cylinder firing events.
Not Run Counter: This parameter displays the number of times a DTC does not run.
Pass Counter: This parameter displays the number of times a DTC passed.
PNP Switch: This parameter displays whether the transmission range selector is in park/neutral or in gear.
Power Enrichment: This parameter displays the status of the operating mode of the control module used to increase fuel delivery during certain acceleration conditions.
Power Steering Switch (If Equipped): This parameter displays the state of the power steering pressure switch.
Rich/Lean to Lean/Rich Ratio Sensor 1: This parameter displays the oxygen sensor rich/lean to lean/rich ratio. The rich/lean average is divided by the lean/rich average in order to determine the oxygen sensor ratio.
Rich/Lean Transition Sensor 1: This parameter displays the oxygen sensor rich/lean and lean/rich switches. A switch is when the oxygen sensor voltage goes above 450 mV and below 450 mV.
Rough Road Sensor (If Equipped): This parameter displays the voltage from the rough road sensor.
Short Term FT Avg.: This parameter displays percentage. This parameter indicates the average of the short term fuel trim cells The short fuel trim cells are rated, or weighted for the amount of which they are used. For example, the control module rates an idle cell higher then a wide open cell. If a fueling malfunction occurs in the idle cell and the wide open, the idle cell would effect more than the wide open cell. If the oxygen sensor indicates a lean air/fuel mixture, the control module will add fuel increasing the short term fuel trim above 0. If the oxygen sensor indicates a rich air/fuel mixture, the control module will reduce fuel decreasing the short term fuel trim below 0.
Short Term FT: This parameter displays the short-term correction to the fuel delivery by the control module in response to the oxygen sensor. If the oxygen sensor indicates a lean air/fuel mixture, the control module will add fuel increasing the short term fuel trim above 0. If the oxygen sensor indicates a rich air/fuel mixture, the control module will reduce fuel decreasing the short term fuel trim below 0.
Spark: This parameter displays the amount of spark advance the control module is commanding on the ignition control circuits. The control module determines the desired advance.
Start Up ECT: This parameter displays the temperature of the engine coolant on start up based on input to the control module from the ECT sensor.
Start Up IAT: This parameter displays the temperature of the intake air at start in the air induction system based on input to the control module from the IAT sensor.
SVS Lamp Command (If Equipped): This parameter displays the control modules commanded state of the service vehicle soon lamp.
TCC Enable Solenoid Command (If Equipped): This parameter displays the control module commanded state of the TCC solenoid.
Total Fuel Trim Average: This parameter displays the overall fuel trim from all the fuel trim cells.
Total Misfire: This parameter displays the total number of cylinder firing events that the control module detected as misfires for the last 200 crankshaft revolution sample period.
TP Sensor: This parameter displays the percent of throttle opening as calculated by the control module using information from the TP sensor.
TP Sensor: This parameter displays the actual voltage on the TP sensor signal circuit as measured by the control module.
TWC Temperature Calculated: This parameter displays the catalytic converter temperature as calculated by the control module.
Vehicle Security Status (If Equipped): This parameter displays the status of the vehicle theft deterrent system. The normal parameter display for the theft deterrent system is Disabled. If a condition exists with the theft deterrent system the parameter will display Enabled and the vehicle will not start.
Vehicle Speed Sensor: This parameter displays the speed of the vehicle as calculated by the control module from information received from the vehicle speed sensor (VSS).