Scan Tool Data Definitions Part 1
Data DefinitionsPart 1
4X Ref. Pulse Counter: Display shows counts from 0 to 255. This is the number of 4X reference pulses between cam pulses. The normal amount of pulses should be 8 with engine running.
Actual EGR Pos: Display shows EGR position in percent from 0 to 100. Actual EGR position represents the linear EGR pintle position signal in percent of travel. 0% displayed indicates a closed EGR valve, EGR flow not allowed.
A/C Relay: Display shows A/C relay On or Off. This display represents the commanded state of the A/C Clutch Control Relay. Clutch should be engaged when On is displayed.
A/C Relay Driver: Display shows OK, Open/Short, Over Current. The PCM monitors output driver (ODM) B #3 for an open or shorted condition if one of the conditions exists the fault line will go low. The scan tool will display the condition that is present.
Air Fuel Ratio: Display shows Air Fuel Ratio from 0 to 1 to 25.5 to 1. Display indicates the air fuel ratio based on oxygen sensor inputs. The PCM uses fuel trims to adjust fueling to attempt to maintain an air fuel ratio of 14.7 to 1.
BARO: Display shows the BARO in kPa from 11 to 105. the BARO reading is taken at key ON and is corrected at wide open throttle (WOT). Multiply your local barometric pressure by 3.386 to obtain a BARO value that should be within 2 kPa of the displayed value.
Calc. Air Flow: The display shows calculated air flow in grams per second from 0 to 511.99. This display indicates the calculated air flow for the second air/fuel transition of the idle catalyst test (P0420).
Calc. Converter Temp: Display shows temperature in degrees C and degrees F from 0°C (32°F) to 765°C (1409°F). This parameter is the PCM calculated temperature of the Three Way Catalyst.
Calculated ECT: The display shows temperature from -40°C to 151°C. This display indicates the predicted coolant temperature the PCM calculates during the Engine Cooling System Performance test (DTC P1483). This display only updates when DTC P1483 is testing.
Catalyst EWMA Samples: The display shows the number of samples from 0 to 255. This display indicates the number of catalyst Exponentially Weighted Moving Average (EWMA) samples that have been completed. The number of samples will reset to 0 if a DTC clear codes or a battery disconnect has occurred. The idle catalyst test requires at least 6 samples to pass but it can fail with less than 6 samples.
Catalyst Test Fail Threshold: The display indicates seconds from -25.6 to + 25.5. This display indicates the passing value for Oxygen Storage content of the exhaust catalyst. This value is used to pass or fail the idle catalyst test (P0420).This display will be fixed at a slightly positive value until DTC P0420 fails. Once failed this value is set to 0.0 seconds until the idle catalyst test (P0420) passes. Although comparing this display to the Catalyst Test Time Difference EWMA may aid in determining if a catalyst is failing always allow the idle catalyst test (DTC P0420) to pass or fail a catalytic converter.
Catalyst Test Time Difference EWMA: The display shows seconds from -25.6 to + 25.5. This display indicates the Oxygen Storage content of the exhaust catalyst. With a properly operating exhaust catalyst the Catalyst Test Time Difference EWMA should always be less than the Catalyst Test Fail Threshold. Although comparing this display to the Catalyst Test Fail Threshold may aid in determining if a catalyst is failing always allow the idle catalyst test (DTC P0420) to Pass or Fail a catalytic converter.
CL Fuel Control Sw. Point O2S: Display shows millivolts from 0 to 1107. This is the oxygen sensor voltage at which closed loop is achieved.
Commanded EGR: Display shows commanded EGR position in percent from 0 to 100. Commanded EGR is the EGR pintle position which is being commanded by the PCM which should be very close to the Actual EGR Pos. display.
Cruise: Display shows cruise state as Disabled or Enabled. If the PCM detects conditions that the vehicle is operating under that cruise should not be allowed, i.e. low vehicle speed, it will send out a signal to disable cruise. If cruise will be allowed it will send out a signal to enable cruise.
Cruise Enable Driver: Display shows OK, Open/Short, Over Current. The PCM monitors output driver (ODM) B #4 for an open or shorted condition if one of the conditions exists the fault line will go Low. The scan tool will display the condition that is present.
Cruise Requested: Display shows No or Yes. The display represents the state of the cruise request input from the Stepper Motor Cruise Control (SMCC) module.
Current Gear: Display shows Current Gear as 1, 2, 3 or 4. This display is the decoded value converted to 1, 2, 3 or 4 from the state of the solenoids, PCM commanded.
Current Octane Level: The display shows 87 to 93. This display indicates the spark advance octane table that the engine is operating in.
Current TWC Test Complete: The display shows No or Yes. This display indicates that at least one pass or fail test decision has been made during the idle catalyst test (P0420). It may take more than one test to obtain a pass or fail decision.
Cycles of Misfire Data: Display shows counts from 0 to 100. Displays which engine cycle of the 100 engine cycle test the PCM is collecting data for P0300.
Delivered Torque Driver: Display shows OK, Open/Short, Over Current. The PCM monitors output driver (ODM) A output #4 for an open or shorted condition if one of the conditions exists the fault line will go low. The scan tool will display the condition that is present.
Desired Idle Speed: Display shows the idle speed that is commanded by the PCM. The PCM will compensate for various engine loads to keep the engine at the desired idle speed from 0 to 2040 RPM.
Desired Torque ABS/TCS: Display shows Desired Torque Level in percent from 0 to 100. The EBTCM sends a Desired Torque Level signal request to the PCM to decrease torque output from the powertrain to reduce wheel slip during acceleration for traction control.
Driver 1: Display shows OK or Fault. This displays the state of ODM #1 output circuits with fault being open or grounded. The output circuits that are monitored are the components connected to PCM connector C2 terminals 30, 31, 32 and 33. Not all terminals may be used depending upon vehicle make and model.
Driver 1 Ground: Display shows OK, Over Voltage, Over Current. This displays the state of ODM #1's input circuit.
Driver 2 Ground: Display shows OK, Over Voltage, Over Current. This displays the state of ODM #2's input circuit.
ECT: Display shows the temperature of the engine coolant from -40° to 215°C and -40° to 419°F
EVAP Canister Purge: Display shows EVAP Purge solenoid in percent from 0 to 100. The evaporative emission purge valve solenoid is a proportional signal used to control the evaporative emission canister purge function. 0% means the valve is commanded fully closed while 100% means that the valve is commanded fully open.
ECT at Start Up: Displays start up ECT in °C/°F. This display is the ECT when engine start up occurred.
EGR Closed Pintle Pos.: Display shows position in volts from 0.0 to 5.00. This display represents the voltage that the PCM has learned as the fully closed EGR valve, 0% pintle position.
EGR Pintle Position: The EGR valve contains a potentiometer type position sensor that provides a voltage proportional to the pintle position. Pintle position is used by the PCM for Closed Loop control of valve pintle position to follow commanded position for diagnostics, and to correct fuel and spark for EGR. This display indicates the actual position of the EGR pintle sensor.
Engine Load: Display shows engine load in percent from 0 to 100. Engine load is calculated by the PCM by engine speed and mass airflow. Reading should increase with an increase in RPM and airflow.
Engine Run Time: Display shows Hours: minutes: seconds. Engine run time measures how long the engine has been running. When the engine is turned OFF, the timer is reset to zero.
Engine Speed: Display shows crankshaft rotation speed in revolutions per minute (RPM) from 0 to 16384.
Engine Speed at Misfire: Display shows RPM at which DTC P0300 was set. When a misfire is detected, the PCM will store the RPM at which the misfire occurred.
Engine Oil Level: Display shows Oil Level OK or Low. The PCM monitors the engine Oil Level during a cold key ON and if the Oil Level switch indicates approximately two quarts below full a message is sent indicating oil is Low. In 1996 model year vehicles this display will indicate what the oil level was indicated at the last cold key ON. In later model year vehicles this display indicates the actual state of the Oil Level circuit/switch.
Engine Oil Life: Display shows Engine Oil Life in percent from 0 to 100. This display represents the Engine Oil Life Index that is calculated and maintained by the PCM.
EVAP Canister Purge: Display shows EVAP Purge solenoid in percent from 0 to 100. The evaporative emission purge valve solenoid is a proportional signal used to control the evaporative emission canister purge function. 0% means the valve is commanded fully closed while 100% means that the valve is commanded fully open.
EVAP Purge Solenoid Driver: Display shows OK, Open/Short, Over Current. The PCM monitors output driver (ODM) A output #5 for an open or shorted condition if one of the conditions exists the fault line will go low. The scan tool will display the condition that is present.
[1][2]EVAP Tank Vacuum Decay Slope: The display shows vacuum decay from 0 to 2 in inches of H2O per second. The vacuum decay slope is used during the PCM's diagnosis of the EVAP system. The PCM will create and hold a vacuum in the EVAP system. The rate at which this stored vacuum is released (the decay slope) determines if a leak is present in the EVAP system.
[1][2]EVAP Test Result: The display indicates the EVAP test result as No Result, Passed, Aborted, Failed - P0440, Failed - P0442, Failed - P0446 or Failed - P01441. This display indicates the test results for the diagnostic tests the PCM performs on the EVAP system. This display is active only during the current ignition cycle. At Key ON the display will indicate No Result until the PCM tests the EVAP system.
[1][2]EVAP Test State: The display shows the EVAP test state as Wait For Purge, Test Running or Test Completed. This display indicates the current state of the PCM's EVAP test or the scan tool's Service Bay Test. Wait For Purge indicates conditions are not correct for sufficient purge flow. Slightly raising engine idle speed may increase purge flow enough to allow the diagnostic tests to start.
[1][2]EVAP Test Abort Reason: The display shows the EVAP test abort reason as Not Aborted, Lost Enable, Small Leak (test timer expired) and Vehicle Not at Rest. This display indicates why the PCM's EVAP test or the scan tool's Service Bay Test was aborted.
[1][2]EVAP Vent Sol. Display shows Open or Closed. This display shows the commanded state of the EVAP Vent Solenoid. The EVAP Vent is normally Open and is only Closed during testing of the EVAP system.
EVAP Vent Valve Driver Display shows Ok, Open/Short or Overvoltage. The PCM monitors the Output Driver Modules for an Open or Shorted condition. This display will indicate the current state of the driver circuit.
Extended Travel Brake: Display shows Released or Applied. This parameter indicates the state of the extended travel brake switch contacts of the torque management brake switch. Scan tool will display Released with the brake pedal released and Applied with the brake pedal applied approximately 40%.
FC Relay 1: Display shows Fan Control Relay state as On or Off. When the PCM is commanding the Fan 1 Relay On, the scan tool display will switch from Off to On.
FC Relay 2 and 3: Display shows Fan Control Relay state as On or Off. When the PCM is commanding the Fan 2 and 3 Relays On, the scan tool display will switch from Off to On.
FP Voltage Feedback: Display shows feedback of 0 to 25.5 volts. FP volt feedback provides information to the PCM about the fuel pump power supply condition through the fuel pump circuit.
Fuel Ctrl. State Bank 1: The display shows Normal, Drive Conditions and Fault. This display when used with the Loop Status display indicates what state of Open or Closed loop the engine is operating. A Fuel Ctrl. State of Driving Conditions (during Open Loop) would indicate the current driving conditions (such as a high throttle angle passing maneuver) is the reason the vehicle is operating in Open Loop.
Fuel Ctrl. State Bank 2: The display shows Normal, Drive Conditions and Fault. This display when used with the Loop Status display indicates what state of Open or Closed loop the engine is operating. A Fuel Ctrl. State of Driving Conditions (during Open Loop) would indicate the current driving conditions (such as a high throttle angle passing maneuver) is the reason the vehicle is operating in Open Loop.
FP Relay: Display shows Fuel Pump Relay as ON or OFF. When the ignition switch is turned to the ON position, the PCM turns the fuel pump relay ON for two seconds. If the PCM does not receive ignition reference pulses within two seconds, the PCM will shut OFF the fuel pump.
Fuel Tank Pressure: The display shows pressure from -17.5 in. H2O to 7.5 in. H2O and from 0 to 5.1 volts. Fuel tank pressure is obtained from the EVAP Pressure sensor. The EVAP Pressure sensor is used during the PCM's diagnosis of the EVAP system. The EVAP Pressure sensor is a sensor that changes resistance based upon fuel tank pressure (or vacuum). A vacuum is considered negative pressure. The PCM provides a 5 volt reference and ground. The EVAP Pressure sensor signal varies between ground and 5 volts as fuel tank pressure varies. As pressure decreases (negative pressure, or vacuum), voltage increases. As pressure increases, voltage decreases (positive pressure, low voltage). The PCM uses the EVAP Pressure sensor values as an indicator of EVAP system efficiency.
Fuel Tank Vapor Press. Slope: The display shows pressure slope from 0 to 2 in inches of H2O per second. The vapor pressure slope is used during the PCM's diagnosis of the EVAP system. The PCM uses pressure slope to determine the amount of vapor pressure being released from the fuel.
Fuel Trim Cell: Display Shows Fuel Trim Cell range from 0 to 16. Fuel trim cell is dependent upon engine speed and mass air flow readings. A plot of RPM vs. MAF is broken into 16 cells. Fuel trim cell indicates which cell is currently active.
Fuel Trim Learn: Display shows Disabled or Enabled. When conditions are appropriate for enabling long term fuel trim corrections, Fuel Trim Learn will display Enabled. This indicates that the long term fuel trim is responding to the short term fuel trim. If the display shows Disabled then long term fuel trim will not respond to changes in short term fuel trim.
Generator PWM: Display shows Generator F Terminal duty cycle in percent from 0 to 100. The generator is able to produce the desired voltage by varying the duty cycle of the field current. At low engine speeds, the field may have a duty cycle of 90 percent. At higher engine speeds, and lower electrical loads, the duty cycle will be less. The generator produces a PWM signal that is monitored by the PCM.
High Elec Load: Display shows Yes or No. Display should show Yes if several accessories are in operation.