Scan Tool Data Definitions Part 1
ENGINE SCAN TOOL DATA DEFINITIONSEngine Speed: Display shows crankshaft rotation speed in revolutions per minute (RPM) from 0 to 16384.
Desired Idle: 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.
MAF: Display shows the amount of airflow entering the engine in grams per second (g/s) from 0 to 655. The scan tool will display 0 gms/sec only until 4X reference pulses are received cranking or running. The PCM updates the MAF sensor display only after 4X reference pulses have been received during an ignition cycle. If during an ignition cycle the vehicle were to stall the MAF display would indicate the last airflow reading obtained while 4X reference pulses were present. If no airflow is monitored by the PCM while the vehicle is running the MAF display will default to 1.2 grams per second.
TP Sensor: Display shows the amount of throttle opening in volts, with closed throttle near 0 volts and wide open throttle above 4.0 volts.
ECT: Display shows the temperature of the engine coolant from -40° to 215°C and -40° to 419°F.
IAT: Display shows the temperature of the intake manifold air from -40° to 215°C and -40° to 419°F.
MAP: Display shows manifold pressure in Kilo Pascal[prime ]s (kPa) from 10 to 105. At key ON ,engine not running, the MAP value will reflect barometric pressure.To check for an accurate MAP reading multiply your local barometric pressure by 3.386 to obtain a map value that should be within 2 kPa of displayed value at key ON engine not running.
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.
TPS Normalized: Display shows percent and degrees from 0 to 100 percent and 0.0 to 81.6 degrees. The PCM will compensate for deposits in the throttle body by learning the closed throttle position as zero percent and zero degrees.
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.
IAC Position: Display shows the commanded IAC pintle position in counts from 0 to 1024. The higher the number of counts, the greater the commanded idle speed. Zero is the fully seated position. Idle air control should respond fairly quickly to changes in engine load to maintain desired idle RPM.
Injector PWM Bank 1: Display shows injector pulse width for cylinders 1, 3, 5, 7 in milliseconds (ms) from 0 to 99.6.
HO2S Bn 1 Sen. 1: Display shows bank 1 sensor 1 HO2S voltage from 0 to 1.16.
Injector PWM Bank 2: Display shows injector pulse width for cylinders 2, 4, 6, 8 in milliseconds (ms) from 0 to 99.6.
HO2S Bn 2 Sen. 1: Display shows bank 2 sensor 1 HO2S voltage from 0 to 1.16.
Rich to Lean Status Bn 1 Sen 1: Display shows HO2S bank 1 sensor 1 RICH or LEAN which indicates whether oxygen sensor voltage is above, rich, or below, lean, bias voltage. Display should change constantly, indicating that the PCM is controlling bank 1 air/fuel mixture.
Rich to Lean Status Bn 2 Sen 1: Display shows HO2S bank 2 sensor 1 RICH or LEAN which indicates whether oxygen sensor voltage is above, rich, or below, lean, bias voltage. Display should change constantly, indicating that the PCM is controlling bank 2 air/fuel mixture.
HO2S Bn 1 Sen. 2: Display shows bank 1 sensor 2 HO2S voltage from 0 to 1.16.
HO2S Bn 1 Sen. 3: Display shows bank 1 sensor 3 HO2S voltage from 0 to 1.16.
Rich to Lean Status Bn 1 Sen 2: Display shows Rich or Lean. This represents the first HO2S in the catalyst monitor. Display should change constantly while in closed loop.
Rich to Lean Status Bn 1 Sen 3: Display shows Rich or Lean. This represents the second HO2S in the catalyst monitor. Display should change much slower when compared to Bank 1 Sensor 2 indicating the catalyst is operating efficiently.
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.
Shrt Term FT Bn 1: Display shows counts from 0 to 255 and percentage from -100% to 99%. The normal position for the short term fuel trim is 128 counts or 0%. A count greater than 128 or a percentage greater than 0% indicates that time is being added to the injector pulse width, increasing the amount of fuel to the engine to compensate for a lean condition sensed by the bank 1 (rear) HO2S. A count less than 128 or less than 0% indicates time is being subtracted from the injector pulse width reducing the amount of fuel to the engine to compensate for a rich condition sensed at the bank 1 (rear) HO2S.
Long Term FT Bn 1: Display shows counts from 0 to 255 and percentage from -100% to 99%. The normal position for the long term fuel trim is 128 counts or 0%. The long term fuel trim is based on short term fuel trim learned values. It is stored in memory blocks of the long term memory according to MAP and RPM values. A count greater than 128 or a percentage greater than 0% indicates that time is being added to the injector pulse width, increasing the amount of fuel to the engine. A count less than 128 or a percentage less than 0% indicates time is being subtracted from the injector pulse width, reducing the amount fuel to the engine.
Shrt Term FT Bn 2: Display shows counts from 0 to 255 and percentage from -100% to 99%. The normal position for the short term fuel trim is 128 counts or 0%. A count greater than 128 or a percentage greater than 0% indicates that time is being added to the injector pulse width, increasing the amount of fuel to the engine to compensate for a lean condition sensed by the bank 1 (rear) HO2S. A count less than 128 or less than 0% indicates time is being subtracted from the injector pulse width reducing the amount of fuel to the engine to compensate for a rich condition sensed at the bank 2 (front) HO2S.
Long Term FT Bn 2: Display shows counts from 0 to 255 and percentage from -100% to 99%. The normal position for the long term fuel trim is 128 counts or 0%. The long term fuel trim is based on short term fuel trim learned values. It is stored in memory blocks of the long term memory according to MAP and RPM values. A count greater than 128 or a percentage greater than 0% indicates that time is being added to the injector pulse width, increasing the amount of fuel to the engine. A count less than 128 or a percentage less than 0% indicates time is being subtracted from the injector pulse width, reducing the amount fuel to the engine.
Loop Status: Display shows OPEN LOOP or CLOSED LOOP Closed Loop displayed indicates that the PCM is controlling fuel delivery according to oxygen sensor voltage. In Open Loop, the PCM ignores the oxygen sensor voltage and bases the amount of fuel to be delivered on other input sensors. Closed Loop operation should begin when the oxygen sensor becomes active, engine coolant temperature exceeds 5°C (41°F) for more than 30 seconds and the PCM has seen a RPM of 1200 or greater for 10 seconds. At extremely high ambient temperatures or when towing a trailer, it is possible for the system to remain in Open Loop operation to control catalytic converter temperatures.
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.
MIL: Display shows ON or OFF. The MIL (Service Engine Soon) is controlled by the PCM and is used to indicate that the PCM has detected a problem that affects vehicle emissions, driveability or could cause powertrain damage.
Ignition 1: Display shows voltage from 0 to 25.5. This represents the system voltage measured by the PCM at its ignition feed.
High Elec Load: Display shows Yes or No. Display should show Yes if several accessories are in operation.
Gen. F Terminal: 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.
Gen. L Terminal: Display shows Off or On. The PCM monitors terminal L, that the PCM is supplying with 12 volts, to the generator voltage regulator to initiate the generator charging mode and to enable the generator self-energizing operation after the engine is running.
Knock Retard: Display shows knock retard from 0 to 45 degrees. Which indicates the amount of spark advance in degrees that the PCM is removing from the Ignition Control (IC) in response to the Knock Sensor (KS) signal.
FP Volt 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 relay or the oil pressure switch/sensor.