Scan Tool Data Definitions Part 2

SCAN TOOL DATA DEFINITIONS

HO2S 2: Scan tool range is 0-1132 mV. Represents the catalyst monitor exhaust oxygen sensor output voltage. If the catalyst is operating efficiently, the heated oxygen sensor (HO2S 1) signal will be far more active than that produced by the HO2S 2 sensor.

HO2S 1 HEATER COMMAND: Scan tool displays ON or OFF. Displays the powertrain control module (PCM) commanded state of the O2 heater.

IAC POSITION: Scan tool range is 0-255 Counts. Displays the commanded position of the idle air control pintle in counts. A larger number of counts means that more air is being commanded through the idle air passage. Idle air control (IAC) position should respond fairly quickly to changes in engine load to maintain desired idle RPM.

IAT SENSOR: Scan tool range is -40°C to +151°C (-40°F to +304°F). The powertrain control module (PCM) converts the resistance of the intake air temperature sensor to degrees.

IGNITION 1 SIGNAL: Scan tool displays 0-25.5 volts. The ignition 1 represents the system voltage measured by the powertrain control module (PCM) at its ignition feed.

IGNITION MODE: Scan tool displays Bypass/IC. Bypass indicates the ignition control (IC) module is keeping the spark advance at a fixed 10 degrees before top dead center (BTDC). Ignition control (IC) indicates that the powertrain control module (PCM) has signaled the ignition module that the PCM is going to control the spark advance.

INJECTOR PWM: Scan tool range is 0-1000 ms. Indicates the amount of time the powertrain control module (PCM) is commanding each injector ON during each engine cycle. A longer injector pulse width will cause more fuel to be delivered. Injector pulse width should increase with increased engine load.

KNOCK RETARD: Scan tool range is 0.0-25.5 degrees. Indicates the amount of spark the powertrain control module (PCM) is removing from ignition control (IC) spark advance in response to the signal from the knock sensors.

LONG TERM FT: Scan tool range is -23 to +16 percent. Long term fuel trim is derived from the short term fuel trim value and represents a long term correction of fuel delivery. A value of 0 percent indicates that fuel delivery requires no compensation to maintain the powertrain control module (PCM) commanded air/fuel ratio. A negative value significantly below 0 percent indicates that the fuel system is rich and fuel delivery is being reduced. A positive value significantly more than 0 percent indicates that a lean condition exists and the PCM is compensating by adding fuel.

LOOP STATUS: Scan tool displays OPEN or CLOSED. Closed Loop indicates that the powertrain control module (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 throttle position (TP) sensor, engine coolant temperature (ECT), and MAF sensor inputs only.

MAF SENSOR: Scan tool range is 0.0-512 g/s. Mass air flow (MAF) is the MAF input frequency converted to grams of air per second. This indicates the amount of air entering the engine.

MAF SENSOR: Scan tool range is 0-32000 Hz. The mass air flow sensor input signal to the powertrain control module (PCM) is a frequency which varies from around 3000 Hz at idle to above 7000 Hz at wide open throttle (WOT). The PCM converts this frequency signal to grams per second to be displayed as mass air flow.

MAP SENSOR: Scan tool range is 10-105 kPa (0.00-4.97 volts). The manifold absolute pressure (MAP) sensor measures the change in the intake manifold pressure from engine load, exhaust gas recirculation (EGR) flow, and speed changes. As intake manifold pressure increases, intake vacuum decreases resulting in a higher MAP sensor voltage and kPa reading. The MAP sensor signal is used to monitor intake manifold pressure changes during the EGR flow test, to update the barometric pressure (BARO) reading, and as an enabling factor for several of the diagnostics.

MIL CIRCUIT STATUS: Scan tool displays Fault or OK. This parameter indicates the state of the driver circuit for this device.

MIL COMMAND: Scan tool displays ON or OFF. Indicates the powertrain control module (PCM) commanded state of the malfunction indicator lamp (MIL).

MISFIRE CURRENT CYL #1/MISFIRE CURRENT CYL #2/MISFIRE CURRENT CYL #3/MISFIRE CURRENT CYL #4/MISFIRE CURRENT CYL #5/MISFIRE CURRENT CYL #6: Scan tool range is 0-198 Counts. The misfire current counters indicate the number of cylinder firing events detected as possible misfires on each cylinder during the last 200 crankshaft revolutions. The number that the counters display are twice the actual number of misfire events detected. The counters may normally display some activity, but the activity should be very low and nearly equal for all the cylinders.

MISFIRE HISTORY CYL #1/MISFIRE HISTORY CYL #2/MISFIRE HISTORY CYL #3/MISFIRE HISTORY CYL #4/MISFIRE HISTORY CYL #5/MISFIRE HISTORY CYL #6: Scan tool range is 0-65535 Counts. The misfire history counters indicate the total level of misfire that has been detected on each cylinder. The number that the counters display are twice the actual number of misfire events detected. The misfire history counters will not update or show any activity until a misfire DTC P0300 has become active. The misfire history counters will be updated every time a 200 crankshaft revolution misfire test failure is detected.

NUMBER OF DTCs: Scan tool displays number. This parameter displays the quantity of active diagnostic trouble codes (DTCs).

O2 HEATER CURRENT: Scan tool displays Amps. The scan tool displays heated oxygen sensor (HO2S) heater current in amps. This parameter displays the current draw of the HO2S 1 heater only. Typically, the HO2S heater current stabilizes at about 0.50-0.60 A after operating temperature is reached. Initial current draw is slightly higher.

PCM/VCM IN VTD FAIL ENABLE: Scan tool displays YES or NO, if applicable. The theft deterrent fuel enable is an input from the vehicle theft deterrent system that signals the powertrain control module (PCM) to enable the injectors and the crank relay if the proper signal is received. The scan tool will normally display INACTIVE. If the vehicle theft deterrent system does not send the correct theft deterrent fuel enable signal to the PCM, the display will switch to ACTIVE and the fuel system and starter control may be disabled. Refer to vehicle theft deterrent diagnosis for further information.

PCM RESET: The scan tool displays Yes or No. This parameter indicates when the internal powertrain control module (PCM) resets. The scan tool displays YES when an internal PCM reset occurred. The scan tool displays NO under the normal operating conditions.

POWER ENRICHMENT: The scan tool displays ACTIVE or INACTIVE. ACTIVE displayed indicates that the powertrain control module (PCM) has detected conditions appropriate to operate in Power Enrichment mode. The PCM will command Power Enrichment mode when a large increase in throttle position and load is detected.

SHORT TERM FT: The scan tool range is -10 percent to +10 percent. This short term fuel trim represents a short term correction to fuel delivery by the powertrain control module (PCM) in response to the amount of time the fuel control oxygen sensor voltage spends above or below the 450 mV threshold.

SPARK: The scan tool range is -64 to +64 degrees. Displays the spark timing being commanded by the powertrain control module (PCM) on the ignition control (IC) circuit. A negative (-) value indicates degrees before top dead center (BTDC) or spark advance. A positive value indicates degrees after top dead center (ATDC) or spark retard.

START-UP ECT: The scan tool range is -40°C to +151°C (-40°F to +304°F). This indicates the engine coolant temperature at the time that the vehicle was started.

START-UP IAT: The scan tool range is -40°C to +151°C (-40°F to +304°F). This indicates the intake air temperature (IAT) at the time that the vehicle was started.

STARTER ENABLE RELAY CIRCUIT STATUS: The scan tool displays Fault / OK. This parameter indicates the state of the driver circuit for this device.

STARTER RELAY COMMAND: This scan tool displays ON or OFF. OFF indicates that the powertrain control module (PCM) is not allowing starter operation due to the engine running, excessive cranking time, trans not in P/N, or other factors.

TCC BRAKE PEDAL SWITCH: The scan tool displays RELEASED or APPLIED. This input to the powertrain control module (PCM) represents the state of the vehicle brake pedal. When the brake switch indicates that the brake pedal is APPLIED, the PCM will command the transaxle torque converter clutch to disengage.

TCC PWM SOLENOID COMMAND: The scan tool displays ON or OFF. This indicates the commanded state of the transaxle torque converter clutch (TCC).

TFP SW: The scan tool displays PARK/NEUTRAL, REVERSE, DRIVE 4, DRIVE 3, DRIVE 2, or LOW. This trans range represents the decoded status of the four inputs from the transaxle internal mode switch assembly. The combination of transaxle inputs indicates the position of the transaxle manual valve.

TORQUE DELIVERED SIGNAL: This scan tool range is 0-100 percent. This parameter indicates the amount of available engine torque.

TORQUE REQUEST SIGNAL: The scan tool range is 0-100 percent. This parameter indicates the desired amount of torque requested by the electronic brake and traction control module (EBTCM).

TP SENSOR: The scan tool range is 0-100 percent or 0.00-5.00 volts. The voltage being monitored by the powertrain control module (PCM) on the throttle position (TP) sensor signal circuit.

TRACTION CONTROL STATUS: The scan tool displays Active or Inactive. The scan tool displays active if the powertrain control module (PCM) receives a signal from the electronic brake and traction control module (EBTCM ) requesting torque reduction during a traction control event.

VEHICLE SPEED SENSOR: The scan tool range is 0-255 km/h (0-155 mph). The vehicle speed sensor signal is converted into mph and km/h for display.

VTD AUTO LEARN TIMER: The scan tool displays ACTIVE or INACTIVE. The auto learn timer is the indication if the vehicle theft deterrent (VTD) system is in the learn mode and has not timed out.

VTD FUEL DISABLE: The scan tool displays ACTIVE or INACTIVE, if applicable. The theft deterrent fuel enable is an input from the vehicle theft deterrent system that signals the powertrain control module (PCM) to enable the injectors and the crank relay if the proper signal is received. The scan tool will normally display INACTIVE. If the vehicle theft deterrent system does not send the correct theft deterrent fuel enable signal to the PCM, the display will switch to ACTIVE and the fuel system and starter control may be disabled. Refer to vehicle theft deterrent diagnosis for further information.

VTD FUEL DISABLE UNTIL IGN. OFF: The scan tool displays Yes or NO. With the ignition ON and a vehicle theft deterrent (VTD) code present, the scan tool displays Yes.