Operation CHARM: Car repair manuals for everyone.

Part 3



Scan Tool Data Definitions

Misfire History Cyl. #1
- This parameter displays the number of possible misfires that have occurred after 195 current misfires have been counted on Cylinder 1 as calculated by the control module. The misfires are calculated based on engine crankshaft rotation speed variations. The scan tool displays an incrementing counter. This counter should display some activity, but the activity should be the same for all cylinders.

Misfire History Cyl. #2
- This parameter displays the number of possible misfires that have occurred after 195 current misfires have been counted on Cylinder 2 as calculated by the control module. The misfires are calculated based on engine crankshaft rotation speed variations. The scan tool displays an incrementing counter. This counter should display some activity, but the activity should be the same for all cylinders.

Misfire History Cyl. #3
- This parameter displays the number of possible misfires that have occurred after 195 current misfires have been counted on Cylinder 3 as calculated by the control module. The misfires are calculated based on engine crankshaft rotation speed variations. The scan tool displays an incrementing counter. This counter should display some activity, but the activity should be the same for all cylinders.

Misfire History Cyl. #4
- This parameter displays the number of possible misfires that have occurred after 195 current misfires have been counted on Cylinder 4 as calculated by the control module. The misfires are calculated based on engine crankshaft rotation speed variations. The scan tool displays an incrementing counter. This counter should display some activity, but the activity should be the same for all cylinders.

Misfire History Cyl. #5
- This parameter displays the number of possible misfires that have occurred after 195 current misfires have been counted on Cylinder 5 as calculated by the control module. The misfires are calculated based on engine crankshaft rotation speed variations. The scan tool displays an incrementing counter. This counter should display some activity, but the activity should be the same for all cylinders.

Misfire History Cyl. #6
- This parameter displays the number of possible misfires that have occurred after 195 current misfires have been counted on Cylinder 6 as calculated by the control module. The misfires are calculated based on engine crankshaft rotation speed variations. The scan tool displays an incrementing counter. This counter should display some activity, but the activity should be the same for all cylinders.

Misfire History Cyl. #7
- This parameter displays the number of possible misfires that have occurred after 195 current misfires have been counted on Cylinder 7 as calculated by the control module. The misfires are calculated based on engine crankshaft rotation speed variations. The scan tool displays an incrementing counter. This counter should display some activity, but the activity should be the same for all cylinders.

Misfire History Cyl. #8
- This parameter displays the number of possible misfires that have occurred after 195 current misfires have been counted on Cylinder 8 as calculated by the control module. The misfires are calculated based on engine crankshaft rotation speed variations. The scan tool displays an incrementing counter. This counter should display some activity, but the activity should be the same for all cylinders.

Power Enrichment
- This parameter indicates if the control module has detected conditions appropriate to operate in Power Enrichment mode. The scan tool will display Active if the mode is in operation, and Inactive if the mode is not in operation. The control module enters Open Loop operation and increases injector pulse width when in power enrichment mode.

Reduced Engine Power
- This parameter indicates if the control module has detected that a TAC system fault has occurred. The scan tool will display Active if the mode is in operation, and Inactive if the mode is not in operation. The control module limits engine power when this mode is Active.

Short Term FT Bank 1
- This parameter displays the short term correction to fuel delivery for bank 1 by the control module in response to the amount of time the oxygen sensor voltage spends above or below the 450 mV threshold. The scan tool will display 0 percent if no adjustments are required. The scan tool will display a higher positive value if fuel has to be added, and a higher negative value if fuel has to be removed.

Short Term FT Bank 2
- This parameter displays the short term correction to fuel delivery for bank 2 by the control module in response to the amount of time the oxygen sensor voltage spends above or below the 450 mV threshold. The scan tool will display 0 percent if no adjustments are required. The scan tool will display a higher positive value if fuel has to be added, and a higher negative value if fuel has to be removed.

Short Term FT Test Avg. Bank 1 or Bank 2
- This parameter is calculated by the control module based on an intrusive test by the control module. The Short Term FT Test Average used for the short term correction of the fuel delivery in each bank. The scan tool will display a high value for a large amount of short term fuel correction, and 0% for no short term fuel trim correction. The scan tool will display a negative value when fuel system is running too rich and fuel is being removed from the combustion event. The scan tool will display a positive value if the fuel system is running lean and fuel is being added to the combustion event.

Spark
- This parameter displays the spark timing being commanded by the control module on the IC circuit. The scan tool will display a negative value if the spark timing is before top dead center (BTDC) or spark advance; the scan tool will display a positive value if the spark timing is after top dead center (ATDC) or spark retard. Because the ignition control module sets spark advance at a fixed value BTDC while operating in bypass mode, the displayed spark advance only reflects true spark timing when the PCM has commanded IC mode.

Start Up ECT
- This parameter Indicates the engine coolant temperature at engine start up as calculated by the control module based on the signal from the ECT sensor. The scan tool will display a higher value on a warmer engine, and a lower value on a colder engine.

Start Up IAT
- This parameter Indicates the intake air temperature at engine start up as calculated by the control module based on the signal from the IAT sensor. The scan tool will display a higher value during warmer underhood temperatures, and a lower value during colder underhood temperatures.

TAC Forced Engine Shutdown
- This parameter indicates the status of TAC control by the control module. The scan tool will display YES if the engine has been shut down due to a throttle control fault. The scan tool will display NO if the engine has not been shut down by a throttle control fault.

TAC Motor
- This parameter indicates the status of the TAC motor driver by the ECM. The scan tool will display Enabled if TAC motor operation is allowed. The scan tool will display disabled if the TAC motor is disabled.

TAC Motor Command
- This parameter indicates the required duty cycle to maintain a desired throttle position. The scan tool will display a higher value if more effort is required to move the throttle to the desired position, such as physical resistance. The scan tool will display a lower value if less effort is required to move the throttle to the desired position.

TCS Torque Request Signal
- This parameter indicates the percentage of available torque requested from the engine to the transmission as calculated by the control module. The scan tool will display a higher value for higher torque, and a lower value for lower torque.

TCS Torque Request Signal
- This parameter indicates the torque requested from the engine to the transmission as calculated by the control module. The scan tool will display a higher value for higher torque, and a lower value for lower torque.

Torque Delivered Signal
- This parameter indicates the torque delivered from the engine to the transmission as calculated by the control module. The scan tool will display a higher value for higher torque, and a lower value for lower torque.

Torque Management Spark Retard
- This parameter indicates how much the ignition spark timing is being retarded to control torque by the control module. The scan tool will display a higher value under extreme torque control conditions such as spinning wheels. The scan tool will display a lower value under low torque control conditions such as light driving.

Total Knock Retard
- This parameter indicates how much ignition spark timing is being retarded due to all control systems monitored by the control module. The scan tool will display a high value during extreme conditions such as high temperatures and antilock braking. The scan tool will display a lower value during lighter driving conditions.

Total Misfire
- This parameter displays the number of possible misfires during the last 200 cylinder firing events detected on all cylinders as calculated by the control module. The misfires are calculated based on engine crankshaft rotation speed variations. The scan tool displays an incrementing counter.

TP Desired Angle
- This parameter indicates the desired throttle angle calculated by the TAC module as commanded by the vehicle operator. The scan tool will display a higher value when the accelerator pedal is depressed, and a lower value as the accelerator pedal is released.

TP Indicated Angle
- This parameter displays the angle of the throttle plate as calculated by the control module using the signals from the throttle position (TP) sensor(s). The TP indicated angle is a range of values indicating a low percentage when the throttle is closed to a high percentage when the throttle is wide open.

TP Performance Test
- This parameter displays the status of the TP performance test by the control module. The scan tool will display OK if no fault is found. The scan tool will display Fault if the control module detects a fault during the test.

TP Sensor 1 Learned Min.
- This parameter displays the learned minimum voltage for TP sensor 1 as determined by the control module this ignition cycle.

TP Sensor 2 Learned Min.
- This parameter displays the learned minimum voltage for TP sensor 2 as determined by the control module this ignition cycle.

TP Sensor 1
- This parameter displays the voltage signal sent to the control module from TP sensor 1 of the throttle assembly. The TP sensor 1 is a range of values indicating a high voltage when the throttle is closed to a low voltage when the throttle plate is fully open.

TP Sensor 1 Indicated Position
- This parameter displays the angle of the throttle position (TP) sensor 1 as calculated by the control module using the signal from the TP sensor 1. The TP sensor 1 is a range of values indicating a low percentage when the throttle is closed to a high percentage when the throttle is fully open.

TP Sensor 2
- This parameter displays the voltage signal sent to the control module from TP sensor 2 of the throttle assembly. The TP sensor 2 is a range of values indicating a low voltage when the throttle is closed to a high voltage when the throttle plate is fully open.

TP Sensor 2 Indicated Position
- This parameter displays the angle of the TP sensor 2 as calculated by the control module using the signal from the TP sensor 2. The TP sensor 2 is a range of values indicating a low percentage when the throttle is closed to a high percentage when the throttle is fully open.

TP Sensors 1 and 2
- This parameter displays the results of a control module test that compares the signals from the TP sensors 1 and 2. The scan tool will display Agree or Disagree. Agree indicates that TP sensor 1 and TP sensor 2 voltages correspond to the same throttle position. Disagree indicates that TP sensor 1 and TP sensor 2 voltages correspond to different throttle positions.

Vehicle Speed Sensor
- This parameter indicates the vehicle speed as calculated by the control module based on a signal from the vehicle speed sensor (VSS). The scan tool will display a higher value at higher vehicle speeds, and a lower value at lower vehicle speeds.

Warm-ups Since DTC Cleared
- This parameter indicates the number of warm up cycles that have occurred Since DTCs were cleared. The scan tool will display a higher counts as more warm up cycles have occurred since the DTCs were cleared.

Warm-ups w/o Emission Faults
- This parameter indicates the number of warm up cycles that have occurred without an emission fault present. The scan tool will display a 0 if a fault has occurred. The scan tool will display a higher count if a number of warm up cycles have occurred without an emission fault.

Warm-ups w/o Non-Emission Faults
- This parameter indicates the number of warm up cycles that have occurred without a non-emission fault present. The scan tool will display a 0 if a fault has occurred. The scan tool will display a higher count if a number of warm up cycles have occurred without a non-emission fault.

Wide Open Throttle
- This parameter indicates the throttle status commanded by the control module. The scan tool will display YES is the vehicle throttle is commanded to wide open. The scan tool will display NO if the vehicle throttle is commanded to an amount less than 100%.