Part 2

Scan Tool Data Definitions

High Spark Modifier
- LOW, MID and HIGH SPARK MODIFIERS are adaptive spark retard values used to control engine spark knock. The HIGH SPARK MODIFIER should display 0 degrees if no spark retard is needed. The high spark modifier is used for high engine speeds. The adaptives are based on ECT and will reset to 0 degrees during cold temperatures. If a hot restart occurs, a percentage of the learned adaptive will be used. The ECM will always work back to zero compensation or no spark retard.

HO2S 1-Range 0-1132 mV
- The front heated oxygen sensor (HO2S) 1 reading represents the exhaust oxygen sensor output voltage. This voltage will fluctuate constantly between 100 mV, lean exhaust to 900 mV, rich exhaust, when operating in a Closed Loop.

HO2S 2- Range 0-1132 mV
- The rear heated oxygen sensor (HO2S) 2 represents the exhaust oxygen output voltage past the catalytic converter. This voltage remains inactive, or the voltage will appear lazy within a range of 100 mV, lean exhaust and 900 mV, rich exhaust, when the system is operating in a Closed Loop.

HO2S 1 Heater Command-Range On/Off
- Indicates the engine control module (ECM) command of the heated oxygen sensor (HO2S) 1 heater.

HO2S 2 Heater Command- Range On/Off
- Indicates the engine control module (ECM) command of the heated oxygen sensor (HO2S) 2 heater.

HO2S 1 Heater Current-Amps
- The parameter displays the current through the control module when the HO2S sensor 1 heater is commanded ON by the control module. HO2S 1 Heater is a range of values indicating a low current when the heater circuit resistance is high to a high current when the heater circuit resistance is low.

HO2S 2 Heater Current-Amps
- The parameter displays the current through the control module when the HO2S sensor 2 heater is commanded ON by the control module. HO2S 2 Heater is a range of values indicating a low current when the heater circuit resistance is high to a high current when the heater circuit resistance is low.

IAC Position-Range 0-255 Counts
- The idle air control (IAC) pintle position command from the engine control module (ECM) is displayed in counts. The higher the counts read, the more the commanded idle speed is. The IAC responds fairly quickly to changes in the engine load in order to maintain the desired idle RPM.

IAC Position W/O A/C
- Indicates the learned idle air control position with the A/C Off.

IAC Position With A/C
- Indicates the learned idle air control position with the A/C On.

IAT Sensor-Range -40 to +151°C (-40 to +304°F)
- The engine control module (ECM) converts the resistance of the intake air temperature (IAT) sensor to degrees in the same manner as the engine coolant temperature (ECT) sensor. Intake air temperature is used by the ECM to adjust fuel delivery and spark timing according to incoming air density.

Ignition 1 Signal-Range 0-25.5 Volts
- The ignition volts represents the system voltage measured by the engine control module (ECM) at the ignition feed circuit.

Injector PWM - Range 0-999.9 mS
- Indicates the base pulse width modulation (PWM) or ON time of the fuel injectors in milliseconds. When the engine load is increased, the injector pulse width will increase.

Injector 1-4 Command-On/Off
- Indicates the engine control module (ECM) command on the fuel injectors.

KS Noise
- Indicates the level of normal noise as seen by the knock sensor at idle. The higher the count value, the higher the amplitude of the noise. Normal noise levels will vary with the SOHC and DOHC engines.

Knock Retard-Range 0-90 Degrees
- The Adaptive Knock Retard indicates the long term amount of the spark advance the engine control module (ECM) removes from the ignition control (IC). The ECM responds to the knock sensor (KS) signal.

Lean/Rich Avg. Time
- Indicates the average time for the O2S-1 to transition from under 300 mV to over 600 mV during the last test sample.

Lean/Rich Transitions
- Indicates the number of times the O2S-1 transitioned from under 300 mV to over 600 mV during the last test sample.

Long Term FT-Range 0-255 (-100 to +100 Percent)
- The long term FT is derived from the short term FT value. The long term FT is used for the long term correction of the fuel delivery. A value of the 128 counts, 0 percent, indicates that the fuel delivery requires no compensation in order to maintain a 14.7:1 air to fuel ratio. A value below 128 counts means that the fuel system is too rich and the fuel delivery is being reduced. The engine control module (ECM) is decreasing the injector pulse width. A value above 128 counts indicates that a lean condition exists for which the ECM is compensating.

Loop Status-Range Open/Closed
- A Closed Loop displayed indicates that the engine control module (ECM) is controlling the fuel delivery according to the oxygen sensor (O2S) 1 voltage. The ECM controls the fuel delivery air to fuel ratio as close to 14.7:1 as possible.

Low Coolant Level
- Displays YES if the coolant in the coolant surge tank is low (switch open).

Low Spark Modifier
- LOW, MID and HIGH SPARK MODIFIERS are adaptive spark retard values used to control engine spark knock. The LOW SPARK MODIFIER should display 0 degrees if no spark retard is needed. The low spark modifier is used for low engine speeds. The adaptives are based on ECT and will reset to 0 degrees during cold temperatures. If a hot restart occurs, a percentage of the learned adaptive will be used. The ECM always works back to zero compensation or no spark retard.

M/T Clutch Disengaged
- Displays YES if the ECM has detected engine flare as a result of the clutch pedal being depressed. There is NO clutch pedal input to the ECM.

MAP Sensor-Range 11-105 kPa, 0-5.0 Volts
- The manifold absolute pressure (MAP) sensor measures the change in the intake manifold pressure which results from engine load and speed changes. As the intake manifold pressure increases, the air density in the intake also increases and additional fuel is required.

MIL Command-Range ON/OFF
- Indicates whether the engine control module (ECM) is commanding the malfunction indicator lamp (MIL) ON or OFF.

Mid Spark Modifier
- LOW, MID and HIGH SPARK modifiers are adaptive spark retard values used to control engine spark knock. The MID SPARK MODIFIER should display 0 degrees if no spark retard is needed. The mid spark modifier is used for mid engine speeds. The adaptives are based on ECT and will reset to 0 degrees during cold temperatures. If a hot restart occurs, a percentage of the learned adaptive will be used. The ECM always works back to zero compensation or no spark retard.

Mileage Since DTC Cleared
- The scan tool displays km or miles. This parameter indicates the mileage accumulated since an emission DTC cleared. The powertrain control module (PCM) stores this mileage in the Freeze Frame and Failure Records memory.

Mileage Since First Fail
- The scan tool displays km or miles. This parameter indicates the mileage accumulated since an emission DTC first failed. The powertrain control module (PCM) stores this mileage in the Freeze Frame and Failure Records memory.

Mileage Since Last Fail
- The scan tool displays km or miles. This parameter indicates the mileage accumulated since an emission DTC last failed. The powertrain control module (PCM) stores this mileage in the Failure Records memory.

Mileage Since MIL Request
- The scan tool displays km or miles. This parameter displays the mileage accumulated since the powertrain control module (PCM) requested the malfunction indicator lamp (MIL) to illuminate. The PCM stores the mileage in the Failure Records memory.

Misfire Current #1-4-Range 0-255 Counts
- Indicates the number of current misfires that are present in the indicated cylinder. Increments only when misfire is current.

Misfire Enabled
- Displays YES when the ECM has detected that all of the misfire enable criteria have been met. Parameters can be found under P0300 DTC PARAMETERS.

Misfire History #1-4-Range 0-255 Counts
- Indicates the number of misfires that have occurred after 195 current misfires have been counted. The current misfire counter will add the misfires to the history misfire counter after 195 total misfires have taken place. If 1 cylinder is misfiring, the misfiring current counter will have 195 misfires counted before adding to its history counter. If 2 cylinders are misfiring, the misfiring current counters will add to their history counters after 97 misfires. Increments only after a misfire diagnostic trouble code (DTC) has been set.

Park/Neutral Switch
- Displays P-N or R-D-L as indicated from the transaxle range switch.

Rich/Lean Avg. Time
- Indicates the average time for the O2S-1 to transition from over 600 mV to under 300 mV during the last test sample.

Rich/Lean Transitions
- Indicates the number of times for the O2S-1 to transition from over 600 mV to under 300 mV during the last test sample.

Short Term FT-Range 0-255 (-100 to +100 Percent)
- Short term FT represents a short term correction to fuel delivery by the engine control module (ECM) in response to the amount of time the oxygen sensor (O2S) voltage spends above or below the 450 mV threshold. If the oxygen sensor has mainly been below 450 mV, indicating a lean air/fuel mixture, short term FT will increase to tell the ECM to add fuel. If the oxygen sensor voltage stays mainly above the threshold, the ECM will reduce fuel delivery to compensate for the indicated rich condition.

Spark-Range 64 to -64 Degrees
- This is a display of the spark advance ignition control (IC) calculation which the engine control module (ECM) is programming in the ignition system. The desired spark advance is computed using data such as engine temperature, RPM, engine load, vehicle speed and operating mode.

Start Up ECT
- Indicates the engine coolant temperature (ECT) at engine start up.

Steering Assist Sol. DC
- Indicates the steering assist solenoid On-time percentage the ECM is commanding. Under 16 km/h (10 mph), the duty cycle will be 0% or full assist. Over 113 km/h (70 mph) the duty cycle will be 100% or no assist. In between speeds will vary.

TP Sensor-Range 0-100 Percent
- The engine control module (ECM) computes the throttle position (TP) from the TP sensor voltage input. The TP angle will auto zero to 0 percent at idle when the TP voltage is below 0.90 volt. The TP angle will read 100 percent at wide open throttle (WOT).

TP Sensor-Range 0.0-0.5 Volts
- The engine control module (ECM) uses the TP sensor to determine the amount of the throttle demanded by the operator of the vehicle. The throttle position (TP) sensor reads between 0.36-0.96 volt at idle to above 4 volts at wide open throttle (WOT).

TR Switch-Range High or Low
- A transaxle mounted switch is used as an input to let the engine control module (ECM) know what position the gear select lever is in. The scan tool status will switch from High to Low as different combinations are met. In Park, PRNDL P and A will be Low and B and C will be High.

Vehicle Speed Sensor-Range 0-255 km/h, 0-255 mph
- The vehicle speed sensor (VSS) signal is converted into km/h (mph) for display. The vehicle speed output from the engine control module (ECM) is 4,000 pulses per mile. The scan tool uses the Class 2 serial data from the ECM to obtain vehicle speed, while the instrument panel cluster, cruise control module and multi-function alarm module use the 4,000 ppm output.

VTD Fuel Cutoff-Range No/Yes
- Indicates if the vehicle theft deterrent (VTD) module has received proper information to enable or disable fuel.