The Scan Tool Data Definitions list contains a brief description of all of the engine related parameters that are available on the scan tool. The list is arranged in alphabetical order. A given parameter may appear in any one of the data lists. In some cases the parameter may appear more than once, or in more than one data list in order to group certain related parameters together. Refer to Transmission Scan Tool Data Values and Scan Tool Data Definitions in Automatic Transmission-4L30-E.

A/C Clutch Relay -- (On/Off): This displays the commanded state of the A/C clutch relay.

AIR Pump Relay -- (On/Off): This displays the commanded state of the AIR pump relay.

AIR Solenoid -- (On/Off): This displays the commanded state of the AIR solenoid.

APP Sensor 1 - Range (0-5 Volts): This displays the voltage received by the ECM from accelerator pedal position sensor 1.

APP Sensor 2 - Range (0-5 Volts): This displays the voltage received by the ECM from accelerator pedal position sensor 2.

Base PW - Range (0.0-6.1 ms): This parameter indicates the average injector pulse width of both bank 1 and bank 2 injectors.

Battery Voltage -- Range (0.0-24.0 Volts): This parameter displays the battery voltage at the ECM.

Calc. Full Pos. Switch-- (Active/Inactive): This parameter indicates that all full load maps are used (for example, the fuel enrichment and the ignition).

Calc. Idle Pos. Switch-- (Active/Inactive): This parameter indicates that all idle maps are used (for example, the injection and the spark advance.

Catalyst Monitor -- (Yes/No): This parameter indicates that the diagnostic tests for the catalyst system have completed.

Cruise Release Brake Switch -- (Applied/Released): This parameter displays whether the Cruise brake switch is applied or released, based on the signal received by the ECM.

Cruise Switch -- (On/Off): This parameter displays whether the cruise switch is on or off, based on the signal received by the ECM.

Desired Idle Speed - Range (0-2,550 RPM): This displays the idle speed that is commanded by the ECM. The ECM will compensate for various engine loads in order to keep the engine close to the desired idle speed.

Driving Cycle Comp. -- (Yes/No): This parameter indicates whether the engine has met the criteria to run the diagnostic tests requiring the engine to operate under predetermined driving conditions.

DTC #1 -- (0000 or DTC Number): This parameter displays the first powertrain DTC number set since the DTCs were cleared.

DTC #2 -- (0000 or DTC Number): This parameter displays the second powertrain DTC number set since the DTCs were cleared.

ECT -- Range ((-40 to 140°C) (-40 to 284°F)): This display shows the temperature of the engine coolant.

Engine Load -- (0-100 percent): This is a calculated value that changes in proportion to the amount of the load on the engine.

Engine Power Relay -- (On/Off): This display indicates the commanded state of the engine controls power relay.

Engine Run Time -- Range (00:00:00 - 23:59:59): This parameter displays the actual time the engine has run during this key cycle.

Engine Speed - Range (0-10,200 RPM): This is a digital tachometer display.

EVAP Canister Purge - Range (0-100 percent): The ECM controls the EVAP Purge valve by using the Pulse Width Modulation (PWM). The display is the commanded pulse width (duty cycle) of the control circuit.

EVAP Vent Solenoid -- (On/Off): This display indicates the commanded state of the EVAP vent solenoid. When the vent solenoid is commanded on, the vent valve is closed. When the vent solenoid is commanded off, the vent valve is open.

Fuel Level -- Range ((0--64 liters) (0--16 gal)): This displays the amount of fuel in the fuel tank as measured by the ECM.

Fuel Level Output - Range (0-5.0 Volts): This parameter indicates the fuel level that is measured in volts in the fuel tank. Zero volts indicates near full while 5.0 volts indicates near empty. The ECM processes the signal voltage and displays the fuel level sensor voltage as approximately one half the actual circuit voltage. The fuel level sensor voltage in the instrument panel data list will read the actual circuit voltage -- approximately twice the voltage displayed in the engine data list. The range in the instrument panel data list is .1 -- 10 volts. This condition is normal.

Fuel Pump Relay -- (On/Off): The ECM enables the fuel pump when the CKP sensor pulses are detected. This display indicates the commanded state of the fuel pump relay.

Fuel Tank Pressure -- Range ((-10.4 to +10.9 in H2O) (-19.4 to +20.3 mm Hg)): This sensor is used in order to monitor the pressure within the EVAP system (which includes the fuel tank). The Fuel Tank Pressure sensor is very sensitive to changes in pressure. Inches of water is a very small unit of pressure. One inch of H2O equals approximately 1.9 mm Hg.

Fuel Tank Pressure - Range (0-5 Volts): This parameter is the actual voltage on the Fuel Tank Pressure sensor signal circuit as measured by the ECM.

HO2S Bank 1 Sensor 1 - Range (.750 to 3.999): This parameter displays the lambda value produced by the wide band oxygen sensor. A lambda value of 1 is equal to the stoichiometric air fuel ratio of 14.7:1. When the exhaust is lean, the oxygen level will be high and the lambda value will be high (greater than 1). When the exhaust is rich, the oxygen level will be low and the lambda value will be low (less than 1).

HO2S Bank 1 Sensor 2 - Range (0 to 1275 mV): This parameter is the actual voltage on the HO2S signal circuit as measured by the ECM.

HO2S Bank 2 Sensor 1 - Range (.750 to 3.999): This parameter displays the lambda value produced by the wide band oxygen sensor. A lambda value of 1 is equal to the stoichiometric air fuel ratio of 14.7:1. When the exhaust is lean, the oxygen level will be high and the lambda value will be high (greater than 1). When the exhaust is rich, the oxygen level will be low and the lambda value will be low (less than 1).

HO2S Bank 2 Sensor 2 - Range (0 to 1275 mV): This parameter is the actual voltage on the HO2S signal circuit as measured by the ECM.

HO2S Heater Bn 1 Sen. 1 -- (High/Low): This parameter indicates the commanded state of the HO2S heater control circuit. When the parameter display is high, the heater is commanded on, when the display is low, the heater is off. The ECM will turn the HO2S heaters on and off depending on the operating conditions of the engine.

HO2S Heater Bn 1 Sen. 2 -- (High/Low): This parameter indicates the commanded state of the HO2S heater control circuit. When the parameter display is high, the heater is commanded on, when the display is low, the heater is off. The ECM will turn the HO2S heaters on and off depending on the operating conditions of the engine.

HO2S Heater Bn 2 Sen. 1 -- (High/Low): This parameter indicates the commanded state of the HO2S heater control circuit. When the parameter display is high, the heater is commanded on, when the display is low, the heater is off. The ECM will turn the HO2S heaters on and off depending on the operating conditions of the engine.

HO2S Heater Bn 2 Sen. 2 -- (High/Low): This parameter indicates the commanded state of the HO2S heater control circuit. When the parameter display is high, the heater is commanded on, when the display is low, the heater is off. The ECM will turn the HO2S heaters on and off depending on the operating conditions of the engine.

IAT -- Range ((-40 to 140°C) (-40 to 284°F)): This display shows the temperature of the air entering the air induction system.

Ignition 1 On --(Yes/No): This parameter displays whether the ignition switch is on or off, based on the signal received by the ECM.

Intake Plenum Switchover Valve -- (Open/Closed): This parameter indicates the commanded position of the Intake Plenum Switchover valve which is part of the Multi-Ram Induction System.

Intake Reson. Tune Valve -- (Open/Closed): This parameter indicates the commanded position of the Intake Resonance Switchover valve which is part of the Multi-Ram Induction System.

Knock Retard Cyl. #1 -- (0-191 degrees): This parameter displays the degrees of spark advance the ECM removes from the cylinder in response to the signal from the knock sensors.

Knock Retard Cyl. #2 -- (0-191 degrees): This parameter displays the degrees of spark advance the ECM removes from the cylinder in response to the signal from the knock sensors.

Knock Retard Cyl. #3 -- (0-191 degrees): This parameter displays the degrees of spark advance the ECM removes from the cylinder in response to the signal from the knock sensors.

Knock Retard Cyl. #4 -- (0-191 degrees): This parameter displays the degrees of spark advance the ECM removes from the cylinder in response to the signal from the knock sensors.

Knock Retard Cyl. #5 -- (0-191 degrees): This parameter displays the degrees of spark advance the ECM removes from the cylinder in response to the signal from the knock sensors.

Knock Retard Cyl. #6 -- (0-191 degrees): This parameter displays the degrees of spark advance the ECM removes from the cylinder in response to the signal from the knock sensors.

Knock Sensor 1 -- (Active/Inactive): This parameter indicates whether the knock sensor has detected any frequencies associated with a knock event.

Knock Sensor 2 -- (Active/Inactive): This parameter indicates whether the knock sensor has detected any frequencies associated with a knock event.

Long Term FT Bank 1 -- Range (-100 to 100 percent): A change made to the fuel delivery will be indicated by the Long and Short Term Fuel Trim values. The Short Term Fuel Trim values change rapidly in response to the HO2S signal voltages. These changes fine tune the engine fueling. The Long Term Fuel Trim values change in response to the trends in the Short Term Fuel Trim. The Long Term Fuel Trim makes coarse adjustments to the fueling in order to re-center and restore control to the Short Term Fuel Trim. The Short Term Fuel Trim and the Long Term Fuel Trim can be monitored with a scan tool. A positive Fuel Trim value indicates that the ECM is adding fuel in order to compensate for a lean condition. A negative Fuel Trim value indicates that the ECM is reducing the amount of fuel in order to compensate for a rich condition.

Long Term FT Bank 2 -- Range (-100 to 100 percent): A change made to the fuel delivery will be indicated by the Long and Short Term Fuel Trim values. The Short Term Fuel Trim values change rapidly in response to the HO2S signal voltages. These changes fine tune the engine fueling. The Long Term Fuel Trim values change in response to the trends in the Short Term Fuel Trim. The Long Term Fuel Trim makes coarse adjustments to the fueling in order to re-center and restore control to the Short Term Fuel Trim. The Short Term Fuel Trim and the Long Term Fuel Trim can be monitored with a scan tool. A positive Fuel Trim value indicates that the ECM is adding fuel in order to compensate for a lean condition. A negative Fuel Trim value indicates that the ECM is reducing the amount of fuel in order to compensate for a rich condition.

Loop Status Bn 1 Sen. 1-- (Open/Closed): A Closed Loop operation displayed indicates that the ECM is controlling the fuel delivery according to the oxygen sensor voltage. In an Open Loop operation, the ECM ignores the oxygen sensor voltage and bases the amount of the fuel to be delivered on other input sensors. At extremely high ambient temperatures or when towing a trailer, it is possible for the system to remain in an Open Loop operation in order to control the catalytic converter temperatures.

Loop Status Bn 1 Sen. 2-- (Open/Closed): Closed Loop operation on sensor 2 indicates the oxygen sensor is at operating temperature and is capable of providing feedback for diagnostic purposes.

Loop Status Bn 2 Sen. 1-- (Open/Closed): A Closed Loop operation displayed indicates that the ECM is controlling the fuel delivery according to the oxygen sensor voltage. In an Open Loop operation, the ECM ignores the oxygen sensor voltage and bases the amount of the fuel to be delivered on other input sensors. At extremely high ambient temperatures or when towing a trailer, it is possible for the system to remain in an Open Loop operation in order to control the catalytic converter temperatures.

Loop Status Bn 2 Sen. 2-- (Open/Closed): Closed Loop operation on sensor 2 indicates the oxygen sensor is at operating temperature and is capable of providing feedback for diagnostic purposes.

MAF - Range (0.0-72 g/s): This parameter indicates the measured quantity of the air flowing into the engine during all operating conditions.

MIL -- (On/Off): This display indicates the commanded state of the Malfunction Indicator Lamp (MIL).

MIL Flashing-- (Yes/No): This display indicates whether the ECM is commanding the MIL to flash due to a potential catalyst damaging misfire.

MIL Request -- (Yes/No): The TCM has no direct control of the engine MIL, but if a transmission fault occurs that is emissions related, the engine MIL must illuminate. If a transmission fault occurs that requires MIL illumination, the TCM will send a signal to the ECM over the CAN bus requesting illumination of the MIL. This parameter indicates the TCM has requested MIL illumination.

Mileage Since DTC Cleared -- Range (0-9999 km): This parameter displays the mileage accumulated since the DTCs were cleared from the ECM memory.

Misfire Current Cyl. #1 - Range (0-255 counts): The display shows the number of misfires that have been detected during the last 200 cylinder firing events. The counters may normally display some activity, but the activity should be nearly equal for all of the cylinders, and in low numbers.

Misfire Current Cyl. #2 - Range (0-255 counts): This display shows the number of misfires that were detected during the last 200 cylinder firing events. The counters may normally display some activity, but the activity should be nearly equal for all of the cylinders, and in low numbers.

Misfire Current Cyl. #3 - Range (0-255 counts): This display shows the number of misfires that were detected during the last 200 cylinder firing events. The counters may normally display some activity, but the activity should be nearly equal for all of the cylinders, and in low numbers.

Misfire Current Cyl. #4 - Range (0-255 counts): This display shows the number of misfires that were detected during the last 200 cylinder firing events. The counters may normally display some activity, but the activity should be nearly equal for all of the cylinders, and in low numbers.

Misfire Current Cyl. #5 - Range (0-255 counts): This display shows the number of misfires that were detected during the last 200 cylinder firing events. The counters may normally display some activity, but the activity should be nearly equal for all of the cylinders, and in low numbers.

Misfire Current Cyl. #6 - Range (0-255 counts): This display shows the number of misfires that were detected during the last 200 cylinder firing events. The counters may normally display some activity, but the activity should be nearly equal for all of the cylinders, and in low numbers.

Misfire History Cyl. #1 - Range (0-255 counts): This displays the total accumulated misfires for each cylinder.

Misfire History Cyl. #2 - Range (0-255 counts): This displays the total accumulated misfires for each cylinder.

Misfire History Cyl. #3 - Range (0-255 counts): This displays the total accumulated misfires for each cylinder.

Misfire History Cyl. #4 - Range (0-255 counts): This displays the total accumulated misfires for each cylinder.

Misfire History Cyl. #5 - Range (0-255 counts): This displays the total accumulated misfires for each cylinder.

Misfire History Cyl. #6 - Range (0-255 counts): This displays the total accumulated misfires for each cylinder.

Number of DTCs -- Range (0-255): This display indicates the actual quantity of the DTCs that are stored in the ECM.

Park/Neutral Switch -- (P-N/R-D-L): The P/N switch position is sent to the ECM from the TCM. This parameter indicates the position of the gear selector based on the signal received by the ECM.

Resume Switch -- (On/Off): This parameter displays whether the cruise control Resume switch is on or off, based on the signal received by the ECM.

Sec. AIR System Ready -- (Yes/No): This parameter indicates that the Sec. AIR System diagnostic test has been performed at least once.

Set Switch -- (On/Off): This parameter displays whether the cruise control Set switch is on or off, based on the signal received by the ECM.

Short Term FT Bank 1 -- Range (-100 to 100 percent): A change made to the fuel delivery will be indicated by the Long and Short Term Fuel Trim values. The Short Term Fuel Trim values change rapidly in response to the HO2S signal voltages. These changes fine tune the engine fueling. The Long Term Fuel Trim values change in response to the trends in the Short Term Fuel Trim. The Long Term Fuel Trim makes coarse adjustments to the fueling in order to re-center and restore control to the Short Term Fuel Trim. The Short Term Fuel Trim and the Long Term Fuel Trim can be monitored with a scan tool. A positive Fuel Trim value indicates that the ECM is adding fuel in order to compensate for a lean condition. A negative Fuel Trim value indicates that the ECM is reducing the amount of fuel in order to compensate for a rich condition.

Short Term FT Bank 2 -- Range (-100 to 100 percent): A change made to the fuel delivery will be indicated by the Long and Short Term Fuel Trim values. The Short Term Fuel Trim values change rapidly in response to the HO2S signal voltages. These changes fine tune the engine fueling. The Long Term Fuel Trim values change in response to the trends in the Short Term Fuel Trim. The Long Term Fuel Trim makes coarse adjustments to the fueling in order to re-center and restore control to the Short Term Fuel Trim. The Short Term Fuel Trim and the Long Term Fuel Trim can be monitored with a scan tool. A positive Fuel Trim value indicates that the ECM is adding fuel in order to compensate for a lean condition. A negative Fuel Trim value indicates that the ECM is reducing the amount of fuel in order to compensate for a rich condition.

Spark -- Range (-133 to 78 degrees): This is the amount of spark advance that is commanded by the ECM. A positive value indicates that the timing is advanced, and a negative value indicates that the timing is being retarded.

Stoplamp Brake Switch Input -- (Applied/Released): This parameter displays whether the Stoplamp brake switch is applied or released, based on the signal received by the ECM.

TAC Learn Counter -- Range (0-255): This parameter displays the learning sequence counter for the throttle actuator controller.

Theft Deterrent Status -- (No Immobilizer/Correct Code/Incorrect Code): This parameter indicates the status of the Theft Deterrent System. The Correct Code must be displayed in order for the vehicle to start. No signal indicates that no signal is being received by the ECM from the immobilizer

TP Angle - Range (0-100 percent): This parameter is the percent of throttle opening as calculated by the ECM using information from the two throttle position sensors.

TP Sensor 1 - Range (0-5.0 Volts): This parameter is the actual voltage on the TP sensor signal circuit as measured by the ECM.

TP Sensor 2 - Range (5.0-0 Volts): This parameter is the actual voltage on the TP sensor signal circuit as measured by the ECM.

Vehicle Speed - Range ((0--317 Kph)(0-198 mph)): A processed wheel speed sensor signal is sent to the ECM from the ABS controller. The ECM calculates the vehicle speed from this signal.

Warm-up Cycle Comp. -- (Yes/No): This parameter indicates whether the engine has met the criteria to run the diagnostic tests requiring the engine at operating temperature.