GM Service Manual Online
For 1990-2009 cars only

The Engine Scan Tool Data Definitions contain a brief description of all engine related parameters available on the scan tool. The list is in alphabetical order. A given parameter may appear in any one of the data lists. In some cases, the parameter more than once or in more than one data list in order to group certain related parameters together.

3X Crank Sensor: Scan tool displays 1200 to 10,000 RPM. This signal is calculated from the 18X pulses and is fed to the PCM by the ignition control module. This is used by the PCM to calculate RPM at engine speeds above 1200 RPM and to initiates injector pulses.

18X Crank Sensor: Scan tool displays 0 to 1200 RPM. This signal is produced by the ignition control module and is fed to the PCM to calculate engine RPM below 1200 RPM.

1-2 Sol.: Scan tool displays OK, Fault or Invalid state. These parameters describe the condition of the control circuit.

2-3 Sol.: Scan tool displays OK, Fault or Invalid state. These parameters describe the condition of the control circuit.

3-2 Downshift Sol.: Scan tool displays OK, Fault or Invalid state. These parameters describe the condition of the control circuit.

A/C High Side Pressure: Scan tool displays 0.00 to 5.00 volts. Represents the A/C refrigerant pressure sensor signal. The amount of pressure indicates the amount of load that the A/C compressor is placing on the engine. The PCM uses this information to adjust idle and to control the cooling fans.

A/C Pressure Out Of Range: Scan tool displays YES or NO. YES displayed indicated that the PCM is monitoring an A/C refrigerant pressure signal voltage which is too high or too low to allow the A/C compressor clutch to engage.

A/C Relay: Scan tool displays OK, Fault or Invalid state. These parameters describe the condition of the control circuit.

A/C Request: Scan tool displays YES or NO. Indicates the state of the A/C request input circuit from the HVAC controls. The PCM uses the A/C request signal to determine whether A/C compressor operation is being requested.

Actual EGR Position: Scan tool displays 0 percent to 100 percent. Represents the actual position of the EGR pintle in percent. 0 percent displayed indicates a fully extended pintle (EGR valve closed).

Air/Fuel Ratio: Scan tool displays 0.0 to 25.5. Air Fuel Ratio indicates the PCM commanded value. In closed loop, Air Fuel Ratio should normally be around 14.2-14.7. A lower Air Fuel Ratio indicates a richer commanded mixture, which may be seen during Power Enrichment or TWC Protection modes. A higher Air Fuel Ratio indicates a leaner commanded mixture. This can be seen during Decel Fuel Mode.

APP Average: Scan tool displays 0-150 counts. When the accelerator pedal is fully depressed the scan tool will display approximately 122 counts. The TAC module takes the voltages from the 3 APP sensors, averages the readings and converts the readings into counts. The scan tool displays the average. The average is different on every vehicle.

APP Indicated Angle: Scan tool displays 0-100 percent. The scan tool displays the Accelerator Pedal Position in percentage. When the APP is at rest, the display shows 0 percent. When the APP is fully depressed, the display shows 100 percent.

APP Sensor 1 / 2 / 3: Scan tool displays 0-5.0 volts. When the accelerator pedal is at 0 percent (pedal at rest), the display shows approximately 1 Volt. When the accelerator pedal is at 100 percent (pedal fully depressed), the display shows approximately 3.6 volts.

APP Sensor 1 / 2 / 3 Angle: Scan tool displays 0-100 percent. When the accelerator pedal is at rest, display shows 0 percent. When the accelerator pedal is fully depressed, display shows 100 percent. This percentage indicates to the TAC module the actual pedal position.

APP Sen. 1 and APP Sen. 2 Disagree: Scan tool displays YES or NO. When the TAC module receives a signal voltage from APP sensor 1 not in proper relationship to APP sensor 2, the scan tool displays YES. The scan tool displays NO under the normal operating conditions.

APP Sen. 1 and APP Sen. 3 Disagree: Scan tool displays YES or NO. When the TAC module receives a signal voltage from APP sensor 1 not in proper relationship to APP sensor 3, the scan tool displays YES. The scan tool displays NO under the normal operating conditions.

APP Sen. 2 and APP Sen. 3 Disagree: Scan tool displays YES or NO. When the TAC module receives a signal voltage from APP sensor 2 not in proper relationship to APP sensor 3, the scan tool displays YES. The scan tool displays NO under the normal operating conditions.

APP Sensor 1 / 2 / 3 Out of Range: Scan tool displays YES or NO. If the APP sensor voltage is not within the specifications, the scan tool displays YES. If the APP sensor voltage is within the specifications, the scan tool displays No.

BARO: Scan tool displays 10 to 105 kPa / 0.00 to 5.00  volts. The barometric pressure reading is determined from the MAP sensor signal monitored during key up and wide-open throttle (WOT) conditions. Barometric pressure is used to adjust fuel delivery and spark advance to compensate for altitude changes.

Brake Switch: Scan tool displays APPLIED or RELEASED. Indicates the brake pedal position. When the brake pedal is depressed a signal voltage is sent to the PCM. If a fault occurs on this circuit known as the cruise control brake switch 2 Circuit, a P1586 will set and cruise will not function.

Cam Signal Present: Scan tool displays YES or NO. If the PCM does not receive a cam signal from the ignition control module the scan tool displays NO.

Clutch Anticipate Switch: Scan Tool Displays APPLIED or RELEASED. The PCM monitors the clutch pedal switch input; if a low voltage is monitored, the PCM considers the clutch anticipate switch closed to ground (clutch pedal released). This is done to avoid a possible RPM flare caused by the sudden change in engine load.

Commanded A/C: Scan tool displays ON or OFF. Represents the PCM commanded state of the A/C compressor clutch relay driver circuit. The A/C compressor clutch should be engaged when Commanded A/C displays ON.

Commanded Gen: Scan tool displays ON or OFF. OFF displayed indicates that the PCM has commanded the generator control circuit OFF.

Cruise: Scan tool displays ENGAGED or DISENGAGED. Represents the state of the Cruise Status Input from the PCM module. Cruise should not display DISENGAGED unless the vehicle is operating in cruise control.

Cruise Disengage History 1-6: Scan tool displays the last 6 cruise control disengages in order from 1 to 6. There are 30 possible causes for the cruise control to disengage.

Cruise Release Switch: Scan tool displays RELEASED or APPLIED. This circuit has the cruise brake switch and the cruise clutch switch wired in series on manual transmission vehicles. Represents the position of the brake pedal and clutch as seen by the PCM. If the brake or clutch pedal is applied the PCM will not allow the cruise to engage. If a fault occurs on this circuit known as the cruise control brake switch CIrcuit, a P0571 will set and cruise will not function.

Cruise Resume/Accel: Scan tool displays ON or OFF. When the Cruise control switch is in the on position and the Resume/Accel switch is activated, the scan tool displays ON. The switch, when in the ON position, sends a signal voltage to the TAC module, that signal is then sent to the PCM across serial data. When the Resume/Accel switch is released the scan tool displays OFF.

Cruise Set/Coast: Scan tool displays ON or OFF. When the Cruise control switch is in the on position and the Set/Coast switch is activated, the scan tool displays ON. The switch, when in the ON position, sends a signal voltage to the TAC module, that signal is then sent to the PCM across serial data. When the Set/Coast switch is released the scan tool displays OFF.

Cruise Switch: Scan tool displays ON or OFF. When you activate the cruise control switch, the scan tool displays ON. The switch, when in the ON position, sends a signal voltage to the TAC module, that signal is then sent to the PCM across serial data. This allows all other functions of the Cruise Control. When you turn off the cruise control switch, the scan tool displays OFF.

Current Gear: Scan tool displays 0-4. The scan tool display the gear that the transmission is in. An illegal transmission position displays 9.

Cyl. 1-6 Ckt. History: Scan tool displays OK, Stuck Low (open) or Stuck High. These Parameters describe the condition of each injector control circuit. If a fault is detected the scan tool will list which the fault type with the corresponding cylinder.

Cyl. 1-6 Ckt. Status: Scan tool displays OK, Stuck Low (open) or Stuck High. These Parameters describe the condition of each injector control circuit.

Decel Fuel Mode: Scan tool displays ACTIVE or INACTIVE. ACTIVE is displayed if the PCM has detected conditions appropriate to operate in Deceleration Fuel Mode. The PCM will command deceleration fuel mode when a sudden decrease in throttle position has been detected while the vehicle is traveling over 25 mph. While in Deceleration Fuel mode, the PCM will decrease the amount of fuel delivered by entering Open Loop and decreasing the injector pulse width.

Desired EGR Position: Scan tool displays 0 percent to 100 percent. Represents the EGR pintle position that the PCM is commanding. Desired EGR Position should stay close to Actual EGR Position.

Desired Idle Speed: Scan tool displays 0 to 3187 RPM. Represents the idle speed that is commanded by the PCM. The PCM will compensate for various engine loads based on engine coolant temperature to keep the engine at the desired idle speed.

Driver Module 1 / 2 / 3 / 4 Status: Scan tool displays Enabled, Off-High volts, Off High Temp or Invalid state. This parameter describes the internal PCM driver module condition. This module controls all the relays/solenoids listed below the Driver Module parameter in the scan tool Output Driver Data List up to the next driver module.

ECT: Scan tool displays -40°C to 151°C, -40°F to 304°F. The engine coolant temperature (ECT) sensor is mounted in the coolant stream. The PCM applies 5 volts to the ECT sensor circuit. The sensor is a thermistor which changes internal resistance as temperature changes. When the sensor is cold (internal resistance high), the PCM monitors a high signal voltage and interprets it as a cold engine. As the sensor warms (internal resistance decreases), the voltage signal decreases and the PCM interprets the lower voltage as a warm engine.

EGR Closed Valve Pintle Position: Scan tool displays 0.0 to 5.0 volts. Represents the learned voltage that the PCM uses to determine whether or not the EGR valve is fully closed (0 percent pintle position). If the Desired EGR Position is 0 percent and a difference of more than 0.4 volt between EGR Feedback and EGR Closed Valve Pintle Position is detected, DTC P1406 will set.

EGR Duty Cycle: Scan tool displays 0 percent to 100 percent. Represents the EGR valve driver PWM signal from the PCM. A duty cycle of 0 percent indicates that no EGR flow is being commanded; a 100 percent duty cycle indicates maximum EGR flow commanded.

EGR Feedback: Scan tool displays 0.00 to 5.00 volts. Indicates the EGR pintle position sensor signal voltage being monitored by the PCM. A low voltage indicates a fully extended pintle (closed valve); a voltage near 5 volts indicates a fully retracted pintle (open valve)

EGR Flow Test Count: Scan tool displays 0 to 255. Indicates the number of EGR flow test samples collected during the current ignition cycle. The maximum number of samples allowed is 1 during normal operation. If the PCM battery feed has been disconnected or a DTC P0401 has been cleared, several EGR flow test samples will be allowed during the next ignition cycle. This is to allow repair verification during a single ignition cycle.

EGR Position Error: Scan tool displays 0 percent to 100 percent. Indicates the difference between Desired EGR Position and Actual EGR Position currently being monitored by the PCM. If the EGR Position Error reaches an unacceptable level, DTC P1406 will set.

Engine Load: Scan tool displays 0 percent to 100 percent. Engine load is calculated by the PCM from engine speed and MAF sensor readings. Engine load should increase with an increase in RPM or air flow.

Engine Run Time: Scan tool displays 00:00:00 to 99:99:99 Hrs:Min:Sec. Indicates the time elapsed since the engine was started. If the engine is stopped, ENGINE RUN TIME will be reset to 00:00:00.

Engine Speed: Scan tool displays 0 to 9999 RPM. Engine speed is computed by the PCM from the 3X reference input. It should remain close to desired idle under various engine loads with engine idling

EVAP Canister Purge: Scan tool displays 0 percent to 100 percent Represents the PCM commanded PWM duty cycle of the EVAP Purge valve. 0 percent displayed indicates no purge; 100 percent displayed indicates full purge.

EVAP Fault History: Scan tool displays NO FAULT, EXCESS VACUUM, PURGE VALVE LEAK, SMALL LEAK or WEAK VACUUM. The EVAP Fault History indicates the status of the EVAP system diagnostics performed by the PCM.

EVAP Purge Sol.: Scan tool displays OK, Fault or Invalid state. These parameters describe the condition of the control circuit.

EVAP Vent Sol.: Listed in the EVAP Data List - Scan tool displays Open or Closed. The scan tool displays Open when the PCM commands the EVAP system to purge. The scan tool will show Closed when the system is not purging.

Fans High Speed: Scan tool displays ON or OFF. Represents the PCM commanded state of both fans.

Fans Low Speed: Scan tool displays ON or OFF. Represents the PCM commanded state of both fans.

Fan Control Relay 1: Scan tool displays OK, Fault or Invalid state. These parameters describe the condition of the control circuit.

Fan Control Relay 2 and 3: Scan tool displays OK, Fault or Invalid state. These parameters describe the condition of the control circuit.

Fuel Level: Scan tool displays 0-100 percent. The scan tool displays in percentage the amount of fuel in the fuel tank.

Fuel Pump: Scan tool displays ON or OFF. Indicates the PCM commanded state of the fuel pump relay control circuit.

Fuel Pump Ckt. History: Scan tool displays OK, Stuck Low (open) or Stuck High. These Parameters describe the condition of the fuel pump control circuit.

Fuel Pump Ckt. Status: Scan tool displays OK, Stuck Low (open) or Stuck High. These Parameters describe the condition of the fuel pump control circuit. If a fault is detected the scan tool will list which the fault type.

Fuel Tank Pressure: Scan tool displays in 0 to 5.00 volts or -32 to 32 (in/H2O). This parameter indicates the pressure\Vacuum inside of the fuel tank. A negative value indicates a vacuum. A positive value indicates a pressure.

Fuel Trim Cell: Scan tool displays 0 to 9 fuel trim cell is dependent upon engine speed and MAF sensor readings. A plot of RPM vs. MAF is divided into 10 cells. Fuel trim cell indicates which cell is currently active.

Fuel Trim Learn: Scan tool displays YES or NO. When conditions are appropriate for enabling long term fuel trim corrections, FUEL TRIM LEARN will display yes. This indicates that the long term fuel trim is responding to short term fuel trim. If the Fuel Trim Learn displays NO, long term fuel trim will not respond to changes in short term fuel trim.

HO2S Bank 1 Sen. 1 / Bank 2 Sen. 1: Scan tool displays READY or NOT READY. Indicates the status of the fuel control exhaust oxygen sensor. The scan tool will indicate that the exhaust oxygen sensors are ready when the PCM detects a fluctuating HO2S voltage sufficient to allow closed loop operation. This will not occur unless the exhaust oxygen sensors are warmed up.

HO2S Bank 1 Sen. 1 / Bank 2 Sen. 1 / Bank 1 Sen. 2:  Scan tool displays 0 to 1132 mV. Represents the fuel control exhaust oxygen sensor output voltage. Should fluctuate constantly within a range between 10 mV (lean exhaust) and 1000 mV (rich exhaust) while operating in Closed Loop.

HO2S Warm-Up Sensor Bank 1 Sen. 1 / Bank 2 Sen. 1 / Bank 1 Sen. 2:  Scan tool displays 00:00 to 99:99 MIN:SEC. Indicates time to warm-up for each HO2S. The HO2S warm up time is used for the HO2S heater test. The PCM will run the heater test only after a cold start (determined by engine coolant and intake air temperature at the time of startup) and only once during an ignition cycle. When the engine is started the PCM will monitor the HO2S voltage. When the HO2S voltage indicates a sufficiently active sensor, the PCM looks at how much time has elapsed since startup. If the PCM determines that too much time was required for the HO2S to become active, a DTC will set. If the engine was warm when started, HO2S Warm-Up will display the value that was stored last time the test ran. If info has been cleared, HO2S Warm-Up will display 00:00.

HO2S XCounts Bank 1 / Bank 2: Scan tool displays 0 to 255. Indicates the number of times the HO2S 1 signal has crossed the 450 mV bias voltage during a 1 second interval. A HO2S 1 signal that almost never crosses the bias voltage could indicate a fuel trim problem, a faulty HO2S 1 circuit, or a faulty HO2S 1.

IAT: Scan tool displays -40°C to 151°C, -40°F to 304°F. The PCM converts the resistance of the intake air temperature sensor to degrees. The PCM uses Intake air temperature (IAT) to adjust fuel delivery and spark timing according to incoming air density. IAT is also compared to ECT at startup to identify cold starts for the HO2S heater and the EVAP diagnostics.

Ignition 1: Scan tool displays 0 to 25.5 volts. Represents the system voltage measured by the PCM at its ignition feed.

Ignition Mode: Scan tool displays BYPASS or IC. Indicates the commanded state of the Bypass signal output from the PCM. When BYPASS is displayed, the ignition control module is controlling the spark advance at a fixed 10 degrees BTDC (Bypass mode). IC displayed indicates that the PCM has requested control of the spark advance (IC mode). The ignition control module determines the correct operating mode based on the level of voltage that the PCM applies to the ignition control module bypass circuit. The PCM provides 5 volts to the ignition control module bypass circuit when conditions are appropriate for PCM control of spark timing (IC mode). If the PCM does not apply 5 volts to the bypass circuit, or if the ignition control module does not receive it, the module will control spark timing.

Injector Pulse Width: Scan tool displays 0 to 1000 msec. Indicates the amount of time the 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 displays 0.0 degrees to 25.5 degrees. Indicates the amount of spark the PCM is removing from IC spark advance in response to the signal from the knock sensors. The Traction Control system Desired Torque signal from the EBTCM may cause knock retard to display a value greater than 0.0 degrees if Traction Control is active.

Long Term Fuel Trim Bank 1 / Bank 2: Scan tool displays -23 percent 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 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 (decreased injector pulse width). A positive value significantly greater than 0 percent indicates that a lean condition exists and the PCM is compensating by adding fuel (increased injector pulse width). Because Long Term Fuel Trim tends to follow Short Term Fuel Trim; a value in the negative range due to canister purge at idle should not be considered unusual. The PCMs maximum authority to control long term fuel trim allows a range between -23 percent and +16 percent. Fuel trim values at or near maximum authority may indicate an excessively rich or lean system.

Loop Status:  Scan tool displays OPEN or CLOSED. Closed Loop 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 TP sensor, engine coolant, and MAF sensor inputs only.

MAF: Scan tool displays 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 Frequency: Scan tool displays 0 to 32000 Hz. The mass air flow sensor input signal to the PCM is a frequency which varies from around 3000 Hz at idle to above 7000 Hz at wide-open throttle. The PCM converts this frequency signal to grams per second to be displayed on the scan tool as MAF.

MAP: Scan tool displays 10-105 kPa/0.00 to 4.97 volts. The manifold absolute pressure (MAP) sensor measures the change in the intake manifold pressure from engine load, 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 BARO reading, and as an enabling factor for many of the diagnostics.

MIL: Listed in Eng 2 Data list - Scan tool displays ON or OFF. Indicates the PCM commanded state of the malfunction indicator lamp.

MIL: Scan tool displays OK, Fault or Invalid state. These parameters describe the condition of the control circuit.

Misfire Current Cyl 1-6: Scan tool displays 0 to 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 1-6: Scan tool displays 0 to 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.

Misfiring Cylinder (Primary) / Misfiring Cylinder (Secondary): Scan tool displays 0 or Cylinder #. If a misfire is being detected, Misfiring Cylinder displays the misfiring cylinder numbers.

Power Enrichment: Scan tool displays ACTIVE or INACTIVE. ACTIVE displayed indicates that the 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. While in Power Enrichment, the PCM will increase the amount of fuel delivered by entering Open Loop and increasing the injector pulse width. This is done to prevent a possible sag or hesitation from occurring during acceleration.

Reduced Engine Power: Scan tool displays ACTIVE or INACTIVE. The scan tool displays Active when the PCM has diagnosed a ETC problem or during drivetrain abuse protection. The PCM limits the engine power.

Rich/Lean Bank 1 / Bank 2: Scan tool displays RICH or LEAN. Indicates whether oxygen sensor voltage is greater than a 600 mV threshold voltage (rich) or less than a 300 mV threshold voltage (lean). Should change constantly while in closed loop, indicating that the PCM is controlling the air/fuel mixture properly.

Short Term Fuel Trim Bank 1 / Bank 2: Scan tool displays -11percent to 20 percent. Short Term Fuel Trim represents a short-term correction to fuel delivery by the PCM in response to the amount of time the fuel control oxygen sensor voltage spends above or below the 450 mV threshold. If the oxygen sensor voltage has mainly remained less than 450 mV, indicating a lean air/fuel mixture, short term fuel trim will increase into the positive range above 0 percent and the PCM will add fuel. If the oxygen sensor voltage stays mainly above the threshold, short term fuel trim will decrease below 0 percent into the negative range while the PCM reduces fuel delivery to compensate for the indicated rich condition. Under certain conditions such as extended idle and high ambient temperatures, canister purge may cause Short Term Fuel Trim to read in the negative range during normal operation. The PCMs maximum authority to control fuel trim allows a range between -11 percent and +20 percent. Fuel trim values at maximum authority may indicate an excessively rich or lean system.

Spark: Scan tool displays -64 degrees to 64 degrees. Displays the spark timing being commanded by the PCM on the 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. Because the ignition control module sets spark advance at a fixed value of 10° BTDC while operating in Bypass mode, the displayed Spark advance only reflects true spark timing when the PCM has commanded IC mode.

Starter Enable Relay: Scan tool displays OK, Fault or Invalid state. These parameters describe the condition of the control circuit.

Starter Inhibit: Scan tool displays ACTIVE or INACTIVE. Indicates if the PCM has received the correct inputs for startup. If ACTIVE is displayed a fault exists in the Theft Deterrent System.

Start-Up ECT: Scan tool displays -40°C to 151°C, -40°F to 304°F. Indicates the engine coolant temperature at the time that the vehicle was started. Used by the HO2S diagnostic to determine if the last startup was a cold start.

Start-Up IAT: Scan tool displays -40°C to 151°C, -40°F to 304°F. Indicates the intake air temperature at the time that the vehicle was started. Used by the HO2S diagnostic to determine if the last startup was a cold start.

TAC Brake Switch: Scan tool displays APPLIED or RELEASED. Indicates the brake pedal position. When the brake pedal is depressed a signal voltage is sent to the TAC module, that signal is then sent to the PCM across serial data. If a fault occurs on this circuit known as the Stoplamp Switch CIrcuit, a P1574 will set.

TAC/PCM Communication: Scan tool displays OK or FAULT. If the communication between the TAC module and the PCM is interrupted the scan tool displays FAULT. The scan tool displays OK under the normal operating conditions.

TCC Enable Sol.: Scan tool displays OK, Fault or Invalid state. These parameters describe the condition of the control circuit.

TCC Sol.: Scan tool displays OK, Fault or Invalid state. These parameters describe the condition of the control circuit.

Total Misfire Current Count: Scan tool displays 0 to 99. Indicates the total number of cylinder firing events that were detected as being misfires during the last 200 crankshaft revolution sample period.

Total Misfire Failures Since First Fail: Scan tool displays 0 to 65535 Counts. Indicates the number of 200 crankshaft revolution sample periods during which the level of misfire was sufficiently high to report a failure.

Total Misfire Passes Since First Fail: Scan tool displays 0 to 65535 Counts. Indicates the number of 200 crankshaft revolution sample periods during which the level of misfire was sufficiently low to report a pass.

TP Desired Angle: Scan tool displays 0-100 percent. The PCM indicates the desired throttle angle for conditions present at that time.

TP Indicated Angle: Scan tool displays 0-100 percent. The TP Indicated angle displays in percentage the amount of throttle opening.

TP Sensor 1 / 2: Scan tool displays 0-5 volts. The scan tool displays the amount of throttle opening in volts. Closed throttle displays approximately 1 volt and wide open throttle displays approximately 4 volts.

TP Sensor 1 / 2 Angle: Scan tool displays 0-100 percent. The scan tool displays the amount of throttle opening in percentage. Closed throttle displays 0 percent and wide open throttle displays near 100 percent.

TP Sensors Disagree: Scan tool displays YES or NO. When the TAC module receives a signal voltage from one of the throttle position sensors not in proper relationship to the other, the scan tool displays YES. The scan tool displays NO under normal operating conditions.

TP Sensor 1 Out of Range: Scan tool displays YES or NO. If the TAC module detects that the voltage is below .37 volts at closed throttle or above 4.7 volts at wide open throttle, the scan tool displays YES. If the voltages are within specifications, the scan tool displays NO.

TP Sensor 2 Out of Range: Scan tool displays YES or NO. If the TAC module detects that the voltage is below .37 volts or at closed throttle or above 4.7 volts at wide open throttle, the scan tool displays YES. If the voltages are within specifications, the scan tool displays NO.

Traction Control: Scan tool displays ACTIVE or INACTIVE. Active will be displayed if a message is received from the EBTCM requesting torque reduction.

Traction Control Desired Torque: Scan tool range 0 percent to 100 percent. Represents the PWM signal from the electronic brake and traction control module. The EBTCM reduces the Traction Control Desired Torque signal pulse width when a drive wheel slippage situation is detected. The PCM monitors the Traction Control Desired Torque signal and reduces drive wheel slippage as necessary by retarding spark timing, or increasing air/fuel ratio. The PCM can also turn OFF up to three fuel injectors if the Traction Control Desired Torque signal indicates a large enough amount of drive wheel slippage. A problem with the Traction Control Desired Torque signal should cause a DTC to set.

Traction Control Torque: Scan tool range 0 percent to 100 percent. Represents the PWM signal which indicates the percent of available torque the engine is delivering to the drive wheels. The EBTCM monitors the Traction Control Torque signal to ensure that the PCM is responding properly to the Traction Control Desired Torque signal.

Transmission Range: Scan tool displays INVALID, PARK/NEUTRAL, REVERSE, DRIVE 4, DRIVE 3, DRIVE 2, or LOW. Transmission Range represents the decoded status of the four inputs from the Transaxle Range Switch Assembly. The combination of transaxle range inputs indicates the position of the transaxle manual valve.

TR Switch A / B / C: Scan tool displays HIGH or LOW. The TR switch A / B / C display represents the states of the four inputs from the transaxle range switch. HIGH displayed indicates a B+ voltage signal being monitored at the PCM, LOW displayed indicates a grounded input signal. The combination of transaxle range inputs indicates the position of the transaxle manual valve.

TWC Protection: Scan tool displays ACTIVE or INACTIVE. ACTIVE displayed indicates that the PCM has detected conditions appropriate to operate in TWC Protection mode. This is determined based on engine load and engine coolant temperature. While in TWC Protection, the PCM will decrease Air/Fuel Ratio to a value that depends on mass air flow (higher Mass Airflow = lower Air/Fuel Ratio).

Vehicle Speed: Scan tool displays 0-255 km/h, 0-155 mph. The vehicle speed sensor signal is converted into mph and km/h for display.

VTD Fuel Disable: Scan tool displays ACTIVE or INACTIVE. The Theft Deterrent Fuel Enable circuit is an input from the vehicle theft deterrent control module that signals the PCM to enable the injectors if the proper signal is received. The scan tool will normally display INACTIVE. If the vehicle theft deterrent control module does not sent the correct Theft Deterrent Fuel Enable signal to the PCM, the display will switch to ACTIVE and the fuel system may be disabled. Refer to DTCs P1626, P1629, or Vehicle Theft Deterrent diagnosis for further information.