For 1990-2009 cars only
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 Request: Scan Tool Displays YES or NO. YES displayed indicates that the HVAC system has requested A/C compressor operation. The HVAC system sends A/C request information to the PCM via serial data (CKT 1807).
Actual EGR Position: Scan Tool Range 0% to 100%. Represents the actual position of the EGR pintle in percent. 0% displayed indicates a fully extended pintle (EGR valve closed).
Air Fuel Ratio: Scan Tool Range 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.
BARO: Scan Tool Range 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.
Change Oil Lamp: Scan Tool Displays ON or OFF. Represents the PCM commanded state of the Change Oil Lamp. The PCM calculates Engine Oil Life based upon the number of engine revolutions seen and operating conditions such as calculated oil temperature. The PCM will command the Change Oil Lamp ON when the remaining oil life is less than 11%.
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 Fan 1 / Commanded Fan 2: Scan Tool Displays ON or OFF. Represents the PCM commanded state of the fan 1 (low speed) and fan 2 (high speed) control circuits.
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 form the SMCC module. Cruise should not display ENGAGED unless the vehicle is operating in cruise control.
Cruise Inhibited: Scan Tool Displays YES or NO. YES displayed indicates that the PCM is commanding the SMCC module to inhibit cruise control operation. Should display YES with park, neutral, reverse or low gear selected.
Current Gear: Scan Tool Displays numbers 1, 2, 3, or 4. The PCM looks at Trans Range position and the gear commanded by the PCM. The actual forward gear that the Transaxle is in will be the lower of the two because the manual valve can override the PCM commanded gear.
Decel Fuel Mode: Scan Tool Displays ACTIVE or INACTIVE. ACTIVE displayed indicates that 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 Range 0% to 100%. 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 Range 0 to 3187 RPM. 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.
ECT: Scan Tool Range -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 Range 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% 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 Range 0% to 100%. 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 Range 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 Range 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 Range 0% to 100%. 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 Range 0% to 100%. 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 Oil Level: Scan Tool Displays OK or LOW. Indicates the oil level as determined by the Engine Oil Level switch.
Engine Oil Life: Scan Tool Range 0% to 100%. Indicates the engine oil life index. The PCM calculates Engine Oil Life based upon the number of engine revolutions seen and operating conditions such as calculated oil temperature. Pressing the Oil Life Monitor reset switch will return the displayed Engine Oil Life to 100%.
Engine Run Time: Scan Tool Range 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 Range 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 Range 0% to 100%. Represents the PCM commanded PWM duty cycle of the EVAP Purge valve. 0% displayed indicates no purge; 100% 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 EVAP system diagnostics performed by the PCM.
EVAP Vent Sol: Scan Tool Displays OPEN or CLOSED. Represents the state of the EVAP Canister fresh air vent solenoid. Should be open during normal operation.
Fuel Level: Scan Tool Range 0% to 25%. The PCM uses the fuel level sensor input to calculate the amount of fuel in the tank. The PCM uses the fuel level input for the EVAP system diagnostics and to control the fuel gauge.
Fuel Pump: Scan Tool Displays ON or OFF. Indicates the PCM commanded state of the fuel pump relay control circuit.
Fuel Pump Speed: Scan Tool Displays NORMAL or HIGH. Indicates the PCM commanded state of the fuel pump speed control PWM circuit to the fuel pump control module. The fuel pump will be run at high speed to deliver more fuel volume when the MAP sensor indicates high engine load or when system voltage is less than 10 volts.
Fuel Tank Pressure: Scan Tool Displays 0 to 64 In. H2O / 0.00 to 5.00 Volts. The signal from the fuel tank pressure sensor is monitored by the PCM to verify that the evaporative emissions control system is operating correctly and leaks are not present. Fuel Tank Pressure level is used extensively for EVAP purge control and EVAP system diagnostics.
Fuel Trim Cell: Scan Tool Range 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 DISABLED or ENABLED. When conditions are appropriate for enabling long term fuel trim corrections, FUEL TRIM LEARN will display ENABLED. This indicates that the long term fuel trim is responding to short term fuel trim. If the Fuel Trim Learn displays DISABLED, long term fuel trim will not respond to changes in short term fuel trim.
Generator Lamp: Scan Tool Displays ON or OFF. The Generator Lamp display indicates the PCM commanded state of the Generator Lamp. The PCM commands the Generator Lamp ON due to low system voltage or a generator fault.
Generator PWM: Scan Tool Range 0% to 100%. Represents the field terminal input from the generator. The field PWM duty cycle indicates generator output level; a higher duty cycle indicates a higher generator output. The PCM uses the generator F terminal signal to adjust spark and IAC to compensate for variances in engine load caused by the generator.
HO2S Sensor 1: Scan Tool Displays NOT READY or 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 Sensor 1: Scan Tool Range 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 Sensor 2: Scan Tool Range 0 to 1132 mV. Represents the catalyst monitor exhaust oxygen sensor output voltage. If the catalyst is operating efficiently, the HO2S 1 signal will be far more active than that produced by the HO2S 2 sensor. If the PCM detects a level of HO2S 2 activity that indicates the catalyst is no longer operating efficiently, DTC P0420 will be set.
HO2S Warm-Up Sensor 1 / HO2S Warm-Up Sensor 2: Scan Tool Range 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: Scan Tool Range 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.
Hot Lamp: Scan Tool Displays ON or OFF. The Hot Lamp Display indicates the PCM commanded state of the Engine Hot Lamp. The PCM commands the Engine Hot Lamp ON when the engine coolant temperature is greater than 124°C (255°F). The PCM commands the Engine Hot Lamp OFF when the engine coolant temperatures is less than 121°C (250°F).
IAC Position: Scan Tool Range 0 to 255. 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. IAC Position should respond fairly quickly to changes in engine load to maintain desired idle RPM.
IAT: Scan Tool Range -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 Range 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° 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 Range 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 Range 0.0 degress 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 FT: Scan Tool Range -23% to 16%. 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% indicates that fuel delivery requires no compensation to maintain the PCM commanded air/fuel ratio. A negative value significantly below 0% indicates that the fuel system is rich and fuel delivery is being reduced (decreased injector pulse width). A positive value significantly greater than 0% 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 PCM s maximum authority to control long term fuel trim allows a range between -23% and +16%. 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.
Low Oil Lamp: Scan Tool Displays ON or OFF. The Low Oil Lamp display represents the PCM commanded state of the Low Engine Oil Lamp. The PCM commands the Lamp ON when the Engine Oil Level Switch indicates that a low oil condition exists.
MAF: Scan Tool Range 0.0-512 g/s. MAF (Mass Air Flow) 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 Range 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 Range 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: Scan Tool Displays ON or OFF. Indicates the PCM commanded state of the Malfunction Indicator Lamp.
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 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 / Misfire History Cyl #2 / Misfire History Cyl #3 / Misfire History Cyl #4 / Misfire History Cyl #5 / Misfire History Cyl #6: Scan Tool Range 0 to 65,535 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 number(s).
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.
Rich/Lean: 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 FT: Scan Tool Range -11% to 20%. 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% and the PCM will add fuel. If the oxygen sensor voltage stays mainly above the threshold, short term fuel trim will decrease below 0% 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 PCM's maximum authority to control fuel trim allows a range between -11% and +20%. Fuel trim values at maximum authority may indicate an excessively rich or lean system.
Spark: Scan Tool Range -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.
Start-Up ECT: Scan Tool Range -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 Range -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.
Supercharger Boost: Scan Tool Range 0% to 100%. Represents the amount of manifold boost pressure commanded by the PCM. 100% displayed indicates full boost commanded.
Throttle At Idle: Scan Tool Displays YES or NO. Indicates whether the TP Angle being monitored by the PCM is at 0%.
Total Misfire Current Count: Scan Tool Range 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 Range 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 Range 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 Angle: Scan Tool Range 0% to 100%. TP Angle is computed by the PCM from the TP Sensor voltage. TP Angle should display 0% at idle and 100% at wide open throttle.
TP Sensor: Scan Tool Range 0.00 to 5.00 Volts. The voltage being monitored by the PCM on the TP sensor signal circuit.
Traction Control: Scan Tool Displays ACTIVE or INACTIVE. ACTIVE displayed indicates that the traction control system is taking action to reduce drive wheel slippage.
Traction Control Desired Torque: Scan Tool Range 0% to 100%. 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, decreasing boost sol. PWM, 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 DTC P1571 to set.
Traction Control Torque: Scan Tool Range 0% to 100%. 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 P / A / B / C: Scan Tool Displays HIGH or LOW. The TR Switch P / 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 Diagnostic: Scan Tool Displays ENABLED or DISABLED. ENABLED displayed indicates that MAF, HO2S, ECT, or VSS DTCs that would disable the TWC diagnostic are not present.
TWC Monitor Test Counter: Scan Tool Range 0-49. The TWC monitor test counter increments while the TWC system diagnostic test is running and taking samples. When the TWC Monitor Test Counter reaches 49, the PCM will update the TWC diagnostic statistical filter. At this point, the TWC Monitor Test Counter will reset to 0 and begin incrementing again. The TWC Monitor Test Counter is most useful when verifying a Three-way catalytic converter replacement or any repair associated with the DTC P0420 diagnostic table.
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 Range 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 PCM enables the fuel injectors if the the proper Theft Deterrent Fuel Enable signal from the Vehicle Theft Deterrent (VTD) Control Module is received. The scan tool normally displays INACTIVE. If the VTD Control Module does not send 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 the Vehicle Theft Deterrent System for further diagnosis.
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 Request: Scan Tool Displays YES or NO. YES displayed indicates that the HVAC system has requested A/C compressor operation. The HVAC system sends A/C request information to the PCM via serial data (CKT 1807).
Actual EGR Position: Scan Tool Range 0% to 100%. Represents the actual position of the EGR pintle in percent. 0% displayed indicates a fully extended pintle (EGR valve closed).
Air Fuel Ratio: Scan Tool Range 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.
BARO: Scan Tool Range 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.
Change Oil Lamp: Scan Tool Displays ON or OFF. Represents the PCM commanded state of the Change Oil Lamp. The PCM calculates Engine Oil Life based upon the number of engine revolutions seen and operating conditions such as calculated oil temperature. The PCM will command the Change Oil Lamp ON when the remaining oil life is less than 11%.
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 Fan 1 / Commanded Fan 2: Scan Tool Displays ON or OFF. Represents the PCM commanded state of the fan 1 (low speed) and fan 2 (high speed) control circuits.
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 form the SMCC module. Cruise should not display ENGAGED unless the vehicle is operating in cruise control.
Cruise Inhibited: Scan Tool Displays YES or NO. YES displayed indicates that the PCM is commanding the SMCC module to inhibit cruise control operation. Should display YES with park, neutral, reverse or low gear selected.
Current Gear: Scan Tool Displays numbers 1, 2, 3, or 4. The PCM looks at Trans Range position and the gear commanded by the PCM. The actual forward gear that the Transaxle is in will be the lower of the two because the manual valve can override the PCM commanded gear.
Decel Fuel Mode: Scan Tool Displays ACTIVE or INACTIVE. ACTIVE displayed indicates that 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 Range 0% to 100%. 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 Range 0 to 3187 RPM. 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.
ECT: Scan Tool Range -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 Range 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% 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 Range 0% to 100%. 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 Range 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 Range 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 Range 0% to 100%. 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 Range 0% to 100%. 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 Oil Level: Scan Tool Displays OK or LOW. Indicates the oil level as determined by the Engine Oil Level switch.
Engine Oil Life: Scan Tool Range 0% to 100%. Indicates the engine oil life index. The PCM calculates Engine Oil Life based upon the number of engine revolutions seen and operating conditions such as calculated oil temperature. Pressing the Oil Life Monitor reset switch will return the displayed Engine Oil Life to 100%.
Engine Run Time: Scan Tool Range 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 Range 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 Range 0% to 100%. Represents the PCM commanded PWM duty cycle of the EVAP Purge valve. 0% displayed indicates no purge; 100% 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 EVAP system diagnostics performed by the PCM.
EVAP Vent Sol: Scan Tool Displays OPEN or CLOSED. Represents the state of the EVAP Canister fresh air vent solenoid. Should be open during normal operation.
Fuel Level: Scan Tool Range 0% to 25%. The PCM uses the fuel level sensor input to calculate the amount of fuel in the tank. The PCM uses the fuel level input for the EVAP system diagnostics and to control the fuel gauge.
Fuel Pump: Scan Tool Displays ON or OFF. Indicates the PCM commanded state of the fuel pump relay control circuit.
Fuel Pump Speed: Scan Tool Displays NORMAL or HIGH. Indicates the PCM commanded state of the fuel pump speed control PWM circuit to the fuel pump control module. The fuel pump will be run at high speed to deliver more fuel volume when the MAP sensor indicates high engine load or when system voltage is less than 10 volts.
Fuel Tank Pressure: Scan Tool Displays 0 to 64 In. H2O / 0.00 to 5.00 Volts. The signal from the fuel tank pressure sensor is monitored by the PCM to verify that the evaporative emissions control system is operating correctly and leaks are not present. Fuel Tank Pressure level is used extensively for EVAP purge control and EVAP system diagnostics.
Fuel Trim Cell: Scan Tool Range 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 DISABLED or ENABLED. When conditions are appropriate for enabling long term fuel trim corrections, FUEL TRIM LEARN will display ENABLED. This indicates that the long term fuel trim is responding to short term fuel trim. If the Fuel Trim Learn displays DISABLED, long term fuel trim will not respond to changes in short term fuel trim.
Generator Lamp: Scan Tool Displays ON or OFF. The Generator Lamp display indicates the PCM commanded state of the Generator Lamp. The PCM commands the Generator Lamp ON due to low system voltage or a generator fault.
Generator PWM: Scan Tool Range 0% to 100%. Represents the field terminal input from the generator. The field PWM duty cycle indicates generator output level; a higher duty cycle indicates a higher generator output. The PCM uses the generator F terminal signal to adjust spark and IAC to compensate for variances in engine load caused by the generator.
HO2S Sensor 1: Scan Tool Displays NOT READY or 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 Sensor 1: Scan Tool Range 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 Sensor 2: Scan Tool Range 0 to 1132 mV. Represents the catalyst monitor exhaust oxygen sensor output voltage. If the catalyst is operating efficiently, the HO2S 1 signal will be far more active than that produced by the HO2S 2 sensor. If the PCM detects a level of HO2S 2 activity that indicates the catalyst is no longer operating efficiently, DTC P0420 will be set.
HO2S Warm-Up Sensor 1 / HO2S Warm-Up Sensor 2: Scan Tool Range 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: Scan Tool Range 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.
Hot Lamp: Scan Tool Displays ON or OFF. The Hot Lamp Display indicates the PCM commanded state of the Engine Hot Lamp. The PCM commands the Engine Hot Lamp ON when the engine coolant temperature is greater than 124°C (255°F). The PCM commands the Engine Hot Lamp OFF when the engine coolant temperatures is less than 121°C (250°F).
IAC Position: Scan Tool Range 0 to 255. 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. IAC Position should respond fairly quickly to changes in engine load to maintain desired idle RPM.
IAT: Scan Tool Range -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 Range 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° 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 Range 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 Range 0.0 degress 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 FT: Scan Tool Range -23% to 16%. 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% indicates that fuel delivery requires no compensation to maintain the PCM commanded air/fuel ratio. A negative value significantly below 0% indicates that the fuel system is rich and fuel delivery is being reduced (decreased injector pulse width). A positive value significantly greater than 0% 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 PCM s maximum authority to control long term fuel trim allows a range between -23% and +16%. 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.
Low Oil Lamp: Scan Tool Displays ON or OFF. The Low Oil Lamp display represents the PCM commanded state of the Low Engine Oil Lamp. The PCM commands the Lamp ON when the Engine Oil Level Switch indicates that a low oil condition exists.
MAF: Scan Tool Range 0.0-512 g/s. MAF (Mass Air Flow) 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 Range 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 Range 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: Scan Tool Displays ON or OFF. Indicates the PCM commanded state of the Malfunction Indicator Lamp.
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 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 / Misfire History Cyl #2 / Misfire History Cyl #3 / Misfire History Cyl #4 / Misfire History Cyl #5 / Misfire History Cyl #6: Scan Tool Range 0 to 65,535 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 number(s).
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.
Rich/Lean: 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 FT: Scan Tool Range -11% to 20%. 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% and the PCM will add fuel. If the oxygen sensor voltage stays mainly above the threshold, short term fuel trim will decrease below 0% 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 PCM's maximum authority to control fuel trim allows a range between -11% and +20%. Fuel trim values at maximum authority may indicate an excessively rich or lean system.
Spark: Scan Tool Range -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.
Start-Up ECT: Scan Tool Range -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 Range -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.
Supercharger Boost: Scan Tool Range 0% to 100%. Represents the amount of manifold boost pressure commanded by the PCM. 100% displayed indicates full boost commanded.
Throttle At Idle: Scan Tool Displays YES or NO. Indicates whether the TP Angle being monitored by the PCM is at 0%.
Total Misfire Current Count: Scan Tool Range 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 Range 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 Range 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 Angle: Scan Tool Range 0% to 100%. TP Angle is computed by the PCM from the TP Sensor voltage. TP Angle should display 0% at idle and 100% at wide open throttle.
TP Sensor: Scan Tool Range 0.00 to 5.00 Volts. The voltage being monitored by the PCM on the TP sensor signal circuit.
Traction Control: Scan Tool Displays ACTIVE or INACTIVE. ACTIVE displayed indicates that the traction control system is taking action to reduce drive wheel slippage.
Traction Control Desired Torque: Scan Tool Range 0% to 100%. 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, decreasing boost sol. PWM, 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 DTC P1571 to set.
Traction Control Torque: Scan Tool Range 0% to 100%. 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 P / A / B / C: Scan Tool Displays HIGH or LOW. The TR Switch P / 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 Diagnostic: Scan Tool Displays ENABLED or DISABLED. ENABLED displayed indicates that MAF, HO2S, ECT, or VSS DTCs that would disable the TWC diagnostic are not present.
TWC Monitor Test Counter: Scan Tool Range 0-49. The TWC monitor test counter increments while the TWC system diagnostic test is running and taking samples. When the TWC Monitor Test Counter reaches 49, the PCM will update the TWC diagnostic statistical filter. At this point, the TWC Monitor Test Counter will reset to 0 and begin incrementing again. The TWC Monitor Test Counter is most useful when verifying a Three-way catalytic converter replacement or any repair associated with the DTC P0420 diagnostic table.
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 Range 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 PCM enables the fuel injectors if the the proper Theft Deterrent Fuel Enable signal from the Vehicle Theft Deterrent (VTD) Control Module is received. The scan tool normally displays INACTIVE. If the VTD Control Module does not send 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 the Vehicle Theft Deterrent System for further diagnosis.
