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 is listed more than once or in more than one data list in order to group certain related parameters together.

3X Crank Sensor: Scan tool displays 1600-10,000 RPM. This signal is calculated from the 7X pulses and is fed to the powertrain control module (PCM) by the ignition control module. This is used by the PCM in order to calculate RPM at engine speeds above 1600 RPM and to initiate injector pulses.

24X Crank Sensor: Scan tool displays 0-1600 RPM. This signal is produced by the ignition control module and is fed to the PCM in order to calculate engine RPM below 1600 RPM.

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

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

Abuse Management: Scan Tool Displays Active or Inactive. Active indicates the PCM is commanding protection against abnormal driveline conditions. For further information refer to Automatic Transmission Diagnosis.

A/C High Side Pressure: Scan tool displays 0.0-5.00 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 in order to adjust the idle and to control the cooling fans.

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 0-100 percent. Represents the actual position of the EGR pintle in percent. 0 percent displayed indicates a fully extended pintle, indicating an EGR valve that is closed.

Air/Fuel Ratio: Scan tool displays 0.0-25.5. Air Fuel Ratio indicates the PCM commanded value. In Closed Loop, the air-to-fuel ratio should normally be approximately 14.2-14.7. A lower air-to-fuel ratio indicates a richer commanded mixture, which may by seen during Power Enrichment or three-way catalytic converter (TWC) Protection modes. A higher air-to-fuel ratio indicates a leaner commanded mixture. This can be seen during Decel Fuel mode.

AIR Active Test Inhibit: Scan tool displays Yes or No. Yes Indicates the Active test is inhibited from running at this time.

AIR Active Test AIR Injection: Scan tool displays Yes or No. Yes Indicates the Active Test is being performed by the PCM for diagnostic purposes.

AIR Diagnostic Complete: Scan tool displays Yes or No. Yes Indicates PCM has completed all AIR Diagnostics.

AIR Passive Test 1 Passed: Scan tool displays Yes or No. Indicates passed or failed Passive Test 1 and will perform the second AIR Passive test.

AIR Passive Test 2 Fail: Scan tool displays Yes or No. Yes indicates either Passive Test 1 or Passive Test 2 failed or is inconclusive, this will cause the AIR Active Test to run.

AIR Passive Test Passed: Scan tool displays Yes or No. Yes indicates AIR Passive Tests 1 and 2 passed and no further action is needed.

AIR Passive Test Inhibited: Scan tool displays Yes or No. Yes indicates the Passive Test is inhibited from running at this time.

AIR Passive Test in Progress: Scan tool displays Yes or No. Yes indicates Passive Tests are in progress.

AIR Pump Relay:  Eng 1, AIR, HO2S Data Lists -- Scan tool indicates On/Off. ODD Data List -- Scan tool indicates OK/Fault/Invalid State. These parameters describe the condition of the Control circuit.

AIR Solenoid: ODD, AIR Data Lists-- Scan tool indicates OK/Fault/Invalid State. AIR, Eng 1, HO2S Data Lists -- Scan tool indicates On/Off. These parameters describe the condition of the Control circuit.

BARO: Scan tool displays 10-105 kPa (0.00-5.00 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 the fuel delivery and the spark advance in order 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.

Cam Signal Present: Scan tool displays YES or NO. NO indicates that the PCM is not receiving a cam signal from the ignition control module.

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 Fuel Pump: Scan tool displays ON or OFF. ON indicates the PCM has commanded the Fuel Pump Relay Control circuit ON.

Commanded Gen: Scan tool displays ON or OFF. OFF indicates the PCM has commanded the Generator Control circuit OFF.

Cruise Mode: Scan tool displays ON or OFF. Represents the state of the cruise status input from the cruise control module. ON indicates vehicle is operating in Cruise Control mode.

Cruise Inhibited: Eng 1-- Scan tool indicates ON or OFF. ODD -- Scan tool indicates OK/Fault/Invalid State. ON or OFF indicates the inhibited or uninhibited state of the cruise control system as commanded by the PCM. OK Fault/Invalid State indicates Cruise Control System Control circuit status.

Current Gear: Scan tool displays 1-4. The scan tool displays the gear that the transmission is in while driving.

Cycles of Misfire Data: Scan tool displays 0-99. Represents number of times the PCM has checked for misfires.

Cyl. 1-6 Ckt. History: Scan tool displays OK, Stuck Low, indicating a circuit that is stuck open, or Stuck High. These parameters describe the condition of each Injector Control circuit. If a fault is detected the scan tool will list the fault type with the corresponding cylinder.

Cyl. 1-6 Ckt. Status: Scan tool displays OK, Stuck Low, indicating a circuit that is stuck 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 more than 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 0-100 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 0-3187 RPM. Represents the idle speed that is commanded by the PCM. The PCM will compensate for various engine loads based on the engine coolant temperature in order 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-+151°C (-40°F-+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 the internal resistance as the temperature changes. When the sensor is cold and the internal resistance is high, the PCM monitors a high signal voltage and interprets it as a cold engine. As the sensor warms and the 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 0.0-5.0 volts. Represents the learned voltage that the PCM uses to determine whether or not the EGR valve is fully closed and is at 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 0-100 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 that maximum EGR flow is commanded.

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

EGR Flow Test Count: Scan tool displays 0-255. 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 0-100 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 0-100 percent. Engine load is calculated by the PCM from the engine speed and the 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 engine oil level as determined by the oil level sensor.

Engine Oil Life: Scan tool displays 0-100 percent. Indicates the percentage of oil life that is left until next recommended oil change.

Engine Oil Pressure: Scan tool displays OK/Low/High. Indicates the engine oil pressure as indicated by the oil pressure sending unit.

Engine Run Time: Scan tool displays 00:00:00-99:99:99 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 0-9999 RPM. Engine speed is computed by the PCM from the 3X reference input. It should remain close to the desired idle during various engine loads with engine idling

EVAP Canister Purge: Scan tool displays 0-100 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 Solenoid: Scan tool displays OK, Fault or Invalid State. These parameters describe the condition of the control circuit.

EVAP Vent Solenoid: Eng 1, EVAP, HO2S Data List -- Scan tool displays Open or Closed. ODD, EVAP Data List -- Scan tool displays OK, Fault, or Invalid State. Open/Closed Indicates the position of the EVAP vent solenoid valve. OK/Fault/Invalid State indicates state of the EVAP Vent Solenoid Control circuit.

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 , or 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, or open, or Stuck High. These parameters describe the condition of the Fuel Pump Control circuit.

Fuel Tank Pressure: Scan tool displays in 0.00-5.00 volts (-32-+32 in/Hg). This parameter indicates the pressure/vacuum inside fuel tank. A negative value indicates a vacuum. A positive value indicates a pressure.

Fuel Trim Cell: Scan tool displays 0-9. Fuel trim cell is dependent upon the engine speed and the MAF sensor readings. A plot of RPM vs. MAF is divided into 10 cells. The 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.

Generator PWM: Scan tool displays 0-100 percent.

Hot Mode: Scan tool displays ON or OFF. ON indicates that the PCM has detected a condition appropriate for Transaxle Hot mode operation. The PCM determines this condition based on the transaxle fluid temperature. While in Hot mode, transaxle shift points may be altered, fourth gear is disabled, and the torque converter clutch (TCC) is forced ON in second gear.

Hot Open Loop: Scan tool displays Active or Inactive.

HO2S Sensor 1: Scan tool displays READY or NOT READY. Indicates the status of the exhaust oxygen sensor. The scan tool will indicate that the exhaust oxygen sensor is ready when the PCM detects a fluctuating HO2S voltage sufficient in order to allow Closed Loop operation. This will not occur unless the exhaust oxygen sensor is warmed up.

HO2S Sensor 1:  Scan tool displays 0-111 mV. Indicates the exhaust oxygen sensor output voltage. While operating in Closed Loop, the voltage should constantly fluctuate from 10 mV, indicating a lean exhaust, to 1000 mV.

HO2S Sensor 2 : Scan tool displays 0-111 mV . Indicates the exhaust oxygen sensor output voltage. Voltage should stay within a limited range when the catalytic converter and HO2S are at operating temperature, indicating an efficiently operating catalyst.

HO2S XCounts: Scan tool displays 0-255. 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+151°C (-40°F-+304°F). The PCM converts the resistance of the intake air temperature sensor to degrees. The PCM uses intake air temperature (IAT) in order to adjust the fuel delivery and the spark timing according to the incoming air density. IAT is also compared to ECT at start-up in order to identify cold starts for the HO2S heater and the EVAP diagnostics.

Ignition 1: Scan tool displays 0-25.5 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 (IC) module is controlling the spark advance at a fixed 10 degrees before top dead center (BTDC) . IC displayed indicates that the PCM has requested control of the spark advance . 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 the conditions are appropriate for PCM control of the spark timing. This represents 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. This represents BYPASS mode.

Injector Pulse Width: Scan tool displays 0-1000 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 0.0-25.5 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 more than 0.0 degrees if the traction control is active.

Long Term Fuel Trim: Scan tool displays -25-+20 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 in order to maintain the PCM commanded air-to-fuel ratio. A negative value significantly below 0 percent indicates that the fuel system is rich and the fuel delivery is being reduced. This condition is represented by a decreased injector pulse width. A positive value significantly more than 0 percent indicates that a lean condition exists and the PCM is compensating by adding fuel. This represents an 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 maximum authority of the PCM to control long term fuel trim allows a range of -27-+27 percent. Fuel trim values at or near the 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 throttle position (TP) sensor, the 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 0-32000 Hz. The mass air flow sensor input signal to the PCM is a frequency which varies from approximately 3000 Hz at idle to more than 7000 Hz at wide-open throttle. The PCM converts this frequency signal to grams per second. The signal is displayed on the scan tool as MAF.

MAP: Scan tool displays 10-105 kPa and 0.00-5.00 volts. The manifold absolute pressure (MAP) sensor measures the change in the intake manifold pressure from the engine load, the EGR flow, and the speed changes. As the intake manifold pressure increases, the intake vacuum decreases, resulting in a higher MAP sensor voltage and kPa reading. The MAP sensor signal is used in order to monitor the 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: IPC Data List -- Scan tool displays ON or OFF. Indicates the PCM commanded state of the malfunction indicator lamp.

MIL: ODD Data List -- 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 0-198 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 that are detected. The counters may normally display some activity, but the activity should be very low and nearly equal for all cylinders.

Misfire History Cyl 1-6: Scan tool displays 0-65535 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.

Non Volatile Memory: Scan tool displays Pass or Fail. This indicates the state of the random access memory (RAM) of the PCM.

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 the throttle position and the engine 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 in order 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.

Short Term Fuel Trim : Scan tool displays -27-+27 percent. Short Term Fuel Trim represents a short-term correction to the 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-to-fuel mixture, the 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, the short term fuel trim will decrease below 0 percent into the negative range while the PCM reduces fuel delivery in order 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 maximum authority of the PCM to control the fuel trim allows a range of -27-+27 percent. Fuel trim values at maximum authority may indicate an excessively rich or lean system.

Spark: Scan tool displays -64-+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 degrees 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 displays -40°C-+151°C ( -40°F-+304°F). Indicates the engine coolant temperature at the time that the vehicle was started. Used by the HO2S diagnostic in order to determine if the last startup was a cold start.

Start-Up IAT: Scan tool displays -40°C-+151°C (-40°F-+304°F). Indicates the Intake Air Temperature at the time that the vehicle was started. Used by the HO2S diagnostic in order to determine if the last start-up was a cold start.

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

Total Misfire Current Count: Scan tool displays 0-99. 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 0-65535 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 Angle: Scan tool displays 0-100 percent. Indicates throttle plate position.

Traction Control: Scan tool displays ACTIVE or INACTIVE. Active will be displayed if a message is received from the electronic brake and traction control module (EBTCM) requesting torque reduction.

Traction Control Desired Torque: Scan tool range 0-100 percent. Represents the pulse width modulation (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 the drive wheel slippage as necessary by retarding the spark timing, or by increasing the air-to-fuel ratio. The PCM can also turn OFF up to three fuel injectors if the Traction Control Desired Torque signal indicates enough drive wheel slippage. A problem with the Traction Control Desired Torque signal should cause a DTC to set.

Traction Control Torque: Scan tool range 0-100 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 in order 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/P: Scan Tool Displays HIGH or LOW. The Transmission Range (TR) Switch A/B/C/P 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 Three-Way Catalytic Converter (TWC) Protection mode. This is determined based on the engine load and the engine coolant temperature. While in TWC Protection, the PCM will decrease the air-to-fuel to a value that depends on mass air flow. Higher mass air flow equals a lower air-to-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 system that signals the PCM in order to enable the injectors if the proper signal is received. The scan tool will normally display INACTIVE. If the Vehicle Theft Deterrent Control system 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.