Scan Tool Data Definitions Part 1

A/C Off For WOT - Scan Tool Displays YES or NO
Yes displayed indicates that the PCM has commanded the A/C compressor clutch relay OFF because the throttle position is greater than the threshold for A/C compressor operation (TP Angle greater than 90%).

A/C 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 Powertrain Control Module (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.
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.

A/C Slugging - Scan Tool Displays ACTIVE or INACTIVE
ACTIVE displayed indicates that the PCM is engaging the A/C compressor clutch at start up to avoid A/C slugging when A/C is requested.

Actual EGR Pos - 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. The Barometric Pressure is used to compensate for altitude differences.

Boost Solenoid Pulse Width Modulated (PWM) - Scan Tool Range 0% to 100%
Represents the amount of manifold boost pressure commanded by the PCM. 100% displayed indicates full boost commanded.
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 and FAN 2 relay drivers.

Commanded Gen - Scan Tool Displays ON or OFF
OFF displayed indicates that the PCM has commanded the generator L terminal OFF.

Commanded Torque Converter Clutch (TCC) - Scan Tool Displays ENGAGED or DISENGAGED
Represents the PCM commanded state of the Transaxle torque converter clutch.

Cruise Engaged - Scan Tool Displays YES or NO
Represents the state of the Cruise Status Input form the SMCC module. CRUISE ENGAGED should not display YES unless the vehicle is operating in a cruise control mode.

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 at idle.

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.

Delivered 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 Delivered Torque signal to ensure that the PCM is responding properly to the Desire Torque signal.

Desired EGR Position - Scan Tool Range 0% to 100%
Represents the EGR pintle position that the PCM is commanding. Desired EGR Pos. should stay close to Actual EGR Pos.

Desired Idle - 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 speed.

Desired Torque - Scan Tool Range 0% to 100%
Represents the PWM signal from the Electronic Brake and Traction Control Module. The Electronic Brake Traction Control Module (EBTCM) reduces the Desired Torque signal pulse width when a drive wheel slippage situation is detected.

The PCM monitors the 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 Desired Torque signal indicates a large enough amount of drive wheel slippage. A problem with the Desired Torque signal should cause DTC P1571 to set.

ECT - Scan Tool Range -40C° to 151°C, -40°F to 304°F
The Engine Coolant Temperature (ECT) sensor is mounted in the coolant stream and sends engine temperature information to the PCM. 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 will decrease and the PCM will interpret 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 EGR PWM is 0% and a difference of more than 0.4 volt between EGR Feedback and EGR Closed Valve Pintle Position is detected, DTC Pi 406 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 tully retracted pintle (open valve).

EGR Pos. 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 is reaches an unacceptable level, DTC Pi 406 will set.

EGR 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, 10 EGR tiow test samples will be allowed during the next ignition cycle. This is to allow repair veritication during a single ignition cycle.

Engine Load - Scan Tool Range 0% to 100%
Engine load is calculated by the PCM trom engine speed and MAF sensor readings. Engine Load should increase with an increase in RPM or air flow.

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 ot 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 Purge PWM - Scan Tool Range 0% to 100%
Represents the PCM commanded PWM duty cycle ot the EVAP Purge Solenoid valve. 0% displayed indicates no purge; 100% displayed indicates full purge.

EVAP Vacuum Switch - Scan Tool Displays PURGE or NO PURGE
The EVAP purge vacuum switch is a normally closed switch positioned in the purge line between the canister and the EVAP purge solenoid. The EVAP purge vacuum switch will open when vacuum increases to greater than 5 inches of water in the purge line. The EVAP Purge Vacuum Switch is used by the PCM to monitor EVAP canister purge solenoid operation and purge system integrity. The EVAP Purge Vacuum Switch should be closed to ground with no vacuum present (0% EVAP Purge PWM). With EVAP Purge PWM at 25% or greater, the EVAP Purge Vacuum Switch should open and purge should be indicated

EVAP Vent Solenoid - Scan Tool Displays OPEN or CLOSED
Represents the state ot the EVAP Canister fresh air vent solenoid. Should be open during normal operation.

Fuel Level Sender - Scan Tool Range 0% to 100%
Represents the fuel tank level sensor input to the PCM. Fuel tank level affects the EVAP system and diagnostic operation.

Fuel Pump - Scan Tool Displays ON or OFF
Indicates the PCM commanded state of the fuel pump relay driver circuit. The fuel pump will be run at high speed to deliver more fuel volume when fuel flow or MAP is greater than a certain level, or when system voltage is less than 10 volts.

Fuel Pump Speed - Scan Tool Displays NORMAL or HIGH
Indicates the status of the PWM signal to the fuel pump control circuit to the [1][2]fuel pump control module.

Fuel Tank Pressure - Scan Tool Range 0 to 64 inch H2O
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 Mass Air Flow (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 NO or YES
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.

Gen F Terminal - Scan Tool Range 0% to 100%
Represents the field terminal input from the generator F terminal. Indicates the generator output level.

Generator Lamp - Scan Tool Displays ON or OFF
ON displayed indicates the PCM commanded state of the generator lamp/check gauges lamp due to low system voltage or a generator fault detected.