grampadirt
On MEDICARE Officially Old
Thought this might help someone,explained a lot to me.(taken from ALLDATAdiy)
Vehicle » Powertrain Management » Computers and Control Systems » Testing and Inspection » Scan Tool Testing and Procedures » Positions
Positions
This information will assist in emission or driveability problems. The displays can be viewed while the vehicle is being driven. Always perform the "On-Board Diagnostic (OBD) System Check" first. The "OBD System Check" will confirm proper system operation. The following positions may not be applicable to all engines:
ENGINE SPEED - Engine speed is computed by the PCM from the fuel control reference input. It should remain close to desired idle under various engine loads with engine idling.
DESIRED IDLE - The idle speed that is commanded by the PCM. The PCM will compensate for various engine loads to maintain the engine at the desired idle speed.
ENGINE COOLANT TEMP - The Engine Coolant Temperature (ECT) sensor is mounted in the intake manifold and sends engine temperature information to the PCM. The PCM supplies 5 volts to the coolant temperature 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 which it interprets 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.
LOOP STATUS - "Closed Loop" displayed 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 MAP sensor inputs only.
MANIFOLD ABSOLUTE PRESSURE (MAP) - The Manifold Absolute Pressure (MAP) sensor measures the change in the intake manifold pressure from engine load and speed changes. As intake manifold pressure increases, the air density in the intake manifold also increases and additional fuel is required.
BAROMETRIC PRESSURE (BARO) - The BARO reading displayed is determined from the MAP sensor at ignition "ON," engine "OFF," and WOT conditions. The BARO reading displayed represents barometric pressure and is used to compensate for altitude differences.
THROTTLE POSITION - Used by the PCM to determine the amount of throttle demanded by the driver. Should read 0.45-65 volt at idle to above 4 volts at Wide Open Throttle (WOT).
THROTTLE ANGLE - Computed by the PCM from TP sensor voltage (throttle position) and should display 0% at idle and 100% at wide open throttle. Refer to DTC 21 if TP sensor angle is not 0% at idle.
O2S - Represents the exhaust oxygen sensor output voltage. Should fluctuate constantly within a range between 100 mV (lean exhaust) and 1000 mV (rich exhaust) when operating in "Closed Loop."
INJECTOR PULSE WIDTH - In this position, the reading is given in milliseconds which is the "on-time" that the PCM is commanding to the injector(s).
SHORT TERM FUEL TRIM (FUEL INTEGRATOR) - Fuel integrator represents a short term correction to fuel delivery by the PCM in response to the amount of time the oxygen sensor voltage spends above or below the 450 mV threshold. If the oxygen sensor voltage has mainly been below 450 mV, indicating a lean air/fuel mixture, fuel integrator will increase to tell the PCM to add fuel. If the oxygen sensor voltage stays mainly above the threshold, the PCM will reduce fuel delivery to compensate for the indicated rich condition.
LONG TERM FUEL TRIM (BLOCK LEARN) - Long term fuel trim is derived from the short term fuel trim value and is used for long term correction of fuel delivery. A value of 128 counts indicates that fuel delivery requires no compensation to maintain a 14.7:1 air/fuel ratio. A value below 128 counts means that the fuel system is too rich and fuel delivery is being reduced (decreased injector pulse width). A value above 128 counts indicates that a lean condition exists and the PCM is compensating by adding fuel (increased injector pulse width).
FUEL TRIM CELL - Fuel trim cell is dependent upon engine speed and MAP sensor readings. A plot of rpm vs. MAP is broken into 16 cells. Fuel trim cell indicates which cell is currently active.
FUEL TRIM ENABLE - If air fuel system is learning "YES" then long term fuel trim is responding to short term fuel trim. If fuel trim enable reads "NO" then long term fuel trim will not respond to change in short term fuel trim normally, learning starts as soon as engine goes into "Closed Loop."
SPARK ADVANCE - This is a display of the spark advance Ignition Control (IC) calculation which the PCM is programming into the ignition system. It computes the desired spark advance using data such as engine temperature, rpm, load, vehicle speed and operating mode.
IDLE SPARK - idle speed control by timing.
K.S. ACTIVITY - indicates whether or not a knock signal is being detected by the PCM.
K.S. RETARD - Indicates the amount of spark advance the PCM is removing from IC in response to the Knock Sensor (KS) signal.
IDLE SPEED CONTROL ACTUATOR - Indicates whether the system is "OFF" or "ON."
4WD LOW SWITCH - Indicator to PCM when driver selects 4WD.
CONVERTER HIGH TEMP - Air fuel ratio enriches from 14.7 to 1 to 12 to 1 to help cool catalytic converter.
FUEL EVAP PURGE - Used to control EVAP canister purge function. 0% indicates the valve is commanded fully closed while 100% indicates that the valve is fully open.
EGR DESIRED POSITION - The PCM command for EGR valve position that is desired.
EGR ACTUAL POSITION - Current actual EGR position of the EGR valve.
EGR PINTLE POSITION - PCM command for linear EGR valve pintle position that is desired.
EGR DUTY CYCLE - The PCM cycles the EGR valve "ON" and "OFF." The "ON" time (duty cycle) of the EGR valve, expressed as a percent, determines how much the exhaust gas is recirculated.
MPH/km/h - Vehicle speed is a PCM internal parameter. It is computed by timing pulses coming from the Vehicle Speed Sensor (VSS) . Vehicle speed is used in checking TCC lock-up speed or speedometer accuracy. Speed is displayed in both Miles Per Hour (mph) and Kilometer Per Hour (km/h).
1 - 2 SHIFT SOL - When the transmission is in first or fourth gear, the Tech 1 should display "ON." When the transmission is in second or third gear, the Tech 1 should indicate "OFF."
2 - 3 SHIFT SOL - When the automatic transmission is in first or second gear, the Tech 1 should indicate "ON." When the transmission is in third or fourth gear, the Tech 1 should display "OFF."
TORQUE CONVERTER CLUTCH (TCC) SOLENOID - In this position, the tool will indicate when the TCC has been commanded by the PCM to turn "ON." This does not necessarily mean that the clutch was engaged but only that the PCM grounded the circuit internally. The best way to determine if the clutch has engaged is to monitor engine rpm when the TCC comes "ON."
TRANS RANGE SWITCH - Displays Park/Neutral, Reverse, Drive 4, Drive 3, Drive 2, Low and Invalid - These values represent the decoded sequence of the Transmission Range (TR) pressure switch assembly circuits and are used to determine manual valve position.
A/B/C RANGE - "ON/OFF" they are used to detect which gear has been manually selected engine must be operating.
TCC BRAKE SWITCH - The brake switch is operated by brake pedal travel. The switch is normally closed when the brake is released. This applies battery voltage to the PCM signal line. When brakes are applied, the PCM receives a Zero (0) volt signal on the signal line which caused TCC to be released. Brake switch input is used for line pressure and TCC control.
FUEL SHUTOFF - Indicates when PCM goes into this mode of operation. It is either rpm or mph activated.
IDLE AIR CONTROL - Displays the commanded position of the idle air control pintle in counts. The greater the number of counts, the greater the idle air passages opened. Idle air control should respond fairly quickly to changes in engine load to maintain desired idle rpm.
PARK/NEUTRAL POSITION - Displays "P-N" or "R-D-L" - "P/N" indicates park or neutral has been selected. "R-D-L" indicates that reverse, or a forward gear has been selected. Engine must be operating.
A/C REQUEST - Displays the state of the A/C signal line to the PCM. Should read "YES" whenever the A/C is requested.
A/C CLUTCH - Displays "ON" when the A/C clutch is engaged.
SYSTEM VOLTS - Battery/Ignition voltage is an analog input signal read by the PCM. It is the ignition switched battery voltage and is mainly used for diagnostics. Certain PCM functions will be modified if the battery voltage falls below or rises above programmed thresholds.
FUEL PUMP VOLTS - This parameter is a reading of the voltage going to the fuel pump. It is used by the PCM as the system voltage. The PCM uses fuel pump volts as a reference.
CALIBRATION ID - The PROM identification parameter describes the particular PROM used in the PCM being tested. The PROM contains the PCM program. PROM ID is used when it is necessary to replace the PROM. PROM ID must be specified when ordering new PROMs. PROM ID should not be confused with "Part Number."
TIME FROM START - Time from start is a measure of how long the engine has been running. If the engine stops, time from start will reset to 0:00:00.
Vehicle » Powertrain Management » Computers and Control Systems » Testing and Inspection » Scan Tool Testing and Procedures » Positions
Positions
This information will assist in emission or driveability problems. The displays can be viewed while the vehicle is being driven. Always perform the "On-Board Diagnostic (OBD) System Check" first. The "OBD System Check" will confirm proper system operation. The following positions may not be applicable to all engines:
ENGINE SPEED - Engine speed is computed by the PCM from the fuel control reference input. It should remain close to desired idle under various engine loads with engine idling.
DESIRED IDLE - The idle speed that is commanded by the PCM. The PCM will compensate for various engine loads to maintain the engine at the desired idle speed.
ENGINE COOLANT TEMP - The Engine Coolant Temperature (ECT) sensor is mounted in the intake manifold and sends engine temperature information to the PCM. The PCM supplies 5 volts to the coolant temperature 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 which it interprets 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.
LOOP STATUS - "Closed Loop" displayed 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 MAP sensor inputs only.
MANIFOLD ABSOLUTE PRESSURE (MAP) - The Manifold Absolute Pressure (MAP) sensor measures the change in the intake manifold pressure from engine load and speed changes. As intake manifold pressure increases, the air density in the intake manifold also increases and additional fuel is required.
BAROMETRIC PRESSURE (BARO) - The BARO reading displayed is determined from the MAP sensor at ignition "ON," engine "OFF," and WOT conditions. The BARO reading displayed represents barometric pressure and is used to compensate for altitude differences.
THROTTLE POSITION - Used by the PCM to determine the amount of throttle demanded by the driver. Should read 0.45-65 volt at idle to above 4 volts at Wide Open Throttle (WOT).
THROTTLE ANGLE - Computed by the PCM from TP sensor voltage (throttle position) and should display 0% at idle and 100% at wide open throttle. Refer to DTC 21 if TP sensor angle is not 0% at idle.
O2S - Represents the exhaust oxygen sensor output voltage. Should fluctuate constantly within a range between 100 mV (lean exhaust) and 1000 mV (rich exhaust) when operating in "Closed Loop."
INJECTOR PULSE WIDTH - In this position, the reading is given in milliseconds which is the "on-time" that the PCM is commanding to the injector(s).
SHORT TERM FUEL TRIM (FUEL INTEGRATOR) - Fuel integrator represents a short term correction to fuel delivery by the PCM in response to the amount of time the oxygen sensor voltage spends above or below the 450 mV threshold. If the oxygen sensor voltage has mainly been below 450 mV, indicating a lean air/fuel mixture, fuel integrator will increase to tell the PCM to add fuel. If the oxygen sensor voltage stays mainly above the threshold, the PCM will reduce fuel delivery to compensate for the indicated rich condition.
LONG TERM FUEL TRIM (BLOCK LEARN) - Long term fuel trim is derived from the short term fuel trim value and is used for long term correction of fuel delivery. A value of 128 counts indicates that fuel delivery requires no compensation to maintain a 14.7:1 air/fuel ratio. A value below 128 counts means that the fuel system is too rich and fuel delivery is being reduced (decreased injector pulse width). A value above 128 counts indicates that a lean condition exists and the PCM is compensating by adding fuel (increased injector pulse width).
FUEL TRIM CELL - Fuel trim cell is dependent upon engine speed and MAP sensor readings. A plot of rpm vs. MAP is broken into 16 cells. Fuel trim cell indicates which cell is currently active.
FUEL TRIM ENABLE - If air fuel system is learning "YES" then long term fuel trim is responding to short term fuel trim. If fuel trim enable reads "NO" then long term fuel trim will not respond to change in short term fuel trim normally, learning starts as soon as engine goes into "Closed Loop."
SPARK ADVANCE - This is a display of the spark advance Ignition Control (IC) calculation which the PCM is programming into the ignition system. It computes the desired spark advance using data such as engine temperature, rpm, load, vehicle speed and operating mode.
IDLE SPARK - idle speed control by timing.
K.S. ACTIVITY - indicates whether or not a knock signal is being detected by the PCM.
K.S. RETARD - Indicates the amount of spark advance the PCM is removing from IC in response to the Knock Sensor (KS) signal.
IDLE SPEED CONTROL ACTUATOR - Indicates whether the system is "OFF" or "ON."
4WD LOW SWITCH - Indicator to PCM when driver selects 4WD.
CONVERTER HIGH TEMP - Air fuel ratio enriches from 14.7 to 1 to 12 to 1 to help cool catalytic converter.
FUEL EVAP PURGE - Used to control EVAP canister purge function. 0% indicates the valve is commanded fully closed while 100% indicates that the valve is fully open.
EGR DESIRED POSITION - The PCM command for EGR valve position that is desired.
EGR ACTUAL POSITION - Current actual EGR position of the EGR valve.
EGR PINTLE POSITION - PCM command for linear EGR valve pintle position that is desired.
EGR DUTY CYCLE - The PCM cycles the EGR valve "ON" and "OFF." The "ON" time (duty cycle) of the EGR valve, expressed as a percent, determines how much the exhaust gas is recirculated.
MPH/km/h - Vehicle speed is a PCM internal parameter. It is computed by timing pulses coming from the Vehicle Speed Sensor (VSS) . Vehicle speed is used in checking TCC lock-up speed or speedometer accuracy. Speed is displayed in both Miles Per Hour (mph) and Kilometer Per Hour (km/h).
1 - 2 SHIFT SOL - When the transmission is in first or fourth gear, the Tech 1 should display "ON." When the transmission is in second or third gear, the Tech 1 should indicate "OFF."
2 - 3 SHIFT SOL - When the automatic transmission is in first or second gear, the Tech 1 should indicate "ON." When the transmission is in third or fourth gear, the Tech 1 should display "OFF."
TORQUE CONVERTER CLUTCH (TCC) SOLENOID - In this position, the tool will indicate when the TCC has been commanded by the PCM to turn "ON." This does not necessarily mean that the clutch was engaged but only that the PCM grounded the circuit internally. The best way to determine if the clutch has engaged is to monitor engine rpm when the TCC comes "ON."
TRANS RANGE SWITCH - Displays Park/Neutral, Reverse, Drive 4, Drive 3, Drive 2, Low and Invalid - These values represent the decoded sequence of the Transmission Range (TR) pressure switch assembly circuits and are used to determine manual valve position.
A/B/C RANGE - "ON/OFF" they are used to detect which gear has been manually selected engine must be operating.
TCC BRAKE SWITCH - The brake switch is operated by brake pedal travel. The switch is normally closed when the brake is released. This applies battery voltage to the PCM signal line. When brakes are applied, the PCM receives a Zero (0) volt signal on the signal line which caused TCC to be released. Brake switch input is used for line pressure and TCC control.
FUEL SHUTOFF - Indicates when PCM goes into this mode of operation. It is either rpm or mph activated.
IDLE AIR CONTROL - Displays the commanded position of the idle air control pintle in counts. The greater the number of counts, the greater the idle air passages opened. Idle air control should respond fairly quickly to changes in engine load to maintain desired idle rpm.
PARK/NEUTRAL POSITION - Displays "P-N" or "R-D-L" - "P/N" indicates park or neutral has been selected. "R-D-L" indicates that reverse, or a forward gear has been selected. Engine must be operating.
A/C REQUEST - Displays the state of the A/C signal line to the PCM. Should read "YES" whenever the A/C is requested.
A/C CLUTCH - Displays "ON" when the A/C clutch is engaged.
SYSTEM VOLTS - Battery/Ignition voltage is an analog input signal read by the PCM. It is the ignition switched battery voltage and is mainly used for diagnostics. Certain PCM functions will be modified if the battery voltage falls below or rises above programmed thresholds.
FUEL PUMP VOLTS - This parameter is a reading of the voltage going to the fuel pump. It is used by the PCM as the system voltage. The PCM uses fuel pump volts as a reference.
CALIBRATION ID - The PROM identification parameter describes the particular PROM used in the PCM being tested. The PROM contains the PCM program. PROM ID is used when it is necessary to replace the PROM. PROM ID must be specified when ordering new PROMs. PROM ID should not be confused with "Part Number."
TIME FROM START - Time from start is a measure of how long the engine has been running. If the engine stops, time from start will reset to 0:00:00.
