The Engine Scan Tool Data Definitions contains 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 may appear
more than once or in more than one data list in order to group
certain related parameters together.
A/C Clutch Feed Back Signal: The scan tool displays relay On or relay OFF. This parameter displays
the signal received from the A/C clutch to the PCM to indicate the A/C clutch
relay is ON or OFF.
A/C Compressor Cycling Switch: The scan tool displays Low Pressure or Normal. This parameter displays
the state of the A/C compressor cycling switch. The A/C compressor cycling
switch is a normally closed switch.
A/C Relay Command: The scan tool displays ON or OFF. This parameter displays the PCM
commanded state of the A/C clutch control relay. When the scan tool displays
ON, the A/C clutch should be engaged.
A/C Sec. High Pressure Switch: The scan tool displays High Pressure or Normal. This parameter
displays the state of the A/C secondary high pressure switch. The A/C secondary
high pressure switch is normally open.
A/C Request Signal: The scan tool displays Yes or No. The A/C Request displays the
state of the A/C request input circuit from the heating, ventilation, and
air conditioning (HVAC) controls. The powertrain control module (PCM) uses
the A/C request signal in order to determine whether the A/C compressor
operation is being requested.
AIR Pump Relay Command: The scan tool displays ON or OFF. The scan tool displays ON when
the PCM grounds the AIR pump relay control circuit. The scan tool displays
OFF when the PCM disables the ground circuit.
APP Average: The scan tool displays 0-125 counts. The TAC Module
takes the voltages from the 3 APP Sensors, averages the readings and converts
the readings into counts. The scan tool displays the average.
The average is different on every vehicle.
APP Indicated Angle: The scan tool displays 0-100 percent. The scan tool
displays the Accelerator Pedal Position in percentage. When the APP is at
rest, the display shows 0 percent. When the APP is fully depressed,
the display shows 100 percent.
APP Sensor 1: The scan tool displays 0-5 volts. When the accelerator
pedal is at 0 percent (pedal at rest), the display shows less than
1.1 volt. When the accelerator pedal is at 100 percent
(pedal fully depressed), the display shows more than 2.0 volts.
APP Sensor 2: The scan tool displays 5-0 volts. When the accelerator
pedal is at 0 percent (pedal at rest), the display shows more than
3.9 volts. When the accelerator pedal is at 100 percent
(pedal fully depressed), display shows less than 3.0 volt.
APP Sensor 3: The scan tool displays 5-0 volts. When the accelerator
pedal is at 0 percent (pedal at rest), display shows more than 3.2 volts.
When the accelerator pedal is at 100 percent (pedal fully
depressed), display shows less than 3.5 volts.
APP Sensor 1: The scan tool displays 0-100 percent. When the accelerator
pedal is at rest, display shows 0 percent. When the accelerator pedal
is fully depressed, display shows 100 percent. This percentage
indicates to the TAC Module the actual pedal position.
APP Sensor 2: The scan tool displays 0-100 percent. When the accelerator
pedal is at rest, display shows 0 percent. When the accelerator pedal
is fully depressed, display shows 100 percent. This percentage
indicates to the TAC Module the actual pedal position
APP Sensor 3: The scan tool displays 0-100 percent. When the accelerator
pedal is at rest, display shows 0 percent. When the accelerator pedal
is fully depressed, display shows 100 percent. This percentage
indicates to the TAC Module the actual pedal position.
APP Sen. 1 and 2 Disagree: The scan tool displays Agree or Disagree. When the TAC module receives
a signal voltage from APP Sensor 1 not in proper relationship to APP Sensor
2, the scan tool displays Disagree . The scan tool displays
Agree under the normal operating conditions.
APP Sen. 1 and 3 Disagree: The scan tool displays Agree or Disagree. When the TAC module receives
a signal voltage from APP Sensor 1 not in proper relationship to APP Sensor
3, the scan tool displays Disagree . The scan tool displays
Agree under the normal operating conditions.
APP Sen. 2 and 3 Disagree: The scan tool displays Agree or Disagree. When the TAC module receives
a signal voltage from APP Sensor 2 not in proper relationship to APP Sensor
3, the scan tool displays Disagree . The scan tool displays
Agree under the normal operating conditions.
Auxiliary Fan Request: The scan tool displays On or Off. The scan tool displays On when
the PCM grounds the auxiliary fan relay control circuit. The scan tool displays
Off when the PCM disables the ground circuit.
BARO: The scan tool displays a range of 10-105 kPa. The
barometric pressure reading is determined from the manifold absolute pressure
(MAP) sensor signal. The PCM monitors the MAP signal during key
up or wide open throttle (WOT) conditions. The barometric pressure
compensates for altitude differences.
CMP Sensor-High to Low: The scan tool displays 0-65,535 counts. The counts
increment as the PCM detects the camshaft position (CMP) sensor signal voltage
going from high to low.
CMP Sensor-Low to High: The scan tool displays 0-65,535 counts. The counts
increment as the PCM detects the CMP signal voltage going from low to high.
Cold Start Up: The scan tool displays Yes or No. A cold start-up is when the engine
coolant temperature (ECT) rises above a predetermined temperature during an
ignition cycle. The next ignition cycle the ECT should be below
a predetermined temperature. Also the ECT and the intake air temperature
(IAT) are less than 50° C (122° F) and are
within 3° C (5° F) of each other at start-up.
When the above is true, the scan tool displays Yes.
Coolant Level Switch: The scan tool displays OK or Low. This parameter indicates when
the engine coolant level is low. The scan tool displays Low when the PCM detects
the engine coolant level is low.
Cruise Control Active: The scan tool displays Yes or No. When the cruise control switch
is on and the set/coast switch is activated, the scan tool displays yes. When
the cruise control switch is ON and the set/coast switch is released, the
scan tool displays No.
Cruise On/Off Switch: The scan tool displays On or Off. When you activate the cruise
control switch, the scan tool displays ON. The switch, when in the ON position,
sends a signal voltage to the Throttle Actuator Control (TAC)
Module. This allows all other functions of the Cruise Control.
When you turn off the cruise control switch, the scan tool displays
OFF.
Cruise Resume/Accel: The scan tool displays On or Off. When the Cruise control switch
is in the on position and the Resume/Accel switch is activated, the scan tool
displays ON. When the Resume/Accel switch is released the scan
tool displays OFF.
Cruise Set/Coast: The scan tool displays On or Off. When the Cruise control switch
is in the on position and the Set/Coast switch is activated, the scan tool
displays ON. When the Set/Coast switch is released the scan
tool displays OFF.
Current Gear: The scan tool displays 0-4. The scan tool displays which
gear the transmission is in. An illegal transmission position displays 9.
Cycles of Misfire Data: The scan tool displays a range of 0-100. The PCM counts the
number of misfire tests during 200 engine revolutions.
Desired EGR Position : The scan tool displays 0-100 percent . This parameter displays
the desired position of the EGR pintle as requested by the PCM. This parameter
should be very close to Actual EGR position.
Desired EGR Position: The scan tool displays 0-5.0 volts. The commanded
EGR is the EGR pintle position commanded by the PCM.
Desired Idle Speed: The scan tool displays a range of 0-3,187 RPM. The
PCM commands the desired idle speed. The PCM compensates for various engine
loads based on ECT in order to keep the engine at the desired
speed.
DTC Set This Ignition: The scan tool displays Yes or No. This parameter indicates if a
diagnostic trouble code (DTC) set during the current ignition cycle.
ECT Sensor: The scan tool displays a range of -39°C to +140°C
(-38°F to +284°F). The PCM applies 5.0 volts to the
ECT sensor circuit. The sensor is a thermistor which changes internal
resistance as the engine temperature changes. When the sensor is
cold, internal resistance high, the PCM senses a high signal voltage
and interprets the voltage 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: The scan tool displays 0-5.0 volts. This display represents
the voltage that the PCM uses in order to determine whether or not the EGR
valve is closed. The voltage displayed will be the closed position
of the EGR pintle learned by the PCM.
EGR Position Sensor: The scan tool displays 0-5 volts. This parameter displays
the actual EGR pintle position in voltage.
EGR Position Sensor: The scan tool displays a range of 0-100 percent.
The PCM supplies a pulse width modulated (PWM) duty cycle to control the
exhaust gas recirculation (EGR) valve. Zero percent indicates no EGR flow.
One hundred percent indicates full EGR flow.
Engine Load: The scan tool displays a range of 0-100 percent . The PCM
calculates the engine load from engine speed and mass air flow (MAF) sensor
readings. The engine load increases with an increase in RPM or
airflow.
Engine Oil Level Switch: The scan tool displays OK or Low. This parameter indicates when
the engine oil level is low. The scan tool displays Low when the PCM detects
the engine oil level is low.
Engine Oil Life Remaining: The scan tool displays 0-100 percent . This display represents
the engine oil life index that is calculated and maintained by the PCM.
Engine Run Time: The scan tool displays Hours, Minutes, Seconds. This displays the
amount of engine run time for the current ignition cycle. When you cycle the
ignition OFF, the timer resets to zero.
Engine Speed: The scan tool displays a range of 0-10,000 RPM.
The PCM computes engine speed from the ignition reference pulses. The engine
speed should remain close to desired idle under various engine
loads with the engine idling.
EVAP Purge Solenoid Command: The scan tool displays a range of 0 percent -100 percent.
The PCM supplies a pulse width modulated (PWM) duty cycle to control the
EVAP purge solenoid valve. 0 percent indicates no purge. 100 percent
indicates full purge.
EVAP Test Result: The scan tool displays if the EVAP test has passed or failed. The
scan tool displays pass when the PCM determines that the EVAP diagnostic
has passed. The scan tool displays fail when the PCM determines that the
EVAP diagnostic has failed.
EVAP Vent Solenoid Command: The scan tool displays Venting or Not Venting. The EVAP canister
vent valve is normally open. The PCM commands the EVAP canister vent valve
closed, during testing of the EVAP system.
Fuel Level Sensor: The scan tool displays 0-5 volts. The scan tool displays
below 1 volt for an empty tank, and close to 2.5 volts
for a full tank.
Fuel Tank Level Remaining: The scan tool displays in liters or gallons the amount of fuel
remaining in the fuel tank.
Fuel Tank Level Remaining: The scan tool displays 0-100 percent. The scan tool displays
in percentage the amount of fuel remaining in the fuel tank.
Fuel Tank Pressure Sensor: The scan tool displays in -32.7 to +13.96 mm/Hg or -17.4
to +7.5 (in H2O). This parameter indicates the pressure vacuum inside of
the fuel tank. A negative value indicates a vacuum. A positive value
indicates a pressure.
Fuel Tank Pressure Sensor: The scan tool displays 0-5 volts. The scan tool displays
in voltage the pressure inside of the fuel tank.
Fuel Tank Rated Capacity: The scan tool displays the capacity of the fuel tank in liters
or gallons.
Fuel Trim Cell: The scan tool displays a range of 0 to 23. The PCM determines from
the manifold absolute pressure (MAP) and RPM inputs which fuel trim cell to
operate the engine in. The fuel trim cell displayed on the scan tool
is the cell that the engine is operating under.
Fuel Trim Learn: The scan tool displays Enabled or Disabled. When conditions are
appropriate for enabling long term fuel trim corrections, the scan tool displays
Enabled. This indicates that the long term fuel trim is responding
to the short term fuel trim. If the scan tool displays Disabled,
then long term fuel trim will not respond to changes in short
term fuel trim.
Generator F Terminal Signal Command: The scan tool displays 0-100 percent. The display
shows generator F terminal duty cycle in percent from 0-100 percent.
The generator is able to produce the desired voltage by varying the duty cycle
of the field current.
Generator L Terminal Signal Command: The scan tool displays On or Off. The scan tool displays Off if
the PCM does not detect a correct voltage on the L-terminal circuit.
The scan tool displays On under normal operating conditions.
HO2S Bank 1 and Bank 2 Sensor 1: The scan tool displays a range of 0-1,106 mV. The
heated oxygen sensor (HO2S) bank 1 and bank 2 sensor 1 parameter represents
the fuel control exhaust oxygen sensor output voltage. The voltage
fluctuates constantly within a range between 10 mV, and 1,000 mV,
while operating in Closed Loop.
HO2S Bank 1 and Bank 2 Sensor 2: The scan tool displays a range of 0-1,106 mV. The
HO2S bank 1 and bank 2 sensor 2 parameter represents the exhaust oxygen
sensor output voltage. The voltage fluctuates constantly within
a range between 10 mV , and 1,000 mV, while operating
in Closed Loop.
IAT Sensor: The scan tool displays a range of -39°C to +140°C
(-38°F to +284°F). The PCM converts the resistance of the intake
air temperature sensor to degrees. The PCM uses the IAT in order
to adjust fuel delivery and spark timing according to incoming
air density.
Ignition 1 Signal: The scan tool displays 0-25.5 volts. The ignition
1 represents the system voltage measured by the PCM at the ignition feed circuit.
Inj. PWM Average Bank 1 and Bank 2: The scan tool displays a range of 0-1,000 milliseconds.
The injector average indicates the amount of time the PCM commands each
injector ON during each engine cycle. A longer injector pulse
width causes more fuel to be delivered. The injector pulse width increases
with an increased engine load.
Knock Retard: The scan tool displays a range of 0.0 degrees-16 degrees.
Knock retard indicates the amount of spark the PCM removes from the ignition
control (IC) spark advance in response to the signal from the knock
sensors.
Long Term FT Avg. Bn1 and Bn2: The scan tool displays percentage. This parameter indicates the
average of all long term fuel trim cells. The short term fuel trim cells are
rated, for the amount of which they are used. For example,
an idle cell is rated higher than a wide open cell. If a fueling malfunction
occurs in the idle cell and the wide open cell, the average would
be more affected by the idle cell than the wide open cell. A negative
value significantly below 0 percent indicates that the fuel system
is rich and fuel delivery is being reduced. A positive value
significantly more than 0 percent indicates that a lean condition
exists and the PCM compensates by adding fuel. When the average
of the cells reach a predetermined high or low, a fuel trim DTC
sets.
Long Term FT Bank 1 and Bank 2: The scan tool displays percentage. The PCM derives the long term
fuel trim from the short term fuel trim value. The long term fuel trim 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/fuel ratio. A negative value
significantly below 0 percent indicates that the fuel system is
rich and the PCM is reducing the fuel delivery. A positive value
significantly more than 0 percent indicates that a lean condition
exists and the PCM compensates by adding fuel. Fuel trim values
at maximum authority indicates an excessively rich or lean system.
Loop Status: The 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,
engine coolant, and MAF sensor inputs only.
Low Oil Lamp Command: The scan tool displays On or Off. The scan tool displays On when
the PCM detects that there is a low oil level condition. The low oil lamp
is then commanded ON by the PCM.
MAF Sensor: The scan tool displays a range of 0.0-655 g/s. The
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 Sensor: The scan tool displays a range of 0-31,999 Hz. The
MAF sensor is a hot wire type air flow sensor. The PCM converts current draw
needed by the MAF to keep the hot wires at a constant into a frequency
signal. The scan tool displays this frequency in a hertz signal.
MAP Sensor: Scan Tool Range 10-105 kPa/0.0-5 volts. 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 intake vacuum decreases resulting
in a higher MAP sensor voltage and kPa reading. The PCM uses
the MAP sensor signal for the following: (1) Updating the BARO
reading; (2) Enabling factor for several of the diagnostics.
MIL Command: The scan tool displays On or Off. The scan tool indicates if the
PCM has commanded the malfunction indicator lamp (MIL) ON.
Mileage Since DTC Cleared: The scan tool displays Kilometers or Miles. This parameter indicates
the distance traveled since on emission diagnostic trouble code cleared. The
PCM stores this information in the Freeze Frame/Failure Records memory.
Misfire Current Cyl. #1 - #8: The scan tool displays a range of 0-255 counts. The
misfire current counters increment at a rate according to the number of possible
misfires the PCM detects on each cylinder during the last 200 cylinder
firing events. The counters may normally display some activity,
but the activity should be nearly equal for all the cylinders.
Misfire History Cyl. #1 - #8: The scan tool displays a range of 0-65,535 counts.
The misfire history counters display the total level of misfire that has been
detected on each cylinder. The misfire history counters will not
update or show any activity until a misfire DTC P0300 has
become active. The misfire history counters will update every
200 cylinder firing events.
PCM Reset: The scan tool displays Yes or No. This parameter indicates when
the internal PCM resets. The scan tool displays YES when an internal PCM reset
occurred. The scan tool displays NO under the normal operating
conditions.
PCM/VCM in VTD Fail Enable: The PCM displays Yes or No. The scan tool displays Yes if the body
control module (BCM) and the PCM lose communications with each other after
the BCM sends the correct password. The scan tool displays No if the
BCM is communicating the correct password to the PCM.
Reduced Engine Power: The scan tool displays Active or Inactive. The scan tool displays
Active when the PCM receives a signal from the TAC module that a throttle
actuator control system fault is occurring. The PCM limits the
engine power.
Short Term FT Avg. Bn1 and Bn2: The scan tool displays percentage. This parameter indicates the
average of the short term fuel trim cells. The short term fuel trim cells
are rated for the amount of which they are used. For example,
the PCM rates an idle cell higher than a wide open cell. If a fueling
malfunction occurs in the idle cell and the wide open cell, the
idle cell would affect more than then the wide open cell. A negative
value significantly below 0 percent indicates that the fuel system
is rich and the PCM is reducing the fuel delivery. A positive
value significantly more than 0 percent indicates that a lean condition
exists and the PCM is compensating by adding fuel. When the average
of the cells reach a predetermined high or low, a fuel trim DTC
sets.
Short Term FT Bank 1 and Bank 2: The scan tool displays percentage. The 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
mainly remains less than 450 mV, indicating a lean air/fuel
mixture, short term fuel trim increases into the positive range
above 0 percent. The PCM adds fuel. If the oxygen sensor voltage
stays mainly above the threshold, the short term fuel trim decreases
below 0 percent into the negative range. The PCM reduces the fuel
delivery in order to compensate for the indicated rich condition.
Under certain conditions such as an extended idle and a high ambient
temperature, the canister purge may cause the short term fuel trim
to read in the negative range during normal operation. The fuel
trim values at maximum authority may indicate an excessively rich
or lean system.
Spark: The scan tool displays a range of -64 degrees to +64 degrees.
The scan tool displays the amount of degrees the PCM commands the spark advance
on the IC circuit. The PCM computes the desired spark advance
using the following: (1) engine coolant temperature (ECT), (2) engine
speed (RPM), (3) load, (4) vehicle speed. The PCM adjusts the timing.
Start Up ECT: The scan tool displays a range of -39°C to +140°C
(-38°F to +284°F). The scan tool displays the engine ECT at
the time the engine was started. The PCM uses start-up ECT for certain
DTCs.
Stoplamp Pedal Switch: The scan tool displays Applied or Released. This parameter indicates
the state of the brake switch circuit input. The scan tool displays Applied
when you apply the vehicle brakes. The scan tool displays Released
when you release the vehicle brakes.
TAC/PCM Communication Signal: The scan tool displays OK or Fault. If the communication between
the TAC Module and the PCM is interrupted the scan tool displays Fault. The
scan tool displays OK under the normal operating conditions.
TCC Brake Pedal Switch: The scan tool displays Applied or Released. This parameter indicates
the state of the TCC/CC brake switch circuit input. Open indicates 0 voltage
input (brake switch open, brake pedal applied). Closed indicates
a B+ voltage input (brake switch closed, brake pedal released).
When you apply the vehicle brakes, the scan tool displays Applied.
The torque converter clutch and cruise control disengages. When
you release the vehicle brakes, the scan tool displays Released.
This allows the cruise control to be resumed and the torque
converter clutch to engage.
TCC Enable Solenoid Command: The scan tool displays Enabled or Disabled. The scan tool displays
Enabled when the electrical system supplies a voltage to the TCC enable solenoid
.
TCC PWM Solenoid Command: The scan tool displays 0-100 percent. This parameter
is the commanded state of the (TCC) PWM solenoid. The scan tool displays 100 percent
when the commanded state of the solenoid is ON. The scan tool displays
0 percent when the solenoid is OFF.
TFP Switch: The scan tool displays PARK/NEUTRAL, REVERSE, DRIVE 4, DRIVE 3,
DRIVE 2, or LOW. Trans range represents the decoded status of the four inputs
from the Transmission Internal Mode Switch Assembly. The combination of the
transmission inputs indicates the position of the transmission manual valve.
TP Desired Angle: The scan tool displays 0-100 percent. The PCM indicates
the desired throttle angle commanded by the vehicle operator.
TP Indicated Angle: The scan tool displays 0-100 percent. The TP Indicated
Angle displays in percentage the amount of throttle opening.
TP Sensor 1: The scan tool displays 0-100 percent. The scan tool
displays the amount of throttle opening in percentage. Closed throttle displays
0 percent and wide open throttle displays near 100 percent.
TP Sensor 1: The scan tool displays 0-5 volts. The scan tool displays
the amount of throttle opening in volts. Closed throttle displays about 1 volt
and wide open throttle displays above 3.5 volts.
TP Sensor 2: The scan tool displays 0-100 percent. The scan tool
displays the amount of throttle opening in percentage. Closed throttle displays
0 percent and wide open throttle displays near 100 percent.
TP Sensor 2: The scan tool displays 5-0 volts. The scan tool displays
the amount of throttle opening in volts. Closed throttle displays about 4 volts
and wide open throttle displays below 1.5 volts.
TP Sensors 1 and 2: The scan tool displays Yes or No. When the TAC module receives
a signal voltage from one of the Throttle Position Sensors not in proper relationship
to the other, the scan tool displays YES. The scan tool displays
NO under normal operating conditions.
TR Switch: The scan tool displays the transmission gear position.
Vehicle Speed Sensor: The scan tool displays km/h and mph. The vehicle speed sensor signal
is converted into km/h and mph for display on the scan tool.
VTD Auto Learn Timer: The scan tool displays Active/Inactive. The auto learn timer is
the indication if the vehicle theft deterrent (VTD) system is in the learn
mode and has not timed out.
VTD Fuel Disabled: The scan tool displays Active/Inactive. If the PCM has not received
the correct password from the BCM, the PCM disables the fuel system and
the scan tool displays Active. The scan tool displays Inactive under
normal operating conditions.
VTD Fuel Disable Until Ignition Off: The scan tool displays Yes or No. With the ignition ON and a VTD
code present, the scan tool displays Yes.
Warm Ups w/o Emission Faults: The scan tool displays a range of 0-255. This parameter
counts the number of warm up cycles without an emission fault present. The
counter increments to 255 and rolls back to 0 unless a fault occurs.
If a fault occurs, the counter reverts back to 0 until the fault
is corrected. Clearing the information with a scan tool or a loss
of power to the PCM also resets the counter to 0.
Warm Ups w/o Non - Emission Faults: The scan tool displays a range of 0-255. This parameter counts
the number of warm up cycles without a non-emission fault present. The counter
increments to 255 and rolls back to 0 unless a fault occurs. If
a fault occurs, the counter reverts back to 0 until the fault
is corrected. Clearing information with a scan tool or a loss
of power to the PCM also resets the counter to 0.