Actron OBD II AutoScanner CP9135 Instructions Manual page 33

Sensor:
Any device that reports information to
the PCM. The job of the sensor is to
convert a parameter such as engine
temperature into an electrical signal
that the PCM can understand.
Sensor 1:
A standard term used to identify the
location of oxygen sensors. Sensor 1 is
located upstream of the catalytic
converter. See O2S, Bank 1, Bank 2.
Sensor 2:
A standard term used to identify the
location of oxygen sensors. Sensor 2 is
located downstream of the catalytic
converter. See O2S, Bank 1, Bank 2.
SFI or SEFI:
Sequential Fuel Injection or Sequential
Electronic Fuel Injection. A fuel
injection system that uses one or more
injectors for each cylinder. The injectors
are mounted in the intake manifold, and
are fired individually.
ST:
Short Term fuel trim.
TBI:
Throttle Body Injection. A fuel injection
system having one or more injectors
mounted in a centrally located throttle
body, as opposed to positioning the
injectors close to an intake valve port.
TBI is also called Central Fuel Injection
(CFI) in some vehicles.
TDC:
Top Dead Center. When a piston is at
its uppermost position in the cylinder.
Throttle Body:
A device which performs the same
function as a carburetor in a fuel injection
system. On a throttle body injection (TBI)
system, the throttle body is both the air
door and the location of the fuel injectors.
On port fuel injection systems (PFI, MPFI,
SFI, etc.) the throttle body is simply an air
door. Fuel is not added until the injectors
at each intake port are activated. In each
case, the throttle body is attached to the
accelerator pedal.
Glossary
TPS:
Throttle Position Sensor.
Potentiometer-type sensor connected to
the throttle shaft. Its voltage signal
output increases as the throttle is
opened. The PCM uses this signal to
control many systems such as idle
speed, spark advance, fuel delivery,
etc.
TTS:
Transmission Temperature Sensor. A
resistance sensor mounted in the
transmission housing in contact with
the transmission fluid. It sends a
voltage signal to the PCM indicating the
temperature of the transmission.
VECI:
Vehicle Emission Control Information. A
decal located in the engine
compartment containing information
about the emission control systems
found on the vehicle. The VECI is the
authoritative source for determining
whether a vehicle is OBD II compliant.
VIN:
Vehicle Identification Number. This is
the factory-assigned vehicle serial
number. This number is stamped on a
number of locations throughout the
vehicle, but the most prominent
location is on top of the dashboard on
the driver's side, visible from outside
the car. The VIN includes information
about the car, including where it was
built, body and engine codes, options,
and a sequential build number.
VSS:
Vehicle Speed Sensor. Sends a
frequency signal to the PCM. The
frequency increases as the vehicle moves
faster to give the PCM vehicle speed
information used to determine shift points,
engine load, and cruise control functions.
WOT:
Wide-Open Throttle. The vehicle
operating condition brought about when
the throttle is completely (or nearly) open.
The PCM will typically deliver extra fuel to
the engine and de-energize the A/C
compressor at this time for acceleration
purposes. The PCM uses a switch or the
Throttle Position Sensor to identify the
WOT condition.
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