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Relay:
An electromechanical device in which connections in one circuit are switched.
Reluctance Sensor:
A type of sensor typically used to measure crankshaft or camshaft speed and/or position, driveshaft speed, and wheel speed.
ROM:
RPM:
Revolutions Per Minute
SAE:
Society of Automotive Engineers.
Scan Tool:
A device that interfaces with and communicates information on a data link.
SDM:
Sensing and Diagnostic Module
Sensor x:
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:
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.
SES:
Service Engine Soon dash light, now referred to as MIL
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.
Solenoid:
A device consisting of an electrical coil which when energized, produces a magnetic field in a plunger, which is pulled to a central position. A solenoid may be used as an actuator in a valve or switch.
STFT:
Short Term Fuel Trim.
STS:
Service Throttle Soon
TAC:
Throttle Actuator Control
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.
TCC:
Torque Converter Clutch
TCM:
Transmission Control Module
TCS:
Traction Control System for PCM and brakes