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BCM:
Body Control Module
Boost Control Solenoid:
A solenoid that is energized by the PCM, in order to control turbo/supercharger boost pressure.
Brake Switch Signal:
An input signal to the PCM indicating that the brake pedal is being pressed. This signal is typically used to disengage Cruise Control systems and Torque Converter Clutch (TCC) solenoids. See also TCC.
CAM:
Camshaft Position Sensor. Sends a frequency signal to the PCM in order to synchronize fuel injector and spark plug firing.
Catalytic Converter:
Designed to reduce exhaust emissions.
CAN:
Controller Area Network
CARB:
California Air Resources Board. Governing body for emissions control in California.
CFI:
Central Fuel Injection (a.k.a. Throttle Body Fuel Injection TBI)
CFI:
Continuous Fuel Injection
CKP REF:
Crankshaft Position Reference.
CKP:
Crankshaft Position. See CPS.
CKT:
Circuit
Closed Loop (CL):
A feedback system that uses the O2 Sensor(s) to monitor the results of combustion. Based on the signal(s) from the O2 sensor(s), the PCM modifies the air/fuel mixture to maintain optimum performance with lowest emissions. In closed loop mode, the PCM can fine tune control of a system to achieve an exact result.
CMP:
Camshaft Position Sensor
CO:
Carbon Monoxide; odorless gas produced by incomplete combustion.
Code Scanner:
A device that interfaces with and communicates information via a data link.
Continuous Memory Codes:
See Pending Codes.
CPS:
Crankshaft Position Sensor. Sends a frequency signal to the PCM. It is used to reference fuel injector operation and synchronize spark plug firing on distributorless ignition systems (DIS).
CTS:
Coolant Temperature Sensor. A resistance sensor that sends a voltage signal to the PCM indicating the temperature of the coolant. This signal tells the PCM whether the engine is cold or warm.
