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RP 146 - Identification Of Standardized Electrical Circuits For Class 8 Vehicles: Definitions

SAE J2191 defines the following terms:

Electrical Circuit -  An electrical circuit includes all of the components and connecting cables, starting from the electrical energy source, going to the functional component(s) and the return route through the energy source.

Ground -  An electrical conductor used as a common return for an electric circuit(s) and with a relative zero potential.

Harness -  A group of two or more cables bundled together.

Original Equipment Manufacturer -  Truck/Engine/Transmission, etc., manufacturer.

Wiring -  Collectively, the cable, terminations, and supporting accessories used in the electrical distribution system.

EXAMPLE
Primary Circuit Identifier Separator Supplemental Suffix
C123 (single space) (OEM Identifier) # (single space) 1512 (Subsystem/Circuit Function)
In this case, the first two digits (15) of the supplemental suffix indicate the circuit is a control (fuel, engine, cruise) circuit. The last two digits (12) indicate the circuit function is electronic engine control.
A partial section of the General Categories code assignment as detailed in the ballot version of SAE J2191 appears below for illustration purposes. A complete set of circuit code assignments is available from the Society of Automotive Engineers, 400 Commonwealth Drive, Warrendale, PA 15096, (412) 776-4841.
Supplemental Suffix  Subsystem Description  Circuit Function 
1501 Control (Fuel, Engine, Cruise) Engine Shutdown
1502 Control (Fuel, Engine, Cruise) Engine Retard On/Off
1503 Control (Fuel, Engine, Cruise) Idle Timers or Shutdown
1504 Control (Fuel, Engine, Cruise) Cruise On/Off
1505 Control (Fuel, Engine, Cruise) Engine Retard Select Sw
1506 Control (Fuel, Engine, Cruise) Throttle (RPM Set)
1507 Control (Fuel, Engine, Cruise) Clutch
1508 Control (Fuel, Engine, Cruise) Cruise Set/Resume
1509 Control (Fuel, Engine, Cruise) Overspeed Protection
1510 Control (Fuel, Engine, Cruise) PTO Set
1511 Control (Fuel, Engine, Cruise) Stop Sw Cruise Override
1512 Control (Fuel, Engine, Cruise) Electronic Engine Control