BREATHER GROUP 4L8764 - Caterpillar

High/Low Logic Circuit
Illustration 1 g00487533
System Schematic For Spare OutputWhen used as a high/low logic circuit.The spare output on the GSC is strictly used for the customer. The spare output is programmed to activate under a variety of conditions. The default is set for the output to activate when the engine is in the cooldown (SP11 = 7). The GSC treats this diagnostic code as a alarm fault. For more information, see Systems Operation, "Spare Input/Output Programming OP6". The responsibility of documenting any connections to this spare output falls on the customer and/or the dealer. Also, The responsibility of troubleshooting any connections to this spare output falls on the customer and/or the dealer. The voltage on the spare output is approximately 3.0 DCV when the spare output is not active. The voltage is approximately 3.0 DCV when there are no connections to the spare output. When the spare output is active, the voltage on the spare output is approximately 0 volts. The spare output is capable of drawing (sinking) approximately 100 mA.ProcedureThe following condition could be a possible cause of a CID 334 FMI 4.
A short to the ground ("B-") of the signal for the spare output is present.Troubleshooting of a spare output fault is direct. The FMI defines the diagnostic code. FMI 4 is a short to ground. In order to find the exact cause of the diagnostic code, use the following information: the FMI, the system schematic for the spare output and the documentation that is provided by the dealer and/or the customerSerial Data Link
Illustration 2 g00487536
System Schematic For Spare OutputWhen used as a serial data link.The GSC communicates with the relay driver module (RDM) by a serial data link. The serial data link is enabled when the setpoint SP11 is 9. For more information, see Systems Operation, "Spare Input/Output Programming OP6".Note: Earlier 103-6177113-4500117-6200120-6880123-6004136-3870 EMCP Electronic Controls do not have the RDM serial data link capability.When the data link malfunctions, R1 output (terminal 2 of the RDM) will be activated on and off at a rate of 0.5 Hz. Relays "R2" through "R9" will maintain the current states or the relays will default to off. This is controlled by a jumper between terminals 6 and 7 of the RDM. If a jumper is NOT present when the serial data link has a fault, the relay outputs ("R2" through "R9") will maintain the current states. If the jumper is present, "R2" through "R9" will default to OFF. Note: The maximum distance between a module and the GSC is 305 m (1000 ft). If this specification is not met, it is possible for the data link to malfunction. Also, a diagnostic code of CID 334 could occur. If the distance is not in compliance with the specification, shorten the distance between the RDM and the GSC.Note: Faults are created