ENGINE AR 1074860 - Caterpillar

spare output of the GSC can be programmed as a high/low logic signal for customer devices. Also, the spare output can be programmed as a serial data link for operating the relay driver module (RDM). When you are troubleshooting CID 334, it is necessary to determine the setting of the spare output. Setpoint SP11 is used to program the spare output. See Systems Operation, "Spare Input/Output Programming OP6".
SP11 = 1 through 8, for high/low logic.
SP11 = 9, for serial data link. If necessary, check the setpoint SP11 in order to determine the operation of the spare output. Perform the corresponding procedure that follows. 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 3.
A short to the battery ("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 3 is a short to the +battery. 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".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