SUPPORT 2312766 - Caterpillar

The Traction Control valve (TCS) is mounted inside the rear of the left frame rail or the rear of the rear frame rail. The solenoid is mounted on the valve.The proportional solenoid valve is an output of the brake ECM. The proportional solenoid valve is designed to regulate the amount of oil that is drained from the control circuit of the selected parking brake. The rate of flow is controlled by a signal from the brake ECM. The solenoid has a resistance of approximately 16 Ohms.The proportional solenoid receives a Pulse Width Modulated signal (PWM) from the brake ECM. As the duty cycle is increased, the proportional solenoid valve will open longer and more oil pressure is allowed to drain from the brake system. Voltage to the proportional solenoid increases proportionally from 0 to approximately 12 Volts as the demand for braking increases.The proportional solenoid has a connector with two contacts. Contact 1 of the solenoid connects to the brake ECM and contact 2 of the solenoid connects to the solenoid return circuit.Note: The ECM diagnoses certain failures in the circuit of the solenoid circuit. The ECM will detect a diagnostic code when an invalid combination of opens and/or grounds exist. This diagnostic code is displayed on the message display. See the diagnostic codes in the Troubleshooting section of this manual.Front Brake Cooling Diverter Solenoid
Illustration 8 g01100269
Front brake cooling diverter solenoid on the 793D located in the compartment behind the cab
When the hydraulic ARC function is activated, the ECM will energize the front brake cooling diverter solenoid. When this occurs, air pressure is applied to the front brake cooling diverter valve which will divert cooling oil to the front brake oil cooler. The ECM will activate diagnostic codes for this solenoid when abnormal conditions are detected. The diagnostic codes are listed in the Troubleshooting section of this manual.Rear Axle Diverter Solenoid
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Rear axle (RAX) diverter solenoid equipped on the 793D trucks
The rear axle diverter solenoid is also referred to as the final drive bypass solenoid. The solenoid is located on the final drive bypass manifold. This solenoid is used to direct lubrication oil flow to the differential and to the final drives or to divert the oil flow to the differential only. This diversion of oil prevents the final drives from receiving excessive oil flow under certain conditions. This solenoid is driven by the rear axle relay based on input from the ECM. When the solenoid is NOT energized, oil will flow to the final drives and to the differential. When the solenoid IS energized, oil will flow the differential. When the rear axle relay energizes the solenoid, a solenoid status input is sent to the ECM through wire K878-WH(White) in order to indicate the state of the solenoid. Rear Axle Supply Solenoid
Illustration 10 g01206167
Rear axle (RAX) Supply solenoid equipped on the 793D trucks
The rear axle supply solenoid is located on the priority valve housing. This solenoid is used to direct or divert lubrication oil flow to the rear axle