BIT-END 2755445 - Caterpillar

Upshift and Downshift Solenoids
Illustration 1 g00388352
Upshift and Downshift SolenoidsThe upshift and downshift solenoids are outputs of the ECM. The upshift solenoid connects to the ECM at connector contact J1-12. The downshift solenoid connects to the ECM at connector contact J1-18. The upshift solenoid and the downshift solenoid are used to shift the transmission. When the ECM decides to shift, the corresponding solenoid is activated with +battery voltage until the shift occurs. The upshift solenoid and the downshift solenoid control the flow of oil that turns the rotary actuator. The rotary actuator is in the transmission hydraulic control system. Movement (turning) of the rotary actuator shifts the transmission. The upshift solenoid and the downshift solenoid are located on the transmission hydraulic controls at the top of the transmission. The ECM records a diagnostic code that occurs with the upshift solenoid and the downshift solenoid. The diagnostic code that is recorded with the upshift solenoid is CID 0707. The diagnostic code that is recorded with the downshift solenoid is CID 0708.Parking Brake Solenoids and Brake Air Supply Solenoid
Illustration 2 g00749518
Tractor's Parking Brake SolenoidScraper's Parking Brake SolenoidBrake Air Supply SolenoidThe parking brake solenoids for the tractor and the scraper are outputs of the ECM. In order to deactivate the parking brakes for the tractor and the scraper, the ECM sends a +battery signal to the parking brake solenoids. When the solenoids are energized the parking brake is NOT applied. The park brake solenoids electrically control the parking brakes of the tractor and the scraper. This prevents the machine from moving, after the machine has come to a stop. The solenoids have a connector with two contacts. Contact 1 of the tractor's parking brake solenoid connects to the ECM at J1-4. Contact 2 connects to ground through the ECM at J1-7. Contact 1 connects to the ECM at J1-10. Contact 2 connects to ground through the ECM at J1-7.The ECM records diagnostic codes that occur with the tractor's parking brake solenoid. A diagnostic code with the Tractor's parking brake solenoid is recorded as a CID 1432. The ECM records diagnostic codes that occur with the scraper's parking brake solenoid. A diagnostic code with the scraper's parking brake solenoid is recorded as a CID 1433. The brake air supply solenoid is an output of the power train ECM. The brake air supply solenoid connects to the ECM at connector contact J1-11. The solenoid connects to ground through the ECM at J1-7.The solenoid controls the air governor that pressurizes the brakes. When the solenoid is turned ON the air governor is activated. When sufficient brake pressure is present, the solenoid is turned OFF.The ECM records diagnostic codes that occur with the brake air supply solenoid. A diagnostic code with the brake air supply solenoid is recorded as a CID 1631.