CORE AS-FUEL COOLER 2938396 - Caterpillar

Uncommanded Motion Detected (UCMD)
Note: The following description applies to EID codes 568, 569, 570, and 571 ONLY.These events are logged when the hystat motor response is faster or the hystat motor response is slower than expected on one track. When any of these events are triggered, the machine will perform an immediate machine shutdown and stop the machine quicker than an operator can respond to a pump and/or motor failure. These events are primarily due to pump failure or motor failure. Motor Speed sensor signals, Engine Speed sensor signals, Travel Pressure sensor signals, and Oil Temperature sensor signals are the inputs used to measure the difference between actual track speed and the track speed commanded by the operator. If a significant difference is detected for a certain length of time, the machine is brought to a stop quickly, and the appropriate EID is logged. To clear the event and allow the machine to move again, the key switch must be cycled.Causes of a UCMD Event
Pump Stuck at Maximum Displacement – The motor speed will always be running at the cross-over gear ratio when commanding a speed in the pump range. If the automatic track speed override is ON, one track will not come to a complete stop and the machine will pivot steer when commanded to stop.
Pump Stuck at Minimum Displacement - The motor does not move when commanding a speed. If the automatic track speed override is ON, one track will not move and the machine will pivot steer when commanded to move forward or rearward.
Motor Stuck at Maximum Displacement – The motor speed will not go above cross-over gear ratio when commanding a speed in the motor range. If the automatic track speed override is ON, one track will travel too fast and the machine will drift severely.
Motor Stuck at Minimum Displacement – The motor speed is always too high as compared to the desired speed. If the automatic track speed override is ON, one track will travel too fast and the machine will drift severely.
Pressure Sensor – If travel pressure diagnostic active, pressure defaults to low pressure. Could have false diagnostic while turning.
Temperature Sensor – If there is a temperature sensor diagnostic, high temperature is assumed which could falsely diagnose event if transmission oil is cold (below 0 °C (32 °F)).Note: Refer to Specifications, Systems Operation, Testing and Adjusting, M0086865, "Automatic Track Speed Control Override" for instructions on enabling the Automatic track speed control override function.
Illustration 1 g01435339
Uncommanded Motion Detected Troubleshooting Flowchart
(Applies to EID codes E0568, E0569, E0570, and E0571 ONLY)
Note: Refer to Specifications, Systems Operation, Testing and Adjusting, M0086865, "Piston Pump and Motor Maximum Displacement - Test" for more information.