BRACKET AS-MOUNTING 6I0988 - Caterpillar

Illustration 1 g03372536
Schematic of the Left Drive Motor Speed Sensors
This diagnostic code is associated with the Left Drive Motor Speed Sensor #1. Each motor has two speed sensors, two signal wires, a power signal wire, and a ground. The ECM is able to diagnose each signal wire independently. Each signal wire provides a frequency input to the ECM that is proportional to motor speed. If this diagnostic code is active, the ECM will keep the code active until a good sensor signal is observed by the Machine ECM. This means that the drive motors must be moved in order for the Machine ECM to determine if the active code can be cleared.This diagnostic code is recorded when the Machine ECM receives an incorrect signal from the speed sensor. The incorrect signal that is being read by the Machine ECM has the following characteristics: Abnormal frequency, pulse width, or periodBefore performing this procedure, inspect the harness connectors that are involved in the circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all circuit connections are clean. Verify that all circuit connections are secure. Verify that all circuit connections are in good condition. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure.System Response:The CID 2685 FMI 08 diagnostic code will generate a level 2 warning. A closed control loop will be disabled. The "Unexpected Motor Speed Detection Control" function will be disabled. While the machine is moving, a level 3 event will be active. This code indicates that the "Unexpected Motor Speed Detection" function is disabled E695.Troubleshooting:Note: The following test procedure may create other diagnostic codes. Clear the diagnostic codes when the problem has been correct. Verify that the CID 2685 FMI 08 diagnostic code is active. Perform the following test.Test Step 1. Check The Power At The Sensor
The machine harness remains disconnected from the sensor.
Turn the key start switch to the ON position.
At the machine harness for the sensor, measure the voltage. Measure the voltage from contact 1 (wire P769-YL(Yellow)) and contact 2 (wire P770-WH(White)).Expected Result:The voltage that is measured is 8.0 1.0 DCV.Results:
OK - The voltage measurement is 8.0 1.0 DCV. The voltage is correct. Proceed to Test Step 3. Proceed