LOCKNUT 1191840 - Caterpillar

Illustration 1 g01352797
Connections of the left track speed sensor
This diagnostic code is associated with the left track speed sensor #1. The FMI 02 means that the ECM has determined that the data is erratic, intermittent, or incorrect. This code applies to wire (769-BU(Blue)).Each speed sensor has two signal wires, a power and ground. The ECM is able to diagnose each signal wire independently. Each signal wire provides a frequency input to the ECM which calculates the revolutions per minute as well as direction. The ECM will keep the diagnostic code active until a good signal is observed by the ECM. This means that the tracks of the machine must be moved in order for the ECM to determine if the active code can be cleared. The possible causes of this diagnostic code are listed below:
The sensor has failed.
Intermittent connections or poor connections
Mechanical devices are loose.
The ECM has failed. This is unlikely.Before 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 of the connections in the circuit are clean and secure. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 2685 FMI 02 is active before performing this procedure.Note: Movement of the tracks is required in order to diagnose this diagnostic code. Use a digital multimeter for the measurements in this procedure.System Response:When this fault is active, the ECM will turn off the straight tracking control. The machine may drift to one direction. The detection of the unexpected motor speed is disabled. A EID 0695 event code is active when the lever is out of neutral. The lever is out of neutral due to this diagnostic code. Once the diagnostic is cleared and the lever is moved to neutral, the active event will be cleared.Test Step 1. CLEARING THE DIAGNOSTIC CODE 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 of the connections in the circuit are clean and secure. Note: The machine may be placed on jack stands for testing the movement of the tracks.
: MAKE SURE PERSONNEL ARE CLEAR FROM THE MACHINE.
Turn the disconnect switch and the keyswitch to ON and start the machine. Go to high idle.
Connect the Cat ET and