TRACK GP 3855458 - Caterpillar

Illustration 1 g02610818
Connections of the transmission input speed sensor
Note: THE HARNESS BETWEEN THE ECM AND THE OEM CONNECTOR IS NOT A CATERPILLAR HARNESS. FOR MORE INFORMATION ABOUT THIS HARNESS PLEASE CONTACT THE OEM MANUFACTURER. This diagnostic code is associated with the transmission input speed sensor. The FMI 2 means that the ECM has determined that the signal frequency or the signal pulse width is not within the expected range. 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. An ECM failure 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 SPN 161 FMI 2 is active before performing this procedure. The engine must be running in order for the diagnostic code to be active.Note: Use a digital multimeter for the measurements in this procedure. Test Step 1. CHECK THE SENSOR.
Turn the disconnect switch and the key start switch to the ON position.
Ensure that the diagnostic code is active.
Disconnect the sensor from the machine harness. Expected Result:The diagnostic code is no longer active.Results:
OK - The diagnostic code is no longer active. The sensor has failed. Repair: Replace the sensor. Verify that the new sensor corrected this diagnostic code. The diagnostic code should not be active.STOP
NOT OK - The diagnostic code remains active. The sensor is not the cause of the diagnostic code. Proceed to Test Step 2.Test Step 2. CHECK FOR A SHORT IN THE HARNESS.
The sensor remains disconnected from the machine harness.
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the J1 and J2 machine harness connectors from the Transmission ECM.
At the J1 machine harness connector for the ECM, measure the resistance between the signal contact J1-68 to all other J1 and J2 contacts. Expected Result:Each resistance measurement should be greater than 5000 ohms.Results:
OK - The resistance that is measured is greater than 5000 ohms for each measurement. The harness is correct. The ECM may have failed.Repair: An ECM failure is unlikely. Exit this procedure and perform this diagnostic code procedure again. If the cause of the diagnostic code is not found, replace the transmission ECM. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace".STOP
NOT OK - The resistance that is measured is NOT greater than 5000 ohms for each measurement. The machine harness has failed.Repair: There is a short in the machine harness. The short is between the signal circuit and the circuit with the low resistance measurement. Repair the