CASE-AXLE 4826772 - Caterpillar

Illustration 1 g02705397
Schematic for the Steering Oil Temperature Sensor
This diagnostic code is recorded when the ECM reads the input signal from the Steering Oil Temperature Sensor and the PWM duty cycle is below normal.The sensor is a PWM sensor that operates at a frequency of approximately 500Hz 200Hz. The sensor sends a PWM input signal to the ECM. The duty cycle of the signal will vary from 5% to 95%.The possible causes of this diagnostic code are listed below:
The signal circuit for the sensor is shorted to ground.
The sensor has failed.
The ECM has failed. This condition is unlikely.System Response:
The events related to this sensor signal will not work properly.
Steering filter bypass warnings may not activate.Note: The following test procedure may create other diagnostic codes. Clear these diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 0075 FMI 04 is active before performing this procedure.Note: Use the 146-4080 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.
Observe the status of the diagnostic code. Disconnect the sensor from the machine harness. Expected Result:The CID 0075 FMI 04 diagnostic code remains active. The FMI has not changed and the FMI 04 diagnostic code is still active.Results:
OK - The diagnostic code remains active. The sensor is correct. Proceed to Test Step 2.
NOT OK - The diagnostic code is no longer active. The sensor has failed.Repair: Replace the sensor.STOPTest Step 2. CHECK THE WIRING HARNESS OF THE SENSOR FOR A SHORT TO GROUND
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness from the sensor.
Disconnect the machine harness connectors from the ECM.
At the machine harness connector for the ECM, measure the resistance from the signal contact "J2-42" (wire C451-YL(Yellow)) of the machine harness to all possible sources of ground. Measure the resistance to all contacts of the machine harness connectors for the ECM. Expected Result:Each resistance measurement is greater than 5000 ohms.Results:
OK - Each resistance measurement is greater than 5000 ohms. The machine harness is correct. Proceed to Test Step 3.
NOT OK - One or more resistance measurements are not correct. There is a short in the machine harness. Repair: The short is between signal contact "J2-42" (wire C451-YL(Yellow)) and the circuit with the low resistance measurement. Repair the machine harness or replace the machine harness.STOPTest Step 3. CHECK IF THE DIAGNOSTIC CODE REMAINS
Inspect the contacts of the harness connectors and clean the contacts.
Reconnect all harness connectors.
Turn the disconnect switch and the key start switch to the ON position.
Operate the machine.
Check the status of the CID 0075 FMI 04 diagnostic code. Expected Result:The CID 0075 FMI 04 diagnostic code is active.Results:
OK - The CID 0075 FMI 04 diagnostic code is active. The diagnostic code has not been corrected. The ECM may have failed.Repair: With Caterpillar Electronic Technician (Cat ET) , if available, perform a "Wiggle