TRANSMISSION AR 2686506 - Caterpillar

Illustration 1 g01365930
Connections of the hydraulic oil temperature sensor
This diagnostic code is associated with the hydraulic oil temperature sensor. The FMI 03 means that the ECM has determined that the voltage of the signal circuit is acceptable, but the voltage of signal circuit is above the normal range.The possible causes of this failure are listed here:
The sensor has failed.
The signal circuit in the machine harness is shorted to ground.
The ECM may have failed. This is unlikely.System Response:This failure causes the hydraulic oil temperature to indicate the maximum value or the hydraulic oil temperature may intermittently indicate the maximum value.Test Step 1. CHECK THE SENSOR.
Disconnect the machine harness from the sensor. Expected Result:The diagnostic code changes from an FMI 03 to an FMI 04.Results:
OK - The diagnostic code changed to an FMI 04. This indicates that the failure is no longer present.Repair: The sensor has failed. Replace the sensor.STOP
NOT OK - The diagnostic code of an FMI 03 remained active. This indicates that the failure remains present. The sensor is not causing the failure. Proceed to Test Step 2.Test Step 2. CHECK 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 machine harness connector from the tractor ECM.
At the harness connector for the sensor, measure the resistance between the contact 2 (wire K977-PK(Pink)) and frame ground.
At the harness connector for the sensor, measure the resistance between the contact 1 (wire J764-BR(Brown)) and frame ground. Expected Result:The resistance is greater than 5000 ohms for both measurements. Results:
OK - The resistance is greater than 5000 ohms. The harness circuit resistance is correct. The tractor ECM has failed.Repair: It is unlikely that the ECM has failed. Exit this procedure and perform this CID 0600 FMI 03 procedure again. If the failure is not found, replace the ECM. See the Testing and Adjusting, "Electronic Control Module - Replace" section of this manual. STOP
NOT OK - The resistance is less than 5000 ohms. The machine harness has failed. There is a short to frame ground in the machine harness. Repair: Repair the machine harness or replace the machine harness.STOP