HEAD 2447778 - Caterpillar

Illustration 1 g01656274
Schematic Of the "Hydraulic Oil Temperature" sensorThis diagnostic code is associated with the "hydraulic oil temperature" sensor. This diagnostic code is recorded when the ECM reads the signal from the "hydraulic oil temperature" sensor (wire 442-GY) as being shorted to the +battery. The sensor produces a PWM signal. The signal (wire 442-GY) connects to contact J1-29 of the ECM.Possible causes of the diagnostic code is listed below:
The supply circuit to the sensor is open.
The return circuit is open.
The signal circuit is shorted to the +battery.
The signal circuit is open or the sensor is disconnected.
The sensor has failed.
The ECM has failed. This is unlikely.Note: Ensure that the CID 0600 FMI 03 diagnostic code is active. This procedure can cause new diagnostic codes to be recorded. Ignore these created diagnostic codes. When the procedure is completed, clear the created diagnostic codes.Test Step 1. CHECK THE VOLTAGE AT THE SENSOR.
Turn the disconnect switch and the key start switch to the ON position.
Disconnect the sensor from the machine harness.
At the machine harness connector for the sensor, measure the voltage between contact 1 (wire 442-GY) and contact 2 (wire L740-BR).Expected Result:The voltage should measure approximately 5 volts DC.Results:
OK - The voltage is approximately 5 volts DC. Proceed to test step 4.
NOT OK - The voltage is not approximately 5 volts DC. Repair: There is a problem with the machine harness or the ECM has failed. It is unlikely that the ECM has failed. Proceed to test step 2.Test Step 2. CHECK FOR AN OPEN IN THE SUPPLY CIRCUIT.
The key start switch and the disconnect switch remain in the ON position.
The sensor remains disconnected from the machine harness.
At the machine harness connector for the sensor, measure the voltage from contact 1 (wire 442-GY) to ground.Expected Result:The voltage should measure approximately 5 volts DC.Results:
OK - The voltage measurement is approximately 5 volts DC. Proceed to test step 3.
NOT OK - The voltage does not measure approximately 5 volts DC.Repair: The supply circuit is not correct. Repair the circuit or replace the circuit.STOPTest Step 3. CHECK FOR AN OPEN IN THE RETURN CIRCUIT.
Turn the key start switch and the disconnect switch to the OFF position.
The sensor remains disconnected from the machine harness.
Disconnect the machine harness connector J1 from the ECM.
At the machine harness connector for the sensor, install a jumper wire from contact 2 (wire L740-BR) to ground.
At the machine harness connector for the ECM, measure the resistance from contact J1-21 (wire L740-BR) to ground.Expected Result:The resistance measurement should measure less than 5000 ohms.Results:
OK - The resistance measurement is less than 5000 ohms. The harness is correct.Repair: The ECM may have failed. It is unlikely that the ECM is faulty. Recheck the status of the diagnostic code. If the diagnostic code remains present, exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, replace the ECM. See Troubleshooting, "Electronic Control Module (ECM) - Replace".STOP
NOT OK - The resistance that is measured is not correct.Repair: There is an