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| Illustration 1 | g02560517 |
Connections of the hydraulic oil temperature sensor | |
This diagnostic code is associated with the hydraulic oil temperature sensor. This diagnostic code is recorded when the ECM reads the signal from the sensor (wire R732-BR) as being shorted to the +battery. The signal (wire R732-BR) connects to contact J1-22 of the ECM. Refer to Systems Operation, "Electrical Input Components" for information regarding the operation of the sensor and the location.
Possible causes of the diagnostic code are listed:
- The return circuit is open.
- The signal circuit is open or the sensor is disconnected.
- The signal circuit is shorted to the +battery.
- The sensor has failed.
- The ECM has failed. The failure of ECM is unlikely.
Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear these diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 0600 FMI 03 is active before performing this procedure.
Note: Use a digital multimeter for the measurements in this procedure.
Test Step 1. CHECK FOR AN OPEN IN THE RETURN CIRCUIT
- Turn the key start switch and the disconnect switch to the OFF position.
- Disconnect the sensor from the machine harness.
- At the machine harness connector for the sensor, measure the resistance from contact 2 (wire 993-BR) to ground.
Expected Result:
The resistance measurement should measure less than 5 ohms.
Results:
- OK - The resistance measurement is less than 5 ohms. The harness is correct. Proceed to Test Step 2.
- NOT OK - The resistance that is measured is not correct.
Repair: There is an open in the machine harness. The open is in the return circuit with the high resistance measurement. Repair the harness or replace the harness.
STOP
Test Step 2. CHECK FOR AN OPEN IN THE SIGNAL CIRCUIT
- Turn the key start switch and the disconnect switch to the OFF position.
- Disconnect the J1 and J2 machine harness connector from the ECM.
- At the machine harness connector for the sensor, install a jumper wire from contact 1 (wire R732-BR) to contact 2 (wire 993-BR).
- At the machine harness connector J1, measure the resistance from contact J1-22 (wire R732-BR) to contact J2-63 (wire 993-BR).
Expected Result:
The resistance should measure less than 5 ohms.
Results:
- OK - The resistance measures less than 5 ohms. Proceed to Test Step 3.
- NOT OK - The resistance measurement is greater than 5 ohms.
Repair: There is an open in the signal circuit. Repair the harness or replace the harness.
STOP
Test Step 3. CHECK THE SIGNAL CIRCUIT FOR A SHORT
- The disconnect switch and the key start switch remain in the OFF position.
- The machine harness connectors J1 and J2 remain disconnected.
- Remove the jumper wire from contact 1 (wire R732-BR) to contact 2 (wire 993-BR).
- At the J1 and J2 machine harness connectors for the ECM, measure the resistance for the signal contact of the sensor J1-22 (wire R732-BR) to all other J1 and J2 contacts.
Expected Result:
Each resistance measurement should be greater than 5000 ohms.
Results:
- OK - Each resistance measurement is greater than 5000 ohms.
Repair: The sensor has failed. Replace the sensor and verify that the new sensor has corrected the problem. If the problem persists, exit this procedure and perform this procedure again. If the cause of the problem is not found, contact your dealership's Technical Communicator for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the ECM requires replacement, refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace" section of this manual for additional information.
STOP
- NOT OK - A resistance measurement is less than 5000 ohms. There is a short in the machine harness. The short is between the signal circuit and the circuit with the low resistance measurement.
Repair: Repair the harness or replace the harness.
STOP