KIT-SEAL 3081185 - Caterpillar

ON position. DO NOT START THE ENGINE.
Disconnect the machine harness connector from the sensor.
At the machine harness connector for the sensor, measure the supply voltage between the power supply contact A (wire R997-OR) and ground contact B (wire J766-PU).Expected Result:The supply voltage measurement is 5.0 0.3 VDC.Results:
OK - The voltage measurement is approximately 5.0 0.3 VDC. The power supply for the sensor is correct. Proceed to Test Step 2.
NOT OK - The voltage measurement is less than 5.0 0.3 VDC. The power supply for the sensor is not correct. Repair: Either the return circuit wire J766-PU or the supply circuit wire R997-OR has a bad connection or an open in the machine harness. Examine all of the connectors that are in the circuit. Ensure that the connections are clean, secure and in good condition.STOPTest Step 2. CHECK FOR AN OPEN IN THE SENSOR CIRCUITThe machine harness connector remains disconnected from the sensor.
Turn the key switch and the disconnect switch to the OFF position.
At the machine harness connector for the sensor, connect a jumper wire between the sensor return contact B (wire J766-PU) and the signal contact C (wire G442-PU) .
Disconnect machine harness connector J1 from the Machine ECM.
At the harness connector for the ECM, measure the resistance between the return contact J1-21 (wire J766-PU) and the signal contact J1-36 (wire G442-PU).Expected Result:The resistance measurement is less than 5 ohms.Results:
OK - The resistance measurement is less than 5 ohms. The sensor circuit is not open. Proceed to Test Step 3.
NOT OK - The resistance measurement is greater than 5 ohms. There is an open or a bad connection in the signal circuit.Repair: A resistance measurement that is greater than 5000 ohms could indicate that a wire is either not connected or is open. A resistance measurement that is greater than 5 ohms but less than 5000 ohms could indicate that one of the connection points in the circuit is not open but is not a good connection.In order to isolate the location of the problem in the circuit, check the involved circuit at the 70 pin bulk head connector that is located on the outside of the cab on the lower right side. The lower of the two 70 pin bulkhead connectors pass most Machine ECM circuits through the cab frame to the ECM. Refer to the Troubleshooting, "General Information" section of this manual for a contact assignment illustration for the two 70 pin bulkhead connectors.Perform the procedure to check the suspect circuit for an open at the correct contacts on the 70 pin bulkhead connector.With the jumper wire still in place at the machine harness connector for the component, check the resistance of the circuits at the frame side of the bulkhead connector. This will give an indication of whether the problem is in the cab portion of the circuit or in the machine side of the circuit.The complete machine Electrical System Schematic details the contact assignments for the bulkhead connectors and all of the