81789M Mariner WASHER

Illustration 1 g01095037
Schematic
Illustration 2 g01093946
Location of engine temperature sensors (1) Engine oil temperature sensor (middle) (2) Inlet manifold temperature sensor (3) Engine oil temperature sensor (end) (4) Coolant temperature sensor (5) Fuel temperature sensor
Illustration 3 g01093944
P2 ECM connector (P2-15) Engine oil temperature (end) (P2-18) Sensor return (P2-32) Coolant temperature (P2-33) Fuel temperature (P2-34) Engine oil temperature (middle) (P2-35) Inlet manifold temperatureTest Step 1. Inspect Electrical Connectors and Wiring
Remove the electrical power from the ECM.
Thoroughly inspect the J2/P2 ECM connector, the suspect sensor connector, and any other connectors in the circuit. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".
Perform a 45 N (10 lb) pull test on each of the wires in the sensor connector and the ECM connector that are associated with the active diagnostic code.
Verify that the latch tab of the connector is properly latched.
Check the ECM connector (allen head screw) for the proper torque. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".
Check the harness and wiring for abrasions and for pinch points from the sensor to the ECM.Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted. The harness and wiring are free of corrosion, of abrasion, and of pinch points.Results:
OK - The connectors and wiring are OK. Proceed to Test Step 2.
Not OK - There is a problem in the connectors and/or wiring.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.Verify that the repair eliminates the problem.STOPTest Step 2. Check for Active Diagnostic Codes
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Restore the electrical power to the ECM.
Monitor the active diagnostic code screen on Cat ET. Check and record any active diagnostic codes.Note: Wait at least 30 seconds in order for the diagnostic codes to become active.
Determine if the problem is related to an open circuit diagnostic code 03 or a short circuit diagnostic code 04.Expected Result:No diagnostic codes are active.Results:
OK - No diagnostic codes are active.Repair: The problem may have been related to a faulty connection in the harness. Carefully reinspect the connectors and wiring. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - A short circuit diagnostic code 04 is active at this time. Proceed to Test Step 3.
Not OK - An open circuit diagnostic code 03 is active at this time. Proceed to Test Step 4.Test Step 3. Disconnect the Suspect Sensor in Order to Create an Open Circuit
Remove the electrical power from the ECM.
Disconnect the suspect sensor from the harness at the sensor connector.
Restore the electrical power to the ECM. Wait at least 30 seconds for activation of the diagnostic codes.
Access the "Active Diagnostic Codes" screen on Cat ET and check for an active open circuit diagnostic code 03 for the suspect sensor.
Remove the electrical power from the ECM.Expected Result:An open circuit diagnostic code 03 is now active for the suspect sensor.Results:
OK - A short circuit diagnostic code 04 was active before disconnecting the sensor. An open circuit diagnostic code 03 became active after disconnecting the sensor.Repair: Temporarily connect a new sensor to the harness, but do not install the new sensor in the engine. Verify that there are no active diagnostic codes for the sensor. If there are no active diagnostic codes for the sensor, permanently install the new sensor. Clear any logged diagnostic codes.Verify that the repair eliminates the problem.STOP
Not OK - The short circuit diagnostic code 04 is still present. The short circuit is between the sensor harness connector and the ECM. Leave the sensor disconnected. Proceed to Test Step 7.Test Step 4. Check the Pull-up Voltage at the Sensor Connector
Disconnect the suspect sensor at the sensor connector.
Restore the electrical power to the ECM.
Measure the voltage between terminal 1 (signal) and terminal 2 (sensor return) at the sensor connector.
Remove the electrical power from the ECM.Expected Result:The voltage is 5 0.2 VDC.Results:
OK - The voltage is 5 0.2 VDC. The correct pull-up voltage is present at the suspect sensor connector.Repair: The open circuit is in the sensor or the wire between the sensor and the sensor connector. Replace the sensor. Do not install the sensor in the engine. Verify that no diagnostic codes are active for the suspect sensor before permanently installing the sensor.STOP
Not OK - The voltage is not 5 0.2 VDC. Proceed to Test Step 5.Test Step 5. Check the Signal Wire for a Short Circuit
Remove the electrical power from the ECM.
Disconnect ECM connectors P2 and ECM connector P1.
Measure the resistance between the terminal for the sensor signal wire at the ECM and every terminal on ECM connector P1 and ECM connector P2.
Reconnect ECM connector P1 and ECM connector P2.Expected Result:The resistance is greater than 20,000 Ohms.Results:
OK - The resistance is greater than 20,000 Ohms. Proceed to Test Step 6.
Not OK - The resistance is less than 20,000 Ohms.Repair: The resist