0446121 JOHNSON WASHER, Cylinder head to block

Illustration 1 g01177671
Schematic for the engine temperature sensors
Test Step 1. Inspect the Electrical Connectors and the Wiring
Turn the keyswitch to the OFF position.
Illustration 2 g01177670
Left side engine view (typical example)
(1) Engine coolant temperature sensor
(2) Intake manifold air temperature sensor
(3) Fuel temperature sensor
(4) J2/P2 ECM connectors
Thoroughly inspect the connectors for sensors (1), (2), and (3). Also, thoroughly inspect connector (4). Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Illustration 3 g01139919
P2 ECM connector
(P2-13) Engine coolant temperature
(P2-30) Sensor return
(P2-56) Intake manifold air temperature
(P2-62) Fuel temperature
Illustration 4 g01155187
(1) Signal
(2) Sensor return
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the temperature sensors.
Check the allen head screw for each of the ECM connectors for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for correct torque values.
Check the harness and wiring for abrasions and for pinch points from each 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 appear to be 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
Restore battery power to the ECM.
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Turn the keyswitch to the ON position.
Monitor the active diagnostic code screen on Cat ET. Check and record any active diagnostic codes. Note: Wait at least 15 seconds in order for the diagnostic codes to become active.
Look for an 03 diagnostic code or an 04 diagnostic code. 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 Troubleshooting, "Electrical Connectors - Inspect" for additional information.STOP
Not OK - An 04 diagnostic code is active at this time. Proceed to Test Step 3.
Not OK - An 03 diagnostic code is active at this time. Proceed to Test Step 4.Test Step 3. Disconnect the Suspect Sensor in Order to Create an Open Circuit
Turn the keyswitch to the OFF position.
Disconnect the suspect sensor from the harness at the sensor connector.
Turn the keyswitch to the ON position. Wait at least 15 seconds for activation of the diagnostic codes.
Access the "Active Diagnostic Codes" screen on Cat ET and check for an active 03 diagnostic code for the suspect sensor.
Turn the keyswitch to the OFF position. Expected Result:A 03 diagnostic code is now active for the suspect sensor.Results:
OK - A 04 diagnostic code was active before disconnecting the sensor. A 03 diagnostic code became active after the sensor was disconnected.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 04 diagnostic code is still present. 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.
Turn the keyswitch to the ON position.
Measure the voltage between terminal 1 (signal) and terminal 2 (sensor common) at the sensor connector.
Turn the keyswitch to the OFF position. Expected Result:The voltage is 5.5 0.5 VDC.Results:
OK - The voltage is 5.5 0.5 VDC. The correct pull-up voltage is present at the suspect sensor connector.Repair: The open circuit is in the sensor or in 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 5.5 0.5 VDC. Proceed to Test Step 5.Test Step 5. Check the Signal Wire for a Short Circuit
Turn the keyswitch to the OFF position.
Remove battery power from the ECM.
Disconnect the P2 connector.
Measure the resistance between the terminal for the sensor signal wire at the ECM and the remaining terminals on the P2 connector.
Measure the resistance between the terminal for the sensor signal wire at the ECM and engine ground.
Reconnect the P2 connector. Expected Result:Each resistance measurement indicates an open circuit.Results:
OK - Each resistance measurement indicates an open circuit. Proceed to Test Step 6.
Not OK - At least one resistance measurement does not indicate an open circuit.Repair: The resistance measurement indicates a low resistance between two or more wires. Repair the connectors or wiring and/or replace the connectors or wiring.STOPTest Step 6. Create a Short at the Suspect Sensor Connector
Install a jumper wire between terminal 1 and terminal 2 on the connector for the suspect sensor. Connect the jumper on the harness side of the connector.
Restore battery power