338-62435-0 Tohatsu O-RING, 1.5 - 1.9

Illustration 1 g01172915
Schematic for the engine temperature sensors
Illustration 2 g01173648
P2 ECM connector (P2-32) Engine coolant temperature (P2-18) Common for the engine temperature sensors (P2-35) Intake manifold air temperature (P2-33) Fuel temperature
Illustration 3 g01131612
Typical sensor locations (1) Engine coolant temperature sensor (2) Intake manifold air temperature sensor (3) Fuel temperature sensorTest Step 1. Inspect Electrical Connectors and Wiring
Turn the keyswitch to the OFF position.
Thoroughly inspect the J2/P2 ECM connector and the suspect sensor connector. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the temperature sensors.
Check the ECM connector (allen head screw) for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
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 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.
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:An 03 diagnostic code is now active for the suspect sensor.Results:
OK - An 04 diagnostic code was active before disconnecting the sensor. An 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 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.
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.
Turn the keyswitch to the OFF position.
Reconnect the P2 connector.Expected Result:Each check of the resistance is greater than 20,000 Ohms.Results:
OK - Each check of the resistance is greater than 20,000 Ohms. Proceed to Test Step 6.
Not OK - At least one check of the resistance is less than 20,000 Ohms.Repair: The low resistance measurement indicates a short circuit 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
Turn the keyswitch to the OFF position.
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.
Turn the keyswitch to the ON position.
Wait at least 15 seconds for activation of the 04 diagnostic code.Note: Monitor the "Active Diagnostic Codes" screen on Cat ET before installing the jumper wire and after installing the jumper wire.
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