68042 Mercury STOP

Illustration 1 g01160620
Schematic for the engine temperature sensorsTest Step 1. Inspect the Electrical Connectors and the Wiring
Turn the keyswitch to the OFF position.
Illustration 2 g01160668
C11 Left side view (1) Engine coolant temperature sensor (2) Intake manifold air temperature sensor (3) Fuel temperature sensor (4) J2/P2 ECM connector
Illustration 3 g01143098
C15 Left side view (1) Engine coolant temperature sensor (2) Intake manifold air temperature sensor (3) Fuel temperature sensor (4) J2/P2 ECM connector
Thoroughly inspect each connector for engine temperature sensors (1), (2), and (3). Also, thoroughly inspect ECM connectors (4). Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Illustration 4 g01139919
P2 ECM connector (P2-13) Engine coolant temperature (P2-30) Sensor return (P2-56) Intake manifold air temperature (P2-62) Fuel temperature
Illustration 5 g01146837
Harness connector for the temperature sensors (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 ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the 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 wiring and/or the connectors. Replace parts, if necessary. 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 the Caterpillar Electronic Technician (ET) to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools".
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 a 03 diagnostic code or a 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 - A 04 diagnostic code is active at this time. Proceed to Test Step 3.
Not OK - A 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.
Access the "Active Diagnostic Codes" screen on Cat ET and check for an active 03 diagnostic code for the suspect sensor. Wait at least 15 seconds in order for the diagnostic code to become active.
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 new 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 active after the sensor has been disconnected. 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 (return) 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 key