864977 Mercruiser HOSE, Thermostat Housing to Elbow

Illustration 1 g01193810
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 g01193815
Locations of the engine temperature sensors (typical left side engine view)
(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 connectors (4). Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Illustration 3 g01250277
Terminal locations at the P2 ECM connector for the engine temperature sensors
(P2-13) Engine coolant temperature
(P2-30) Sensor return
(P2-56) Intake manifold air temperature
(P2-62) Fuel temperature
Illustration 4 g01155187
Terminal locations at the connector for the temperature sensors
(1) Sensor 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 screws for each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and the wiring for abrasions and for pinch points from each of the temperature sensors to the ECM connector. Expected Result:All connectors, pins, and sockets are completely coupled and 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
Connect the 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 30 seconds in order for the diagnostic codes to become active.
Look for a -03 diagnostic code or a -04 diagnostic code.
Turn the keyswitch to the OFF position. Expected Result:No diagnostic codes are active.Results:
OK - No diagnostic codes are active.Repair: There is not an electrical problem with the temperature sensors at this time. The problem may have been related to a faulty connection in the harness. Carefully reinspect the connectors and wiring. If an intermittent electrical problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect" for additional information.STOP
Not OK - A -04 diagnostic code is active at this time. The ECM is detecting a short circuit for one of the temperature sensors. Proceed to Test Step 3.
Not OK - A -03 diagnostic code is active at this time. The ECM is detecting an open circuit for one of the temperature sensors. Proceed to Test Step 4.Test Step 3. Disconnect the Suspect Sensor in Order to Create an Open Circuit
Disconnect the suspect sensor from the engine harness.
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. Note: Wait at least 30 seconds for activation of the diagnostic codes.
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: There may be a problem with the sensor. 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 new 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 5.Test Step 4. Create a Short at the Sensor Connector
Disconnect the suspect sensor at the sensor connector.
Fabricate a jumper wire that is long enough to create a short between terminal 1 (signal) and terminal 2 (sensor return) at the suspect sensor's connector. Crimp connector pins to each end of the jumper wire.
Install the jumper wire into the terminals on the harness side of the sensor connector.
Turn the keyswitch to the ON position.
Access the "Active Diagnostic Code" screen on Cat ET. Check for an active -04 diagnostic code for the suspect sensor. Note: Wait at least 30 seconds for activation of the diagnostic codes.
Turn the keyswitch to the OFF position. Expected Result:A -04 diagnostic code is now active for the suspect sensor.Results:
OK - A -03 diagnostic code was active before creating the short at the sensor connector. A -04 diagnostic code became active after creating the short at the sensor connector.Repair: There may be a problem with the sensor. 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 new sensor. If there are no active diagnostic codes for the sensor, permanently install the new sensor. Clear any logged diagnostic codes.STOP
Not OK - A -03 diagnostic code is still active for the suspect sensors. Proceed to Test Step 5.Test Step 5. Check the Operation of the ECM
Fabricate a jumper wire that is long enough to reach from a terminal at the ECM connector