11379 Mercury O-RING

Illustration 1 g01150024
Coolant level sensor
(1) Sensor
(2) Sensor probe (brass dowel)
(3) Plastic cover Coolant level sensor (1) contains no moving parts. The sensor provides the same function as a switch. The state of the switch is dependent on the capacitance value that is detected. The sensor contains a probe (2) that is covered with plastic (3).When the probe is immersed in coolant, the sensor senses a particular capacitance. The sensor's electronics react by sinking the signal to the digital return (ground).When the probe is not immersed in coolant, the capacitance value changes. The change in the capacitance value is detected by the sensor's electronic circuits. The sensor sources approximately +5 VDC to the signal wire. The Electronic Control Module (ECM) detects the voltage and the ECM activates the event code.The event code is probably caused by a low coolant level. The next likely cause is a problem with a wiring harness or with the sensor. The least likely cause is a problem with the ECM.
Illustration 2 g01150032
Typical location of the coolant level sensor
(4) Coolant level sensor
Illustration 3 g01204527
Schematic for coolant level sensor
Pressurized System: Hot coolant can cause serious burns. To open the cooling system filler cap, stop the engine and wait until the cooling system components are cool. Loosen the cooling system pressure cap slowly in order to relieve the pressure.
Test Step 1. Inspect the Electrical Connectors and the Wiring
Remove electrical power from the ECM.
Illustration 4 g01150055
Engine view
(5) J2/P2 connectors
Thoroughly inspect connectors (5). Inspect the connectors for sensor (4). Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Illustration 5 g01204728
P2 ECM connector
(P1-15) SCAC coolant level sensor
(P1-30) Engine coolant level sensor
(P2-57) +8 V digital supply
(P2-66) Digital sensor return
(P2-65) +8 V digital supply
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit for the coolant level sensor.
Check the allen head screw on each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values. Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted, and 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 with the connectors and/or the wiring.Repair: Repair the wiring and connectors or replace the wiring or the connectors. Ensure that all of the seals are properly connected. Verify that the repair eliminates the problem.Verify that the repair eliminates the problem.STOPTest Step 2. Check the Supply Voltage at the Sensor Connector
Disconnect the coolant level sensor.
Restore electrical power to the ECM.
Illustration 6 g01132478
Harness connector for the coolant level sensor
(A) +8 VDC
(B) Return
Measure the voltage between terminals A (+8 VDC) and B (return) at the harness connector for the coolant level sensor.
Remove electrical power from the ECM. Expected Result:The voltage measurement is 8.0 0.4 VDC.Results:
OK - The voltage measurement is 8.0 0.4 VDC. The supply voltage is reaching the sensor. Proceed to Test Step 3.
Not OK - The voltage measurement is not 8.0 0.4 VDC. The digital sensor supply voltage is not reaching the sensor.Repair: Refer to Troubleshooting, "Digital Sensor Supply Circuit - Test".STOPTest Step 3. Disconnect the Coolant Level Sensor and Monitor the Status of "Coolant Level"
Connect the Caterpillar Electronic Technician (ET) to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools".
Disconnect the coolant level sensor connectors.
Restore electrical power to the ECM.
Monitor the status of "Coolant Level" on Cat ET.
Remove electrical power from the ECM. Expected Result:The status changes from "OK" to "Low" when the sensor is disconnected.Results:
OK - The status is "Low" when the sensor is disconnected. Proceed to Test Step 4.
Not OK - The status is "OK" when the sensor is disconnected. Proceed to Test Step 5.Test Step 4. Short the Harness and Monitor the Status of "Coolant Level"
Restore electrical power to the ECM and monitor the status of "Coolant Level" on Cat ET.
Install a jumper wire between terminals B (return) and C (signal) on the harness connector for the coolant level sensor.
Monitor the status of "Coolant Level" on Cat ET while the jumper wire is installed.
Remove the jumper wire.
Remove electrical power from the ECM. Expected Result:The status changes from "Low" to "OK" when the jumper wire is installed.Results:
OK - The status changes from "Low" to "OK" when the jumper wire is installed. The ECM and the wiring to the coolant level sensor are OK.Repair: Perform the following procedure:
Pressurized System: Hot coolant can cause serious burns. To open the cooling