RING-RETAINING 2L6965 - Caterpillar

System Operation Description:Use this procedure to troubleshoot any suspect problems with the circuit for the coolant level sensor.The coolant level sensor monitors the engine coolant level in order to warn the operator in the event that the coolant level is low.The coolant level sensor 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 at the probe of the sensor. The sensor contains a probe that is covered with plastic.When the sensor's probe is immersed in coolant, the sensor senses a particular capacitance. The sensor's electronics react by sinking the signal to the sensor return (ground).The coolant level sensor requires +8 VDC to operate. This voltage is supplied to the sensor by the ECM. The voltage is supplied to terminal ( A) of the sensor. This supply voltage is also used by the coolant temperature sensor and the rack position sensor. A malfunction with the coolant level sensor or the wiring of the sensor can cause problems with these sensors. When the probe is not immersed in coolant, approximately +5 VDC is sourced to the signal wire. When this condition is detected by the Electronic Control Module (ECM), a code is activated.
Illustration 1 g01624976
Schematic for coolant level sensor
Illustration 2 g01635514
(10) +8 VDC (26) Coolant level (35) Analog returnThe activation of the following code and/or a warning lamp is probably caused by a low coolant level. The next likely cause is a problem with the wiring harness, a connector, or the sensor. The least likely cause is a problem with the ECM.
Table 1
Diagnostic Code    
Code and Description     Flash Code     Default Conditions which Generate this Code     System Response    
111-01 Low Coolant Level Warning     62     The coolant level sensor sends a signal to the engines' Electronic Control Module (ECM) that indicates a low coolant level.     The code is logged. Also, the diagnostic lamp is illuminated.    Note: In order to log a fault, the sensor must detect low coolant for ten seconds. Use this procedure in order to troubleshoot any suspect problems with the coolant level sensor(s) or with the wiring circuit.Test Step 1. Inspect the Electrical Connectors and the Wiring
Remove electrical power from the ECM.
Thoroughly inspect the connector for the coolant level sensor and the P7 connector. Inspect the ECM connector J14/P14. 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 circuit for the coolant level sensor.
Check the allen head screw on the 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