BATTERY 3T5770 - Caterpillar

Illustration 1 g00527487
Simplified System Schematic For Engine Coolant Loss Sensor (ECLS)The EMCP II + system monitors engine coolant in order to protect the engine in case of a coolant temperature problem. The engine coolant loss function is an option that requires the presence of the optional coolant loss sensor. The coolant loss sensor is usually mounted near the top of the radiator.The sensor is powered by an 8 volt sensor supply from the GSC+. When coolant is NOT present at the sensor, a high signal is sent to the GSC+. A high signal is approximately +5 DCV. When coolant is present at the sensor, a low signal (battery negative) is sent to the GSC+.Note: The GSC+ is usually programmed to treat coolant loss sensor problems as an alarm fault. P004 is equal to 0. If the GSC+ is programmed to shutdown, P004 is equal to 1. The operator is not required to press the "Alarm Codes" key in order to view the CID 111 FMI 3. The CID 111 FMI 3 is automatically shown on the upper display.The possible causes of a CID 111 FMI 3 are listed below.
A short to +battery of the sensor signal
An open circuit of the sensor signalBegin performing these procedures only when CID 111 FMI 3 is showing and the "DIAG" indicator is FLASHING on the upper display. The flashing indicator means that the diagnostic code is active. The GSC+ treats a CID 111 FMI 3 as an alarm fault. Active alarm faults are shown on the display when the alarm code key is pressed and the engine control switch (ECS) is in any position except the OFF/RESET position. For an inactive fault, the problem may be intermittent. See Testing And Adjusting, "Electrical Connector - Inspect" in order to troubleshoot an inactive fault. Also use the preceding system schematic. Clear the fault from the fault log after troubleshooting is complete.Note: If a CID 269 FMI 3 or a CID 269 FMI 4 is active, correct the diagnostic code prior to proceeding with this procedure.Test Step 1. CHECK THE SENSOR VOLTAGE SUPPLY CIRCUIT.
Turn the ECS to OFF/RESET. Then, turn the ECS to the STOP position.
Disconnect the sensor from the engine harness. The sensor remains fastened to the engine.
At the engine harness side of the sensor connector, measure the voltage (DCV) that is between contact "A" and contact "B". Contact "A" is the supply for the sensor. Contact "B" is