CONTROL ASSEMBLY 6S8128 - Caterpillar

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Schematic of the Engine Coolant Temperature Sensor
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Illustration of the Engine Coolant Temperature Sensor
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Engine Coolant Temperature Sensor locationThis diagnostic code is associated with the Engine Coolant Temperature Sensor. The FMI 03 diagnostic code is activated when the ECM detects that voltage of the input signal from the Engine Coolant Temperature Sensor is above normal.The operating range for the output voltage of the sensor is approximately 0 VDC to 5 VDC.Conditions that could cause this diagnostic code to be activated are:
The sensor has failed.
The return circuit of the sensor is open in the machine harness.
The signal circuit in the machine harness is shorted to a source of positive voltage.
The signal circuit in the machine harness is open or the sensor is disconnected.
The ECM has failed. This is unlikely. Note: Before performing this procedure, inspect the harness connectors that are involved in the circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, secure and in good condition. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes. Clear any created diagnostic codes after the original diagnostic code has been corrected.System Response:A Level 2 warning will be generated.The diagnostic code of CID 0110 FMI 03 will be logged in the internal memory of the ECM. When the diagnostic code occurs, the following responses will occur.
The LCD gauge bar will flash at a full deflection.
A warning indicator is activated on the display.Test Step 1. CHECK THE CONTROL AND THE HARNESS
Turn the key start switch to the OFF position.
Wait approximately 10 seconds for the ECM to power down.
Disconnect the machine harness connector from the engine coolant temperature sensor.
Turn the key start switch to the ON position.
At the machine harness connector for the sensor, measure the voltage (VDC) between the signal contact 1 (wire 441-OR) and the return contact 2 (wire J765-BU). Expected Result:The voltage is between 0 and 5 VDC.Results:
OK - The voltage is between 0 and 5 VDC. The ECM and the harness are correct. Repair: Temporarily connect a new Engine Coolant Temperature Sensor to the harness. Do not install the sensor. Verify that the replacement sensor has cleared the CID 0110 FMI 03 code. If the code is no longer active, permanently install the new Engine Coolant Temperature Sensor.Verify that there are no active diagnostic codes for the Engine Coolant Temperature Sensor. Clear any logged diagnostic codes.STOP
NOT OK - The voltage is not between 0 and 5 VDC. Proceed to Test Step 2.Test Step 2. CHECK THE HARNESS FOR AN OPEN CIRCUIT
The sensor remains disconnected.
Turn the disconnect switch and the key start switch to the OFF position.
Disconnect the J1 and J2 machine harness connectors from the ECM.
At the harness connector for the sensor, place a jumper from contact 1 to contact 2.
At the J1 connector for the