P0117 - ENGINE COOLANT TEMPERAURE CIRCUIT LOW INPUT

The ECT sensor (Engine Coolant Temperature) is a thermistor that is located in the engine block. This sensor of general form consists of two cables. One cable is the 5 volt reference of the Power Train Control Module and the other cable is a ground that is supplied by the PCM. When the coolant temperature changes, the resistance of the sensor changes as well.

When the engine is hot, the resistance of the sensor is low, and when the engine is cold, the resistance is low. If the PCM (Powertrain Control Module) discovers that the signal voltage is low to the range that allows the sensor to operate normally, the fault code P0117 OBD2 is established.

• Check Engine light illuminates on the board.
• There is no fuel savings.
• The engine can be turned off.
• Black smoke expelled by the exhaust.

The problems that can lead to the establishment of a P0117 code can be:

• The engine may be overheated.
• There may be a short to ground signal ECT (Engine Coolant Temperature).
• Engine Coolant Temperature sensor (ECT) connectors may be defective.
• ECT sensor cables may be in poor condition.
• Maybe the ECT (Engine Coolant Temperature) terminals are loose.
• The Coolant Temperature Sensor (ECT) defective.

At the time of solving the diagnostic code P0117 OBDII you could review the next components:

• Verify if the engine has not overheated.
• Check the cables and their respective connectors for some of these present wear. Repair or change if necessary.
• With the engine cold and using a scan tool, verify that the reading of the Engine Coolant Temperature sensor matches the IAT sensor (Intake Air Temperature) if it does not change the Coolant Temperature Sensor (ECT).
• If the reading of the Coolant Temperature Sensor (ECT) is above 260 degrees ° F, disconnect the sensor at which the temperature should fall around -30 ° F or less. If you do it this way, it is indicative that there is an internal short circuit. You can replace the ECT sensor.
• If the reading does not change when the sensor is switched off, there may be a short circuit in the signal from the ECT (Engine Coolant Temperature) sensor wiring. Maybe the cables are rubbing against each other. Repair or change as necessary.
• If the ECT sensor reading is within the expected specifications, the problem may be intermittent. That's why you manipulate the wiring and its connectors while watching the reading with the scan tool. If you notice loose cables you can repair or change if necessary.
• Change the Coolant Temperature Sensor (ECT).