P0119 - ENGINE COOLANT TEMPERATURE SENSOR CIRCUIT INTERMITTENT

When the P0119 OBDII fault code is set, it is because the vehicle’s computer has detected an intermittent signal from the ECT (Engine Coolant Temperature) sensor. The PCM always monitors the ECT Sensor for a reference signal, which is 5 volts.

This sensor has 2 wires, one for reference voltage and the other for ground. It is a negative coefficient sensor. For example, when the temperature increases, the resistance decreases. When there are variations in the resistance, it is due to changes in the voltage, which are recognized by the PCM as changes in the ECT sensor. It is worth mentioning that there are other models of these sensors that have 3 wires, being the third wire for the input signal supply to the meter. Although the location of this sensor varies by manufacturer, it is always threaded into an engine coolant line.

If the PCM receives signals from the ECT Sensor for some time and these signals prove to be intermittent or erratic, the Check Engine light will illuminate next to this code.

• MIL light ON.
• The motor is inactive during cold starts.
• Stumble on acceleration.
• The engine has high temperatures.

Reasons for setting the DTC P0119 OBD2 code:

• The engine coolant level may be below the required level.
• The thermostat may be faulty.
• The Coolant Temperature Sensor (ECT) may be in bad condition.
• The electrical system related to the ECT Sensor may have problems.

To troubleshoot faults related to the P0119 OBDII error code, try this:

• See Technical Service Bulletins (TSB).
• Check some electrical components such as cables and connectors. Repair or replace any of these that are burnt or damaged.
• Check the ECT sensor connector for corrosion. Replace if necessary.
• With the engine cool, remove the high-pressure cap and check that the coolant level is adequate for proper operation. Look for coolant leaks. If such leaks are found, repair them and refill the system with the appropriate coolant.
• Change the ECT Sensor.