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P0119 Code – What Does It Mean & How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.


The OBD codes are an essential tool in the world of vehicle diagnostics to detect possible problems with a vehicle’s systems. One such code related to the OBD diagnostic sensor circuit of the engine is P0119 DTC Coolant Trouble Code. It is crucial that you understand the meaning and implications of P0119 in order to keep your car running at its optimum while tackling any problems caused by it.


The P0119 code specifically states that there is a fault in the ECU Coolant Temperature sensor circuit. The ECT shall monitor the engine’s temperature and transmit this information to the Control Module (ECM) via its sensor. In order to ensure optimum performance and fuel economy, the ECM shall use this information for the adjustment of various engine parameters.


The P0119 error code may be caused by a number of things:

  • A defective ECT sensor: Over time, the ECT sensor may degrade or grow imprecise, giving false indications of the temperature.
  • Wire Problems: Signal transmission might be hampered by corroded or damaged wire that connects the ECT sensor to the ECM.
  • Connector issues: Corroded or loose connectors might prevent the ECT sensor and ECM from properly communicating.
  • Coolant Level: The accuracy of the ECT sensor may be impacted by insufficient engine coolant or a cooling system leak.
  • Short or Open ECT Sensor Circuit: The code might be activated by any short or open circuit in the ECT sensor circuit.


When the P0119 code is triggered, you may observe various symptoms indicating potential issues with your vehicle:

  • Illuminated Check Engine Light: The most apparent sign of a trouble code, the check engine light is activated.
  • Problems with engine performance: Due to inaccurate temperature measurements, the engine may have reduced power, hesitancy, or poor acceleration.
  • Excessive heating or cooling: If the engine temperature gauge fluctuates wildly, there might be a cooling system issue.
  • Poor Fuel Efficiency: Fuel efficiency might be decreased by using fuel-to-air ratios that are not optimally calculated due to incorrect temperature data.


A methodical strategy is needed to correctly identify the P0119 code’s root cause. The following diagnostic procedures can be carried out by a skilled mechanic or an OBD-II scanner:

  • Checking for Codes: The P0119 code may be read and retrieved from the vehicle’s ECM using an OBD-II scanner.
  • Visual Inspection: To find any obvious problems, the ECT sensor, it’s wiring, and its connections must be thoroughly inspected visually.
  • Testing the ECT Sensor: The resistance and voltage output of the sensor should be measured with a multimeter in order to evaluate its performance.
  • Checking Coolant Level and System: To make sure the cooling system and coolant level are within the acceptable limit, the technician will examine them.

Common mistakes

Some typical errors can happen during diagnostics and repairs, resulting in inaccurate or inefficient fixes:

  • Ignoring wire and Connectors: A loose connector or broken wire is frequently the cause of problems but is frequently disregarded.
  • Replacing the ECT Sensor Without Testing: Before contemplating a replacement, the sensor’s operation must be properly tested.
  • Ignoring Cooling System Issues: Cooling system problems should be resolved since they may affect the readings from the ECT sensor.

How serious is this?

The significance of the code P0119 depends on a number of factors. Although this may be just a small inconvenience, failure to address the issue could result in engine performance problems, decreased fuel efficiency, and potentially damaged engines over time. It is advised to diagnose and repair it as soon as possible in order not to cause additional complications.

What repairs can fix the code?

repair manuals

Once the root cause of the P0119 code is identified, the following repairs can be undertaken:

  • Replacement of the ECT Sensor: If the sensor is broken, a suitable and superior replacement should be used.
  • Fixing wires and connections: If required, damaged wires or connections should be fixed or replaced.
  • Fixing Cooling System Issues: Any leaks in the cooling system or issues with the coolant level should be fixed right away.

Related codes

Occasionally, other DTCs might accompany the P0119 code, providing additional insights into related issues. Commonly related codes include P0117 (Engine Coolant Temperature Circuit Low Input) and P0118 (Engine Coolant Temperature Circuit High Input).


There are indications from the P0119 DTC code that the engine Coolant Temperature sensor circuit may have some problems. You may be able to effectively address this problem by understanding its meaning, causes, symptoms, and appropriate treatment. 

In addition to clearing the code, swift diagnosis and correct repair are also essential parts of ensuring your vehicle functions at its optimum performance, leading to a more reliable driving experience.  In order to ensure that your car remains in top condition, make sure you consult with a trained mechanic who will diagnose accurately and perform appropriate safety repairs.

P0119 Code – What Does It Mean & How To Fix It