Which Codes Will This Page Cover?
- P0118 Engine Coolant Temperature Sensor 1 Circuit High
- P0115 Engine Coolant Temperature Sensor 1 Circuit
- P0116 Engine Coolant Temperature Sensor 1 Circuit Range/Performance
- P0117 Engine Coolant Temperature Sensor 1 Circuit Low
- P0119 Engine Coolant Temperature Sensor 1 Circuit Intermittent
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What Is the P0118 Code?
Symptoms
Causes
Seriousness
Can I Still Drive?
Diagnose
Difficulty of Inspecting
Get Additional Help
The P0118 code refers to issues with the Engine Coolant Temperature (ECT) circuit and its accompanying sensor. The ECT is a thermistor, or an electrical resistor, whose resistance is significantly reduced by heating. The ECT is located in the coolant passage in your engine’s cylinder head. The job of an ECT sensor is to monitor and control the rise and fall of the engine’s coolant temperature. So, when the sensor is operating normally, then the resistance of the circuit will be high when the engine coolant temperature is low, and the resistance will drop when the coolant temperature increases.
The ECT works with the Power Control Module (PCM), which monitors voltage drops to determine the coolant temperature. So when the engine has been running for more than a few minutes, and the ECT reads a less than freezing temperature, the PCM will think there is a circuit fault and set the P0118 code. The PCM will also set the code if it determines that the ECT sensor resistance is out of the predefined specification.
What Are the Symptoms of a P0118 Code?
You may run into several symptoms with the P0118 code, and the first is that the PCM will turn on your vehicle’s Check Engine Light. The PCM may also cause your car to go into a failsafe mode, substituting input to 176 degrees Fahrenheit. You may also notice that your engine has a hard time starting when the engine is cold or running rough and hesitating until it warms up. Finally, poor fuel economy may also happen in some instances.
What Are Some Causes of a P0118 Code?
You may run into several symptoms with the P0118 code, and the first is that the PCM will turn on your vehicle’s Check Engine Light. The PCM may also cause your car to go into a failsafe mode, substituting input to 176 degrees Fahrenheit. You may also notice that your engine has a hard time starting when the engine is cold or running rough and hesitating until it warms up. Finally, poor fuel economy may also happen in some instances.
How Serious Is the P0118 Code?
The P0118 code will often put your vehicle into a failsafe mode, which can cause the engine to run rough or hesitate until it warms up to operating temperature. Because of this failsafe mode, your vehicle may experience excessive fuel consumption and carbon fouling of engine components. This means that the P0118 code should be potentially severe because it can lead to other costly issues if left untreated.
Can I Still Drive with a P0118 Code?
As mentioned, because the P0118 code causes your vehicle to fall into a failsafe mode, it’s not recommended to drive your car for extended periods when the code sets. This is because driving the vehicle while it’s in failsafe mode can put added pressure and stresses on your engine’s components and lead to further damage and costly repairs. In addition, you may run into issues caused by the additional carbon build-up or ignition problems and other issues.
How Easy Is It to Diagnose a P0118 Code?
Diagnosing a P0118 code can be lengthy as multiple engine components will need checking. This is why this process is best left to qualified technicians who have experience diagnosing these issues. With that said, the first thing a technician will do is inspect the engine for any disconnected sensor connectors or damaged connectors. They will also look for any corrosion or damage to the sensor connectors and perform the necessary repairs. When they connect the two connector pins, they will look for a reading above 286 degrees Fahrenheit, which would indicate the wiring is good. One mistake that can occur during the diagnosing process is not visually inspecting the problem area initially. Another mistake is replacing the ECT sensor without confirming that the sensor is causing the P0118 code to set.
How Difficult Is It to Inspect a P0118 Code?
Inspecting the P0118 code begins with assessing if the ECT sensor needs replacing. If the resistance is out of the vehicle’s specified parameters, you will need to replace the sensor. If the resistance is within specifications, the connector will need to be checked for its voltage and ground connection. Most often, the ECT connector will need replacing because the ECT sensor cannot function properly without a good connection. The technician will also repair or replace the wiring open circuit if that is what is needed.
Finally, you may need to replace the ECT sensor altogether if it isn’t functioning correctly. And since there are many parts involved with this process, it’s not recommended that you DIY a P0118 code issue yourself because you may risk repairing the wrong component. This will lead to further damage down the road and more costly repairs.
Need Additional Help with Your P0118 Code?
By following our tips and guidelines regarding the P0118 code, you should have the tools necessary to spot the signs that your vehicle is having issues. Taking the proper steps to get your vehicle to a qualified service station will prevent you from needing more costly repairs and will ensure that your vehicle stays in good mechanical shape.
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