So, if you find yourself in a situation where you can’t remember the last time that the coolant has been changed, it may be worth a shot to just change it and see if you get lucky. A bad PCM can cause the the code to be triggered.Įngine coolant can cause the code to throw if it gets corroded enough. They typically aren’t going to be as prevalent though. There can be other causes of P0118 in your Sonic. Replacing the sensor straight away isn’t much of a gamble. If it remains the same, than the sensor is not working properly. If you have a volt meter, you could test the signal coming from it as the engine warms up. If you’re not getting 5 volts, re-inspect the wiring harness. It operates by receiving a 5 volt signal from the computer and a ground. Here’s a great guide on inspecting your wiring harness.Īfter thoroughly evaluating the wiring harness, it would be time to take a look at the sensor itself. After that, inspect the harness for wiring problems. Start by inspecting where the harness plugs into the Temp Sensor. It’s often the reason why the code was thrown. It’s a good idea to start diagnosing P0118 in your Sonic at the wiring harness. Here’s a great video from CarNToys from YouTube on this exact problem. Most of the time, the cause of P0118 is going to be related to the wiring or the sensor in some way or another. It’s just as likely that the only sign that you’ll get from the Sonic is the check engine light itself.Īs P0118 can greatly affect the drivability of your Sonic, we recommend fixing it as soon as possible.

These symptoms include failure to start, rough idle, misfiring, decreased fuel economy, and the service engine soon light.

P0118 is sometimes accompanied by noticeable symptoms.

This code is thrown when the resistance coming from the coolant temp sensor does not change as the vehicle warms up. P0118: Engine Coolant Temp Sensor Circuit → High Input It is a general code, which means that it’s going to have the same meaning for the Chevy Sonic as it would any other vehicle.

Coolant in chevy sonic engine