P0118 GMC Code - Engine Coolant Temperature Circuit High Input
Quick Answer
The P0118 GMC code indicates that there is a high input signal from the engine coolant temperature (ECT) sensor circuit. Common causes include Faulty ECT sensor: The most common cause of the P0118 code is a malfunctioning ECT sensor that is sending incorrect high voltage signals, Wiring issues: Corrosion, damage, or loose connections in the ECT sensor circuit can lead to high input signals and trigger the code, Coolant level: Low coolant levels or air pockets in the cooling system can affect the ECT sensor readings and cause high input signals. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P0118 GMC indicates Engine Coolant Temperature Circuit High Input.
- Common causes
- Common causes include Faulty ECT sensor: The most common cause of the P0118 code is a malfunctioning ECT sensor that is sending incorrect high voltage signals, Wiring issues: Corrosion, damage, or loose connections in the ECT sensor circuit can lead to high input signals and trigger the code, Coolant level: Low coolant levels or air pockets in the cooling system can affect the ECT sensor readings and cause high input signals.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
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Code P0118 GMC Description
The P0118 GMC code indicates that there is a high input signal from the engine coolant temperature (ECT) sensor circuit. The ECT sensor is responsible for monitoring the temperature of the engine coolant and sending this information to the engine control module (ECM). When the ECM receives a high voltage signal from the ECT sensor circuit, it triggers the P0118 code. This can lead to various issues with the vehicle's performance and overall functioning.
Common Causes of P0118 GMC
- Faulty ECT sensor: The most common cause of the P0118 code is a malfunctioning ECT sensor that is sending incorrect high voltage signals.
- Wiring issues: Corrosion, damage, or loose connections in the ECT sensor circuit can lead to high input signals and trigger the code.
- Coolant level: Low coolant levels or air pockets in the cooling system can affect the ECT sensor readings and cause high input signals.
- ECM malfunction: In rare cases, a faulty ECM can misinterpret the ECT sensor data and trigger the P0118 code.
Symptoms of P0118 GMC
- Engine overheating: A malfunctioning ECT sensor can lead to inaccurate temperature readings, causing the engine to overheat.
- Poor fuel economy: Incorrect coolant temperature readings can result in the engine running rich or lean, leading to decreased fuel efficiency.
- Rough idling: The ECM may struggle to adjust engine parameters based on faulty coolant temperature data, resulting in rough idling or stalling.
- Check Engine Light: The P0118 code will trigger the check engine light on the dashboard, signaling a problem with the ECT sensor circuit.
How to Fix P0118 GMC
- Diagnose the issue: Use a scan tool to retrieve the P0118 code and perform a visual inspection of the ECT sensor and wiring.
- Test the ECT sensor: Check the resistance of the ECT sensor with a multimeter to determine if it is functioning correctly.
- Inspect wiring: Check the wiring harness for any damage, corrosion, or loose connections that may be causing the high input signal.
- Replace ECT sensor: If the sensor is faulty, replace it with a new one and ensure it is properly installed.
- Clear codes: Clear the P0118 code from the ECM using a scan tool and test drive the vehicle to ensure the issue has been resolved.
Cost to Fix P0118 GMC
The typical repair costs for addressing a P0118 GMC code can range from $100 to $300, depending on the specific cause of the issue and the cost of parts and labor. Keep in mind that diagnostic time and labor rates at auto repair shops can vary, so it's advisable to check with local shops for a more accurate estimate.
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Information for Specific GMC Models
- P0118 2014 GMC Sierra — Engine Coolant Temperature Circuit High Input
- P0118 2015 GMC Sierra — Engine Coolant Temperature Circuit High Input
- P0118 2016 GMC Sierra — Engine Coolant Temperature Circuit High Input
- P0118 2017 GMC Sierra — Engine Coolant Temperature Circuit High Input
- P0118 2018 GMC Sierra — Engine Coolant Temperature Circuit High Input
Frequently Asked Questions about P0118 GMC Code
No Frequently Asked Questions about P0118 GMC Code found.
Discuss the causes and fixes for P0118 GMC OBDII Code
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ive replaced the temp sensor. ive checked harness has 4.7. i replaced thermostat. and nothing!!! never been more frusterated!! its a 01 gmc sierra 2500. did a efan conversion and had it tuned at a shop he tells me its the sensor or a wire. ive checked everything!!!! what is wrong with this POS??
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Unfortunately, I haven't encountered that problem before. However, I checked a national database of repairs and found that the issue is usually caused by the sensor itself or its connector. A poor connection resulting from loose or rusted pins in the connector can set the code. You can try wiggling the connector while the engine is running a few times to see if that triggers the code.
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