Engine-CodesGMC – P0118 2017 GMC Sierra

P0118 2017 GMC Sierra Code - Engine Coolant Temperature Circuit High Input

Quick Answer

The P0118 code on a 2017 GMC Sierra indicates that there is a high input signal coming from the engine coolant temperature sensor. Common causes include Faulty engine coolant temperature sensor, Wiring issues or a poor connection in the coolant temperature sensor circuit, Low coolant levels or a coolant leak. 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 2017 GMC Sierra indicates Engine Coolant Temperature Circuit High Input.
Common causes
Common causes include Faulty engine coolant temperature sensor, Wiring issues or a poor connection in the coolant temperature sensor circuit, Low coolant levels or a coolant leak.
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.
Table of contents Created and updated by William Orellana on Aug 19, 2024
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Code P0118 2017 GMC Sierra Description

The P0118 code on a 2017 GMC Sierra indicates that there is a high input signal coming from the engine coolant temperature sensor. This sensor is responsible for monitoring the temperature of the engine coolant and sending this information to the engine control module (ECM). A high input signal means that the sensor is reporting a temperature that is higher than expected. This can lead to various issues with the vehicle's performance, as the ECM relies on accurate temperature readings to adjust fuel mixture, ignition timing, and other parameters.

OBDII Code P0118 2017 GMC Sierra - Engine Coolant Temperature Circuit High Input
P0118 2017 GMC Sierra Code - Engine Coolant Temperature Circuit High Input

Common Causes of P0118 2017 GMC Sierra

  1. Faulty engine coolant temperature sensor
  2. Wiring issues or a poor connection in the coolant temperature sensor circuit
  3. Low coolant levels or a coolant leak
  4. ECM software or hardware issues
  5. Engine overheating

Symptoms of P0118 2017 GMC Sierra

  1. Check Engine Light illuminated on the dashboard
  2. Engine running hotter than normal
  3. Poor fuel economy
  4. Rough idling or stalling
  5. Reduced engine power

How to Fix P0118 2017 GMC Sierra

  1. Begin by checking the coolant level and ensuring there are no leaks in the system.
  2. Inspect the wiring and connectors related to the engine coolant temperature sensor for any damage or corrosion.
  3. Test the engine coolant temperature sensor using a multimeter to determine if it is functioning correctly.
  4. If the sensor is faulty, replace it with a new one and clear the diagnostic trouble codes from the ECM.
  5. Reset the ECM to clear the P0118 code and monitor the vehicle for any recurring issues.

Cost to Fix P0118 2017 GMC Sierra

The cost of repairing a P0118 code on a 2017 GMC Sierra can vary depending on the specific cause of the issue. In general, replacing a faulty engine coolant temperature sensor can cost between $50 to $150 for the part, with additional labor costs of around $100 to $200. If wiring or other components need to be repaired or replaced, the total cost could be higher. It is recommended to consult with a professional mechanic for an accurate estimate based on the specific circumstances of your vehicle.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0118 2017 GMC Sierra Code

What does the OBDII code P0118 mean for a 2017 GMC Sierra?

P0118 indicates that the Engine Control Module (ECM) has detected a high voltage signal from the Engine Coolant Temperature (ECT) sensor, suggesting the sensor or circuit is malfunctioning.

What are common symptoms of code P0118 on a 2017 GMC Sierra?

Symptoms may include an illuminated check engine light, poor fuel efficiency, engine running too rich, difficulty starting, and erratic temperature gauge readings.

What causes the P0118 code on a 2017 GMC Sierra?

Common causes include a faulty ECT sensor, damaged wiring or connectors, a short circuit, or issues with the ECM.

Can I drive my 2017 GMC Sierra with a P0118 code?

Driving with a P0118 code is possible but not recommended, as it may lead to poor engine performance and potential long-term damage.

How do I diagnose the P0118 code on a 2017 GMC Sierra?

Diagnose the issue by inspecting the ECT sensor, wiring, and connectors for damage, and testing the sensor’s voltage output with a multimeter.

How do I fix the P0118 code on a 2017 GMC Sierra?

Repairs may involve replacing the ECT sensor, repairing damaged wiring or connectors, or addressing ECM issues if the problem persists.

How much does it cost to fix the P0118 code on a 2017 GMC Sierra?

Repair costs can range from $50 to $200 for parts and labor, depending on whether you replace the ECT sensor or repair wiring.

Will a faulty ECT sensor affect fuel economy on a 2017 GMC Sierra?

Yes, a malfunctioning ECT sensor can cause the engine to run rich, leading to decreased fuel efficiency.

Can a P0118 code cause overheating in a 2017 GMC Sierra?

While the code itself doesn’t directly cause overheating, inaccurate temperature readings may prevent the ECM from properly managing cooling systems.

How can I prevent the P0118 code from occurring again on my 2017 GMC Sierra?

Regular inspection of the ECT sensor, wiring, and connectors for wear or corrosion and addressing issues promptly can help prevent recurrence.

Discuss the causes and fixes for P0118 2017 GMC Sierra OBDII Code

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