P0118 2017 GMC Sierra Code - Engine Coolant Temperature Circuit High Input
Quick Answer
The Engine Coolant Temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. Common causes include Low engine coolant level, Leaking or stuck open thermostat, Faulty Engine Coolant Temperature (ECT) sensor. 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 Low engine coolant level, Leaking or stuck open thermostat, Faulty Engine Coolant Temperature (ECT) sensor.
- 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.
Code P0118 2017 GMC Sierra Description
The ECM uses this high side coolant rationality diagnostic to determine if the input from the ECT sensor is skewed warmer than normal. The internal clock of the ECM will record the amount of time the ignition is OFF. If the calibrated ignition OFF time is met at start-up, the ECM will compare the temperature difference between the ECT and the intake air temperature (IAT) to determine if the temperatures are within an acceptable operating range of each other. The Diagnostic Trouble Code (DTC) will be set when the ECM detects a the ECT is colder than -39°C (-38°F) for greater than 5 s.
What are the Possible Causes of the DTC P0118 2017 GMC Sierra?
- Low engine coolant level
- Leaking or stuck open thermostat
- Faulty Engine Coolant Temperature (ECT) sensor
- Engine Coolant Temperature sensor harness is open or shorted
- Engine Coolant Temperature sensor electrical circuit poor connection
- Faulty Engine Control Module (ECM)
How to Fix the DTC P0118 2017 GMC Sierra?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0118 2017 GMC Sierra code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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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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