AutoCodesChevrolet – P0118 Chevrolet

P0118 Chevrolet 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 Chevrolet 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.
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Code Popularity 58,118
How popular is this code, among other codes? Medium
Table of contents Created and updated by William Orellana on Mar 30, 2024
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Code P0118 Chevrolet Description

The Engine Coolant Temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The Engine Control Module (ECM) supplies 5 V to the ECT sensor signal circuit and a ground for the low reference circuit.
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.
OBDII Code P0118 Chevrolet - Engine Coolant Temperature Circuit High Input - AutoCodes.com
P0118 Chevrolet Code - Engine Coolant Temperature Circuit High Input

What are the Possible Causes of the DTC P0118 Chevrolet?

  • 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 Chevrolet?

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.

Code Tech Notes

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0118 Chevrolet 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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Information for Specific Chevrolet Models

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 Chevrolet Code

1. What are the common symptoms of OBDII code P0118 (Chevrolet)?

The common symptoms of P0118 include the engine running hotter than normal, the temperature gauge reading unusually high, and potential issues with the vehicle's fuel efficiency.

2. What are the possible causes of OBDII code P0118 (Chevrolet)?

The potential causes of P0118 include a faulty engine coolant temperature (ECT) sensor, a malfunctioning thermostat, wiring issues in the ECT circuit, or low coolant levels.

3. How can I diagnose the OBDII code P0118 (Chevrolet)?

To diagnose P0118, you can use an OBDII scanner to retrieve the trouble code, visually inspect the ECT sensor and its wiring for any signs of damage, and test the sensor's resistance with a multimeter.

4. Can a faulty thermostat trigger OBDII code P0118 (Chevrolet)?

Yes, a faulty thermostat can cause the engine coolant temperature to be higher than normal, triggering the P0118 trouble code due to incorrect temperature readings being sent to the engine control module.

5. What are some repair tips for fixing OBDII code P0118 (Chevrolet)?

Repair tips for P0118 include replacing the ECT sensor if it is faulty, checking and replacing the thermostat if needed, ensuring proper coolant levels, and inspecting the wiring for any faults.

6. Is it safe to continue driving with OBDII code P0118 (Chevrolet) present?

It is not recommended to drive with P0118 as it can lead to engine overheating and potential damage. It's best to address the issue promptly to avoid more serious problems.

7. Can a low coolant level trigger OBDII code P0118 (Chevrolet)?

Yes, low coolant levels can impact the engine coolant temperature readings, causing the ECT sensor to detect high temperatures and trigger the P0118 trouble code.

8. How much does it typically cost to repair OBDII code P0118 (Chevrolet)?

The cost to repair P0118 can vary depending on the root cause of the issue. Generally, replacing the ECT sensor can cost between $50 to $200, while replacing a faulty thermostat can range from $100 to $300.

9. Will resetting the trouble code resolve OBDII code P0118 (Chevrolet)?

Resetting the trouble code may temporarily clear the check engine light, but if the underlying issue causing P0118 is not addressed, the code is likely to reappear.

10. Can a DIY enthusiast fix OBDII code P0118 (Chevrolet) at home?

Depending on the cause of P0118, DIY enthusiasts with automotive repair experience can potentially fix the issue at home by replacing the ECT sensor, checking the thermostat, and ensuring proper coolant levels. However, complex wiring issues may require professional assistance.

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