AutoCodes – Chevrolet – P1118 Chevrolet

P1118 Chevrolet Code - Engine Coolant Temp. Signal Out-Of-Range High

Quick Answer

The Engine Coolant Temperature (ECT) sensor contains a semiconductor device which changes resistance based on temperature (a thermistor). Common causes include Faulty Engine Coolant Temperature (ECT) sensor, Low engine coolant level, Engine Coolant Temperature (ECT) sensor harness is open or shorted. 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: P1118 Chevrolet indicates Engine Coolant Temp. Signal Out-Of-Range High.
Common causes: Common causes include Faulty Engine Coolant Temperature (ECT) sensor, Low engine coolant level, Engine Coolant Temperature (ECT) sensor harness is open or shorted.
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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 7,620

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Apr 24, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P1118 Chevrolet Description

The Engine Coolant Temperature (ECT) sensor contains a semiconductor device which changes resistance based on temperature (a thermistor). The ECT sensor mounts in the left bank cylinder head near the front of the engine. The ECT sensor has a signal circuit and a ground circuit. The PCM applies a voltage (about 5.0 volts) on the signal circuit to the sensor. The PCM monitors changes in this voltage caused by changes in the resistance of the sensor in order to determine the engine coolant temperature.
When the engine coolant is cold, the sensor (thermistor) resistance is high, and the PCMs signal voltage is only pulled down a small amount through the sensor to ground. The PCM senses a high signal voltage (low temperature). When the engine coolant is warm, the sensor resistance is low, and the signal voltage is pulled down a greater amount. This causes the PCM to sense a low signal voltage (high temperature).

OBDII Code P1118 Chevrolet - Engine Coolant Temp. Signal Out-Of-Range High - AutoCodes.com — P1118 Chevrolet Code - Engine Coolant Temp. Signal Out-Of-Range High

What does this mean?

What are the Possible Causes of the DTC P1118 Chevrolet?

Faulty Engine Coolant Temperature (ECT) sensor
Low engine coolant level
Engine Coolant Temperature (ECT) sensor harness is open or shorted
Engine Coolant Temperature (ECT) sensor electrical circuit poor connection
Faulty engine coolant thermostat

How to Fix the DTC P1118 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.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1118 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.

Need more information about the P1118 Chevrolet code?

Need more information on how to fix the P1118 Chevrolet code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P1118 Chevrolet code diagnosed by a professional: Find a repair shop in your area

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.