AutoCodes – GMC – P0119 2018 GMC Sierra

P0119 2018 GMC Sierra Code - Engine Coolant Temperature Circuit Intermittent

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: P0119 2018 GMC Sierra indicates Engine Coolant Temperature Circuit Intermittent.
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 229

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 May 20, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0119 2018 GMC Sierra 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 Intermittent for greater than 3 s.

OBDII Code P0119 2018 GMC Sierra - Engine Coolant Temperature Circuit Intermittent - AutoCodes.com — P0119 2018 GMC Sierra Code - Engine Coolant Temperature Circuit Intermittent

What does this mean?

What are the Possible Causes of the DTC P0119 2018 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 P0119 2018 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 P0119 2018 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.

Need more information about the P0119 2018 GMC Sierra code?

Need more information on how to fix the P0119 2018 GMC Sierra code? Get Access to Factory Service Manuals

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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 P0119 2018 GMC Sierra Code

What does the OBDII code P0119 mean for a 2018 GMC Sierra?

P0119 indicates an intermittent issue with the engine coolant temperature sensor circuit, which may cause improper readings of the engine’s temperature.

What are the symptoms of code P0119 on a 2018 GMC Sierra?

Symptoms may include poor engine performance, erratic temperature gauge readings, hard starting, decreased fuel efficiency, and potential overheating.

What causes the P0119 code on a 2018 GMC Sierra?

Common causes include a faulty engine coolant temperature (ECT) sensor, damaged wiring, loose or corroded electrical connections, or issues in the PCM.

Can I drive my 2018 GMC Sierra with a P0119 code?

While the vehicle may still run, driving with this code can lead to performance issues and potential engine overheating. It’s best to address the issue promptly to avoid damage.

How do I diagnose the P0119 code on a 2018 GMC Sierra?

Diagnosis involves inspecting the ECT sensor, checking wiring and electrical connections for damage or corrosion, and testing the sensor with a multimeter for proper resistance.

How do I fix the P0119 code on a 2018 GMC Sierra?

Repairs may include replacing the ECT sensor, repairing or replacing damaged wiring, cleaning corroded connectors, or updating/reprogramming the PCM if necessary.

What tools are needed to troubleshoot the P0119 code on a 2018 GMC Sierra?

You’ll typically need a diagnostic scan tool, a multimeter, and basic hand tools to inspect and test the ECT sensor and related wiring.

Does a faulty ECT sensor affect fuel economy on a 2018 GMC Sierra?

Yes, a malfunctioning ECT sensor can cause inaccurate temperature readings, leading to improper fuel-air mixture adjustments and decreased fuel efficiency.

What is the cost to repair a P0119 code on a 2018 GMC Sierra?

Repair costs vary but may range from $50 to $150 for an ECT sensor replacement, plus additional labor costs if professional service is needed.

Can a P0119 code trigger other issues in my 2018 GMC Sierra?

Yes, unresolved P0119 issues can lead to overheating, engine misfires, and improper operation of the cooling system, potentially causing further damage.