AutoCodes – Chevrolet – P0128 2014 Chevrolet Silverado

P0128 2014 Chevrolet Silverado Code - Engine Coolant Temperature Below Thermostat Regulating Temperature

Quick Answer

The Engine Control Module (ECM) monitors the temperature of the engine coolant for engine control and as enabling criteria for some diagnostics. Common causes include Leaking or stuck open thermostat, Low engine coolant level, Insufficient warm-up time. 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: P0128 2014 Chevrolet Silverado indicates Engine Coolant Temperature Below Thermostat Regulating Temperature.
Common causes: Common causes include Leaking or stuck open thermostat, Low engine coolant level, Insufficient warm-up time.
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 1,773

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 11, 2023

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes ▶
Cost to Diagnose
FAQs
Comments
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Code P0128 2014 Chevrolet Silverado Description

The Engine Control Module (ECM) monitors the temperature of the engine coolant for engine control and as enabling criteria for some diagnostics. The amount of heat an engine generates is proportional to the amount of air that enters the engine. The ECM monitors this amount of air to calculate a theoretical Engine Coolant Temperature (ECT). The ECM uses the calculated temperature to determine if the engine has warmed up to the thermostat regulating temperature. Suppose the measured actual coolant temperature does not increase typically or does not reach the thermostat regulating temperature. In that case, diagnostics that use the ECT as enabling criteria, may not run when expected. If the measured engine coolant temperature fails to reach the thermostat regulating temperature, before a predetermined amount of air has entered the engine, this Diagnostic Trouble Code (DTC) sets.

OBDII Code P0128 2014 Chevrolet Silverado - Engine Coolant Temperature Below Thermostat Regulating Temperature - AutoCodes.com — P0128 2014 Chevrolet Silverado Code - Engine Coolant Temperature Below Thermostat Regulating Temperature

What does this mean?

What are the Possible Causes of the DTC P0128 2014 Chevrolet Silverado?

Leaking or stuck open thermostat
Low engine coolant level
Insufficient warm-up time
Faulty Engine Coolant Temperature (ECT) sensor
Engine Coolant Temperature sensor harness is open or shorted
Engine Coolant Temperature sensor electrical circuit poor connection

How to Fix the DTC P0128 2014 Chevrolet Silverado?

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 does this mean?

Code Tech Notes

If the cooling system is not leaking and the fluid level is OK, replacing the thermostat usually takes care of the problem.

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What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0128 2014 Chevrolet Silverado 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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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 P0128 2014 Chevrolet Silverado Code

What does OBDII code P0128 mean for a 2014 Chevrolet Silverado?

Code P0128 indicates that the engine coolant temperature is not reaching the thermostat's expected operating range within a specified time.

What are the common symptoms of code P0128 in a 2014 Chevrolet Silverado?

Symptoms may include poor fuel economy, longer warm-up times, engine running cooler than normal, and the check engine light turning on.

What causes the P0128 code on a 2014 Chevrolet Silverado?

Common causes include a stuck-open thermostat, low coolant levels, a faulty coolant temperature sensor, or wiring issues related to the sensor.

Can driving with code P0128 damage my 2014 Chevrolet Silverado?

Driving with this code for short periods may not cause immediate damage, but prolonged driving can lead to reduced fuel efficiency and potential wear on engine components due to improper operating temperatures.

How do I diagnose code P0128 on a 2014 Chevrolet Silverado?

Start by checking the coolant level, inspecting the thermostat for functionality, and testing the coolant temperature sensor and its wiring for proper operation.

What tools are needed to fix code P0128 on a 2014 Chevrolet Silverado?

You may need a scan tool, a multimeter for testing sensors, basic hand tools for thermostat replacement, and a coolant funnel for refilling the system.

How much does it cost to fix code P0128 on a 2014 Chevrolet Silverado?

Repair costs vary, but replacing a thermostat typically costs $150â€“$300, while replacing a coolant temperature sensor can cost $100â€“$200, depending on labor rates.

Can I fix code P0128 myself on a 2014 Chevrolet Silverado?

Yes, if you have basic automotive repair skills, you can replace the thermostat or coolant temperature sensor yourself. Ensure you follow the correct procedures and safety precautions.

How do I know if the thermostat is stuck open on my 2014 Chevrolet Silverado?

A stuck-open thermostat often results in the engine taking longer to warm up, and the temperature gauge may read lower than normal during operation.

Does code P0128 affect emissions on a 2014 Chevrolet Silverado?

Yes, an engine running cooler than designed may not reach optimal combustion temperatures, potentially increasing emissions and reducing fuel efficiency.