P0128 Chevrolet 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 Chevrolet 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.
Code P0128 Chevrolet Description
What are the Possible Causes of the DTC P0128 Chevrolet?
- 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 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
User Submitted Video
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0128 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
- P0128 2014 Chevrolet Silverado — Engine Coolant Temperature Below Thermostat Regulating Temperature
- P0128 2015 Chevrolet Silverado — Engine Coolant Temperature Below Thermostat Regulating Temperature
- P0128 2016 Chevrolet Silverado — Engine Coolant Temperature Below Thermostat Regulating Temperature
- P0128 2017 Chevrolet Silverado — Engine Coolant Temperature Below Thermostat Regulating Temperature
- P0128 2018 Chevrolet Silverado — Engine Coolant Temperature Below Thermostat Regulating Temperature
Frequently Asked Questions about P0128 Chevrolet Code
1. What are the common symptoms of OBDII code P0128 in a Chevrolet?
- Common symptoms include the engine running colder than normal, decreased fuel efficiency, and the check engine light illuminating on the dashboard.
2. What can cause the OBDII code P0128 in a Chevrolet?
- The code P0128 in a Chevrolet is often caused by a malfunctioning thermostat, low coolant levels, a faulty coolant temperature sensor, or a problem with the cooling system.
3. How serious is the OBDII code P0128 in a Chevrolet?
- While the code itself may not cause immediate harm to the engine, it can lead to decreased fuel efficiency and potentially cause overheating issues if left unresolved for an extended period.
4. How can I diagnose the OBDII code P0128 in a Chevrolet?
- Diagnosing the code P0128 involves checking the engine coolant level, inspecting the thermostat, testing the coolant temperature sensor, and ensuring the cooling system is functioning properly.
5. What are some repair tips for resolving the OBDII code P0128 in a Chevrolet?
- Repair tips include replacing the thermostat, topping up coolant levels, testing and replacing the coolant temperature sensor if necessary, and ensuring the cooling system is free of leaks or blockages.
6. Can I continue driving my Chevrolet with the OBDII code P0128?
- It is not recommended to continue driving with the code P0128 unresolved, as it can lead to reduced engine efficiency and potential overheating issues, which may cause further damage.
7. How much does it typically cost to repair the OBDII code P0128 in a Chevrolet?
- The cost of repairing the code P0128 in a Chevrolet can vary depending on the underlying cause, but it typically ranges from $100 to $300 for parts and labor.
8. Will resetting the check engine light resolve the OBDII code P0128 in a Chevrolet?
- Resetting the check engine light will only temporarily clear the code, but it will not fix the underlying issue causing the P0128 fault. It's important to diagnose and repair the problem to prevent future issues.
9. Can a DIY enthusiast fix the OBDII code P0128 in a Chevrolet?
- Depending on your mechanical skills and access to tools, some DIY enthusiasts may be able to address the P0128 code by following repair guides and videos. However, complex issues may require professional assistance.
10. How often does the OBDII code P0128 occur in Chevrolet vehicles?
- The OBDII code P0128 is a relatively common issue in Chevrolet vehicles, especially in older models or those with high mileage. Regular maintenance and inspections can help prevent this code from occurring.
Discuss the causes and fixes for P0128 Chevrolet OBDII Code
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Let engine warm up in a closed and safe place so engine temperature reaches 175%F allowing the fans to operate and sending to the ECU recognition of temperature reading for thermostat to open. Also make sure there is no air in the trapped int he radiator or emgine block side , there sould be a relief valve on both.... chevrolet anyway..
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I have a 2011 Chevy Cruze LT 1.4L that is popping this code along w/ a dashboard msg that says "AC turned off due to high engine temp" & the temp gauge is pegged on cold. I took it to the dealer. They said it was my water pump. Since it was under a TSB they replaced my water pump at no charge. They also mentioned my Optima battery was at a low charging state which was replaced under warranty. A week later (exactly) the code pops again & the dashboard msg pops up. At the dealership I told them to check the thermostat & the ECT sensor but I'm not confident that they did that. Has anyone else seen this type of issue before & what seemed to be the fix? I purchased a new ECT sensor & plan on replacing that but I'm wondering if I just need to go ahead & replace the thermostat as well. Any ideas? Thanks for your help in advance!
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The thermostat is the most common problem for the P0128 code, and according to a national database of repairs, the sensor is the second most common cause. I were you I would replace both, the thermostat and the sensor. In my opinion the thermostat is like a maintenance and should be replace every 5 years or 60K miles
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Before replacing the thermostat, disconnect and reconnect the battery. This reset usually solves the problem.
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