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Engine-Codes – KIA – P0128 KIA

P0128 KIA Code - Coolant Thermostat Malfunction

Quick Answer

The P0128 diagnostic trouble code for KIA vehicles indicates a malfunction in the coolant thermostat. Common causes include Faulty thermostat, Low coolant level, Coolant leaks. 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 KIA indicates Coolant Thermostat Malfunction.
Common causes
Common causes include Faulty thermostat, Low coolant level, Coolant leaks.
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.
What is this?
Table of contents Created and updated by William Orellana on Aug 18, 2024
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Code P0128 KIA Description

The P0128 diagnostic trouble code for KIA vehicles indicates a malfunction in the coolant thermostat. The thermostat is a crucial component of the engine's cooling system, responsible for regulating the flow of coolant to maintain optimal engine temperature. When the thermostat malfunctions, it can lead to improper engine temperature regulation, potentially causing overheating or inefficient fuel combustion. This can have detrimental effects on the vehicle's overall performance and longevity.

OBDII Code P0128 KIA - Coolant Thermostat Malfunction
P0128 KIA Code - Coolant Thermostat Malfunction

Common Causes of P0128 KIA

  1. Faulty thermostat
  2. Low coolant level
  3. Coolant leaks
  4. Electrical issues with the coolant temperature sensor
  5. Clogged coolant passages

Symptoms of P0128 KIA

  1. Engine running hotter or colder than usual
  2. Decreased fuel efficiency
  3. Check Engine Light illuminated on the dashboard
  4. Poor heater performance
  5. Engine overheating

How to Fix P0128 KIA

  1. Diagnostic Testing: Use an OBD-II scanner to retrieve the specific diagnostic trouble code and confirm the issue is related to the coolant thermostat.
  2. Coolant System Inspection: Check for leaks, verify coolant level, and inspect the condition of the coolant.
  3. Replace Thermostat: Remove the old thermostat, replace it with a new one, and ensure proper installation.
  4. Check Sensor: Verify the coolant temperature sensor is functioning correctly and replace if necessary.
  5. System Flush: Perform a coolant system flush to remove any contaminants and ensure proper coolant circulation.

Cost to Fix P0128 KIA

The typical repair costs for a coolant thermostat malfunction can range from $150 to $300, including parts and labor. However, actual costs may vary depending on the specific diagnosis time and labor rates at auto repair shops. It's recommended to obtain quotes from local service providers for a more accurate estimate.

What does this mean?

Tech Notes for P0128 KIA

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

There is a factory service bulletin for the following Kia models:
2012-2013 Kia Rio
2012-2013 Kia Soul
The Factory Service Bulletin recommends reprogramming the Engine Control Module (ECM) to fix the problem.

When is the Code Detected?

The engine coolant temperature does not reach to specified temperature even though the engine has run long enough.

Need more information about the P0128 KIA code?

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Need Help with the Code?

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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 KIA Code

1. What are the common symptoms of OBDII code P0128 in a KIA vehicle?

- Common symptoms include the engine running hotter or colder than normal, a decrease in fuel efficiency, and the coolant temperature gauge fluctuating erratically.

2. What are some possible causes of the OBDII code P0128 in a KIA car?

- Possible causes include a malfunctioning thermostat, a faulty engine coolant temperature sensor, low coolant levels, or a problem with the cooling system.

3. How serious is a coolant thermostat malfunction indicated by OBDII code P0128 in a KIA?

- Ignoring a coolant thermostat malfunction can lead to engine overheating, potential damage to engine components, and reduced overall vehicle performance.

4. Can I continue driving my KIA with the OBDII code P0128 triggered?

- It is not recommended to continue driving your KIA with the P0128 code triggered, as it can lead to potential engine damage and unsafe driving conditions.

5. How can I diagnose a coolant thermostat malfunction causing the OBDII code P0128 in my KIA?

- Diagnosing the issue involves checking the coolant level, inspecting the thermostat, testing the engine coolant temperature sensor, and examining the cooling system for leaks or blockages.

6. What are some repair tips for fixing the OBDII code P0128 in a KIA due to a coolant thermostat malfunction?

- Repair tips include replacing the thermostat, ensuring proper coolant levels, checking and replacing the engine coolant temperature sensor if necessary, and flushing the cooling system.

7. How much does it typically cost to repair the OBDII code P0128 indicating a coolant thermostat malfunction in a KIA?

- Repair costs can vary depending on the exact cause of the issue, but replacing a faulty thermostat or sensor can range from $150 to $300, while more extensive repairs may cost upwards of $500.

8. Can a DIY enthusiast fix the OBDII code P0128 due to a coolant thermostat malfunction in a KIA?

- DIY enthusiasts with mechanical knowledge and the right tools can often replace a thermostat or sensor themselves, but it's essential to follow proper procedures and safety precautions.

9. How long does it take to repair the OBDII code P0128 related to a coolant thermostat malfunction in a KIA?

- The repair time can vary depending on the exact cause and complexity of the issue, but a straightforward thermostat replacement typically takes around 1-2 hours.

10. Are there any preventive maintenance tips to avoid triggering the OBDII code P0128 in a KIA due to a coolant thermostat malfunction?

- Regularly checking coolant levels, performing cooling system inspections, following the manufacturer's recommended maintenance schedule, and addressing any cooling system issues promptly can help prevent the P0128 code from appearing.

Discuss the causes and fixes for P0128 KIA OBDII Code

Submit a New Comment

  • My 2007 KIA SEDONA EX has a problem with the engine light coming on more frequently than I think it should. In the winter it didn't warm up to operating temp as I was only driving 6 miles one way to my destination. but now it warms up ok but the light still comes on. I have replaced the thermostat twice
    and it is ok for a while then the engine light comes on again. It will reset itself after a while if getting up to temperature. Has anyone else experienced this and if so any solutions would help. Email me, JIM @ [email protected] and Thanks to any and all.

    Reply to Comment