P0128 Code - Coolant Thermostat Malfunction
Quick Answer
The thermostat is a component that blocks the flow of coolant to the radiator until the engine has warmed up. 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 indicates Coolant Thermostat Malfunction.
- 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 Description
What are the Possible Causes of the DTC P0128?
- 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?
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 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 Makes
- P0128 Acura — Cooling System Malfunction
- P0128 Audi — Coolant Temperature Below Operating Range
- P0128 BMW — Thermostat Low Coolant Temperature
- P0128 Buick — Engine Coolant Temperature Below Thermostat Regulating Temperature
- P0128 Cadillac — Engine Coolant Temperature Below Thermostat Regulating Temperature
- P0128 Chevrolet — Engine Coolant Temperature Below Thermostat Regulating Temperature
- P0128 Chrysler — Thermostat Rationality
- P0128 Dodge — Thermostat Rationality
- P0128 Ford — Coolant Thermostat
- P0128 GMC — Engine Coolant Temperature Below Thermostat Regulating Temperature
- P0128 Honda — Cooling System Malfunction
- P0128 Hyundai — Coolant Thermostat
- P0128 Infiniti — Thermostat Function
- P0128 Isuzu — Engine Coolant Temperature Below Thermostat Regulating Temperature
- P0128 Jaguar — Coolant Thermostat Malfunction
- P0128 Jeep — Thermostat Rationality
- P0128 KIA — Coolant Thermostat Malfunction
- P0128 Lexus — Coolant Thermostat
- P0128 Mazda — Coolant Thermostat Malfunction
- P0128 Mercedes-Benz — Coolant Thermostat Malfunction
- P0128 MINI — Thermostat Low Coolant Temperature
- P0128 Mitsubishi — Coolant Thermostat Malfunction
- P0128 Nissan — Thermostat Function
- P0128 Pontiac — Engine Coolant Temperature Below Thermostat Regulating Temperature
- P0128 Saturn — Engine Coolant Temperature Below Thermostat Regulating Temperature
- P0128 Scion — Coolant Thermostat
- P0128 Subaru — Coolant Thermostat Malfunction
- P0128 Toyota — Coolant Thermostat
- P0128 Volkswagen — Coolant Temperature Below Operating Range
Frequently Asked Questions about P0128 Code
1. What are the common symptoms of an OBDII code P0128 (Coolant Thermostat Malfunction)?
- The common symptoms include the engine running hotter or colder than normal, decreased fuel efficiency, and the Check Engine light illuminating.
2. What are the possible causes of an OBDII code P0128?
- Possible causes include a faulty thermostat, low coolant level, a problem with the cooling system, or issues with the engine's temperature sensor.
3. How serious is an OBDII code P0128?
- While driving with a P0128 code may not cause immediate harm to your vehicle, it can lead to reduced fuel efficiency, engine overheating, and potential damage if left unresolved.
4. How can I diagnose an OBDII code P0128?
- You can diagnose a P0128 code by using an OBDII scanner to read the code and checking the coolant level, thermostat, and cooling system components for any issues.
5. What are some repair tips for fixing an OBDII code P0128?
- Repair tips include replacing the thermostat, checking and refilling the coolant level, inspecting the cooling system for leaks, and ensuring the engine temperature sensor is functioning correctly.
6. Can I continue driving with an OBDII code P0128?
- It is not recommended to continue driving with a P0128 code, as it can lead to potential engine damage and reduced performance if the underlying issue is not addressed promptly.
7. How much does it typically cost to repair an OBDII code P0128?
- The cost of repairing a P0128 code can vary depending on the root cause of the issue, but it may range from $100 to $300 for parts and labor.
8. How long does it take to fix an OBDII code P0128?
- The repair time for a P0128 code can vary depending on the extent of the issue, but it typically takes around 1-2 hours to diagnose and fix the problem.
9. Can I reset the Check Engine light after fixing an OBDII code P0128?
- Yes, you can reset the Check Engine light using an OBDII scanner after fixing the underlying issue causing the P0128 code.
10. What steps can I take to prevent an OBDII code P0128 in the future?
- To prevent a P0128 code in the future, make sure to perform regular maintenance on your vehicle, including checking the coolant level, thermostat, and cooling system components for any signs of wear or malfunction.
Discuss the causes and fixes for P0128 OBDII Code
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The check engine light on my nissan murano blinked 5 times what does this mean?
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Reading blinking lights it's not a very accurate way to diagnose or read code, the best way is to use a scanner to get the correct code. Some auto parts or shops will read the code free for you.
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I have a 2001 Pontiac Aztec I have a code po128 pd I changed the coolant tempature sensor the service vehicle soon light comes back on and then the tempature gauge in the car drops down to cold and doesn't read what would cause that to happen
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Your next step it's probably replacing the thermostat.
P0128 Pontiac - Engine Coolant Temperature Below Thermostat Regulating Temperature
Read more: https://www.autocodes.com/p01...
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I changed the thermostat and the engine light usually comes back on by now and I drove more than I did before I drove over about a 100 miles and the light hasn't came back on yet do u think I fixed my promblem
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If the light hasn't come back ON, then It's very likely that the problem is fixed
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I have this same code P0128 on Toyota Corolla 1999 but all temp reading are perfectly fine. What do you think please. Also can this code affect anything else in the car
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The code means that at some point the coolant system thermostat did not worked as designed. If the thermostat gets stuck, then engine could overheat and get damage. I recommend replacing the coolant thermostat and service the coolant system.
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Hello, I have a BMW 535I. I have a code p0128 in my car, but does this code cause smoke?
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