P0128 Honda Code - Cooling System Malfunction
Quick Answer
The thermostat is closed when the engine coolant temperature is low, and it stops the circulation of engine coolant to speed up engine warm-up. Common causes include Low engine coolant level, Leaking or stuck open thermostat, Faulty Engine Coolant Temperature (ECT) Sensor 1. 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 Honda indicates Cooling System Malfunction.
- Common causes
- Common causes include Low engine coolant level, Leaking or stuck open thermostat, Faulty Engine Coolant Temperature (ECT) Sensor 1.
- 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 Honda Description
What are the Possible Causes of the DTC P0128 Honda?
- Low engine coolant level
- Leaking or stuck open thermostat
- Faulty Engine Coolant Temperature (ECT) Sensor 1
- Faulty Engine Coolant Temperature Sensor 2
- Faulty Intake Air Temperature (IAT) Sensor
- Faulty Manifold Absolute Pressure (MAP) Sensor
- Faulty Crankshaft Position (CKP) Sensor
- Faulty Barometric Pressure (BARO) Sensor
- Faulty Radiator Fan
How to Fix the DTC P0128 Honda?
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
When troubleshooting a 2000-2001 Accord or 2001-2002 Civic, if the PGM Tester tells you there is a DTC P0128 (Cooling System Malfunction) or P1486 (Cooling System Malfunction) set, it's really reporting the same thing. DTC P0128 is an SAE or generic Diagnostic Trouble Code (DTC) while P1486 is a manufacturer-specific DTC. Since these DTCs are similar, the PGM Tester sometimes reports a P0128 when it detects a P1486 or vice versa.
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What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0128 Honda 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 Honda Models
- P0128 2008 Honda Accord — Coolant System Malfunction
- P0128 2009 Honda Accord — Coolant System Malfunction
- P0128 2010 Honda Accord — Coolant System Malfunction
- P0128 2016 Honda CR-V — Cooling System Malfunction
- P0128 2017 Honda CR-V — Cooling System Malfunction
- P0128 2018 Honda CR-V — Cooling System Malfunction
- P0128 2019 Honda CR-V — Cooling System Malfunction
- P0128 2020 Honda CR-V — Cooling System Malfunction
- P0128 2021 Honda CR-V — Cooling System Malfunction
Frequently Asked Questions about P0128 Honda Code
1. What does the OBDII code P0128 mean on a Honda?
P0128 indicates that the engine coolant temperature is not reaching the expected level within a specified time, suggesting a potential cooling system malfunction.
2. What are the common symptoms of code P0128 in a Honda?
Symptoms include the check engine light turning on, poor fuel efficiency, underperforming heater, or the temperature gauge reading lower than normal.
3. What causes the P0128 code on a Honda?
Common causes include a stuck-open thermostat, low coolant levels, a faulty coolant temperature sensor, or issues with the engine control module (ECM).
4. Can you drive a Honda with a P0128 code?
Yes, you can drive with a P0128 code temporarily, but prolonged driving may result in increased fuel consumption and potential engine wear due to improper operating temperatures.
5. How do you fix a P0128 code on a Honda?
The most common fix is replacing the thermostat. Other potential repairs include topping off or replacing coolant, checking the coolant temperature sensor, or inspecting the wiring and connectors.
6. How much does it cost to fix a P0128 code on a Honda?
Replacing the thermostat typically costs between $150 and $300, depending on the model and labor rates. Other repairs, such as replacing the coolant temperature sensor, may cost less.
7. Can low coolant cause a P0128 code on a Honda?
Yes, low coolant levels can prevent the engine from reaching optimal operating temperatures, triggering the P0128 code.
8. What tools are needed to diagnose a P0128 code on a Honda?
You’ll need an OBDII scanner, a thermometer or infrared temperature gun to measure coolant temperature, and basic hand tools for inspecting and replacing components.
9. How does a stuck-open thermostat cause the P0128 code?
A stuck-open thermostat allows excessive coolant flow, preventing the engine from warming up to its proper operating temperature.
10. Can a faulty coolant temperature sensor trigger the P0128 code on a Honda?
Yes, if the coolant temperature sensor sends incorrect readings to the ECM, it may mistakenly trigger the P0128 code.
Discuss the causes and fixes for P0128 Honda OBDII Code
-
I have Honda civic 2011 and i am facing a very big challenge any time I fill the coolant container water and i drive the car for about 20 minutes I experience water shortage in the coolant container I have done the necessary checks on the radiator and pipes in the engine.I have changed the thermostat but still not ok what should I do now
-
Are there any coolant leaks?
If no leaks are found, then you may have a blown head gasket.
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