P0128 2017 GMC Sierra Code - Engine Coolant Temperature Below Thermostat Regulating Temperature
Quick Answer
The P0128 code for a 2017 GMC Sierra indicates that the engine coolant temperature is below the thermostat regulating temperature. Common causes include Faulty Thermostat: A malfunctioning thermostat that is stuck open or opening too soon can cause the engine coolant temperature to remain below the optimal level, Low Coolant Level: Insufficient coolant in the system can prevent the engine from reaching the desired temperature, Coolant Leak: A leak in the cooling system can lead to a loss of coolant, affecting the engine's ability to regulate temperature. 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 2017 GMC Sierra indicates Engine Coolant Temperature Below Thermostat Regulating Temperature.
- Common causes
- Common causes include Faulty Thermostat: A malfunctioning thermostat that is stuck open or opening too soon can cause the engine coolant temperature to remain below the optimal level, Low Coolant Level: Insufficient coolant in the system can prevent the engine from reaching the desired temperature, Coolant Leak: A leak in the cooling system can lead to a loss of coolant, affecting the engine's ability to regulate temperature.
- 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 P0128 2017 GMC Sierra Description
The P0128 code for a 2017 GMC Sierra indicates that the engine coolant temperature is below the thermostat regulating temperature. This means that the engine is not reaching the optimal operating temperature as specified by the manufacturer. The thermostat plays a crucial role in regulating the coolant flow through the engine to maintain the ideal temperature for efficient combustion and overall performance. When the engine coolant temperature is below the thermostat regulating temperature, it can lead to various issues that affect the vehicle's performance and fuel efficiency.
Common Causes of P0128 2017 GMC Sierra
- Faulty Thermostat: A malfunctioning thermostat that is stuck open or opening too soon can cause the engine coolant temperature to remain below the optimal level.
- Low Coolant Level: Insufficient coolant in the system can prevent the engine from reaching the desired temperature.
- Coolant Leak: A leak in the cooling system can lead to a loss of coolant, affecting the engine's ability to regulate temperature.
- Faulty Coolant Temperature Sensor: A defective coolant temperature sensor can provide inaccurate readings to the engine control module, leading to the P0128 code.
- Cooling System Blockage: Blockages in the cooling system, such as a clogged radiator or heater core, can impede the flow of coolant and affect the engine's temperature regulation.
Symptoms of P0128 2017 GMC Sierra
- Check Engine Light: The most common symptom associated with the P0128 code is the illumination of the Check Engine Light on the vehicle's dashboard.
- Poor Fuel Economy: Running below the optimal temperature can lead to decreased fuel efficiency, as the engine may not operate efficiently.
- Engine Running Cool: The engine may take longer to warm up or may not reach the expected operating temperature.
- Reduced Heater Performance: The vehicle's heater may not provide sufficient heat, especially in colder weather.
- Overheating: In some cases, the engine may overheat due to the thermostat not functioning properly.
How to Fix P0128 2017 GMC Sierra
- Check Coolant Level: Begin by checking the coolant level in the system and topping it up if it is low. Ensure that there are no leaks in the system.
- Test Thermostat: Test the thermostat to see if it is functioning correctly. Replace it if necessary.
- Inspect Coolant Temperature Sensor: Check the coolant temperature sensor for any signs of damage or malfunction. Replace it if needed.
- Flush Cooling System: Flush the cooling system to remove any blockages or contaminants that may be affecting the engine's temperature regulation.
- Clear Code: After addressing the underlying issue, clear the diagnostic trouble code from the vehicle's computer system to reset the Check Engine Light.
Cost to Fix P0128 2017 GMC Sierra
The cost of repairing a P0128 code on a 2017 GMC Sierra can vary depending on the specific cause of the issue and the labor rates at the auto repair shop. Typically, replacing a faulty thermostat can cost between $150 to $300, including parts and labor. Coolant temperature sensor replacement may cost around $100 to $200. Flushing the cooling system can range from $100 to $200. Overall, the total repair cost for addressing the P0128 code may range from $300 to $700, depending on the extent of the issue and the parts needed. It is advisable to consult with a qualified mechanic or auto repair shop to get an accurate estimate based on the specific circumstances of the vehicle. Please note that labor rates can vary significantly based on location and the shop's expertise. It is recommended to compare prices and services offered by different shops before proceeding with the repair.
Tech Notes for P0128 2017 GMC Sierra
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