P0128 2016 GMC Sierra Code - Engine Coolant Temperature Below Thermostat Regulating Temperature
Quick Answer
The P0128 diagnostic trouble code for a 2016 GMC Sierra indicates that the engine coolant temperature is below the thermostat regulating temperature. Common causes include Faulty thermostat: The most common cause of the P0128 code is a malfunctioning thermostat that is stuck open, preventing the engine from reaching the proper operating temperature, Low coolant level: Insufficient coolant in the system can also cause the engine to run cooler than normal, Faulty engine coolant temperature sensor: A defective coolant temperature sensor may provide inaccurate readings to the ECM, triggering the P0128 code. 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 2016 GMC Sierra indicates Engine Coolant Temperature Below Thermostat Regulating Temperature.
- Common causes
- Common causes include Faulty thermostat: The most common cause of the P0128 code is a malfunctioning thermostat that is stuck open, preventing the engine from reaching the proper operating temperature, Low coolant level: Insufficient coolant in the system can also cause the engine to run cooler than normal, Faulty engine coolant temperature sensor: A defective coolant temperature sensor may provide inaccurate readings to the ECM, triggering the P0128 code.
- 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 2016 GMC Sierra Description
The P0128 diagnostic trouble code for a 2016 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 engine control module (ECM) constantly monitors the temperature of the engine coolant to ensure that it is within the correct range. When the temperature falls below the specified threshold, the P0128 code is triggered.
Common Causes of P0128 2016 GMC Sierra
- Faulty thermostat: The most common cause of the P0128 code is a malfunctioning thermostat that is stuck open, preventing the engine from reaching the proper operating temperature.
- Low coolant level: Insufficient coolant in the system can also cause the engine to run cooler than normal.
- Faulty engine coolant temperature sensor: A defective coolant temperature sensor may provide inaccurate readings to the ECM, triggering the P0128 code.
- Coolant leaks: Leaks in the cooling system can lead to a loss of coolant, affecting the engine temperature.
- Faulty radiator fan: A malfunctioning radiator fan may not cool the engine properly, leading to lower operating temperatures.
Symptoms of P0128 2016 GMC Sierra
- Poor fuel economy: Operating below the optimal temperature can lead to decreased fuel efficiency as the engine may run rich to compensate for the cooler temperature.
- Check Engine Light: The P0128 code will trigger the check engine light to illuminate on the dashboard.
- Reduced heater performance: The cabin heater may not produce as much heat as usual due to the lower engine temperature.
- Engine running rough: The engine may run rough or misfire due to the incorrect temperature affecting combustion.
How to Fix P0128 2016 GMC Sierra
- Check coolant level: Verify that the coolant level is at the proper level and top off if necessary.
- Test thermostat: Test the thermostat to ensure it is functioning correctly. Replace if it is stuck open.
- Inspect coolant temperature sensor: Check the coolant temperature sensor for any signs of damage or malfunction. Replace if necessary.
- Check for leaks: Inspect the cooling system for any leaks and repair as needed.
- Test radiator fan: Verify that the radiator fan is functioning properly and replace if it is not operating correctly.
Cost to Fix P0128 2016 GMC Sierra
The typical repair costs for addressing a P0128 code can vary depending on the specific cause of the issue. Generally, replacing a thermostat can range from $150 to $300, including parts and labor. Coolant temperature sensor replacement may cost between $100 to $200, while repairing coolant leaks can range from $200 to $500. Overall, the total repair cost for addressing a P0128 code can range from $200 to $800, depending on the extent of the issue and the specific repairs needed. It's essential to consider additional diagnostic time and labor rates, which can vary based on the factors mentioned earlier.
Tech Notes for P0128 2016 GMC Sierra
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