P1258 2018 GMC Sierra Code - Engine Coolant Overtemperature Protection Mode Active
Quick Answer
The P1258 diagnostic trouble code (DTC) for a 2018 GMC Sierra indicates that the Engine Coolant Overtemperature Protection Mode is active. Common causes include Low coolant levels, Malfunctioning thermostat, Faulty coolant temperature sensor. 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
- P1258 2018 GMC Sierra indicates Engine Coolant Overtemperature Protection Mode Active.
- Common causes
- Common causes include Low coolant levels, Malfunctioning thermostat, Faulty coolant temperature sensor.
- 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 P1258 2018 GMC Sierra Description
The P1258 diagnostic trouble code (DTC) for a 2018 GMC Sierra indicates that the Engine Coolant Overtemperature Protection Mode is active. This means that the engine's cooling system has detected that the coolant temperature is too high, prompting the vehicle's computer to limit engine power to prevent damage due to overheating. When this code is triggered, the engine may go into a reduced power mode to prevent further overheating and potential damage.
Common Causes of P1258 2018 GMC Sierra
- Low coolant levels
- Malfunctioning thermostat
- Faulty coolant temperature sensor
- Clogged radiator or cooling system
- Water pump failure
Symptoms of P1258 2018 GMC Sierra
- Reduced engine power
- Engine overheating warning light illuminated on the dashboard
- Rough idling or stalling
- Loss of acceleration power
- Increased coolant temperature readings on the gauge
How to Fix P1258 2018 GMC Sierra
- Check and top up coolant levels: Ensure that the coolant reservoir is filled to the proper level and that there are no leaks in the system.
- Replace thermostat: If the thermostat is stuck closed or malfunctioning, it can cause the engine to overheat. Replace the thermostat with a new one.
- Check and replace coolant temperature sensor: A faulty sensor can give incorrect temperature readings to the engine computer, triggering the overtemperature protection mode. Replace the sensor if needed.
- Flush and refill cooling system: If the radiator or cooling system is clogged with debris or old coolant, a flush and refill may be necessary to restore proper cooling efficiency.
- Inspect and replace water pump: A failing water pump can lead to poor coolant circulation, resulting in overheating. Inspect the water pump for any signs of leakage or wear, and replace if necessary.
Cost to Fix P1258 2018 GMC Sierra
The cost of repairing a P1258 code on a 2018 GMC Sierra can vary depending on the specific cause of the issue. On average, the repair costs for this issue can range from $200 to $600, including parts and labor. It's important to note that diagnostic time and labor rates at auto repair shops can vary, so it's advisable to check with local shops for a more precise estimate. Additional costs may apply if other components need to be replaced or if further diagnostics are required.
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