GMC Terrain Coolant Temperature Sensor: A Complete Guide (2010-2022)
Is your Terrain's temperature gauge acting up, or is the cooling fan always on? Your coolant sensor might be the problem.
- A bad coolant sensor affects more than the temperature gauge; it directly impacts fuel economy and cooling fan operation.
- Common signs of failure on the Terrain include fans that won't shut off and an A/C that stops working.
- Replacement is a simple, low-cost DIY job for most owners, with the main challenge being access to the sensor.
- An affordable aftermarket sensor is a practical and effective solution for this specific repair.
Symptoms of a Failing Coolant Temperature Sensor
When the coolant temperature sensor on your GMC Terrain starts to fail, it sends incorrect information to the engine's computer. This can cause a range of noticeable problems. You might see a Check Engine Light, or your temperature gauge on the dashboard could be stuck on cold or hot, or swing back and forth wildly. Other common signs include the engine cooling fans running all the time, even when the engine is off, or not turning on at all, which can lead to overheating. You may also experience poor fuel economy, a rough idle, difficulty starting, or even see black smoke from the exhaust pipe.
🎬 Watch: 5 common symptoms of a faulty temperature sensorChoosing the Right Aftermarket Sensor
When replacing the ECT sensor, you have a choice between an original equipment (OEM) part from a dealer (like ACDelco) and an aftermarket part. For a component like this, an aftermarket sensor is often a reliable and budget-friendly choice that performs well.
- OEM (ACDelco): This is the same part your Terrain was built with. It guarantees perfect fit and function but comes at a higher price.
- Replacement Brand: This is a standard aftermarket option designed to meet original specifications. It offers a significant cost saving, making it a practical choice for this repair without a compromise in core function.
Pro Tip: Check the Connector
Before you buy, it's a good idea to look at your old sensor's electrical connector. Make sure the new part has the same shape and number of pins. Sometimes, the connector itself can be corroded or damaged and may need to be replaced as well.
Cost of Replacing a GMC Terrain Coolant Sensor
The cost can vary depending on the part you choose and whether you do the work yourself or hire a mechanic.
| Part/Service | Estimated Cost |
|---|---|
| New OEM Sensor (ACDelco) | $50 - $75 |
| New Aftermarket Sensor (Replacement) | $20.68 |
| Shop Labor | $95 - $180 |
| Total (DIY with Aftermarket Part) | $20.68 |
| Total (Shop Install with Aftermarket Part) | $115 - $200 |
Warning: Let the Engine Cool Down
Always let your vehicle's engine cool down completely before starting this repair. The cooling system is pressurized and the coolant can be extremely hot, posing a risk of serious burns.
Frequently Asked Questions
Where is the coolant temperature sensor located on my GMC Terrain?
The location varies depending on your engine:
- 2010-2017 2.4L I4: The sensor is typically located below the exhaust manifold, and can be in a tight spot to access. 🎬 See this walkthrough for replacing the sensor on 2.4L engines
- 2010-2017 3.0L & 3.6L V6: You can find it on the front of the engine, near the starter motor.
- 2018-2022 1.5L & 2.0L Turbo: The sensor is usually near the thermostat housing on the front-left side of the engine.
Can I replace the sensor myself?
Yes, this is a DIY-friendly job for many people with basic tools. The main tool needed is a 19mm deep socket and a ratchet. The process involves disconnecting the electrical plug, unscrewing the old sensor, and quickly screwing the new one in. Be prepared for a small amount of coolant to leak out; have a catch pan ready. After installation, you may need to clear the check engine light with a scanner or by disconnecting the negative battery terminal for about 10 minutes.
What do the check engine codes P0117, P0118, and P0128 mean?
These are common codes related to the ECT sensor.
- P0117 (Circuit Low): The computer is getting a signal that is too low (high resistance), making it think the engine is extremely hot.
- P0118 (Circuit High): The computer is getting a signal that is too high (low resistance), making it think the engine is extremely cold. This can cause the cooling fans to run constantly and disable the A/C.
- P0128 (Coolant Temp Below Regulating Temp): This code means the engine isn't warming up as fast as the computer expects. While this often points to a thermostat that is stuck open, it can also be caused by a faulty ECT sensor giving incorrect readings. 🎬 Watch: How to diagnose and fix a P0128 trouble code
Are there any recalls for the GMC Terrain coolant sensor?
There are no specific recalls for the coolant temperature sensor on the 2010-2022 GMC Terrain. However, a technical service bulletin (TSB) was issued for some models suggesting that if issues are present, a technician should inspect the sensor's electrical terminals and consider updating the engine computer's software.
Helpful Videos
Technical Specifications
OEM Part Numbers: 12608814
The sensor is a thermistor that changes electrical resistance based on coolant temperature. It typically has a 2-pin electrical connector and is installed with a 19mm deep socket.
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- GMC Terrain: