Cadillac CTS Engine Coolant Temperature Sensor Guide (2013-2019)
Everything a Cadillac CTS owner needs to know about a failing engine coolant temperature sensor and how to choose the right replacement.
- A failing ECT sensor can cause overheating, poor fuel economy, and a Check Engine Light with codes like P0117 or P0118.
- For best results and reliability, choose an OEM-equivalent brand like ACDelco or Delphi.
- Replacement is simple on the 3.6L V6 but very difficult on the 2.0L Turbo, which significantly impacts labor costs.
- Before replacing the sensor, always inspect the electrical connector for corrosion or damage, as this can cause the same symptoms.
Understanding Engine Coolant Temperature Sensor Failure in the Cadillac CTS
A faulty Engine Coolant Temperature (ECT) sensor can cause a range of confusing problems for your 2013-2019 Cadillac CTS. Because this sensor provides critical data to the engine's computer, its failure can mimic other, more serious issues. Symptoms can range from a simple Check Engine Light to noticeable performance problems like rough idling, poor fuel economy, or even engine overheating because the cooling fans don't turn on when they should. In some cases, a bad sensor can even cause the A/C system to stop working, as the car's computer shuts it down as a precaution.
Symptoms of a Bad ECT Sensor
- Check Engine Light: Often the first sign, with codes like P0117 (Circuit Low), P0118 (Circuit High), or P0119 (Circuit Intermittent) stored in the computer. 🎬 See a detailed explanation of the P0118 trouble code.
- Engine Overheating: If the sensor fails to report a high temperature, the cooling fans may not activate, causing the engine to overheat.
- Cooling Fans Run Constantly: A sensor that's stuck sending a "hot" signal can cause the cooling fans to run all the time, even when the engine is cold, potentially draining the battery.
- Poor Fuel Economy: The computer might enrich the fuel mixture, thinking the engine is cold when it isn't, leading to wasted gas.
- Rough Idle or Hard Starting: Incorrect fuel and timing adjustments based on bad temperature data can make the engine run poorly.
- Inaccurate Temperature Gauge: The gauge on your dashboard may read incorrectly or not move at all.
A Note on Engine Differences
The replacement procedure for the ECT sensor varies significantly between the 2.0L Turbo and 3.6L V6 engines. The 3.6L V6 is generally easier, with the sensor located on the driver's side of the engine. 🎬 Watch a walkthrough for the 3.6L V6 sensor replacement. The 2.0L Turbo is much more difficult, requiring the removal of the windshield wiper assembly and vacuum pump to access the sensor on the back of the engine. This dramatically increases labor time and cost.
Choosing the Right Aftermarket Sensor
For a critical electronic part like an ECT sensor, brand quality matters. While many options are available, they generally fall into three tiers for your Cadillac CTS.
Tier 1: OEM & Premium Aftermarket
Brands: ACDelco, Delphi
ACDelco is GM's official parts brand, making it the true original equipment (OE) choice. Delphi was the original parts manufacturer for GM for many years and is often identical to the ACDelco part, sometimes at a lower price. For maximum reliability and peace of mind, choosing one of these two brands is the safest bet. They are engineered to the exact specifications of your CTS.
Tier 2: Reputable Aftermarket
Brands: NGK, Standard Motor Products (SMP), Hella, Holstein
These brands have a strong reputation for producing quality electronic components that meet or exceed OEM standards. Standard Motor Products, in particular, is a well-regarded name in the industry. An option from this tier is a solid choice that balances cost and quality, often providing performance very close to the original part.
Tier 3: Value Brands
Brands: Walker Products, Four Seasons, Facet, Global Parts, True Tech
These brands focus on providing a cost-effective solution. While they are designed to function as a direct replacement, their long-term durability and the precision of their temperature readings may not be as consistent as higher-tier brands. They can be a suitable option for a budget-conscious repair, but for a vehicle like the CTS, investing a few extra dollars in a Tier 1 or Tier 2 brand is often recommended.
Pro Tip: Check the Connector
Sometimes, the problem isn't the sensor itself but the wiring connector attached to it. Over years of heat cycles, the plastic can become brittle and the terminals can corrode. Before replacing the sensor, inspect the connector and wiring for any signs of damage. If it's corroded or broken, you may need to replace the connector pigtail as well.
Cost to Replace a Cadillac CTS Engine Coolant Temperature Sensor
| Part Type | Part Cost | Labor Cost (Shop) | Total Estimated Cost |
|---|---|---|---|
| New Aftermarket | $10 - $42 | $80 - $250+ | $90 - $292+ |
| New OEM (ACDelco) | $15 - $58 | $80 - $250+ | $95 - $308+ |
Frequently Asked Questions
Where is the ECT sensor located on my 2013-2019 Cadillac CTS?
It depends on your engine. On the 3.6L V6, it's typically on the driver's side cylinder head, sometimes near the oil dipstick tube, and may have a foil heat shield around the wire. On the 2.0L Turbo engine, it is in a much more difficult-to-access spot on the back of the engine, under the vacuum pump.
🎬 Watch this difficult 2.0L Turbo sensor and vacuum pump removal.Do I need to drain the coolant to replace the sensor?
Not necessarily. If you are quick, you can swap the old sensor for the new one with very little coolant loss—often just a few tablespoons. Having the new sensor ready to thread in immediately after removing the old one is key. Make sure the engine is completely cool before attempting this.
Are there any recalls for the ECT sensor on the Cadillac CTS?
Our search of the NHTSA database found no specific recalls for the engine coolant temperature sensor on the 2013-2019 Cadillac CTS. The most common issues are related to general wear and tear.
Can a bad ECT sensor cause my car not to start?
Yes, it can. A sensor that sends a false "very hot" signal to the computer might cause a hard starting or no-start condition. Conversely, a sensor sending a false "very cold" signal can cause the engine to flood with too much fuel, making it difficult to start.
What happens if I ignore a bad ECT sensor?
Ignoring it can lead to more serious problems. You could experience progressively worse fuel economy, damage to the catalytic converter from a rich fuel mixture, or catastrophic engine damage from overheating if the fans fail to turn on. It's a cheap part that protects an expensive engine, so it's best to replace it promptly.
Helpful Videos
Technical Specifications
OEM Part Numbers: 12650595 12656444 12608814 12639899 12611420
Typically a 2-pin thermistor sensor that threads into a coolant passage on the engine block or cylinder head.
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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.
- Cadillac CTS:
- 🎬 Helpful Videos
- 🛍️ Shop This Part
- Understanding Engine Coolant Temperature Sensor Failure in the Cadillac CTS
- Symptoms of a Bad ECT Sensor
- A Note on Engine Differences
- Choosing the Right Aftermarket Sensor
- Tier 1: OEM & Premium Aftermarket
- Tier 2: Reputable Aftermarket
- Tier 3: Value Brands
- Pro Tip: Check the Connector
- Cost to Replace a Cadillac CTS Engine Coolant Temperature Sensor
- Frequently Asked Questions
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