Lexus GS350 (2007-2020) Engine Coolant Temperature Sensor Guide
Learn about common failure symptoms and how to choose the right replacement coolant temperature sensor for your GS350.
- A failing ECT sensor on a GS350 often causes a Check Engine Light with codes P0117 or P0118, poor fuel economy, and rough running.
- The sensor is located in a difficult-to-reach spot at the rear of the engine, making replacement labor-intensive.
- For reliability, it is highly recommended to use an OEM-equivalent brand like Denso or NGK, as they are trusted original suppliers for Lexus.
- Driving with a bad sensor is not advised as it can lead to engine damage from overheating or other long-term issues.
Is Your GS350's Coolant Sensor Failing?
A bad Engine Coolant Temperature (ECT) sensor can cause a surprising number of problems. Because the sensor's reading affects so many engine functions, a false signal can make the car's computer think the engine is cold when it's hot, or vice versa. This can lead to noticeable performance issues.
🎬 Watch this video to see common symptoms of a bad sensor.Key Failure Symptoms:
- Check Engine Light: This is the most common sign. The computer will log a fault code like P0117 (Circuit Low) or P0118 (Circuit High).
- Poor Fuel Economy: If the sensor incorrectly tells the computer the engine is cold, the ECU will enrich the fuel mixture, wasting gas.
- Rough Idle or Stalling: Incorrect fuel and timing adjustments can make the engine run poorly, especially when it should be at a stable idle.
- Hard Starting: The engine may be difficult to start, either when it's cold or after it has warmed up.
- Black Smoke from Exhaust: This is a sign of a rich fuel mixture, where the engine is getting too much gasoline and not enough air, often caused by a faulty sensor reading.
- Engine Overheating: If the sensor fails to report a high temperature, the cooling fans may not turn on when needed, causing the engine to overheat.
- Inaccurate Temperature Gauge: The gauge on your dashboard may show erratic readings, stay on cold, or jump to hot unexpectedly.
It is not recommended. Driving with a faulty ECT sensor can lead to poor performance, increased fuel consumption, and potentially severe engine damage from overheating if the cooling fans don't operate correctly. It's best to get the issue diagnosed and repaired as soon as possible.
Choosing the Right Aftermarket Sensor for Your GS350
When replacing the ECT sensor, you have a choice between Genuine OEM (Original Equipment Manufacturer) parts and a wide variety of aftermarket options. For a critical component like this, quality matters.
For Lexus vehicles, Denso is the original equipment manufacturer for many electronic parts, including sensors. Choosing a Denso-branded aftermarket sensor is often the safest bet, as it is likely identical to the part sold at a Lexus dealership, but at a lower price. Forum users and mechanics often recommend sticking with OEM or Denso for critical sensors to avoid compatibility issues and ensure accurate readings.
Aftermarket Brand Tiers for Lexus GS350
- OEM-Equivalent (Recommended): Denso, NGK/NTK. These brands are known OEM suppliers and are trusted for their quality and reliability. They are designed to match the original part's performance exactly.
- Quality Aftermarket: Standard Motor Products (SMP), Beck Arnley, Delphi. These are reputable aftermarket brands. While Beck Arnley used to be known for reboxing OEM parts, their sourcing has become more varied. SMP and Delphi can be good choices, but it's important to verify the specific part's quality, as some may be sourced from different manufacturers.
- Budget-Friendly: Facet, URO Parts, Walker Products, and other lower-priced brands. While tempting due to their low cost, these sensors can be a gamble. They may not have the same accuracy or longevity as higher-quality options, potentially leading to performance issues or a premature failure. Some forum users have reported fitment issues with certain aftermarket brands not fitting correctly into aftermarket radiators.
Cost of Replacing the Engine Coolant Temperature Sensor
The cost can vary significantly depending on whether you do the work yourself or take it to a repair shop. The part itself is relatively inexpensive, but labor can be high due to the sensor's location.
| Part/Service | Estimated Cost |
|---|---|
| New OEM Lexus Sensor | $45 - $70 |
| New Aftermarket Sensor | $13 - $85 |
| Shop Labor | $317 - $465 |
| Total Professional Replacement | $360 - $550+ |
Frequently Asked Questions
Where is the ECT sensor located on the Lexus GS350?
On the 2007-2020 Lexus GS350 with the 2GR-FSE engine, the engine coolant temperature sensor is located on the back of the engine, underneath the intake manifold area. It is difficult to access. Replacement requires removing the engine cover and air intake assembly to reach the sensor, which is situated on a coolant crossover pipe.
🎬 See a step-by-step guide for replacing the sensor on your GS350.Is this a difficult DIY job?
For the average DIY mechanic, this is a moderately difficult job. While the sensor itself is simple to unclip and unscrew, its location makes it challenging. It requires removing several components to gain access and can take an hour or more. You will also lose some coolant, so you should be prepared to top it off. A deep 19mm socket with extensions is typically required.
🎬 Learn how to easily access the hidden sensor on F Sport models.Are there any recalls for the GS350 coolant sensor?
No, there are no specific recalls or widespread customer support programs from Lexus or NHTSA for the engine coolant temperature sensor on the 2007-2020 GS350. Any failure is considered a standard repair.
Do I need to drain the coolant to replace the sensor?
You do not need to drain the entire cooling system, but you will lose a small amount of coolant when you remove the old sensor. It's a good idea to have the new sensor ready to install quickly to minimize coolant loss. After installation, check your coolant level in the reservoir and top it off with the correct type of Toyota/Lexus Super Long Life Coolant.
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Technical Specifications
OEM Part Numbers: 89422-33030 89422-30030
2-Terminal Blade Connector, M12 x 1.5 Thread
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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.
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