Engine Intake Manifold Temperature Sensor Guide for 1991-2002 Saturn SL
Fix your Saturn's rough idle and poor fuel economy by choosing the right temperature sensor.
- A bad IAT sensor on a Saturn SL commonly causes a Check Engine Light with codes like P0110 or P0113, along with poor gas mileage and a rough idle.
- Replacement is extremely easy for a DIY mechanic, requiring only a 13mm wrench and about 15 minutes.
- The sensor is located in the plastic air intake tube near the air filter box, not on the engine itself.
- Quality aftermarket brands like Standard Ignition are a reliable and cost-effective choice for this repair.
Is your Saturn SL running rough or getting bad gas mileage?
A failing Engine Intake Manifold Temperature Sensor, more commonly called the Intake Air Temperature (IAT) sensor, could be the culprit. This small sensor plays a big role in how your engine performs. When it goes bad, the engine's computer gets wrong information about the air temperature, leading to a host of noticeable problems. 🎬 Watch this video to learn more about bad IAT sensor symptoms. Fortunately, on the 1991-2002 Saturn SL, this is one of the easiest and cheapest parts to replace yourself.
Symptoms of a Bad IAT Sensor
A bad IAT sensor usually won't stop you from driving, but it will make your car run poorly. Here are the most common signs:
- Check Engine Light: This is often the first sign. The sensor will trigger a fault code, lighting up the warning on your dash.
- Poor Fuel Economy: If the sensor tells the computer the air is colder than it is, the computer will inject too much fuel, wasting gas.
- Rough Idle: An incorrect air/fuel mixture can make your engine idle unevenly or feel shaky when stopped.
- Failed Emissions Test: With the fuel mixture out of balance, your car will produce more pollution and likely fail an emissions test.
- Hard Starting: The wrong fuel mixture can make the engine difficult to start, especially in very hot or cold weather. 🎬 See a visual guide on signs of a faulty sensor.
Choosing the Right Aftermarket Sensor
For a vehicle like the 1991-2002 Saturn SL, new OEM (Original Equipment Manufacturer) parts are often unavailable. Aftermarket parts are your main option, and for a simple sensor like the IAT, they offer excellent value. The key is to choose a brand with a good reputation. Based on the available options, here is a breakdown:
- Good (Best): Standard Ignition (SMP) is a well-respected brand known for making high-quality aftermarket parts that often meet or exceed original specifications. They are a trusted choice for reliability and performance.
- Better (Value): Motorad is a known aftermarket brand that produces a wide range of parts. While some of their components receive mixed reviews, for a basic sensor, they generally provide a functional and budget-friendly option.
- Basic (Economy): True Tech appears to be a value-focused brand. While there is less specific information on their sensors, reviews for their business operations are generally positive, suggesting a focus on customer satisfaction. This brand is likely the most economical choice.
Cost of Replacing the IAT Sensor
| Part/Service | Estimated Cost |
|---|---|
| New Aftermarket Part | $9.09 - $20.49 |
| Shop Labor | $50 - $100 |
| DIY Total | $9.09 - $20.49 |
| Shop Total | $60 - $120 |
Note: Prices are estimates and can vary based on your location, the specific retailer, and the brand you choose.
Frequently Asked Questions (FAQ)
Where is the IAT sensor located on a 1991-2002 Saturn SL?
The IAT sensor is located in the plastic air intake tube, between the air filter box and the engine's throttle body. As you stand in front of the car, it's usually in the corner of the air filter box assembly closest to you. It is screwed into the intake tube and has a two-wire electrical connector.
🎬 Watch this video to help you locate the sensor on your car.Can I replace this sensor myself?
Yes, this is a very easy job for a DIYer. The only tools you typically need are a 13mm wrench or socket and possibly a pair of pliers to help release the electrical connector clip. The entire process takes less than 15 minutes.
What happens if I don't replace a bad IAT sensor?
While the car will still run, you will continue to experience poor fuel economy, rough performance, and high emissions. Over the long term, running a consistently rich fuel mixture can lead to other problems, like fouled spark plugs and carbon buildup. Given the low cost and ease of replacement, it's best to fix it promptly.
Are there any recalls for the Saturn SL IAT sensor?
No, a search of the National Highway Traffic Safety Administration (NHTSA) database shows no recalls specifically for the Engine Intake Manifold Temperature Sensor on the 1991-2002 Saturn SL.
Is the Intake Air Temperature Sensor the same as the Mass Airflow (MAF) Sensor?
No. On the Saturn SL, these are separate components. The IAT is a simple two-wire temperature sensor. Some other vehicles integrate the IAT sensor into the Mass Airflow (MAF) sensor assembly, but that is not the case here.
Helpful Videos
Technical Specifications
OEM Part Numbers: 21025106
2-terminal thermistor, typically with brass or plastic tip. Connector is a rectangular 2-pin female plug.
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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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