Cadillac Seville 1995-1999 Engine Intake Manifold Temperature Sensor Guide
Having issues with rough idling or poor fuel economy on your Northstar V8? Your IAT sensor might be the culprit.
- A bad IAT sensor on a 1995-1999 Seville commonly causes a P0113 code, poor fuel economy, and rough idling.
- Replacement is extremely easy and can be done in minutes with basic tools, making it a great DIY repair.
- For this vehicle, the IAT is a standalone sensor in the air intake tube, not part of the MAF sensor.
- Premium aftermarket brands like Standard Ignition offer a reliable alternative to OEM parts.
Is Your Seville's IAT Sensor Failing?
A faulty Intake Air Temperature (IAT) sensor can cause a range of noticeable problems in your Cadillac Seville. Because the sensor sends incorrect information to the engine's computer, the air-to-fuel mixture becomes unbalanced. This can lead to several issues, from minor annoyances to more significant performance problems.
Common Symptoms of a Bad IAT Sensor:
- Check Engine Light: This is the most common sign. A failing IAT sensor will often trigger a trouble code, most frequently P0113, which indicates a high voltage reading in the sensor's circuit.
- Poor Fuel Economy: If the sensor incorrectly tells the computer the air is very cold, the engine will run rich (too much fuel), wasting gas.
- Rough Idle or Stalling: An incorrect air-fuel mixture can make your Seville's engine idle unevenly or even stall, especially when it's warming up.
- Hard Starting: If the sensor is providing a bad reading, the engine may receive too much or too little fuel during cranking, making it difficult to start.
- Reduced Engine Power: Your engine may feel sluggish or hesitate during acceleration because the computer is confused by the bad sensor data.
Pro Tip: Check the Connection First. Before replacing the sensor, inspect the wiring and connector. A loose connection or corroded pins can cause the same symptoms as a failed sensor. Also, check for cracks in the air intake duct that could let in unmetered air.
Choosing the Right Aftermarket Sensor
For a vehicle like the 1995-1999 Seville, the original GM/ACDelco part may be hard to find or expensive. Aftermarket parts offer a cost-effective solution. For this sensor, you don't necessarily need the OEM part to restore proper function, but quality still matters.
- Premium Aftermarket (e.g., Standard Ignition): Brands like Standard Motor Products (SMP) are well-established in the industry and are known for producing high-quality replacement parts that meet or exceed OE specifications. They perform extensive testing and are a trusted choice for professional technicians. This is a reliable option for peace of mind.
- Budget-Friendly (e.g., True Tech): Other brands are available at a lower price point. While there is limited public information or reviews on brands like True Tech, they provide a functional replacement for owners on a tight budget. For a simple component like an IAT sensor, a budget part may perform adequately, but long-term reliability is less certain compared to premium brands.
Cost of Replacing the IAT Sensor
This is an inexpensive and straightforward repair, especially if you do it yourself.
| Part / Service | Estimated Cost |
|---|---|
| New OEM (ACDelco) | $40 - $60 |
| New Aftermarket | $19.54 - $42.24 |
| Shop Labor for Installation | $50 - $100 |
Frequently Asked Questions (FAQ)
Where is the IAT sensor located on my 1995-1999 Seville?
The IAT sensor is typically located in the air intake duct, between the air filter box and the engine's throttle body. It is a small, two-wire sensor that screws or pushes into the plastic intake tube. For the 1995-1999 Seville, it is a separate component and not integrated into the Mass Airflow (MAF) sensor like on later models.
Can I replace this sensor myself?
Yes, this is a very easy DIY job. It usually requires no special tools beyond a screwdriver or a small wrench. The process involves unplugging the electrical connector, unscrewing or popping out the old sensor, installing the new one, and reconnecting the plug. The entire job can typically be done in under 15 minutes.
What does the code P0113 mean?
P0113 means the PCM has detected that the voltage signal from the IAT sensor circuit is too high (often over 4.7-5.0 volts). The sensor is designed to have high resistance (and high voltage) when cold and low resistance when hot. A P0113 code usually points to an open circuit, a bad connection, or a failed sensor, which the computer interprets as an impossibly cold air temperature, like -40°F.
Are there any recalls for the IAT sensor on the 1995-1999 Seville?
No, there are no specific recalls or widespread Technical Service Bulletins (TSBs) from GM or the NHTSA related to the Engine Intake Manifold Temperature Sensor for this generation of the Cadillac Seville.
Technical Specifications
OEM Part Numbers: 25036751 25037225
The sensor is a two-terminal thermistor that screws or pushes into the air intake duct. It operates on a 5-volt reference signal from the PCM.
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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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