1995-1997 Geo Metro Intake Air Temperature Sensor: A Mechanic's Guide
Fixing poor mileage and rough running in your Metro could be as simple as replacing this one sensor.
- A bad IAT sensor on your Geo Metro will likely cause a check engine light with codes P0110, P0112, or P0113.
- Symptoms include poor gas mileage, rough running, and failing an emissions test.
- Replacement is extremely easy for a DIYer and can be done in under 15 minutes with basic tools.
- Aftermarket sensors from brands like Standard Ignition are a reliable and cost-effective choice for this vehicle.
Is a Bad Intake Temp Sensor Hurting Your Metro?
If your Geo Metro has a failing intake air temperature (IAT) sensor, the engine's computer gets wrong information. It might add too much or too little fuel. This can lead to a few noticeable problems. You might see your check engine light come on, get worse gas mileage than usual, or notice the engine running rough, especially when it's idling or you're trying to accelerate. In some cases, it can make the car hard to start when it's cold.
Symptoms of a Failing IAT Sensor
- Check Engine Light: This is the most common sign. The computer will store a trouble code like P0110, P0112, or P0113.
- Poor Fuel Economy: The computer may be dumping too much fuel into the engine, wasting gas.
- Rough Idle or Hesitation: An incorrect air/fuel mixture can make the engine run unevenly.
- Failed Emissions Test: An improper fuel mixture will increase harmful emissions.
- Hard Starting: The engine may struggle to start, especially in cold weather, if the computer thinks the air is a different temperature than it really is.
Don't Confuse It with the Coolant Sensor
Your Metro has two important temperature sensors: the IAT and the Coolant Temperature Sensor (CTS). The IAT measures air temperature, while the CTS measures engine coolant temperature. They are different parts and are not interchangeable, though they can sometimes cause similar symptoms. Make sure you are diagnosing and replacing the correct sensor.
Choosing the Right Aftermarket Sensor
For a 1995-1997 Geo Metro, finding a brand-new original equipment (OEM) sensor is unlikely and not cost-effective. The good news is that aftermarket parts are readily available, affordable, and get the job done. The IAT sensor is a simple part, so a quality aftermarket version is a reliable choice for this car.
You will likely find two main brands available:
- Standard Ignition (SMP): Often considered a top-tier aftermarket brand. They have a long history of making quality electronic parts and sensors that meet or exceed original specifications. Technicians often trust this brand for its reliability.
- Motorad: This is a standard-tier aftermarket brand. While they produce a wide range of parts, online discussions from mechanics and DIYers sometimes show mixed reviews on the long-term durability of some of their products, like thermostats. For a simple sensor on a budget-friendly car like the Metro, it is likely a sufficient and cost-effective option.
How Much Does a New IAT Sensor Cost?
Replacing the IAT sensor on your Metro is one of the more affordable repairs you can make. The cost will depend on the brand you choose and whether you do the work yourself.
| Part/Service | Estimated Cost |
|---|---|
| New Aftermarket Part | $13.46 - $46.82 |
| Shop Labor | $50 - $95 |
| DIY Total Cost | $13.46 - $46.82 |
| Shop Repair Total Cost | $63.46 - $141.82 |
Frequently Asked Questions
Where is the IAT sensor located on a 1995-1997 Geo Metro?
The Intake Air Temperature sensor is typically a standalone sensor. Look for it screwed into the plastic air intake ducting between the air filter box and the engine's throttle body. It will be a small, plastic sensor with a two-wire electrical connector.
Can I replace this sensor myself?
Yes, this is a very easy DIY job. It usually requires no special tools beyond what's in a basic toolkit. You simply unplug the electrical connector, unscrew the old sensor, screw in the new one, and reconnect the plug. The entire process should take less than 15 minutes.
What happens if I don't replace a bad IAT sensor?
You can continue to drive the car, but you will experience the symptoms of failure. This includes poor gas mileage, a rough-running engine, and you will not be able to pass an emissions test. Over time, running a consistently rich fuel mixture can lead to other problems, like fouled spark plugs.
What do the trouble codes P0112 and P0113 mean?
These codes point to a specific problem in the IAT sensor circuit. P0112 means "Circuit Low Input," which usually indicates a short in the wiring or sensor. P0113 means "Circuit High Input," which usually means there is an open circuit, like a broken wire or an unplugged sensor. In either case, the first step is usually to inspect the wiring and then replace the sensor.
Technical Specifications
2-terminal, screw-in thermistor sensor.
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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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