Intake Air Temperature Sensor 1 Circuit Low Input
The P0112 code means the vehicle's onboard diagnostic system has detected: Intake Air Temperature Sensor 1 Circuit Low Input. This is a moderate severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- easy
- Estimated cost
- $15-$150
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What Are the Symptoms of P0112?
- Check Engine Light on
- Engine may run lean (ECM reads the air as hot and pulls fuel)
- Possible hard starting when warm
- Minor performance issues
What Causes P0112? (Most Likely First)
- IAT sensor shorted internally causing low voltage Very High
- Short to ground on signal wire High
- Failed sensor reading stuck at extreme hot temperature Moderate
Can I Still Drive with P0112?
Yes, but fix soon. P0112 is rated moderate severity. It is not an immediate stop-driving fault, but it will not clear itself — book the repair rather than ignoring the light.
Frequently Asked Questions
What temperature does a low IAT input simulate, and does it richen or lean the mixture?
A shorted (low-voltage) IAT circuit reads at the extreme HOT end of the sensor range, often around 300F. The ECU thinks the incoming air is extremely hot and pulls fuel out, leaning the mixture. (The extreme-cold, -40F condition is the opposite fault, P0113 Circuit High Input.)
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose P0112?
-
Check IAT voltage: at room temperature should be about 2-3V. Below 0.3V indicates a short.
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Disconnect the IAT sensor. If voltage rises to 5V at the connector, the sensor is shorted internally.
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Inspect wiring for shorts to ground.
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Replace sensor if confirmed faulty.
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
P0112 on Diesel, EV & Equipment
The same code ID appears across other engines and platforms. The diagnostic flow varies by manufacturer — these are the platform-specific breakdowns:
Which Vehicles Commonly Get P0112?
- Toyota Tacoma and 4Runner
- Ford Focus and Escape
- Chevrolet Traverse
- Honda Element
- Dodge Caliber
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