OBD-II Code · Sensors
P0112
IAT Sensor Low Input
Severity
low
Lowest on our scale. Fix it when convenient.
Can you drive it
Only if running normally
A short trip to a shop may be reasonable if the light is steady and the car runs normally. Stop safely for a flashing light, severe shaking, overheating, loss of power, or another urgent warning. The code alone cannot confirm safety.
Indicative cost (USD)
$50–$200
Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
IAT voltage too low.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then work the likely-causes list in the order shown.
That order is what a shop checks first for this code — wiring and connections before the component they run to, because a connector costs nothing to inspect and is a common answer.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
Likely causes
- Failed sensorMost common
- Short to ground
Read the full diagnostic procedureP0112 means IAT signal voltage is below the floor — under roughly 0.2V on a standard NTC thermistor, which translates to a reported intake air temper…
P0112 means IAT signal voltage is below the floor — under roughly 0.2V on a standard NTC thermistor, which translates to a reported intake air temperature above 250F. The ECM treats this as a short to ground or a failed sensor.
Cheapest-first ladder
unplug the IAT connector (or MAF connector if IAT is integrated) and check whether the scan tool reading swings to -40F (which means the ECM is seeing open-circuit, confirming the sensor was shorting low internally and replacement fixes it); if the scan tool still reads 250F+ with the connector unplugged, the signal wire is shorted to ground in the harness — inspect chafe points at the valve cover, intake manifold ribs, and where the harness crosses any sharp metal; verify the 5V reference at the connector is 4.9-5.1V key-on (IAT typically uses the same 5V bus as TPS and MAP on most platforms); on integrated MAF/IAT sensors a P0112 paired with any P010x MAF code usually means the entire MAF unit needs replacement since the IAT element is part of the same circuit board; expected voltage at 70F ambient is 2.5-3.0V, at 200F hot-soak is 0.5-1.0V, and shorted-to-ground is essentially 0V. Do not replace an integrated MAF for P0112 alone before checking the harness for a chafe — a $5 wire repair is faster than a $300 MAF.
Vehicle-specific patterns2004-2010 Ford F-150 5.4L 3V sees P0112 from the same MAF harness chafe at the valve cover that causes P0100/P0104, since IAT is integrated; 2007-201…
- 2004-2010Ford F-150 5.4L 3V sees P0112 from the same MAF harness chafe at the valve cover that causes P0100/P0104, since IAT is integrated;
- 2007-2014GM 5.3L Silverado sees P0112 from the separate IAT sensor in the intake tube failing internally with the element shorting to housing ground;
- 2005-2010Subaru EJ25 sees P0112 from corroded MAF/IAT connector pins where moisture intrusion shorts the IAT signal to a 12V or ground pin;
- 2003-2008Honda J35 sees P0112 from internal MAF/IAT circuit board failure where the IAT thermistor shorts and the entire MAF must be replaced.
Estimated repair$15 to $350.
Look up another code
P0112 — frequently asked
What does a P0112 code mean?
IAT voltage too low.
What causes a P0112 code?
Common causes: Failed sensor; Short to ground.
What are the symptoms of a P0112 code?
Typical symptoms: Check engine light.
Is it safe to drive with a P0112 code?
Only if running normally. A short trip to a shop may be reasonable if the light is steady and the car runs normally. Stop safely for a flashing light, severe shaking, overheating, loss of power, or another urgent warning. The code alone cannot confirm safety. Estimated repair: $50-$200.
How do I diagnose a P0112 code?
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed. 1. Note every code that is set, not just this one. 2. Read the freeze frame — the conditions the fault was recorded under. 3. Confirm the fault is current rather than history. 4. Then work the likely-causes list in the order shown.
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