P0112 code: Intake Air Temperature (IAT) Sensor Circuit Low
P0112 means intake Air Temperature (IAT) Sensor Circuit Low. The code says where to look, not what failed — the fix depends on which cause your car actually has.
What P0112 means
The intake-air-temperature (IAT) sensor tells the computer how warm the incoming air is, which fine-tunes fueling and timing. P0112 means that signal is reading low — which the computer interprets as impossibly hot air (or a wire shorted to ground). It's the mirror of P0113. Usually it's a failed sensor, a wire shorted to ground, or a corroded connector. On many cars the IAT is built into the MAF sensor. It has only a minor effect on how the car runs.
P0112 symptoms
- Check-engine light, often with no noticeable change
- Slightly rough running or hesitation in some cases
- Minor drop in fuel economy
What it costs to fix P0112
Typical range: $30–$350 · about ~0.2–1 hrs of labor
| If the cause is… | Part | Labor |
|---|---|---|
| IAT sensor (standalone) | $15–$60 | ~0.2–0.5 hrs |
| MAF assembly (when IAT is integrated) | $80–$300 | ~0.2–0.5 hrs |
| Wiring / connector repair | $10–$120 | ~0.5–1 hrs |
A standalone IAT sensor is cheap; the cost only jumps if the IAT is built into the MAF and the whole assembly is replaced. Often it's just a corroded connector — clean and check that first.
The price swings on which cause it turns out to be — so confirm the cause before paying. Diagnose P0112 for my exact vehicle →
How to fix P0112
Easy — basic tools, most owners can do this
- Confirm the reading is stuck hot
Check intake air temperature on live data with the engine cold: it should roughly match the outside temperature. A reading pinned at an extreme hot value regardless of conditions confirms the signal is shorted low, the mirror image of P0113.
- Unplug the sensor and watch the reading flip
With the key on, disconnect the IAT connector. If the displayed temperature immediately swings to full cold, the wiring is intact and the sensor itself is internally shorted — replace it. If the reading stays pinned hot even unplugged, the harness has a wire shorted to ground.
- Inspect the connector and harness
Check the connector for moisture, green corrosion bridging terminals, or crushed wiring where the harness routes past brackets and the airbox. A pinched wire touching ground produces exactly this code and often comes and goes with engine vibration.
- Replace the sensor or repair the short
Swap the IAT sensor (or the MAF assembly if it's built in) if the unplug test condemned it — usually a two-minute job. For a harness short, repair the damaged section and protect it with loom or tape so it can't chafe through again.
DIY or shop? The unplug test makes this one of the easiest codes to self-diagnose: two minutes with a scan tool tells you sensor versus wiring with high confidence. A standalone sensor swap is cheap and trivially easy. Shop help is only worth it if the IAT lives inside a pricey MAF unit and you want the diagnosis double-checked, or if an intermittent harness short refuses to show itself.
Tools for the DIY steps: OBD2 scanner with live data · Electrical contact cleaner · Screwdriver · Electrical tape or wire loom · Multimeter (optional)
Not sure which step applies to your car? Get the likely cause for your exact vehicle before buying anything for P0112.
Start a case with P0112 and your car. Redline weighs these causes against what your car shows, and names the check that would settle it before you buy parts.
Can I drive with P0112?
Redline can’t determine from a symptom or code alone whether your car is safe to drive.
P0112: common questions
Can I drive with P0112?
The code by itself can't answer that, but P0112 is one of the lower-urgency codes, with only a minor effect on how the engine runs. Fix it before an emissions test and to clear the light; if the engine starts running badly, get it checked sooner.
What does "circuit low" mean for P0112?
The sensor's voltage is at the low end, which the computer reads as extremely hot or shorted-to-ground air. That points to a failed sensor or a short rather than a real temperature.
Is P0112 the same as P0113?
Same sensor, opposite reading: P0112 reads too low (interpreted as hot/shorted), P0113 reads too high (interpreted as cold/open). Both are usually a sensor, connector, or wiring fix.
How much does it cost to fix P0112?
Often inexpensive — a standalone IAT sensor or a connector cleaning is cheap. The cost only rises if the sensor is integrated into the MAF and the whole unit is replaced.
Related trouble codes
Don’t have a scanner yet? A ~$25 Bluetooth adapter reads codes like P0112 from your phone. See our guide to the best OBD2 Bluetooth adapters. Run a repair shop? See Redline for shops.
Generic OBD-II reference. Manufacturer-specific behavior varies. Confirm with a scan tool and, for safety-related codes, a professional inspection. Cost ranges are reference ranges, not quotes.
Seeing P0112 on your car?
Every problem becomes a Case. Tell Redline what the car is doing: it shows what the evidence supports, what’s still missing, and what to check next, before you approve a repair.
“Inner pad ~1 mm. Outer pad 3 mm.”
Next: check the slide pins move freely before buying parts.