P0112: Intake Air Temperature Sensor 1 Circuit Low (Bank 1)
TL;DR
P0112 = IAT sensor circuit low input. Severity: low. Top causes: faulty IAT sensor (45%), wiring short to ground (30%), connector fault (20%), other (5%). Often a cheap sensor or wiring fix.
Can I keep driving with P0112?
IF it runs normally → you can drive and fix it at your convenience; the effect is usually minor. IF you notice poor cold-start behavior or worse economy → fix it sooner, as fueling/timing may be slightly off.
Symptoms
- Check engine light on
- Often no noticeable drivability change
- Slightly worse fuel economy
- Minor hesitation in some cases
- Possible hard cold start
Top causes (ranked by probability)
| Likely cause | Probability | Notes |
|---|---|---|
| Faulty IAT sensor | 45% | |
| Wiring short to ground | 30% | |
| Corroded or loose connector | 20% | |
| Other circuit fault | 5% |
What does P0112 mean?
Technical explanation
The IAT sensor is a thermistor whose resistance changes with intake air temperature; the ECM uses it to fine-tune fueling and timing. P0112 sets when the signal voltage is low, implying unrealistically high intake temperature. Common causes are a shorted or failed sensor, a wiring short to ground, or a corroded connector. On many vehicles the IAT is built into the MAF sensor.
In simple terms
A small sensor measures the temperature of the air entering your engine. P0112 means it’s reading as if the air is extremely hot, which usually means the sensor or a wire is faulty. It rarely changes how the car drives, but it should be fixed so fueling is accurate.
How to diagnose P0112 (step by step)
- Read IAT live data. A reading stuck very high (with low voltage) confirms it.
- Inspect the connector. Check for corrosion, damage or a loose IAT connector.
- Check wiring for a short to ground. A grounded signal wire pulls the reading low.
- Test the sensor resistance. Compare against the temperature/resistance spec.
- Replace the IAT (or MAF if integrated). If the sensor is out of spec, replace it.
Repair options & cost
- Replace the IAT sensor
- Repair the wiring short
- Clean/repair the connector
🔧 Doing it yourself? Buy the part: Intake air temp (IAT) sensor
| DIY cost | $10–$60 |
|---|---|
| Workshop cost | $60–$180 |
| Repair time | 20–40 minutes |
Costs are local ballpark ranges and vary by region and vehicle.
Tools you’ll need
Scan your car: recommended OBD-II scanners →Vehicle-specific notes
- On many cars the IAT is integrated into the MAF sensor — you may replace the MAF assembly.
- P0112 is the low-signal counterpart to P0113 (high).
- A short to ground in the signal wire is a common cause — inspect the harness.
Common mistakes to avoid
- Replacing the sensor when the wiring is shorted
- Overlooking that the IAT is part of the MAF on some vehicles
- Ignoring a corroded connector
- Assuming it’s a serious fault — it’s usually minor
Frequently asked questions
What does P0112 mean?
The intake air temperature sensor circuit is reading low, signaling implausibly hot intake air — usually a faulty sensor, a wiring short to ground, or a bad connector.
Is P0112 serious?
No, it’s low severity and rarely affects drivability much. Still fix it so fueling and timing stay accurate.
Can I fix P0112 myself?
Often yes. The IAT sensor is inexpensive and easy to swap; first check the connector and wiring for a short to ground.
P0112 summary
| Meaning | IAT sensor circuit low input |
|---|---|
| Severity | Low |
| Safe to drive? | Generally safe |
| Top cause | Faulty IAT sensor (45%) |
| DIY cost | $10–$60 |
| Shop cost | $60–$180 |