P0112 — Intake Air Temperature Circuit Low Input Bank 1

OBD2 code P0112 flags a problem with the throttle and intake air metering (intake air temperature circuit low input bank 1). Short, gentle driving to a shop is usually possible. Common culprits: intake air leaks after the MAF sensor, failed electronic throttle motor, contaminated or failed MAF/MAP sensor.

powertrain (engine/transmission)

Is it safe to drive?

Short-term drivable with prompt attention P0112 is usually not an immediate no-drive condition, but the false low-temperature signal can cause rough running, hesitation, or stalling. Avoid extended driving if those symptoms are severe, and complete the circuit or sensor repair promptly.

Typical symptoms

The check-engine light may illuminate and the OBD2 system may store P0112.
The reported intake temperature may remain near the minimum scanner value, such as -40°F or -40°C.
The engine may idle roughly, hesitate, or stall while the incorrect cold-air signal is active.
Cold starting and engine warm-up may be noticeably slower or less stable than normal.
Fuel-trim values may become unusually high or negative while P0112 remains active.

Common causes

The Bank 1 intake air temperature sensor has failed with an internal short to ground.
A damaged intake-air-temperature signal wire is shorted to ground or another low-voltage circuit.
Corrosion, water intrusion, or a loose terminal has created a poor connection in the IAT sensor connector.
An open sensor-ground or PCM reference connection is pulling the IAT input voltage too low.
A chafed intake harness or connector pin has broken the sensor circuit near the air intake housing.
A powertrain control module input or internal reference failure is possible but less common.

How to diagnose with an OBD scanner

Confirm P0112 with live data Connect an OBD2 scanner such as an ELM327 adapter with AIScanAuto, read stored codes, and select the intake-air-temperature live-data parameter. If P0112 is present, compare the displayed IAT value with actual ambient temperature and watch whether it rises as the intake air warms.
Inspect the IAT sensor and connector Locate the intake air temperature sensor on the intake duct or air-intake housing. Disconnect it carefully and inspect the connector and wiring for corrosion, water, spread pins, crushed terminals, and chafing that could short the circuit to ground.
Check for a shorted circuit Using the vehicle wiring diagram, test the IAT signal path for continuity to ground with the sensor disconnected. An unintended low-resistance path identifies a wiring or connector fault; do not replace the sensor until this test is completed.
Test the sensor and control circuit Measure the IAT sensor resistance and compare it with the manufacturer temperature specification. A correct sensor changes resistance as its temperature changes. Also verify the PCM-provided reference voltage, sensor ground, and connector continuity where applicable.
Repair and verify the repair Repair the damaged wire or terminal, clean and reseat the connector, or replace an out-of-specification IAT sensor. Clear P0112 with the scanner, confirm that live intake temperature now tracks ambient conditions and rises with engine heat, then verify that P0112 does not return.

Approximate repair cost

A typical independent-shop estimate for diagnosing and repairing P0112 is USD $100-$350. This commonly includes diagnostic time, an intake air temperature sensor, connector cleaning, and minor wire or terminal repairs. Figures are estimates and vary by region, vehicle configuration, and labor rates.

Common questions

Can I continue driving with P0112?

Yes, if the engine runs normally, but P0112 can cause incorrect fuel control, rough idle, hesitation, or stalling. Repair it promptly and avoid driving if the engine becomes unstable.

Does P0112 always mean the IAT sensor is bad?

No. P0112 can also result from a shorted wire, damaged connector, poor ground, or a failed PCM input. Testing the wiring and sensor prevents replacing parts unnecessarily.

What intake temperature should I see with a scanner?

The live IAT value should be reasonably close to the temperature of the air entering the sensor and should rise as that air warms. A value fixed near the extreme minimum suggests an open or shorted circuit.

How do I know the P0112 repair worked?

After repairing the circuit or sensor, clear P0112, verify that live IAT data changes with real intake temperature, and complete a warm drive cycle. The code should remain cleared rather than immediately returning.

The Intake Air Temperature Circuit Low Input Bank 1 fault (P0112) is one of the more common throttle-related codes that shows up on modern vehicles. When this code appears, the engine control unit has detected that the signal from the intake air temperature sensor has fallen below the expected minimum voltage threshold. The ECU relies on this reading to calculate air density and adjust fuel delivery accordingly. If the sensor reports an unrealistically cold reading or a short circuit, the module flags the fault and illuminates the check engine light.

P0112 specifically refers to Bank 1, which is the engine bank containing cylinder number one. On V-type engines, this distinction matters because there are two separate intake tracts. For inline engines, there's only one bank, so Bank 1 is the only sensor location. When the ECU logs P0112, it also captures a freeze frame snapshot showing engine RPM, load percentage, coolant temperature, and vehicle speed at the exact moment the fault occurred. This diagnostic data is invaluable for narrowing down when and why the problem surfaced.

The throttle and intake air metering system is a closed-loop circuit. The throttle position sensor tells the ECU the driver's intent, while the mass airflow (MAF) or manifold absolute pressure (MAP) sensor measures how much air is actually entering the engine. When these readings don't match expected values across multiple drive cycles, the ECU sets P0112 and stores the failure conditions so a technician can reproduce them during testing.

Common symptoms of P0112

Check Engine Light illuminated on the dashboard
Unstable or abnormally high idle speed
Sluggish or unresponsive throttle pedal
Engine stalling when decelerating to a stop
Reduced power mode (limp home) with limited acceleration
Occasional hesitation or stumble during acceleration

What causes P0112?

The root causes range from simple contamination to complete component failure:

Carbon buildup on the throttle plate causing it to stick or move incorrectly
Faulty throttle position sensor (TPS) sending incorrect voltage signals
Failed electronic throttle motor unable to actuate the plate properly
Contaminated or failed mass airflow (MAF) or manifold absolute pressure (MAP) sensor
Damaged wiring harness, corroded connectors, or loose pins in the throttle circuit
Poor ground connection in the sensor circuit causing voltage anomalies

How to diagnose P0112

Follow this logical sequence to avoid replacing good parts:

Connect an OBD2 scanner and confirm P0112 is stored. Record the freeze frame data—this shows RPM, load, coolant temperature, and speed when the fault occurred. Reproducing those exact conditions during the drive cycle test is essential.
Check for any related diagnostic trouble codes. Codes like P0100 through P0105 indicate MAF/MAP circuit issues that often accompany P0112. Manufacturer TSBs (technical service bulletins) for your specific make, model, and year may document known failures or required software updates.
Perform a thorough visual inspection of the wiring harness and all connectors in the throttle circuit. Look for frayed wires, melted insulation near heat sources, green corrosion on terminals, and ensure all connectors are fully seated with the locking tabs engaged.
Remove the throttle body and physically inspect the plate for carbon deposits, then verify it moves through its full range without binding. Clean with appropriate throttle body cleaner if residue is present.
With the engine running, monitor throttle position percentage and MAF/MAP sensor readings in the scanner's live data mode. Manually operate the throttle pedal and watch for smooth, linear changes in the values. Erratic or stuck readings indicate a faulty sensor.
Clear P0112, complete a full drive cycle that reproduces the freeze frame conditions (same RPM, load, temperature), then rescan to confirm the code does not return. A recurring P0112 confirms an active fault that requires component replacement.

Repair options with costs

Address the least expensive likely causes before purchasing major components:

Throttle body cleaning (parts and labor): $80–$200
Throttle body assembly replacement (parts and labor): $250–$700
MAF or MAP sensor replacement (parts and labor): $150–$400

How much does it cost to fix P0112?

Total repair cost depends entirely on which component is at fault. The most common scenario—a dirty throttle body—typically falls between $80 and $200 when performed at an independent shop. Sensor replacement runs $150–$400 depending on the part and labor time. Full throttle body assembly replacement is the most expensive scenario, reaching $700 on some vehicles with complex integrated electronics. An accurate diagnosis before purchasing parts is the single best way to avoid overspending on this code.

Can you drive with P0112?

Drive with caution. P0112 frequently triggers reduced power mode, where the engine limits RPM and throttle opening to protect itself. This limp-home state provides enough performance to reach a repair facility at low speed, but aggressive driving and highway merging become hazardous. If the throttle pedal becomes unresponsive or the engine stalls unexpectedly, stop driving immediately and arrange a tow. Do not ignore a persistent check engine light combined with stalling—this condition can leave you stranded.