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DTC code page

P0112: Intake Air Temperature Sensor 1 Circuit Low Input

Quick answer: The ECU sees the IAT signal pulled low, which usually means the reported intake temperature is implausibly hot.

Drivers also search this fault as intake air temperature circuit low input, IAT low voltage, IAT sensor reads hot all the time.

Severity: medium Family: powertrain Related paths: 10
Meaning

What P0112 usually means

P0112 means the intake-air-temperature signal voltage is lower than expected. On the common thermistor-style IAT circuit, that usually translates to an air temperature the ECU believes is far hotter than reality. When that happens, the engine computer may lean or de-rate certain strategies because it thinks the intake charge is already heat-soaked. The result is often weak response, odd hot-weather behavior, or drivability that feels worse than the simple wording of the code suggests.

Fast triage

Start here before chasing parts

  • Scan first: save freeze-frame and pending codes before clearing anything.
  • Confirm the complaint: compare the stored code with current drivability symptoms.
  • Use context: trims, live data, and related codes usually narrow the fault faster than guesswork.
  • Work simplest to hardest: leaks, connectors, maintenance items, and known patterns before expensive components.
Initial checks

What to check first

  • Check live IAT before startup and see whether it is reading far hotter than ambient air.
  • Inspect the connector and nearby harness for abrasion, moisture, or an obvious short-to-ground path.
  • If the vehicle has reduced-power complaints in hot conditions, use that timing as part of the diagnosis instead of treating it like a generic code.
Driving risk

Can you keep driving?

P0112 often still allows the car to move, but false hot intake data can flatten response and trigger reduced-power behavior badly enough that it is worth fixing before summer or towing conditions expose it harder.

Moderate urgency: This code often allows short-term driving, but the right fix usually comes faster when you diagnose it early instead of waiting for more codes.
Likely causes

Common causes behind this code

  • IAT sensor internally shorted low
  • Signal wire shorted toward ground
  • Connector contamination or water intrusion altering the circuit
  • Integrated MAF/IAT assembly fault
  • Rare control-module input fault after circuit testing

Cause phrases often tied to this code: shorted IAT signal wire, sensor internally shorted, connector contamination, ground short, false hot intake reading.

Diagnostic order

Suggested workflow

  1. Compare IAT with real ambient temperature on a cold engine to prove whether the hot reading is false.
  2. Inspect the wiring and connector for shorts, contamination, or terminal damage.
  3. Verify the reference and ground relationship at the sensor or integrated MAF assembly.
  4. If the IAT element is built into the MAF, compare airflow and IAT behavior together during a road test.
  5. After repair, confirm the reading no longer pegs hot and that reduced-power or hesitation symptoms improve.
Avoid guesswork

Common mistakes

  • Assuming hot weather alone explains the code without checking whether the sensor is reporting something impossible.
  • Replacing unrelated cooling-system parts because the scan tool shows a hot number somewhere on the screen.
  • Ignoring integrated-MAF designs where the temperature fault may not be serviceable separately.
Repair path

Practical fix guidance

  • Repair the short or contaminated connection first, because many low-input faults return if the wiring branch is left untouched.
  • If the sensor element itself is proven bad, replace the correct serviceable part or full MAF assembly as required by the design.
  • Retest under the same hot-soak or warm-weather conditions that made the complaint noticeable.
Vehicle context

Affected brands in this MVP

Brand hubs help broaden internal linking now and can evolve into make-specific diagnostic notes later.

Aliases and common searches

English phrases tied to P0112

Useful when the driver knows the wording but not the exact DTC yet.

  • intake air temperature circuit low input
  • IAT low voltage
  • IAT sensor reads hot all the time
Related search intent

Queries this page can answer naturally

  • P0112 code meaning
  • what does P0112 mean
  • intake air temp circuit low input
  • IAT reading too hot
FAQ

Quick questions about P0112

Does P0112 mean the intake air is really too hot?

Not necessarily. Most of the time it means the circuit is making the ECU believe the air is much hotter than reality.

Can P0112 cause reduced power?

Yes. Some vehicles back off load or fueling strategy when they think intake temperature is extremely high.

What is the quickest clue for P0112?

A cold engine showing an intake-air temperature that already looks heat-soaked is a strong sign the reading is false.