P0113 — Intake air temperature sensor — circuit high input

P0113 records an electrically high intake-air temperature input, not necessarily hot intake air. With a conventional NTC thermistor and ECU pull-up, an open sensor path may yield high signal voltage and an implausibly cold displayed temperature. Other vehicles integrate IAT into a MAF/MAP sensor or use different signal arrangements. Identify the sensor and circuit type before assigning a temperature or resistance meaning.

Affected system: Intake air temperature sensing

Symptoms

• Check-engine lamp and an implausible intake-air temperature in scan data.
• Starting difficulty, altered fuelling or reduced performance on some engines; symptoms depend on fallback strategy.

Possible causes

• Open/disconnected IAT sensor circuit or loose, corroded connector.
• Broken signal/return wire or unintended voltage feed to the input, according to circuit design.
• Defective standalone IAT thermistor or integrated MAF/MAP/IAT assembly.
• Control-unit input fault only after sensor and wiring have been objectively excluded.

What to check

• 1. Save P0113, other intake/MAF/MAP codes and freeze-frame. Find out whether IAT is a standalone thermistor or integrated into another sensor on this engine.
• 2. After a genuine cold soak, compare IAT, ambient and coolant temperatures using live data. A wildly cold IAT while other readings are reasonable suggests a sensor/circuit interpretation fault, not real cold air.
• 3. With ignition switched off, inspect the relevant connector for looseness, corrosion, damaged pins, oil/water and harness chafing. Do not replace the MAF assembly based on P0113 alone.
• 4. Using the VIN-specific diagram, have the signal and reference/ground circuit measured. High voltage or a lost return must be interpreted against that circuit; do not apply a universal voltage threshold to all sensor types.
• 5. Where the sensor is a disconnected passive NTC thermistor, test its resistance against the OEM temperature table under safe conditions. A failed/open component versus correct sensor resistance isolates different repair paths; do not resistance-test active electronics or a powered circuit.
• 6. Perform a manufacturer-approved continuity/short test on the harness with modules isolated as required. If wiring and sensor are within specification but the ECU still reports an implausible value, investigate the module/input with qualified diagnostic support.
• 7. Repair the verified connector, wire or component, repeat the cold-data comparison and ensure code/monitor behaviour normalizes; do not rely only on deleting the DTC.

Also written as: P0113-00, P011300, PO113 (some scan tools add the fault-type byte, e.g. -00).