OBD Code P0113: Intake Air Temperature Circuit High Input

Q: What does OBD code P0113 mean?

Intake Air Temperature Circuit High Input. Your engine's intake air temperature sensor is reading hotter than it should, like a thermometer stuck on a high number. The ECU thinks the incoming air is too warm, which throws off fuel calculations.

Q: What are the symptoms of fault code P0113?

Check Engine Light illuminated, Rich running condition or black smoke from exhaust, Reduced fuel economy

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What This Actually Means

In plain language — no jargon

Your engine's intake air temperature sensor is reading hotter than it should, like a thermometer stuck on a high number. The ECU thinks the incoming air is too warm, which throws off fuel calculations.

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Symptoms You May Notice

3 known symptoms for this code

Check Engine Light illuminated

Rich running condition or black smoke from exhaust

Reduced fuel economy

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Embedded Systems Insight

What the ECU/ECM is actually computing

The ECU monitors voltage from the Intake Air Temperature (IAT) sensor, which uses a thermistor that changes resistance based on air temp. High voltage signals indicate cold air; low voltage indicates hot air. A 'high input' fault means the ECU sees a voltage signal above its maximum expected threshold, typically indicating a sensor or wiring fault rather than actual high temperatures.

Voltage & Parameter Thresholds

Parameter	Normal Range	Fault Condition
IAT Sensor Voltage	0.5–4.5V (depending on actual temp)	>4.5V or open circuit condition
IAT Temperature Reading	-40°C to 125°C	Below -40°C equivalent voltage

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Diagnostic & DIY Fix Guide

Check these in order — from cheapest to most complex

1

IAT sensor connector

Inspect and reseat the connector at the intake manifold or air intake tube for corrosion or loose pins.

2

IAT sensor wiring harness

Check for damaged, pinched, or corroded wires between the sensor and ECU; repair or replace as needed.

3

IAT sensor

Replace the sensor itself if connector and wiring are clean and secure.