What P0113 Means
P0113 means the intake air temperature (IAT) sensor circuit is reporting a voltage higher than the PCM's plausible range, which the ECU interprets as an implausibly low or extreme temperature reading (since IAT sensors typically work as thermistors where resistance, and therefore voltage, moves inversely with temperature). The PCM uses IAT data alongside MAF or MAP readings to calculate air density, since colder, denser air needs proportionally more fuel than warm air for the same volume. A high-input fault usually means the circuit has gone to a very high resistance state, which the PCM reads as an unrealistically cold intake temperature regardless of actual conditions. This is generally one of the less urgent OBD-II codes on this list — it affects fuel trim precision rather than engine safety — but a stuck IAT reading can quietly hurt fuel economy and cold-start behavior for a long time if it isn't addressed, since the PCM keeps adjusting fuel delivery based on a temperature that isn't real.
Common Causes
- Open circuit or broken wire in the IAT sensor harness
- Corroded, loose, or disconnected IAT sensor electrical connector
- Failed IAT sensor with an internally open or excessively high-resistance element
- Damaged wiring from rodent damage, chafing, or heat exposure near the intake tract
- On sensors integrated into the MAF housing, a failed MAF/IAT combo unit affecting only the temperature portion
Symptoms You Might Notice
- Check Engine Light on, often with no other noticeable drivability symptoms in mild cases
- Slightly rough cold start or extended cranking in colder weather
- Minor reduction in fuel economy as fuel trims compensate for the incorrect reading
- Occasional hesitation on acceleration if the fuel mixture is meaningfully skewed
- In some vehicles, a temporary loss of certain adaptive strategies like knock-based timing adjustments
What to Check First
- 1
Locate the IAT sensor — either a standalone sensor in the intake tract or combined with the MAF sensor — and inspect its connector for corrosion or a loose pin
- 2
Use a scan tool to check the live IAT reading against actual ambient/underhood temperature; an implausibly cold reading with the engine warm confirms the fault
- 3
Check continuity and resistance of the IAT sensor itself with a multimeter, comparing against factory specification at known temperatures
- 4
Inspect the wiring harness between the sensor and PCM for damage, especially near heat sources or areas exposed to rodent activity
- 5
Replace the sensor (or MAF/IAT combo unit) if it fails the resistance check, then clear the code and confirm the live reading tracks properly afterward
Frequently Asked Questions
Is P0113 urgent to fix?
Not urgently — it's a low-severity code that mainly affects fuel trim accuracy rather than engine safety. That said, it's worth fixing reasonably soon since it can quietly hurt fuel economy and cold-start performance the longer it's left.
Can I still pass an emissions test with P0113?
No — any stored Check Engine Light code, including P0113, will typically fail an OBD-II emissions inspection in jurisdictions that check for it, so it needs to be resolved before an inspection.
Is the IAT sensor expensive to replace?
Generally one of the more affordable sensor replacements on this list, whether it's a standalone sensor or combined with the MAF housing, though the combo unit costs more than a standalone sensor alone.
Reviewed by Emmanuel Erere, Auto Mechanic. Causes and diagnostic steps checked for workshop accuracy.