Intake Air Temperature Too High
The PCM detected that intake air temperature is higher than the maximum allowable threshold, typically above 215°F (102°C). This causes the engine to miscalculate fuel delivery and ignition timing, leading to poor performance and increased emissions. The code sets when the IAT sensor reports abnormally high readings for an extended period.
What You Might Notice
- Hesitation or surging at idle or light acceleration
- Diminished fuel economy
- Decreased engine performance, especially on cold start
- Check Engine light illumination
- Rough idle or stalling
Most Common Causes
- 1
Faulty IAT sensor
The intake air temperature sensor may be failing and sending false high-temperature signals to the PCM. Sensor degradation or contamination can cause it to read incorrectly over time.
- 2
IAT sensor wiring or connector issues
Open, shorted, or corroded wiring/connectors in the IAT sensor circuit can cause signal transmission errors. Loose connectors or damaged harnesses are common culprits.
- 3
Clogged or restricted air filter
A dirty air filter reduces airflow and increases intake air temperature as air is compressed through the restriction. This legitimate temperature rise can trigger the code.
- 4
Damaged intake air inlet pipe
Cracks or breaks in the intake duct allow hot engine compartment air to enter, raising intake temperature above normal operating levels.
How to Diagnose It
- 1
Check Faulty IAT sensor — The intake air temperature sensor may be failing and sending false high-temperature signals to the PCM. Sensor degradation or contamination can cause it to read incorrectly over time.
- 2
Check IAT sensor wiring or connector issues — Open, shorted, or corroded wiring/connectors in the IAT sensor circuit can cause signal transmission errors. Loose connectors or damaged harnesses are common culprits.
- 3
Check Clogged or restricted air filter — A dirty air filter reduces airflow and increases intake air temperature as air is compressed through the restriction. This legitimate temperature rise can trigger the code.
- 4
Check Damaged intake air inlet pipe — Cracks or breaks in the intake duct allow hot engine compartment air to enter, raising intake temperature above normal operating levels.
How to Fix It
- 1
Inspect and replace IAT sensor
Locate the IAT sensor (typically in the intake air duct or air filter housing), test it with a multimeter, and replace if readings are out of specification or resistance values are incorrect.
- 2
Check and repair IAT sensor wiring
Inspect the IAT sensor harness and connectors for corrosion, loose connections, or visible damage. Repair or replace damaged wiring and ensure all connectors are firmly seated.
- 3
Replace air filter
Remove and inspect the engine air filter; replace it if it is dirty or clogged. A clean filter restores proper airflow and allows intake temperatures to normalize.
- 4
Repair or replace intake inlet pipe
Visually inspect the intake air duct and inlet pipe for cracks, splits, or disconnections. Repair with appropriate clamps or sealant, or replace the pipe if damage is severe.
Need a deeper diagnosis?
Search for related repair guides or browse by system.