P0113: OBD-II code P0113 means the intake air temperature (IAT) sensor is reading falsely hot — usually an open circuit or a bad sensor.

Symptoms

• Check engine light is on; engine may run rich or lean depending on how the PCM compensates for a false hot-air reading.
• Slightly reduced fuel economy and rough cold starts because the PCM defaults IAT to an assumed value.
• Symptoms are often mild — many drivers only notice the code when they scan for another issue.

Common causes

• A failed IAT sensor with an open internal thermistor — the most common cause.
• Damaged wiring or an unplugged connector at the IAT sensor (often integrated with the MAF sensor).
• Corroded pins in the sensor connector adding resistance and biasing the signal high.

What to do?

Backprobe the IAT signal with a DMM — voltage should track temperature (higher voltage means colder). Compare live IAT to actual ambient at cold start. Replace the sensor (or MAF/IAT combo unit) if it reads open. Repair wiring and clean the connector if damaged.