Intake air temperature sensor

What it means

This small sensor tells the computer how warm the incoming air is. Cold air is denser and needs more fuel. On many cars it is built into the mass air flow sensor. The code means the reading is missing or unbelievable, so the computer falls back on a fixed value.

Codes in this group

Bank 1 is the side of the engine that has cylinder 1. Sensor 1 is before the catalytic converter and sensor 2 is after it. More terms explained.

What you may notice

• Often nothing you can feel
• Slightly harder cold starting
• Slightly higher fuel use

Common causes

Most likely first:

• An unplugged sensor, often after air filter service
• Damaged wiring or a corroded plug
• A failed sensor

What to check first

• Check that the plug on the air intake or the air flow sensor was reconnected after any recent service
• Look for chafed wires near the air box

Have a mechanic confirm. A fault code tells you which system reported a problem, not which part has failed. The same code can have several causes, and they differ between car models. Use this page to understand the code, then have a qualified mechanic test the car before any part is replaced.

After the repair

Once the cause is fixed, the code can be cleared with a scan tool, or the warning light goes out by itself after several trips without the fault. Clearing a code without fixing the cause only hides it for a while. More about clearing codes.

Related codes

Mass air flow (MAF) sensor (P0100), Manifold pressure (MAP) and barometric sensor (P0105), Engine coolant temperature sensor (P0115), Thermostat and engine warm-up (P0125), Throttle position sensor (P0120), Accelerator pedal sensor and throttle agreement (P2120), Electronic throttle actuator (P2100), Oxygen sensor before the catalytic converter (sensor 1) (P0130). All codes.

Written in November 2026. These are generic OBD-II codes, the same on all makes. Causes and repair steps differ between models.