P0113 Intake Air Temperature Sensor 1 Circuit High Input
The intake air temperature signal is pegged high — the computer is being told the incoming air is impossibly hot, usually because the circuit is open.
Fuel & air
The IAT sensor is a thermistor: its resistance falls as air warms. A high signal voltage corresponds to very cold air or, far more often, to an open circuit that looks electrically identical. The ECU uses air temperature to fine-tune fuelling and timing, so a wrong reading skews both.
Diagnose P0113 on your specific vehicle Add your year, make and model for ranked causes, repair videos and the exact parts you needCan I keep driving?
Driveable
Yes. Expect somewhat rough cold starts and slightly worse economy.
How serious
Low to moderate. The engine runs, but fuelling and timing are being calculated from bad data.
Symptoms you'll notice
- Hard starting when cold
- Rough idle after a cold start
- Slightly reduced fuel economy
- Check-engine light with little else wrong
- Black smoke on startup in some cases
What causes P0113
Ordered by what to check first — how likely each cause is, weighed against what it costs to rule out. Working down the list in order is what stops you replacing an expensive part to fix a cheap problem.
Open circuit in the sensor wiring
A broken signal wire or a disconnected plug reads as maximum voltage. This is the most common cause and the cheapest to fix — check the connector is fully seated before anything else.
Failed IAT sensor
The thermistor itself can fail open. On many engines it's built into the mass airflow sensor rather than separate, which changes what you have to buy.
Corroded connector
Green or crusty pins add resistance that reads as a colder-than-real temperature and eventually as an open circuit.
Sensor disturbed during other work
If the code appeared right after an air filter or intake job, suspect a connector knocked loose rather than a failed part.
How to diagnose it
- Compare the IAT reading on live data against actual ambient temperature with the engine cold — they should agree closely.
- Unplug the connector and inspect for corrosion, damage and backed-out pins.
- Measure sensor resistance and compare against the temperature/resistance table in the service data.
- Jumper the signal wire to ground briefly with the key on: if the reading swings to maximum temperature, the wiring and ECU are fine and the sensor is at fault.
Parts you might need
Tools for the job
- Multimeter
- OBD-II scanner with live data
Related trouble codes
- P0101 — Mass Air Flow Circuit Range/Performance Problem
- P0128 — Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)
Fitment matters. Causes and parts above are the common cases for P0113 across vehicles. The specific part numbers, procedures and torque specs vary by year, make, model and engine — always confirm against service data for your vehicle before buying parts or starting work.