P0113: Intake Air Temperature Sensor 1 Circuit High
Title: SAE J2012 generic definition. Manufacturer-specific definitions and enhanced codes can differ; check service information for the exact vehicle.
What P0113 means
The intake air temperature (IAT) sensor signal voltage is too high, so the ECM sees air that is impossibly cold.
What sets it
Most IAT sensors are thermistors whose resistance drops as temperature rises. The ECM supplies a reference voltage through a resistor, and reads the voltage at the sensor. An open circuit (unplugged sensor, broken wire, open ground) pushes the signal toward the full reference voltage, which the ECM reads as extremely cold air. When the voltage stays above the calibrated limit, P0113 sets. On many vehicles the IAT is built into the MAF sensor.
Symptoms
- Often none
- Slight drivability change or hard starting in extreme weather
- IAT reading stuck at a very cold value in live data
Is it safe to drive?
General guidance, not a guarantee: Generally safe to drive. The ECM usually substitutes a default value. If in doubt, have it towed and diagnosed.
Common causes
Listed roughly from most to least common in general practice. The real order varies by vehicle, mileage and history.
- Unplugged or loose connector: common after air filter or intake work
- Open sensor
- Broken signal or ground wire
- Corroded terminals
Test before you replace: diagnostic sequence
General guidance only. Always follow the vehicle manufacturer's service information, specifications and safety procedures. Any figures below are general guidelines that defer to the manufacturer's specification.
- Read the IAT PID. A reading stuck at the lowest value the scan tool can show (often -40°F, which is also -40°C) suggests an open circuit (general guideline; check the manufacturer's data for this vehicle).
- Compare IAT with coolant temperature on a fully cold-soaked engine; both should read close to ambient.
- Inspect the connector and recent work areas (air box, MAF) for an unplugged or damaged connector.
- Unplug the sensor and briefly jumper the signal to ground per accepted practice. If the reading jumps to very hot, the wiring and ECM are fine and the sensor is open. Only if the manufacturer's procedure allows. Some ECMs and circuits can be damaged by jumpering; use a fused jumper or a test resistor where specified.
- If it doesn't change, check the signal and ground circuits back to the ECM, including voltage drop on the ground.
- Replace the sensor (or the MAF assembly if it is integrated) once the circuit is proven good.
Bench note: A reading of -40 points to an open circuit. A reading that is wrong but believable points to a sensor that is out of calibration, and that usually sets a different code.
How-to guides for this code
Related codes
FAQ
Is P0113 serious?
Usually not. The ECM substitutes a default value, but get it fixed to restore accurate fuel and spark control.
Why did it set after an air filter change?
The IAT or MAF connector is often bumped or left unplugged during filter service. Check it first.
Is the IAT part of the MAF?
On many vehicles, yes. Check the service information before ordering parts.
Sources
- SAE J2012, Diagnostic Trouble Code Definitions (standard page; code titles only)
- Generic code title cross-check: obd-codes.com generic code list
Written with AI assistance and reviewed for accuracy; not a substitute for OEM service information. Shop Docs Studio is not affiliated with SAE, EPA, CARB or any vehicle manufacturer.