Intake Air Temperature (IAT) Sensor Circuit High
In short
P0113 means the engine computer (PCM) is seeing an abnormally high voltage on the intake air temperature sensor circuit, which it interprets as impossibly cold incoming air. In the real world this is most often caused by a damaged or disconnected IAT sensor connector or an open (broken) signal wire, and sometimes a failed sensor itself. The high voltage tells the PCM the air is extremely cold, so it adds extra fuel, which can hurt fuel economy and drivability.
Is it safe to drive with P0113?
In most cases the vehicle is safe to drive for short periods because the IAT signal is a minor input the PCM can partly compensate for using a default value. However, you may notice rougher cold starts, worse fuel economy, and the check engine light will stay on, so you should diagnose and repair it promptly to avoid masking other issues and to pass emissions testing.
Symptoms
- Illuminated check engine light with code P0113 stored
- Noticeably reduced fuel economy
- Hard starting or rough idle, especially when the engine is cold
- Black smoke or a rich-running condition under some conditions
- Hesitation or sluggish acceleration
- Scan tool shows an unrealistically low IAT reading (well below ambient, often around -40 F)
Common causes (most → least likely)
How to diagnose it (before buying parts)
- 1 Scan and record freeze-frame data, then view live IAT data — a reading pinned at the minimum (often around -40 F) while the engine is warm confirms an open/high-voltage circuit.
- 2 Locate and inspect the IAT sensor (standalone in the intake tube or integrated into the MAF sensor); check the connector for corrosion, bent or backed-out pins, and loose seating, and reseat it.
- 3 Inspect the wiring harness from the sensor to the PCM for chafing, rodent damage, melted insulation, or breaks, paying attention to areas that flex or run near hot components.
- 4 With the connector unplugged, jumper the two signal terminals together — if the IAT reading swaps to a maximum/hot value, the wiring and PCM are good and the sensor is likely faulty; if it stays cold, the fault is in the wiring or PCM.
- 5 Use a multimeter to verify reference/signal voltage and a clean ground at the connector, and ohm-check the sensor against the manufacturer's temperature-resistance table before condemning any part.
Repair options & cost
By manufacturer
On many Ford engines the IAT element is integrated into the MAF sensor; connector corrosion and a failed MAF/IAT assembly are frequent causes, so test before replacing the whole unit.
GM vehicles commonly use a standalone IAT in the intake duct; weathered connectors and chafed harness wiring near the intake are typical triggers for high-circuit codes.
Toyota often combines the IAT with the MAF sensor; intermittent open circuits from connector contamination or a worn sensor element are the usual culprits.
VW/Audi frequently integrate the IAT into the MAF or boost-pressure sensor on turbo engines; connector pin issues and sensor failure are common on higher-mileage cars.
Frequently asked questions
Can I drive with a P0113 code?
Yes, you can usually drive short distances safely because the PCM falls back to a default air-temperature value. Expect worse fuel economy and possibly rough cold starts, and get it fixed soon so it does not hide other problems or cause an emissions test failure.
What is the difference between P0113 and P0112?
P0113 means the IAT circuit voltage is too high, which the PCM reads as extremely cold air, typically from an open circuit or disconnected sensor. P0112 is the opposite — voltage too low, read as extremely hot air, usually from a shorted-to-ground wire or failed sensor.
How much does it cost to fix a P0113 code?
If it is just a dirty or loose connector, the fix can cost nothing to about 80 dollars. A new IAT sensor runs roughly 50 to 300 dollars including labor, while wiring repairs can add more depending on how much harness damage there is.
Will a bad IAT sensor cause the car to run rich or lean?
A P0113 high reading tells the PCM the air is very cold, so it tends to add fuel and run rich, which can lower fuel economy and cause black smoke. It rarely leaves you stranded but should be corrected for proper drivability and emissions.