P1113
NissanNissan: Intake Air Temperature (IAT) Sensor Circuit Open/Short
Medium SeverityThis code indicates an electrical problem with the Intake Air Temperature (IAT) sensor circuit, meaning the engine computer is not receiving correct temperature readings. This can lead to incorrect fuel mixture calculations, potentially affecting fuel economy and engine performance.
⚠️ Before You Begin (Safety First)
Always ensure the vehicle is turned off and cool before working on any engine components. Disconnect the negative battery terminal to prevent accidental shorts or electrical hazards. Wear appropriate safety gear, such as gloves and eye protection.
Common Symptoms
- Check Engine Light illumination
- Reduced fuel economy
- Rough idle
- Engine hesitation or poor acceleration
- Increased emissions
- Difficulty starting (especially in extreme temperatures)
Common Causes
- Faulty Intake Air Temperature (IAT) sensor
- Corroded or loose IAT sensor connector
- Damaged or broken wiring in the IAT sensor circuit
- Short circuit in the IAT sensor wiring
- Damaged Engine Control Unit (ECU) (rare)
Frequently reported on: Nissan Altima 2002, Nissan Maxima 2004, Nissan Frontier 2007, Nissan Sentra 2003, Nissan Xterra 2008
Diagnostic Steps
- Visually inspect the IAT sensor and its wiring for any obvious signs of damage, corrosion, or loose connections.
- Disconnect the IAT sensor and test its resistance using a multimeter, comparing readings to manufacturer specifications at various temperatures.
- Check for voltage at the IAT sensor connector to ensure the sensor is receiving power.
- Inspect the entire IAT sensor circuit wiring for continuity and shorts using a multimeter.
- If the sensor is faulty, replace the Intake Air Temperature sensor.
- Clear the diagnostic trouble code using an OBD-II scanner and re-test the vehicle.
👨🔧 When to Call a Professional
If after replacing the IAT sensor the code persists, or if you are unsure about testing electrical circuits, it is best to consult a professional mechanic as there may be deeper wiring or ECU issues.
Commonly Asked Questions
What is an IAT sensor and what does it do?
The IAT sensor measures the temperature of the air entering the engine. This information is used by the engine control unit (ECU) to calculate the correct fuel injection timing and amount for optimal combustion.
Can I drive with a P1113 code?
While you can usually drive with a P1113 code, it's not recommended for extended periods as it can lead to reduced fuel efficiency, increased emissions, and potentially cause other engine issues over time due to incorrect fuel mixtures.
Is replacing the IAT sensor difficult?
For most Nissan vehicles, replacing the IAT sensor is a relatively easy DIY task, often involving simply unplugging the old sensor and screwing in a new one, usually located in the intake manifold or air intake tube.
How much does an IAT sensor cost?
An IAT sensor is typically inexpensive, usually ranging from $15 to $50 for the part itself. Professional replacement costs would include labor.
What if replacing the IAT sensor doesn't fix the code?
If the code persists after replacing the sensor, the issue likely lies within the wiring harness leading to the sensor, a poor connection at the sensor plug, or less commonly, a problem with the Engine Control Unit (ECU). Further electrical diagnosis would be required.