P1110
ToyotaIntake Air Temperature (IAT) Sensor (D/C) Open/Short
Medium SeverityThis code indicates an electrical problem with the Intake Air Temperature Sensor circuit, specifically an open circuit or a short circuit. This prevents the engine control unit from accurately reading the temperature of the air entering the engine, which can affect fuel mixture and engine performance.
⚠️ Before You Begin (Safety First)
Always ensure the engine is off and cool before working on any engine components. For electrical work, it is strongly recommended to disconnect the battery's negative terminal to prevent accidental shorts or electrical shock. Wear appropriate safety glasses and gloves.
Common Symptoms
- Check Engine Light illuminated
- Reduced fuel economy
- Rough idle or poor engine performance
- Difficulty starting in extreme temperatures
- Engine running rich or lean
Common Causes
- Faulty or damaged Intake Air Temperature (IAT) sensor
- Open circuit in the IAT sensor wiring
- Short circuit in the IAT sensor wiring
- Corrosion or loose connections at the IAT sensor connector
- Damaged or corroded engine control unit (ECU) pins (less common)
Frequently reported on: 2002-2006 Toyota Camry, 2000-2005 Toyota Corolla, 1998-2004 Toyota Tacoma, 2001-2007 Toyota Highlander
Diagnostic Steps
- Locate the Intake Air Temperature (IAT) sensor, typically found in the air intake duct or manifold.
- Visually inspect the sensor and its electrical connector for any obvious damage, corrosion, or loose wires.
- Disconnect the IAT sensor connector and inspect the pins for cleanliness and secure fitment.
- Using a multimeter, test the resistance of the IAT sensor itself. Compare readings to specifications found in your vehicle's service manual. An open circuit (infinite resistance) or a short circuit (zero resistance) indicates a faulty sensor.
- Test the wiring harness for continuity and voltage. Ensure there is proper voltage supply and ground to the sensor, and no open or short circuits in the signal wire back to the ECU.
- If the sensor tests faulty or the wiring is compromised, replace the IAT sensor or repair the wiring as necessary.
- Clear the P1110 code using an OBD-II scanner and test drive the vehicle to confirm the repair.
👨🔧 When to Call a Professional
If you have replaced the IAT sensor and thoroughly inspected the wiring without resolving the code, it's time to consult a professional. There might be a deeper issue within the wiring harness or the engine control unit itself, which requires specialized diagnostic tools and expertise.
Commonly Asked Questions
What does the Intake Air Temperature (IAT) sensor do?
The IAT sensor measures the temperature of the air entering the engine. This information is crucial for the engine control unit (ECU) to calculate the correct fuel-to-air mixture for optimal combustion and emissions.
Can I drive my car with a P1110 code?
While you can usually drive with a P1110 code, it's not recommended for extended periods. The engine's performance, fuel economy, and emissions will be negatively affected, and prolonged driving could potentially lead to other issues if the engine runs too rich or too lean.
How do I test the IAT sensor with a multimeter?
Disconnect the sensor's electrical connector. Set your multimeter to the ohms setting. Place the probes on the two terminals of the sensor. The resistance should change with temperature (e.g., lower resistance when warm, higher when cold). Consult your vehicle's service manual for specific resistance values at various temperatures.
Is the IAT sensor expensive to replace?
The IAT sensor is generally an inexpensive part, typically ranging from $20 to $60. It's also usually easy to access and replace, making it a relatively low-cost DIY repair.
Will clearing the P1110 code fix the problem?
Clearing the code will only turn off the Check Engine Light temporarily. If the underlying issue (faulty sensor, wiring problem) is not addressed, the code will reappear once the ECU detects the fault again during subsequent driving cycles.