P1112
HondaIntake Air Temperature (IAT) Sensor Circuit Intermittent Low Voltage
Medium SeverityThis code indicates that the vehicle's engine control module (ECM) is detecting an intermittent low voltage signal from the Intake Air Temperature (IAT) Sensor. This typically means the sensor is sending incorrect information about the air temperature entering the engine, which can lead to improper fuel mixture calculations and drivability issues for the driver.
⚠️ Before You Begin (Safety First)
Always ensure the engine is off and cool before working on any engine components. Disconnect the negative battery terminal before performing any electrical work to prevent accidental short circuits or electrical shocks. Wear appropriate personal protective equipment, such as safety glasses and gloves.
Common Symptoms
- Check Engine Light illuminated
- Poor fuel economy
- Rough idle
- Hesitation during acceleration
- Difficulty starting, especially in extreme temperatures
- Engine running rich or lean
Common Causes
- Faulty Intake Air Temperature (IAT) sensor
- Corroded or damaged IAT sensor connector
- Frayed, broken, or shorted wiring in the IAT sensor circuit
- Loose connection at the IAT sensor or ECM
- ECM internal fault (rare)
Frequently reported on: 2006 Honda Civic, 2008 Honda Accord, 2010 Honda CR-V, 2005 Honda Pilot, 2007 Honda Odyssey
Diagnostic Steps
- Locate the Intake Air Temperature (IAT) sensor, which is typically found in the intake manifold or air intake tube after the air filter.
- Visually inspect the IAT sensor and its electrical connector for any signs of damage, corrosion, or loose connections.
- Carefully disconnect the electrical connector from the IAT sensor.
- Inspect the pins within the connector and on the sensor for any bent, corroded, or broken components.
- If corrosion is present, clean the terminals using electrical contact cleaner and a small brush.
- Using a multimeter, test the resistance of the IAT sensor. Compare the reading to your vehicle's service manual specifications for different temperatures.
- If the sensor tests faulty or shows intermittent readings, replace it with a new one.
- Reconnect the new or cleaned IAT sensor and clear the P1112 code using an OBD-II scanner.
- Start the engine and monitor for the return of the code or symptoms.
👨🔧 When to Call a Professional
If you have replaced the Intake Air Temperature Sensor and inspected the wiring, but the P1112 code returns or symptoms persist, it's time to consult a professional. The issue might involve more complex wiring diagnostics or even a problem with the engine's computer (ECM).
Commonly Asked Questions
What is an Intake Air Temperature (IAT) sensor?
The IAT sensor measures the temperature of the air entering the engine. This information is crucial for the engine control module (ECM) to calculate the correct fuel-to-air ratio for optimal engine performance and emissions.
Can I drive with a P1112 code?
While you may be able to drive with this code, it is not recommended for extended periods. An intermittent low voltage signal means the engine isn't getting accurate air temperature data, which can lead to poor fuel economy, reduced engine performance, and potentially long-term engine damage if the fuel mixture is consistently incorrect.
How do I clear the P1112 code?
After addressing the underlying issue (e.g., replacing the sensor or repairing wiring), you can clear the code using an OBD-II scan tool. Disconnecting the car's battery for a few minutes can also clear the code, but this will also reset other vehicle systems.
Is the IAT sensor difficult to replace?
For most Honda models, replacing the IAT sensor is a relatively straightforward and easy DIY task. It typically involves locating the sensor, disconnecting an electrical connector, and unscrewing or unlatching the sensor from its housing.
Where is the IAT sensor located on my Honda?
On most Honda vehicles, the IAT sensor is located in the air intake tube between the air filter box and the throttle body, or sometimes directly on the intake manifold.
What tools do I need to replace an IAT sensor?
You will typically need basic hand tools like a screwdriver or a small socket set, electrical contact cleaner, and possibly a multimeter for testing. An OBD-II scanner is also helpful for reading and clearing the code.