P1112
HyundaiHyundai-specific code indicating an intermittent low voltage condition detected in the Intake Air Temperature (IAT) sensor circuit.
Medium SeverityThis code signifies that the Intake Air Temperature (IAT) Sensor is intermittently sending a voltage signal that is too low, suggesting a potential malfunction or poor connection within its circuit. This can lead to the engine's computer miscalculating the air density, affecting fuel delivery and ignition timing, which may result in drivability issues or reduced fuel efficiency.
⚠️ Before You Begin (Safety First)
Always ensure the engine is off and cool before working on any engine components. Disconnect the negative battery terminal to prevent accidental electrical shorts or injury. Use appropriate eye protection and gloves. Be cautious around hot engine parts and electrical connections.
Common Symptoms
- Check Engine Light illumination
- Reduced fuel economy
- Rough idle or poor engine performance
- Hesitation or stalling during acceleration
- Difficulty starting the engine in extreme temperatures
Common Causes
- Faulty Intake Air Temperature (IAT) sensor
- Corrosion or damage to the IAT sensor connector or terminals
- Open or short circuit in the IAT sensor wiring harness
- Poor electrical connection at the IAT sensor or Engine Control Unit (ECU)
- Contamination or blockage affecting the IAT sensor's ability to read air temperature
Frequently reported on: Hyundai Elantra 2007-2010, Hyundai Sonata 2006-2009, Hyundai Santa Fe 2008-2012, Hyundai Accent 2006-2011
Diagnostic Steps
- Locate the Intake Air Temperature (IAT) sensor, typically found in the intake manifold or air intake ducting.
- Visually inspect the IAT sensor and its electrical connector for any signs of damage, corrosion, or loose connections. Clean any visible corrosion using electrical contact cleaner.
- Carefully disconnect the electrical connector from the IAT sensor.
- Using a multimeter, test the resistance of the IAT sensor at various ambient temperatures (refer to your vehicle's service manual for specific resistance values at different temperatures). A faulty sensor will show out-of-spec readings or an open circuit.
- Inspect the wiring harness leading to the IAT sensor for any fraying, cuts, or pinches. Check for continuity and proper voltage supply (usually 5V reference from the ECU) to the sensor connector using a multimeter.
- If the sensor is faulty based on testing, or if visual inspection reveals significant damage, replace the IAT sensor with a new, OEM-quality part.
- Reconnect the electrical connector firmly to the new sensor. Clear the P1112 code using an OBD-II scanner and perform a test drive to ensure the code does not return.
👨🔧 When to Call a Professional
If after inspecting wiring and replacing the Intake Air Temperature (IAT) Sensor the code persists, or if you suspect deeper electrical issues such as a short to ground within the harness or a faulty Engine Control Unit (ECU), it is best to consult a professional mechanic. Diagnosing intermittent electrical faults can be complex and may require specialized tools and expertise.
Commonly Asked Questions
What does an intermittent low voltage mean for the IAT sensor?
An intermittent low voltage indicates that the sensor's signal to the engine computer is occasionally dropping below expected thresholds. This can be due to a faulty sensor, a loose connection, or a wiring issue causing a temporary break or short in the circuit.
Can I drive with a P1112 code?
While you can typically drive with this code, it's not recommended for long. The engine's fuel mixture and timing may be incorrect, leading to reduced performance, poor fuel economy, and potentially increased emissions or long-term engine damage if left unaddressed.
Where is the IAT sensor located on my Hyundai?
The Intake Air Temperature (IAT) sensor is commonly located in the air intake ducting, near the air filter box, or directly on the intake manifold. Its exact position can vary by Hyundai model and engine type, so consulting your vehicle's service manual is best.
Do I need to replace the entire mass airflow (MAF) sensor if I have this code?
Not necessarily. On some vehicles, the IAT sensor is integrated into the MAF sensor. However, if your Hyundai has a separate IAT sensor, you only need to replace that specific component. Always confirm if your IAT sensor is a standalone unit or part of a MAF sensor assembly.
After replacing the IAT sensor, the code came back. What should I check next?
If the code returns after replacing the IAT sensor, the issue likely lies in the wiring harness or the electrical connector. Thoroughly inspect for damaged wires, poor connections, or corrosion that might still be causing the intermittent low voltage. You may also need to check the Engine Control Unit (ECU) if all other components and wiring are confirmed good.