P1112
ChryslerIntake Air Temperature (IAT) Sensor Circuit Intermittent Low Voltage
Medium SeverityThis code indicates that the vehicle's engine control module (ECM) has detected an intermittent low voltage signal from the Intake Air Temperature (IAT) sensor circuit. This can lead to the ECM miscalculating the engine's fuel mixture, potentially causing performance issues and reduced fuel efficiency.
⚠️ Before You Begin (Safety First)
Always allow the engine to cool down before working near hot components. Disconnect the negative battery terminal before performing any electrical work to prevent accidental shorts or shocks.
Common Symptoms
- Check Engine Light illuminated
- Rough idle
- Reduced fuel economy
- Poor engine performance, especially during cold starts
- Increased emissions
Common Causes
- Faulty Intake Air Temperature (IAT) sensor
- Corroded or loose IAT sensor electrical connector
- Damaged or frayed wiring in the IAT sensor circuit
- Intermittent short to ground in the IAT circuit
- Faulty Engine Control Module (ECM) (less common)
Frequently reported on: Chrysler 300 (2005-2010), Dodge Grand Caravan (2008-2015), Jeep Grand Cherokee (2005-2010), Dodge Ram 1500 (2002-2008), Chrysler PT Cruiser (2001-2010)
Diagnostic Steps
- Locate the Intake Air Temperature (IAT) sensor, typically found in the intake manifold or air intake tube.
- Inspect the IAT sensor's electrical connector for corrosion, damage, or loose connections. Clean or secure as necessary.
- Check the wiring leading to the IAT sensor for any visible damage, fraying, or signs of rodent activity.
- Using a multimeter, test the IAT sensor's resistance at various temperatures to confirm it is within specifications.
- If the sensor tests faulty or shows intermittent readings, replace the IAT sensor.
- Clear the P1112 diagnostic trouble code using an OBD-II scanner and test drive the vehicle to ensure the issue is resolved.
👨🔧 When to Call a Professional
If after replacing the Intake Air Temperature sensor, the code P1112 returns or the vehicle exhibits complex drivability issues, it is advisable to consult a professional mechanic to diagnose potential wiring harness damage or ECM faults.
Commonly Asked Questions
What is the Intake Air Temperature (IAT) sensor?
The IAT sensor measures the temperature of the air entering the engine, providing this data to the ECM to help calculate the correct fuel injection amount.
Can I drive with a P1112 code?
While you can typically drive with this code, it's not recommended for extended periods as it can lead to reduced fuel economy, increased emissions, and potential damage to other components over time due to an incorrect fuel mixture.
Is the IAT sensor difficult to replace?
No, in most Chrysler vehicles, the IAT sensor is easily accessible and can be replaced with basic hand tools, making it a straightforward DIY repair.
How do I know if it's the sensor or the wiring?
A multimeter can be used to test the sensor's resistance and the voltage at the connector. If the sensor's readings are inconsistent or the voltage at the harness is incorrect, further wiring inspection or testing is needed.
Will clearing the code fix the problem?
Clearing the code will turn off the Check Engine Light temporarily, but it will return if the underlying issue with the IAT sensor or circuit is not resolved.