P0112
UniversalIntake Air Temperature Circuit Low Input
Medium SeverityThis code indicates that the Powertrain Control Module (PCM) has detected a voltage reading from the Intake Air Temperature (IAT) sensor that is lower than expected. A low voltage signal typically implies that the PCM is receiving a signal indicating very cold intake air, or there is an electrical issue like a short circuit to ground.
⚠️ Before You Begin (Safety First)
Always ensure the vehicle is safely parked with the engine off and cool before performing any work. Disconnect the negative battery terminal to prevent accidental electrical shorts. Wear appropriate eye protection and gloves.
Common Symptoms
- Check Engine Light illuminated
- Poor fuel economy
- Rough idle
- Engine may run rich
- Reduced engine performance
Common Causes
- Faulty Intake Air Temperature (IAT) sensor
- Short circuit to ground in the IAT sensor signal wire
- Open circuit in the IAT sensor ground wire
- Damaged IAT sensor connector
- Faulty Powertrain Control Module (PCM) (rare)
Frequently reported on: General/Universal
Diagnostic Steps
- Visually inspect the Intake Air Temperature (IAT) sensor and its wiring connector for any damage, corrosion, or loose connections.
- Disconnect the IAT sensor and check the resistance across its terminals using a multimeter; compare to manufacturer specifications.
- Check for proper voltage (typically 5V reference) at the IAT sensor connector with the ignition on.
- If the sensor is faulty, replace it with a new one.
- Clear the code and test drive the vehicle to see if the code returns.
👨🔧 When to Call a Professional
If after inspecting and replacing the Intake Air Temperature sensor, the code P0112 persists, or if you suspect a wiring issue that is beyond your comfort level, it's best to consult a professional mechanic. Complex electrical diagnostics often require specialized tools and expertise.
Commonly Asked Questions
What does P0112 mean?
It indicates the engine computer is receiving a lower-than-expected voltage signal from the Intake Air Temperature sensor, suggesting very cold air or an electrical fault.
Can I drive with a P0112 code?
While often not critical, it can affect fuel economy and emissions. It's best to diagnose and fix it soon to prevent potential further issues or failed emissions tests.
Where is the IAT sensor located?
The IAT sensor is typically located in the intake manifold, air intake duct, or integrated into the Mass Air Flow (MAF) sensor assembly. Its exact location varies by vehicle.
How can I test the IAT sensor?
You can test the IAT sensor by checking its resistance with a multimeter and comparing it to the manufacturer's specifications for different temperatures. You can also check for 5V reference voltage at the connector.
What is the most common fix for P0112?
The most common fix is replacing a faulty Intake Air Temperature sensor, especially if wiring appears intact and the reference voltage is correct.