P0112
UniversalIntake Air Temperature Circuit Low Input
The intake air temperature (IAT) sensor reports the temperature of air entering the engine so the engine computer can adjust engine operation. P0112 means the computer detected a low electrical input in the IAT circuit; it does not by itself prove the sensor has failed. Depending on the circuit and vehicle, the reading may be interpreted as an unusually high air temperature and can affect fueling or other engine adjustments.
⚠️ Before You Begin (Safety First)
This code alone usually does not require stopping immediately. If the engine runs very poorly, stalls, or becomes unsafe to control, stop driving when safe and arrange help. Avoid touching hot engine parts while inspecting the area.
Common Symptoms
- The check-engine light may be on because the computer detected an out-of-range IAT circuit input.
- There may be no noticeable change in how the vehicle runs.
- Incorrect intake-air temperature information can affect engine adjustments and may contribute to rough running, hesitation, or reduced fuel economy.
- Starting or drivability problems may occur if the incorrect reading significantly affects engine control.
Common Causes
- A damaged, contaminated, or internally faulty IAT sensor may produce an incorrect circuit signal.
- Wiring damage or a connector problem, such as corrosion or a poor connection, may cause the circuit input to be low.
- A short to ground or another circuit fault may pull the signal lower than expected.
- A fault in the engine computer is possible but should be considered only after the sensor and wiring have been tested.
Diagnostic Steps
- Check whether the check-engine light is accompanied by serious running problems; if the vehicle is unsafe to drive, stop and arrange professional help.
- With the engine off and cool, visually inspect accessible IAT sensor wiring and connectors for damage, looseness, or corrosion.
- If you have a scan tool, note the IAT reading and compare it with other temperature readings when conditions make a comparison meaningful; an implausible reading can help guide diagnosis but does not identify the failed part by itself.
- Use the correct service information for your vehicle before disconnecting components or testing wiring. If electrical testing is needed and you are not equipped to do it safely, ask a qualified technician to continue.
When to Call a Professional
Use a scan tool to compare the IAT reading with other temperature readings under suitable conditions, then inspect the sensor connector and wiring. If needed, test the sensor and circuit using the vehicle-specific wiring diagram and service information. Confirm the cause before replacing parts.
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Commonly Asked Questions
Does P0112 mean the IAT sensor must be replaced?
No. The code identifies a low circuit input, not a confirmed failed part. The sensor, connector, wiring, or another circuit fault may be responsible.
Does low input mean the incoming air is actually cold?
Not necessarily. The code describes the electrical input detected by the computer, not a confirmed physical air temperature. The reading's interpretation depends on the vehicle's circuit design.
Can I keep driving with P0112?
If the vehicle runs normally, the code alone is generally not an immediate stop-driving condition, but arrange diagnosis. Stop when safe if severe running problems or unsafe behavior occur.
What is a useful first diagnostic check?
Inspect the accessible sensor connector and wiring, then compare scan-tool temperature data with other readings when conditions allow. Vehicle-specific service information is needed for electrical tests and repair procedures.
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