P0111

Universal

Intake Air Temperature Circuit Range/Performance Problem

Definition source: General OBD-II reference catalog
Definition verification: Not independently verified for display.
Time: Varies by diagnosis and vehicle | Diagnostic difficulty: Medium
Low Severity

The engine computer monitors the intake air temperature sensor, which reports the temperature of air entering the engine. P0111 means the reading or its behavior is outside the range the computer expects. The code identifies a circuit performance condition, not proof that the sensor itself has failed. Depending on the vehicle, an incorrect temperature reading may affect engine management and fuel economy, or there may be no noticeable symptoms.

Report an error with this code

⚠️ Before You Begin (Safety First)

This code alone does not usually indicate an immediate safety hazard. If the engine runs very poorly, stalls, loses power, or the check-engine light flashes, stop driving when it is safe to do so and have the vehicle assessed. Avoid testing electrical circuits with improvised methods that could damage components.

Common Symptoms

  • There may be no noticeable symptoms, particularly if the reported temperature remains close enough for normal engine operation.
  • Fuel economy or engine performance may be affected if the computer uses an inaccurate intake-air temperature reading to adjust engine operation.
  • Starting or drivability may be less consistent in some conditions if the temperature signal is implausible or intermittent.
  • The check-engine light may be on.

Common Causes

  • The intake air temperature sensor may give an inaccurate, erratic, or slow-changing reading.
  • A loose, corroded, contaminated, or damaged connector may interrupt or distort the sensor signal.
  • Wiring damage or a circuit connection problem may cause an implausible or intermittent reading.
  • The installed sensor may be incorrect for the vehicle, or an earlier repair may have left the circuit or connector improperly assembled.
  • An intake-air condition or operating circumstance may make the reading appear implausible; vehicle-specific diagnosis is needed to distinguish this from a sensor or circuit fault.

Diagnostic Steps

  1. Confirm the code with a scan tool and note any other codes; related codes can help identify whether the issue may involve a wider circuit or engine-management problem.
  2. With the engine off and cool, visually inspect the accessible sensor connector and wiring for looseness, corrosion, dirt, chafing, or obvious damage. Do not pull on wires or force the connector.
  3. Check that any recent work around the intake or sensor has not left a connector disconnected or wiring routed incorrectly.
  4. If your scan tool displays live data, observe the intake-air temperature reading and note whether it appears plausible for the vehicle's conditions. Interpretation depends on the vehicle and circumstances.
  5. If the code returns or the reading seems implausible, use vehicle-specific service information or seek professional diagnosis before replacing the sensor or probing the circuit.

When to Call a Professional

A technician can compare intake-air temperature scan data with other available temperature readings under suitable conditions, then check whether the reading changes plausibly as the air temperature changes. Inspect the connector and wiring, and test the sensor and circuit using the vehicle-specific wiring diagram and service information before replacing parts.

Compare component listings

Confirm diagnosis and vehicle fitment before buying. A listing does not prove that a part needs replacement. We may earn a commission from qualifying purchases.

Search Amazon Search eBay

Commonly Asked Questions

Does P0111 prove the intake air temperature sensor is bad?

No. The code reports a range or performance problem in the intake air temperature circuit. The sensor, connector, wiring, or conditions affecting the reading may need to be checked before deciding what to repair.

What does the intake air temperature sensor do?

It reports the temperature of air entering the engine. The engine computer uses that information as part of engine management.

Can I keep driving with P0111?

If the vehicle runs normally, this code alone is not usually an immediate reason to stop. Arrange diagnosis, and stop when safe if the engine stalls, loses significant power, runs very poorly, or the check-engine light flashes.

How can a technician distinguish a sensor fault from a wiring problem?

A technician can review scan data, inspect the connector and wiring, and test the sensor and circuit using the vehicle-specific service information. The code by itself does not identify which part or connection is at fault.

Related Diagnostic Video

Browse Available Code Guides

Previous and next available guides in database record order, across makes. Adjacent entries may share a code number and do not necessarily describe related faults.