Diagnostic Trouble Code P0112

P0112 “Intake Air Temperature Sensor 1 Circuit Low”


What is code P0112?

Code P0112 stands for “Intake Air Temperature Sensor 1 Circuit Low”. This diagnostic trouble code can show up for a number of reasons that have to do with the intake air temperature (IAT) sensor on your engine. Therefore, it is important to have a qualified technician diagnose the specific problem that caused the code to be stored in your vehicle’s computer.

Get this checked out soon by a CarAdvise shop, where the work will be guaranteed, and one of our expert techs will review any repair orders.

What does code P0112 mean?

When a code P0112 shows up on a diagnostic scan of your vehicle, a technician knows that there is something going on with the intake air temperature sensor on your engine.

Your engine requires that a specific mixture of air and fuel enter the combustion chambers in order for combustion to happen properly. When that air/fuel ratio is out of balance, whether too rich (too much fuel) or too lean (not enough fuel), your engine will not run as it should. Fuel economy also decreases, while harmful emissions from the exhaust system increase.

To help achieve this balance between air and fuel, several sensors are in place to monitor engine data. One of these sensors is the intake air sensor. The sensor might be mounted in the intake tube, air cleaner housing, or the intake manifold. In any case, the sensor detects the temperature of the air that enters the combustion chambers.

Since cool air is denser than warm air, more fuel is needed when temperatures are low. Conversely, on a warm day, less fuel is needed to mix with the less-dense air. The IAT sensor continuously monitors the temperature and relays the data to the  ECM (Engine Control Module) that oversees engine function. The ECM then adjusts how much and at what pressure fuel is injected into the combustion chambers. It also adjusts when the spark plugs should fire and other dynamics in response to the intake air temperature level.

If the ECM detects that the voltage coming from the IAT sensor is low (indicating higher than normal intake air temperature) while data from other sensors is within acceptable limits, it stores code P0012 and turns on the check engine light.


What causes code P0112?

A number of causes can trigger a code P0112. That is why an accurate diagnosis is essential. Causes of this code include:

Most likely

Other possibilities

  • Damaged, dirty, or deteriorated wiring to the intake air temperature sensor
  • Corrosion on the sensor connector or ECM connector


What symptoms are associated with this code?

Common signs associated with a code P0112 include the following:

  • The check engine light is on or flashing
  • Reduced fuel economy
  • Difficulty starting the engine
  • Engine runs rough, heistates, or lacks power
  • Black smoke coming from the tailpipe
  • Failed emissions test


How does a technician diagnose code P0112?

If a diagnostic scan of your vehicle indicates a code P0112, a technician will perform tests to pinpoint the problem. These tests include checking for any related trouble codes. The technician will also use the scan tool to view data from the IAT sensor to determine what conditions were present when the code was set. The wiring from the ECM to the IAT sensor will be inspected for cracks, corrosion, contamination, or bent pins on the connectors. The technician might also perform tests on the IAT sensor itself with a multimeter and verify that adequate voltage is reaching the sensor when it is in operation.


How serious is this code?

Short-term issues associated with a code P0112 can lead to reduced fuel economy and a rough-running engine. Higher intake air temperatures cause NOx levels to increase in the exhaust system. A failed emissions test would be likely. In the long term, the problem can lead to pinging upon acceleration, which can damage the pistons inside your engine. A code P0112 should be diagnosed and repaired in a reasonable amount of time, generally a week or so.

Get this checked out soon by a CarAdvise shop, where the work will be guaranteed, and one of our expert techs will review any repair orders.


Related Diagnostic Trouble Codes

P0100 Mass Air Flow Sensor (MAF) Circuit Problem 

P0102 Mass Air Flow (MAF) A Circuit Low

P0113 Intake Air Temperature Sensor 1 Circuit High


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