Description
OBD-II Trouble Code Description for P0112 Subaru
Intake Air Temperature Sensor 1 Circuit Low
What does this mean?
OBD2 Code P0112 Subaru definition:
The IAT (intake air temperature) sensor simply measures the temperature of air that is entering the engine. Intake air temperature is important because the higher the intake air, the higher the combustion temperatures. High combustion temperatures result in increased Nox (Nitrogen oxides) emissions. To keep these higher temps from causing increased combustion temps, the intake air tubing should be intact, allowing the engine to “breathe” air that isn’t sampled from the engine compartment. The IAT measures air temp by using a thermistor, or a thermometer of sorts. The thermistor is supplied 5 volts reference voltage from the PCM (powertrain control module) and a ground. Usually, when the air temperature is cold the resistance in the thermistor is high and when the air temperature is warmer, the resistance decreases. This change in resistance changes the 5 V reference from the PCM, thereby informing the PCM of the temperature of incoming air. If the PCM notices that the incoming air temp is unusually high, say, 300 degrees, when the engine temp is still relatively low, it will set a P0112 Subaru.
Symptoms
Possible sumptoms of OBD code P0112 Subaru
There may be no noticeable symptoms of a P0112 Subaru code other than an MIL (Malfunction Indicator Lamp). However, a emissions test may reveal higher Nox readings depending on the type of IAT failure. Or the engine may ping under load, depending on the type of IAT failure.
Causes
Possible causes of OBD code P0112 Subaru
No reference voltage to the IAT sensor due to an open wire Excessively high intake air temperatures Short to ground on signal circuit Damaged IAT connector Bad PCM
Possible Solutions
Hook up your scan tool or code reader and read the IAT reading. With a cold engine, the IAT should roughly match the coolant reading, since both will read ambient temperature. If the IAT is reading excessively high, check the IAT connector for damage. If you find none, unplug the IAT sensor and recheck the reading. It should now read the minimum, around -20 deg. If it does, then replace the IAT sensor. But, if the reading is still high, unplug the sensor and check for resistance across the two wiring harness terminals. If there is infinite resistance, then the PCM itself is bad. If the resistance isn’t infinite, then check and repair the short to ground on the signal circuit.
The OBD2 Code Information Be Applicable For Subaru:
2013 Subaru WRX Concept,2013 Subaru Viziv Concept,2013 Subaru Outback,2013 Subaru Legacy,2013 Subaru Impreza,2013 Subaru BRZ,2012 Subaru XV,2012 Subaru Impreza,2011 Subaru XV Concept,2011 Subaru Outback,2011 Subaru Impreza,2011 Subaru Forester,2010 Subaru Legacy,2010 Subaru Impreza,2009 Subaru Impreza,2008 Subaru Impreza,2008 Subaru Forester,2006 Subaru Impreza,2005 Subaru R1,2005 Subaru Pleo,2004 Subaru Impreza,2004 Subaru Forester,2003 Subaru Traviq
Note:
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