P0111 Acura Intake Air Temperature Circuit Range/Performance Problem

Description

OBD-II Trouble Code Description for P0111 Acura

IAT Circuit Malfunction

What does this mean?

OBD2 Code P0111 Acura definition:
The IAT (Intake Air Temperature) sensor is a thermistor that varies resistance based upon the temperature of the engine intake air. Usually a two wire sensor. One wire is supplied 5 Volt from the PCM (Powertrain Control Module) and the other is a ground. The PCM monitors the change in the 5 Volt supplied to determine air temperature. When the intake air is cold, the resistance is high, resulting in a high signal voltage. When the intake air is warm, the reistance is low, resulting in a low signal voltage. This code means that the PCM saw a larger-than-normal change in a shorter-than-expected time on the IAT signal circuit.

Symptoms

Possible sumptoms of OBD code P0111 Acura
Since this code is likely pointing to an intermittent problem on the IAT circuit, there may not be any symptoms at present. However, the MIL will likely be on. The car MAY exhibit some drivability problems, but it is more likely that there will be no noticeable symptoms to the driver.

Causes

Possible causes of OBD code P0111 Acura
a bad IAT sensor an open in the signal or ground circuit a short to ground on the signal circuit poor connection at sensor or PCM

Possible Solutions

If there are other IAT codes present, diagnose them first. If not, then, using a scan tool verify the IAT voltage with KOEO (Key on engine off). If, on a cold engine it reads the same as the CTS (Coolant temperature sensor), then the problem is intermittent. But if the IAT reading isn’t the same as the CTS refer to diagnostic procedure for P0110 Acura. If your scan tool has a freeze frame failure records feature, use it to see what the IAT reading was at the time of the failure. If the reading was at negative 30 or so degrees F (indicating it was at the extreme coldest reading), then there was an intermittent high resistance reading on the IAT signal circuit. Check for an open ground on the ground circuit and signal circuit. If they are OK, try raising and lowering the temperature of the IAT sensor artificially. Do this by removing the IAT and putting it in a freezer and then applying heat with a heat gun (be careful not to apply too much heat to the IAT with the heat gun or it’ll melt the sensor). Watch the resistance change using an ohmmeter attached to each terminal. It should vary smoothly with no sudden jumps. If the reading jumps suddenly, then repace the IAT sensor. However if the freeze frame reading was at the highest extreme (above 250 deg. F) then there was an intermittent low resistance on the signal circuit. Check for a short to ground on the signal circuit. If it appears OK, then do the above artificial heat test and replace the IAT as necessary. If the problem can’t be duplicated, use a voltmeter to watch the signal voltage as you “wiggle” test the wiring harness. Watch for a sudden change in voltage indicating a short or open. Replace IAT as necessary. This is a pretty simple code and it only really looks for extremely short changes that are relatively high in voltage. It’s usually the sensor that is bad unless the vehicle is extremely old, in which case there may be harness problems.

Related Codes

P0095 Acura P0096 Acura P0097 Acura P0098 Acura P0099 Acura P0109 Acura P0110 Acura P0112 Acura P0113 Acura P0114 Acura

The OBD2 Code Information Be Applicable For Acura:

2014 Acura RLX,2014 Acura MDX,2013 Acura SUV-X Concept,2013 Acura RDX,2013 Acura NSX Concept,2013 Acura MDX Concept,2013 Acura ILX Endurance Racer,2013 Acura ILX,2012 Acura TL,2012 Acura RLX Concept,2012 Acura NSX Concept,2012 Acura ILX Street Build Concept,2012 Acura ILX Concept,2011 Acura TSX Sport Wagon,2011 Acura TSX Sedan,2010 Acura ZDX,2010 Acura TSX V6,2010 Acura RDX,2010 Acura MDX,2009 Acura ZDX Concept,2009 Acura TSX,2009 Acura TL,2009 Acura RL,2007 Acura TSX,2007 Acura TL Type-S,2007 Acura TL,2007 Acura RDX,2007 Acura MDX,2007 Acura Advanced Sports Car Concept,2006 Acura RDX Prototype,2006 Acura MD-X Concept,2006 Acura Advanced Sedan Concept,2005 Acura TSX A-Spec Concept,2005 Acura TSX,2005 Acura TL,2005 Acura RSX Type-S,2005 Acura RSX A-Spec Concept,2005 Acura RSX,2005 Acura RL with ASPEC Performance Package,2005 Acura RL ASPEC Concept,2005 Acura RL,2005 Acura RDX Concept,2005 Acura NSX,2005 Acura MDX,2004 Acura TL with ASPEC Performance Package,2004 Acura TL 25 Hours of Thunderhill,2004 Acura RL Prototype,2004 Acura 3.2 TL,2003 Acura TL ASPEC Concept,2003 Acura 3.2 CL Type-S,2002 Acura NSX sketches,2001 Acura NSX-T,2001 Acura Integra

Note:

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