Description
OBD-II Trouble Code Description for P0111 Alfa Romeo
IAT Circuit Malfunction
What does this mean?
OBD2 Code P0111 Alfa Romeo 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 Alfa Romeo
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 Alfa Romeo
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 Alfa Romeo. 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.
The OBD2 Code Information Be Applicable For Alfa Romeo:
2014 Alfa Romeo MiTo new,,2014 Alfa Romeo Giulietta new,,2014 Alfa Romeo 4C,,2013 Alfa Romeo Gloria Concept,,2013 Alfa Romeo Disco Volante Touring,,2012 Alfa Romeo Disco Volante Touring Concept,,2011 Alfa Romeo TZ3 Stradale,,2011 Alfa Romeo Giulietta,,2011 Alfa Romeo 4C Concept,,2010 Alfa Romeo TZ3 Corsa,,2010 Alfa Romeo Pandion Concept,,2010 Alfa Romeo MiTo Quadrifoglio Verde,,2010 Alfa Romeo MiTo 1.4 MultiAir,,2010 Alfa Romeo 2uettottanta Concept,,2010 Alfa Romeo 159 1750 TBi,,2009 Alfa Romeo MiTo UK Version,,2009 Alfa Romeo MiTo GTA Concept,,2009 Alfa Romeo Mi.To,,2009 Alfa Romeo Brera S,,2009 Alfa Romeo 8C Spider,,2009 Alfa Romeo 159 Sportwagon,,2009 Alfa Romeo 159,,2007 Alfa Romeo GT Q2,,2007 Alfa Romeo 8c Competizione,,2007 Alfa Romeo 147 Q2,,2007 Alfa Romeo 147 Murphy and Nye,,2007 Alfa Romeo 147 CnC,,2006 Alfa Romeo Spider UK Version,,2006 Alfa Romeo Spider,,2006 Alfa Romeo 159 Sportwagon,,2005 Alfa Romeo Brera UK Version,,2005 Alfa Romeo Brera,,2005 Alfa Romeo 159,,2004 Alfa Romeo Visconti Concept ItalDesign,,2004 Alfa Romeo 8C Competizione,,2004 Alfa Romeo 166,,2004 Alfa Romeo 156 GTA Autodelta,,2004 Alfa Romeo 156 Crosswagon Q4,,2004 Alfa Romeo 156 Crosswagon,,2004 Alfa Romeo 147 5door,,2004 Alfa Romeo 147 3door,,2003 Alfa Romeo Spider,,2003 Alfa Romeo Kamal Concept,,2003 Alfa Romeo GTV,,2003 Alfa Romeo GT,,2003 Alfa Romeo 156 Sportwagon 2.0 JTD,,2003 Alfa Romeo 156 GTA Autodelta,,2003 Alfa Romeo 156 2.4 JTD,,2003 Alfa Romeo 147 TI,,2002 Alfa Romeo 147 JTD 16V,,2002 Alfa Romeo 147 GTA
Note:
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