Description
OBD-II Trouble Code Description for P0142 Alfa Romeo
O2 Sensor Circuit
What does this mean?
OBD2 Code P0142 Alfa Romeo definition:
The oxygen sensors are critical to the engine running properly. It basically informs the PCM (Powertrain Control Module) of oxygen content of the exhaust. The PCM then uses this information to regulate fuel injector pulse. Inaccurate or faulty O2 sensors can cause the PCM to add or take away fuel based on the faulty O2 sensor voltage which can cause a host of problems. A P0142 Alfa Romeo code definition:the Bank 1,3 O2 sensor or the 3rd downstream (post-cat) O2 sensor on Bank 1. It is a four wire sensor. The PCM supplies a ground circuit and a reference voltage circuit of about 0.5 volts. Also for the O2 sensor heater element there is a battery voltage supply wire and another ground circuit for that. The O2 sensor heater allows the O2 sensor to warm up faster, thus achieving closed loop in less time than it would normally take for the exhaust to warm the sensor up to operating temperature. The O2 sensor varies the supplied reference voltage based on oxygen content in the exhaust. It is capable of varying from about 0.1 to 0.9 volts, 0.1v indicating lean exhaust and 0.9v indicating rich exhaust. This P0142 Alfa Romeo code indicates that the Bank 1,3 O2 sensor is stuck low for too long or isn’t active at all.
Symptoms
Possible sumptoms of OBD code P0142 Alfa Romeo
Often post-cat O2 sensor problems present few symptoms since they are inputs to the PCM to monitor catalytic converter quality and don’t directly control fuel. sometimes no symptoms are noticeable. However the following may be possible on some vehicles: MIL (Malfunction Indicator Lamp) illumination Decrease in MPG Increase in tailpipe emissions
Causes
Possible causes of OBD code P0142 Alfa Romeo
Potential causes of a P0142 Alfa Romeo code include: Bad O2 sensor Signal shorted to voltage Wiring problems due to contact with exhaust components Holes in exhaust near O2 sensor
Possible Solutions
If you have access to a scan tool, check the signal voltage for the Bank 1,3 oxygen sensor with the engine at normal operating temperature. Is it stuck low currently? If so, increase RPM for a few seconds and see if it affects the reading. If it begins working with increased RPM, check for holes in the exhaust near the O2 sensor that may cause a false lean. If the exhaust pipe is intact, the sensor is sluggish, replace it. If the Bank 1,3 O2 sensor voltage reading remains low with increased RPM, unplug it and then observe the reading. It should have increased to about 0.5 volts or thereabouts. If it did, check for water intrusion or other connector problems. If none are found, replace the shorted O2 sensor. If the voltage reading is still stuck low after unplugging the sensor, then suspect a wiring problem. Using a voltmeter, with the O2 sensor unplugged, check for voltage on the signal circuit at the O2 sensor connector (PCM side). It can vary with model, but should be about 0.5 volts and not above 1 volt. If the voltage reading is too high, repair short to voltage on signal circuit. If the signal voltage checks out, suspect the PCM.
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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