Description
OBD-II Trouble Code Description for P0146 Alfa Romeo
O2 Sensor Circuit No Activity Detected
What does this mean?
OBD2 Code P0146 Alfa Romeo definition:
The catalytic converter is used to control emissions. The o2 sensor on Bank 1, position 3 is aft of the converter and monitors the catalyst efficiency. The PCM (Powertrain Control Module) does this by comparing the post-cat o2 sensor to the pre-cat o2 sensors. The o2 sensor is a four wire sensor. The PCM supplies a reference to the sensor of about half a volt and also supplies a sensor ground and 12 volts for the heater element. The fourth wire is a ground for the heater element (the heater in the sensor helps the sensor to warm up faster which allows the engine to reach closed loop sooner). The sensor varies the supplied reference voltage based on oxygen content of the exhaust. Oxygen sensors are capable of varying between 0.1 volts to 0.9 volts. Lean exhaust produces low voltage and causes the supplied 0.45 volts to drop. Rich exhaust produces high voltage and causes the supplied 0.45 voltage to increase. Pre-catalyst o2 sensors switch between low and high voltage rapidly. However a post-cat o2 sensor may switch much slower & not vary as much (this is normal). If the sensor doesn’t respond as it should or there are too few switches in a given time period, P0146 Alfa Romeo may set.
Symptoms
Possible sumptoms of OBD code P0146 Alfa Romeo
Symptoms of a P0146 Alfa Romeo DTC may include: MIL (Malfunction Indicator Lamp) on May idle or drive poorly Fuel economy may decrease
Causes
Possible causes of OBD code P0146 Alfa Romeo
Potential causes of an P0146 Alfa Romeo code include: Bad Bank 1, position 3, o2 sensor Wiring problem, melted harness, broken connectors, etc. Bad PCM
Possible Solutions
1. Start the engine and allow it to reach operating temperature. Using a scan tool, observe the Bank 1 position 3 o2 sensor. If it isn’t moving between 0.1 and 0.9 volts, increase the engine RPM to a fast idle and then recheck the sensor voltage reading. If it starts switching now, the sensor may be sluggish and/or intermittently going “dormant”. Replacing the sensor at this point would be a good idea. Visually check the o2 sensor for contaminates, etc. If you suspect it’s contaminated with coolant or oil, replace it. a. But, if it still isn’t responding after increasing engine RPM, turn off the engine and unplug the 1/3 o2 sensor. With KOEO (key on engine off) check that there is battery voltage and ground to the o2 sensor heater element. If the heater element has no battery voltage it can cause the o2 sensor to go “dormant” and not switch properly which can cause a P0146 Alfa Romeo. So, diagnose that problem first(there will usually be other codes present). b. If there is power and ground to the heater element check that the sensor ground is present. If it is, connect a jumper wire between the sensor ground and signal wire. Now the 1/3 o2 sensor reading should be low. If so, replace the Bank 1 position 3 o2 sensor. c. If, after connecting the jumper wire, the o2 sensor reading still remains “stuck”, check for wiring problems, harness contacting exhaust components, or broken connectors. Repair as necessary. Then recheck. d. If you can find no wiring problems and the o2 sensor reading on the scan tool doesn’t change after installing the jumper wire, recheck at the PCM connector. If it still shows no change, the PCM may be at fault.
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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