Audi P0140 HO2S12 Sensor Circuit No Activity Detected

Description

OBD-II Trouble Code Description for P0140 Audi

O2 Sensor Circuit No Activity Detected

What does this mean?

OBD2 Code P0140 Audi definition:
The Powertrain control module (PCM) will provide a .45 volt reference voltage to the Oxygen sensor. When the O2 sensor reaches operating temperature, it will generate a voltage that will vary depending on the oxygen content of the exhaust. Lean exhaust generates a low voltage (less than .45V) and rich exhaust generates a high voltage (greater than .45V). O2 sensors on a specific bank marked as “sensor 2” (as this one is) are used to monitor emissions. A Three-Way Catalyst (TWC) system (catalytic converter) is used to control tailpipe emissions. The PCM uses the signal received from Oxygen sensor 2 (#2 indicates aft of catalytic converter, #1 indicates pre-converter) to read efficiency of TWC. Normally this sensor will switch between high and low voltage at a noticeably slower rate than the front sensor. This is normal. If the signal received from rear (#2) O2 sensor indicates that the voltage has “stuck” between .425V to .474 V, the PCM determines this sensor is inactive and this code will set.

Symptoms

Possible sumptoms of OBD code P0140 Audi
Your check engine light(CEL), or malfuction indicator lamp (MIL) will be illuminated. There will not likely be any noticeable drivability problems other than the MIL. The reason is this: The rear or post catalytic converter Oxygen sensor does not affect fuel deliver(this is an exception on Chryslers). It only MONITORS the efficiency of the catalytic converter. For this reason, you will likely not notice any engine trouble.

Causes

Possible causes of OBD code P0140 Audi
The causes for a P0140 Audi code are fairly few. They could be any of the following: Shorted heater circuit in O2 sensor. (Usually requires replacement of heater circuit fuse in fuse block also) Shorted signal circuit in O2 sensor Melting of harness connector or wiring due to contact with exhaust system Water intrusion in harness connector or PCM connector Bad PCM

Possible Solutions

This is a fairly specific problem and shouldn’t be too difficult to diagnose. First, start engine and warm up. Using a scan tool, watch the Bank 1, sensor 2, o2 sensor voltage. Normally the voltage should switch slowly above and below .45 volts. If it does, the problem is likely intermittent. You’ll have to wait for the problem to surface before you can accurately diagnose. However, if it doesn’t switch, or is stuck then perform the following: 2. Shut off vehicle. Visually check the Bank1,2 harness connector for melting or chafing of the harness or the connector. Repair or replace as needed 3. Turn ignition on, but engine off. Disconnect the O2 sensor connector and check for 12Volts at the Heater Circuit supply and for proper ground on the heater circuit ground circuit. a. If 12V heater supply is missing, check the proper fuses for an open in the circuit. If heater circuit fuse is blown, then suspect a bad heater in the o2 sensor causing a blown heater circuit fuse. Replace sensor and fuse and recheck. b. If ground is missing, trace the circuit and clean or repair ground circuit. 4. Next, with connector still unplugged, check for 5 Volts on the reference circuit. If this is missing, check for 5 Volts at the PCM connector. If 5 Volts is present at the PCM connector but not at the o2 sensor harness connector, then there is an open or short in the reference wire supply between the PCM and the o2 sensor connector. However, if there is no 5 Volts present at the PCM connector, the PCM is likely at fault due to internal short. Replace PCM. ** (NOTE: on Chrysler models, a common problem is the 5Volt reference circuit can be shorted out by any sensor on the car that uses a 5 Volt reference. Simply unplug each sensor one at a time until the 5 Volts reappears. The last sensor you unplugged is the shorted sensor. Replacing it should fix the 5 Volt reference short.) 5. If all the voltages and grounds are present, then replace the Bank 1,2 O2 sensor and re-test.

The OBD2 Code Information Be Applicable For Audi:

2013 Audi TT ultra quattro Concept,2013 Audi TT RS plus,2013 Audi TTS Roadster competition,2013 Audi TTS Coupe competition,2013 Audi Sport quattro Concept,2013 Audi SQ5 TDI,2013 Audi S8,2013 Audi S7 Sportback,2013 Audi S6 Avant,2013 Audi S6,2013 Audi S4 Avant,2013 Audi S4,2013 Audi RS5 DTM,2013 Audi RS4 Avant,2013 Audi R8 e-tron Concept,2013 Audi R8 V10 plus,2013 Audi R8 V10 Spyder,2013 Audi R8 V10,2013 Audi R8,2013 Audi Q5,2013 Audi Nanuk quattro Concept,2013 Audi A8 L Hybrid,2013 Audi A8 Hybrid,2013 Audi A6 allroad quattro,2013 Audi A6 Black Edition,2013 Audi A4 allroad quattro,2013 Audi A4 Avant,2013 Audi A4,2013 Audi A3 e-tron Concept,2013 Audi A3,2013 Audi A1 quattro,2012 Audi e-bike Worthersee Concept,2012 Audi S5 Sportback,2012 Audi S5 Cabriolet,2012 Audi S5,2012 Audi RS Q3 Concept,2012 Audi RS5,2012 Audi RS3 Sportback,2012 Audi R8 GT Spyder,2012 Audi R8 Exclusive Selection,2012 Audi Q5 Hybrid quattro,2012 Audi Q3 Vail Concept,2012 Audi Q3 Jinlong Yufeng Concept,2012 Audi Q3,2012 Audi Crosslane Coupe Concept,2012 Audi A8 L Security,2012 Audi A6 L e-tron Concept,2012 Audi A6 Hybrid,2012 Audi A6 Avant,2012 Audi A6,2012 Audi A5 Sportback,2012 Audi A5 DTM,2012 Audi A5 Coupe,2012 Audi A5 Cabriolet,2012 Audi A1 amplified,2012 Audi A1 Sportback,2011 Audi Urban Spyder Concept,2011 Audi Urban Concept,2011 Audi TT Roadster,2011 Audi TT Coupe,2011 Audi TTS Roadster,2011 Audi TTS Coupe,2011 Audi S5 Sportback,2011 Audi RS5,2011 Audi R8 Spyder 5.2 FSI quattro,2011 Audi R8 Spyder 4.2 FSI quattro,2011 Audi R8 GT,2011 Audi R18,2011 Audi Q7,2011 Audi A8 L,2011 Audi A8,2011 Audi A7 Sportback,2011 Audi A3 e-tron Concept,2011 Audi A3 Sportback,2011 Audi A3 Concept,2011 Audi A3 Cabriolet,2011 Audi A3,2011 Audi A2 Concept,2011 Audi A1 clubsport quattro Concept,2011 Audi A1,2010 Audi quattro Concept,2010 Audi e-tron Spyder Concept,2010 Audi e-tron Concept,2010 Audi TT RS Roadster,2010 Audi TT RS,2010 Audi TT GT4 Concept,2010 Audi S5 Cabriolet,2010 Audi R8 V10 5.2 FSI quattro,2010 Audi Q7,2010 Audi A8 Hybrid Concept,2010 Audi A5 Sportback,2010 Audi A5 Cabriolet,2010 Audi A4 allroad quattro,2010 Audi A1 e-tron Concept,2009 Audi e-tron Concept,2009 Audi TTS Roadster,2009 Audi TTS Coupe,2009 Audi Sportback Concept,2009 Audi S6 Avant,2009 Audi S6,2009 Audi S4 Avant,2009 Audi S4,2009 Audi S3 Sportback,2009 Audi S3,2009 Audi RS6,2009 Audi R8 GT3,2009 Audi Q7 V12 TDI,2009 Audi Q5 Custom Concept,2009 Audi Q5,2009 Audi A6 allroad quattro,2009 Audi A6 Avant,2009 Audi A6,2009 Audi A4 Avant,2009 Audi A4,2009 Audi A3 Sportback,2009 Audi A3,2008 Audi TT clubsport quattro Concept,2008 Audi TT Roadster 3.2 quattro,2008 Audi TT Coupe,2008 Audi S8,2008 Audi S6,2008 Audi S5,2008 Audi S4 Cabriolet,2008 Audi RS6 Avant UK Version,2008 Audi RS6 Avant,2008 Audi RS4 Cabriolet,2008 Audi RS4,2008 Audi R8 V12 TDI Concept,2008 Audi R8 TDI Le Mans Concept,2008 Audi R8,2008 Audi Q7,2008 Audi A8 L,2008 Audi A8 4.2 TDI quattro,2008 Audi A8L W12 quattro,2008 Audi A8,2008 Audi A6 Avant,2008 Audi A6,2008 Audi A5 3.0 TDI quattro,2008 Audi A5,2008 Audi A4 US Version,2008 Audi A4 TDI Concept e,2008 Audi A4 Cabriolet,2008 Audi A4,2008 Audi A3 US Version,2008 Audi A3 TDI clubsport quattro Concept,2008 Audi A3 Cabriolet,2008 Audi A1 Sportback Concept,2007 Audi metroproject quattro Concept,2007 Audi TT clubsport quattro Concept,2007 Audi TT Roadster 2.0 TFSI,2007 Audi TT Roadster,2007 Audi TT Coupe S-line,2007 Audi TT Coupe,2007 Audi S3,2007 Audi R8,2007 Audi Q7 V12 TDI Concept,2007 Audi Q7 V12 TDI,2007 Audi Cross Coupe quattro Concept,2007 Audi Cross Cabriolet quattro Concept,2006 Audi S8,2006 Audi S6 Avant,2006 Audi S6,2006 Audi S4 Cabriolet,2006 Audi Roadjet Concept,2006 Audi RS 4 Cabriolet,2006 Audi RS 4 Avant,2006 Audi RS4,2006 Audi Q7,2006 Audi A8 Security,2006 Audi A6 allroad quattro,2006 Audi A4 Cabriolet,2006 Audi A3 2.0T,2005 Audi allroad quattro V8 4.2,2005 Audi allroad quattro V6 2.7T,2005 Audi TT quattro sport,2005 Audi TT Roadster 3.2,2005 Audi TT Roadster 1.8T,2005 Audi TT Coupe 3.2,2005 Audi TT Coupe 1.8T,2005 Audi Shooting Brake Concept,2005 Audi S4 Cabriolet,2005 Audi S4 Avant,2005 Audi S4,2005 Audi RS4,2005 Audi Q7 Hybrid Concept,2005 Audi Allroad quattro Concept,2005 Audi A8 L W12,2005 Audi A8 L 4.2,2005 Audi A8 4.2 TDI quattro,2005 Audi A8 4.2,2005 Audi A8 3.2 FSI quattro,2005 Audi A8L 4.2 TDI quattro,2005 Audi A6 Avant,2005 Audi A6 4.2 quattro Sline,2005 Audi A6 3.2,2005 Audi A6 3.0 TDI quattro,2005 Audi A6L,2005 Audi A4 DTM Edition,2005 Audi A4 Cabriolet,2005 Audi A4 Avant 3.2 quattro,2005 Audi A4 3.2 quattro,2005 Audi A4 3.0 TDI quattro,2005 Audi A4 2.0T,2005 Audi A3 2.0 TDI 3-door,2004 Audi S4 Cabriolet,2004 Audi RSQ Concept,2004 Audi RS6 plus,2004 Audi A8 L 6.0 W12 quattro,2004 Audi A8 L 3.0 quattro,2004 Audi A8 4.2 quattro,2004 Audi A8 3.7 quattro,2004 Audi A8 3.0 TDI quattro,2004 Audi A8,2004 Audi A3 Sportback quattro,2004 Audi A3 Sportback S-line,2004 Audi A3 Sportback,2004 Audi A3 3-door,2003 Audi allroad quattro,2003 Audi TT Roadster 3.2 quattro,2003 Audi TT 3.2 DSG quattro,2003 Audi Pikes Peake quattro Concept,2003 Audi Nuvolari quattro Concept,2003 Audi Le Mans quattro Concept,2003 Audi A8 L 4.2 quattro,2003 Audi A8 4.0 TDI quattro,2003 Audi A4,2003 Audi A3 3.2 V6 3-door,2003 Audi A3 3-door,2003 Audi A2,2002 Audi allroad quattro 4.2,2002 Audi allroad quattro,2002 Audi TT Roadster,2002 Audi S6 Avant,2002 Audi S6,2002 Audi S4 Avant,2002 Audi S4,2002 Audi S3,2002 Audi RS6 Sedan,2002 Audi RS6 Avant,2002 Audi RS6,2002 Audi A6,2002 Audi A4 Cabriolet 3.0,2002 Audi A4 Cabriolet 2.4,2002 Audi A4 Cabriolet 1.8 T,2002 Audi A4 Cabriolet,2002 Audi A4 Avant,2002 Audi A4,2002 Audi A3 3-door,2002 Audi A2,2001 Audi TT Coupe,2001 Audi Avantissimo Concept,2001 Audi A8 L 6.0 quattro,2001 Audi A6 Avant,2001 Audi A6,2001 Audi A4 Avant,2001 Audi A4

 

Note:

1. The list of automotive Makes at the right edge of the screen. The currently selected ODB-ii codes is for the Audi makes.

2. Look up the other OBD II Trouble Codes, please use the search box. Enter the 5 character trouble codes in the search box and submit the search.

3. Don’t assume a particular OBD-II code means the same for other auto manufacturers as there are many makes specific codes in use.

4. If your OBD-II trouble codes are for a different car, select that vehicle series before searching for the diagnostic codes because not all OBD2 codes used by one manufacture are used by the other makes.

5. The information contained on this site is presented for informational purposes only. We are not responsible for any actions you take on your vehicle. If you have any doubt as to repairs on your vehicle, please contact your technician.