Mercedes-Benz P0163 O2 Sensor Circuit Low Voltage Bank 2 Sensor 3

Description

OBD-II Trouble Code Description for P0163 Mercedes

O2 Sensor Circuit Low Voltage

What does this mean?

OBD2 Code P0163 Mercedes definition:
This code definition:a fault in one of the post-catalyst O2 sensors on Bank 2. This oxygen sensor is used for a specific purpose. This is it in a nutshell: The Catalytic Converter is used to help control emissions, to “clean up” the exhaust gasses. The PCM (Powertrain Control Module) uses the signal from post catalyst heated oxygen sensors to monitor the catalyst’s efficiency by comparing it to the O2 sensors in front of the catalyst. If the PCM sees little or no difference between the exhaust quality in post- and pre- catalyst sensors then it knows that the catalyst is not working properly. To over simplify: a post-cat sensor’s main job is to monitor catalyst efficiency, not control fuel management. If you have a P0163 Mercedes, that doesn’t mean your catalyst is bad (in fact, it usually never does). This code basically means that the Bank 2, Sensor 3 (or third o2 sensor back on bank 2) signal voltage is below what is considered normal for that sensor. It’s a four wire sensor being supplied a 0.5 volt reference voltage on the signal wire and a ground, as well as a power and ground circuit for the o2 sensor heater element. Changes in oxygen content cause resistance changes inside the sensor. This changing resistance affects the 0.5 volts on the signal/reference circuit. A heated o2 sensor is capable of switching between 0.1 volts and 0.9 volts with 0.1 volts indicating lean and 0.9 volts indicating rich. However, a properly working post-catalyst sensor will exhibit small changes at a slower rate than front (pre-catalyst) O2 sensors. It may switch slightly above and below 0.45 volts at the rate of about 1 switch per second or less. The PCM monitors this signal change to determine if the catalyst is working properly. If the PCM determines that the Bank 2,3 O2 sensor signal voltage is below a certain threshold for too long, P0163 Mercedes will set.

Symptoms

Possible sumptoms of OBD code P0163 Mercedes
Rear O2 sensor problems won’t usually cause drivability issues since they are an input that measures catalyst efficiency (unlike front O2 sensors). However if you have other codes present, like lean codes or pre-O2 sensor codes, then they may cause drivability problems. The following symptoms may be present: MIL (Malfunction Indicator Lamp) illumination Engine performance issues Engine running rough Engine running rich (only if PCM is trying to add fuel to compensate for low O2 sensor voltage reading) Engine running lean (only if vacuum leak is large enough that PCM can’t compensate by adding fuel) Poor idle

Causes

Possible causes of OBD code P0163 Mercedes
Potential causes of a P0163 Mercedes code include: Air leaks in exhaust in front of O2 sensor giving false reading Engine running excessively lean O2 sensor connector damaged/corroded O2 sensor signal circuit is shorted to ground O2 sensor ground circuit is open O2 sensor has failed (it may be contaminated with fuel or coolant) PCM has failed

Possible Solutions

It’s always good to start with checking for air leaks in the exhaust manifold and in the exhaust pipes. Fix these first. With KOER (Key on engine running) use a scan tool or a voltmeter check the O2 sensor signal voltage with engine warm. You may have to increase the RPM to a fast idle to check the voltage of the bank 2,3 sensor. If it’s voltage is stuck low (less than 0.5 volts) and you don’t have any other O2 sensor codes present in the PCM, then the sensor is probably bad. If the voltage isn’t stuck low and the O2 sensor seems to be operating fine, it’s likely sticking low intermittently. This often turns out to be the sensor. In either case, replacing the sensor can be an effective way to diagnose the problem. But it can also be an expensive diagnostic tool, especially if it turns out to be a wiring issue, instead of a sensor. So, if you’re interested in knowing for sure what the problem is before spending unnecessarily, then perform the following: 1. Turn off the engine and unplug the 2,3 O2 sensor connector. Inspect for corrosion, etc. Repair as necessary. Make sure that there is battery voltage present and ground present for the O2 sensor heater. If there isn’t, then diagnose that first then retest. The O2 sensor depends on the heater to warm it up so it can start working quicker. If the heater element is bad or there isn’t the proper voltage supplying it, the sensor may set this code. Usually heater problems have codes associated with them, too. If you find there is no battery voltage feeding the O2 sensor use the associated code to diagnose that. If you find the heater element bad, replace the sensor. If the heater element checks out then, using a jumper wire, supply a chassis ground to the O2 sensor connector (PCM side) ground circuit. Now observe the scan tool bank 2,3 O2 sensor reading. If it is now at about a half a volt then replace the O2 sensor. If, after supplying a ground to the unplugged PCM side of the O2 sensor connector, the voltage reading doesn’t change then check the harness for short to ground. Check for harness making contact with exhaust components. Check pins for damage, and for moisture. Repair as necessary. If you can find no harness problems, then the PCM may be at fault.


The OBD2 Code Information Be Applicable For Mercedes-Benz:

2013 Mercedes-Benz SLS AMG GT,2013 Mercedes-Benz SL65 AMG,2013 Mercedes-Benz SL550,2013 Mercedes-Benz SL500,2013 Mercedes-Benz SL-Class,2013 Mercedes-Benz GLK350 4Matic,2013 Mercedes-Benz GLK-Class,2013 Mercedes-Benz GL63 AMG,2013 Mercedes-Benz GL-Class,2013 Mercedes-Benz G63 AMG 6×6 Concept,2013 Mercedes-Benz G63 AMG,2013 Mercedes-Benz G550,2013 Mercedes-Benz G350 Bluetec,2013 Mercedes-Benz G-Class,2013 Mercedes-Benz E300 BlueTEC Hybrid,2013 Mercedes-Benz Citan,2013 Mercedes-Benz CLS Shooting Brake,2013 Mercedes-Benz A-Class AMG Sport,2013 Mercedes-Benz A-Class,2012 Mercedes-Benz SLS AMG Roadster,2012 Mercedes-Benz SLK55 AMG,2012 Mercedes-Benz SLK350,2012 Mercedes-Benz SLK250 CDI,2012 Mercedes-Benz SLK-Class,2012 Mercedes-Benz ML63 AMG,2012 Mercedes-Benz M-Class,2012 Mercedes-Benz E63 AMG Wagon,2012 Mercedes-Benz E63 AMG,2012 Mercedes-Benz CLS63 AMG,2012 Mercedes-Benz CLS550,2012 Mercedes-Benz CLS350 CDI,2012 Mercedes-Benz CLS-Class,2012 Mercedes-Benz C63 AMG,2012 Mercedes-Benz C-Class,2012 Mercedes-Benz B-Class,2011 Mercedes-Benz Vito,2011 Mercedes-Benz Viano,2011 Mercedes-Benz SLS AMG,2011 Mercedes-Benz S63 AMG,2011 Mercedes-Benz S600 Pullman Guard,2011 Mercedes-Benz R-Class,2011 Mercedes-Benz ML 63 AMG,2011 Mercedes-Benz G-Class,2011 Mercedes-Benz F125 Concept,2011 Mercedes-Benz E550 Cabriolet,2011 Mercedes-Benz E350 Cabriolet,2011 Mercedes-Benz E350 4Matic Wagon,2011 Mercedes-Benz E-Class L,2011 Mercedes-Benz E-Class Cabriolet,2011 Mercedes-Benz CL65 AMG,2011 Mercedes-Benz CL63 AMG,2011 Mercedes-Benz CL500,2011 Mercedes-Benz CL-Class,2011 Mercedes-Benz C-Class DR 520,2011 Mercedes-Benz B55 Concept,2011 Mercedes-Benz A-Class E-CELL,2011 Mercedes-Benz A-Class Concept,2010 Mercedes-Benz S65 AMG,2010 Mercedes-Benz S63 AMG,2010 Mercedes-Benz S400 BlueHYBRID,2010 Mercedes-Benz S-Class,2010 Mercedes-Benz ML450 Hybrid,2010 Mercedes-Benz GLK-Class,2010 Mercedes-Benz GL550,2010 Mercedes-Benz E63 AMG Estate,2010 Mercedes-Benz E63 AMG,2010 Mercedes-Benz E550 Coupe,2010 Mercedes-Benz E550,2010 Mercedes-Benz E350 Coupe,2010 Mercedes-Benz E350,2010 Mercedes-Benz E-Class,2010 Mercedes-Benz Biome Concept,2010 Mercedes-Benz B-Class F-Cell,2009 Mercedes-Benz SL65 AMG,2009 Mercedes-Benz SL63 AMG,2009 Mercedes-Benz SL-Class,2009 Mercedes-Benz ML 63 AMG,2009 Mercedes-Benz M-Class,2009 Mercedes-Benz G55 AMG,2009 Mercedes-Benz G-Class,2009 Mercedes-Benz CLS 63 AMG,2009 Mercedes-Benz CLS 280,2009 Mercedes-Benz CLC,2009 Mercedes-Benz B-Class,2009 Mercedes-Benz A-Class,2008 Mercedes-Benz SL,2008 Mercedes-Benz SLR,2008 Mercedes-Benz R-Class,2008 Mercedes-Benz CL65 AMG,2008 Mercedes-Benz C63 AMG,2008 Mercedes-Benz C-Class,2007 Mercedes-Benz S 63 AMG,2007 Mercedes-Benz S 600 Guard,2007 Mercedes-Benz S 500 4MATIC,2007 Mercedes-Benz S65 AMG,2007 Mercedes-Benz S550,2007 Mercedes-Benz R 63 AMG,2007 Mercedes-Benz G-Class,2007 Mercedes-Benz CL 63 AMG,2007 Mercedes-Benz CL 600,2007 Mercedes-Benz CL 500,2007 Mercedes-Benz CLS 63 AMG,2007 Mercedes-Benz CLS 350 CGI,2006 Mercedes-Benz SL 65 AMG,2006 Mercedes-Benz SL 600,2006 Mercedes-Benz SL 55 AMG,2006 Mercedes-Benz SL 500,2006 Mercedes-Benz SL 350,2006 Mercedes-Benz SLK 55 AMG SS,2006 Mercedes-Benz SL-Class,2006 Mercedes-Benz S-Class,2006 Mercedes-Benz R500,2006 Mercedes-Benz ML 63 AMG,2006 Mercedes-Benz ML500,2006 Mercedes-Benz ML350,2006 Mercedes-Benz GL 420 CDI,2006 Mercedes-Benz GL450,2006 Mercedes-Benz GL-Class,2006 Mercedes-Benz E 63 AMG,2006 Mercedes-Benz E-Class,2006 Mercedes-Benz CLK 63 AMG,2006 Mercedes-Benz B200 CDI,2006 Mercedes-Benz B150,2005 Mercedes-Benz SLK350,2005 Mercedes-Benz CLS500,2005 Mercedes-Benz CLK350,2005 Mercedes-Benz AClass

 

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